diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/model/LocalCache.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/model/LocalCache.kt
index ff7f498420..d82d2c221a 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/model/LocalCache.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/model/LocalCache.kt
@@ -75,6 +75,8 @@ import com.vitorpamplona.quartz.experimental.nipsOnNostr.NipTextEvent
 import com.vitorpamplona.quartz.experimental.nns.NNSEvent
 import com.vitorpamplona.quartz.experimental.notifications.wake.WakeUpEvent
 import com.vitorpamplona.quartz.experimental.profileGallery.ProfileGalleryEntryEvent
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.RoadEventConfirmationEvent
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
 import com.vitorpamplona.quartz.experimental.zapPolls.ZapPollEvent
 import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageEvent
 import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
@@ -3870,6 +3872,14 @@ object LocalCache : ILocalCache, ICacheProvider {
                     consume(event, relay, wasVerified)
                 }
 
+                is RoadEventReportEvent -> {
+                    consumeRegularEvent(event, relay, wasVerified)
+                }
+
+                is RoadEventConfirmationEvent -> {
+                    consumeRegularEvent(event, relay, wasVerified)
+                }
+
                 is RelayDiscoveryEvent -> {
                     consumeBaseReplaceable(event, relay, wasVerified)
                 }
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/model/topNavFeeds/aroundMe/AroundMeExpander.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/model/topNavFeeds/aroundMe/AroundMeExpander.kt
index dd5325011e..1e83a7dc03 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/model/topNavFeeds/aroundMe/AroundMeExpander.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/model/topNavFeeds/aroundMe/AroundMeExpander.kt
@@ -20,7 +20,7 @@
  */
 package com.vitorpamplona.amethyst.model.topNavFeeds.aroundMe
 
-import com.vitorpamplona.amethyst.service.location.GeoHash
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.GeoHash
 
 fun compute50kmLine(geoHash: GeoHash): List<String> {
     val hashes = mutableListOf<String>()
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/LocationGeoHash.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/LocationGeoHash.kt
new file mode 100644
index 0000000000..4540a537c1
--- /dev/null
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/LocationGeoHash.kt
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.service.location
+
+import android.location.Location
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.GeoHash
+
+/**
+ * Android `Location` glue for the platform-agnostic [GeoHash] that now lives in
+ * Quartz. The encode/decode/neighbor logic is shared in `commonMain`; only these
+ * conversions to/from the Android `Location` type stay here.
+ */
+fun Location.toGeoHash(charsCount: Int = GeoHash.MAX_CHAR_PRECISION): GeoHash = GeoHash.encode(latitude, longitude, charsCount)
+
+fun GeoHash.toLocation(): Location =
+    Location("").also {
+        it.latitude = centerLat
+        it.longitude = centerLon
+    }
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/LocationState.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/LocationState.kt
index 46b719eccf..298799e119 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/LocationState.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/LocationState.kt
@@ -21,6 +21,7 @@
 package com.vitorpamplona.amethyst.service.location
 
 import android.content.Context
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.GeoHash
 import com.vitorpamplona.quartz.nip01Core.tags.geohash.GeohashPrecision
 import com.vitorpamplona.quartz.utils.Log
 import kotlinx.coroutines.CoroutineScope
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt
index e41f4ae5e9..5202720733 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt
@@ -174,6 +174,8 @@ import com.vitorpamplona.amethyst.ui.note.types.RenderRelayLeaveRequest
 import com.vitorpamplona.amethyst.ui.note.types.RenderRelayMembershipList
 import com.vitorpamplona.amethyst.ui.note.types.RenderRelayRemoveMember
 import com.vitorpamplona.amethyst.ui.note.types.RenderReport
+import com.vitorpamplona.amethyst.ui.note.types.RenderRoadEventConfirmation
+import com.vitorpamplona.amethyst.ui.note.types.RenderRoadEventReport
 import com.vitorpamplona.amethyst.ui.note.types.RenderRootSiteEvent
 import com.vitorpamplona.amethyst.ui.note.types.RenderSoftwareApplication
 import com.vitorpamplona.amethyst.ui.note.types.RenderSoftwareAsset
@@ -235,6 +237,8 @@ import com.vitorpamplona.quartz.experimental.nip82SoftwareApps.asset.SoftwareAss
 import com.vitorpamplona.quartz.experimental.nip82SoftwareApps.release.isNip82SoftwareRelease
 import com.vitorpamplona.quartz.experimental.nip95.header.FileStorageHeaderEvent
 import com.vitorpamplona.quartz.experimental.nipsOnNostr.NipTextEvent
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.RoadEventConfirmationEvent
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
 import com.vitorpamplona.quartz.experimental.zapPolls.ZapPollEvent
 import com.vitorpamplona.quartz.nip01Core.tags.geohash.geoHashOrScope
 import com.vitorpamplona.quartz.nip02FollowList.ContactListEvent
@@ -1285,6 +1289,14 @@ private fun RenderNoteRow(
             RenderBirdex(baseNote)
         }
 
+        is RoadEventReportEvent -> {
+            RenderRoadEventReport(baseNote)
+        }
+
+        is RoadEventConfirmationEvent -> {
+            RenderRoadEventConfirmation(baseNote)
+        }
+
         is HighlightEvent -> {
             RenderHighlight(
                 baseNote,
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/creators/location/LoadCityName.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/creators/location/LoadCityName.kt
index 05cce5516b..2fd6d60d36 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/creators/location/LoadCityName.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/creators/location/LoadCityName.kt
@@ -30,7 +30,8 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.platform.LocalContext
 import com.vitorpamplona.amethyst.service.location.CachedReversedGeoLocations
-import com.vitorpamplona.amethyst.service.location.toGeoHash
+import com.vitorpamplona.amethyst.service.location.toLocation
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.toGeoHash
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlin.coroutines.resume
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/RoadEvent.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/RoadEvent.kt
new file mode 100644
index 0000000000..d560d3d173
--- /dev/null
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/RoadEvent.kt
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.note.types
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.ui.note.creators.location.LoadCityName
+import com.vitorpamplona.amethyst.ui.theme.placeholderText
+import com.vitorpamplona.amethyst.ui.theme.replyModifier
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.RoadEventConfirmationEvent
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadEventStatus
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
+import com.vitorpamplona.quartz.experimental.roadstr.report.tags.RoadEventType
+
+/** Emoji marker for a road event category — keeps the card icon-light and locale-independent. */
+private fun RoadEventType.emoji(): String =
+    when (this) {
+        RoadEventType.POLICE -> "👮"
+        RoadEventType.SPEED_CAMERA -> "📷"
+        RoadEventType.TRAFFIC_JAM -> "🚗"
+        RoadEventType.ACCIDENT -> "💥"
+        RoadEventType.ROAD_CLOSURE -> "⛔"
+        RoadEventType.CONSTRUCTION -> "🚧"
+        RoadEventType.HAZARD -> "⚠️"
+        RoadEventType.ROAD_CONDITION -> "🛣️"
+        RoadEventType.POTHOLE -> "🕳️"
+        RoadEventType.FOG -> "🌫️"
+        RoadEventType.ICE -> "🧊"
+        RoadEventType.ANIMAL -> "🦌"
+        RoadEventType.OTHER -> "📍"
+    }
+
+private fun RoadEventType.labelRes(): Int =
+    when (this) {
+        RoadEventType.POLICE -> R.string.road_event_police
+        RoadEventType.SPEED_CAMERA -> R.string.road_event_speed_camera
+        RoadEventType.TRAFFIC_JAM -> R.string.road_event_traffic_jam
+        RoadEventType.ACCIDENT -> R.string.road_event_accident
+        RoadEventType.ROAD_CLOSURE -> R.string.road_event_road_closure
+        RoadEventType.CONSTRUCTION -> R.string.road_event_construction
+        RoadEventType.HAZARD -> R.string.road_event_hazard
+        RoadEventType.ROAD_CONDITION -> R.string.road_event_road_condition
+        RoadEventType.POTHOLE -> R.string.road_event_pothole
+        RoadEventType.FOG -> R.string.road_event_fog
+        RoadEventType.ICE -> R.string.road_event_ice
+        RoadEventType.ANIMAL -> R.string.road_event_animal
+        RoadEventType.OTHER -> R.string.road_event_other
+    }
+
+/**
+ * Self-contained card for a Roadstr road event report (kind 1315).
+ *
+ * Shows the category (emoji + localized label), the optional free-text comment,
+ * and the location resolved from the finest published geohash. Identical in the
+ * feed and the opened thread view, so it takes no `makeItShort` flag — mirroring
+ * [RenderBirdex].
+ */
+@Composable
+fun RenderRoadEventReport(baseNote: Note) {
+    val noteEvent = baseNote.event as? RoadEventReportEvent ?: return
+
+    val type = remember(noteEvent) { noteEvent.roadEventType() }
+    val comment = remember(noteEvent) { noteEvent.content.trim() }
+    val geohash = remember(noteEvent) { noteEvent.geohashes().maxByOrNull { it.length } }
+
+    Column(MaterialTheme.colorScheme.replyModifier.padding(10.dp)) {
+        val title =
+            if (type != null) {
+                "${type.emoji()} ${stringResource(type.labelRes())}"
+            } else {
+                stringResource(R.string.road_event_unknown)
+            }
+
+        Text(text = title, style = MaterialTheme.typography.titleMedium)
+
+        if (comment.isNotEmpty()) {
+            Spacer(Modifier.height(6.dp))
+            Text(
+                text = comment,
+                style = MaterialTheme.typography.bodyMedium,
+                maxLines = 4,
+                overflow = TextOverflow.Ellipsis,
+            )
+        }
+
+        if (geohash != null) {
+            Spacer(Modifier.height(6.dp))
+            RoadEventLocation(geohash)
+        }
+    }
+}
+
+/**
+ * Self-contained card for a Roadstr confirmation/denial (kind 1316).
+ *
+ * Shows whether the referenced report was confirmed (still there) or denied
+ * (no longer there), plus a one-line description of the action.
+ */
+@Composable
+fun RenderRoadEventConfirmation(baseNote: Note) {
+    val noteEvent = baseNote.event as? RoadEventConfirmationEvent ?: return
+
+    val status = remember(noteEvent) { noteEvent.status() }
+    val geohash = remember(noteEvent) { noteEvent.geohashes().maxByOrNull { it.length } }
+
+    Column(MaterialTheme.colorScheme.replyModifier.padding(10.dp)) {
+        val emoji = if (status == RoadEventStatus.NO_LONGER_THERE) "❌" else "✅"
+        val titleRes =
+            if (status == RoadEventStatus.NO_LONGER_THERE) {
+                R.string.road_event_denied
+            } else {
+                R.string.road_event_confirmed
+            }
+
+        Text(text = "$emoji ${stringResource(titleRes)}", style = MaterialTheme.typography.titleMedium)
+
+        Spacer(Modifier.height(4.dp))
+        Text(
+            text =
+                stringResource(
+                    if (status == RoadEventStatus.NO_LONGER_THERE) {
+                        R.string.road_event_denies_report
+                    } else {
+                        R.string.road_event_confirms_report
+                    },
+                ),
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.placeholderText,
+        )
+
+        if (geohash != null) {
+            Spacer(Modifier.height(6.dp))
+            RoadEventLocation(geohash)
+        }
+    }
+}
+
+/** A single "📍 City" line that reverse-geocodes [geohash], falling back to the raw geohash. */
+@Composable
+private fun RoadEventLocation(geohash: String) {
+    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+        Text(text = "📍", style = MaterialTheme.typography.bodyMedium)
+        LoadCityName(geohashStr = geohash) { cityName ->
+            Text(
+                text = cityName,
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.placeholderText,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+            )
+        }
+    }
+}
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/threadview/ThreadFeedView.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/threadview/ThreadFeedView.kt
index 55cd5886a1..2820260a0e 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/threadview/ThreadFeedView.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/threadview/ThreadFeedView.kt
@@ -192,6 +192,8 @@ import com.vitorpamplona.amethyst.ui.note.types.RenderRelayJoinRequest
 import com.vitorpamplona.amethyst.ui.note.types.RenderRelayLeaveRequest
 import com.vitorpamplona.amethyst.ui.note.types.RenderRelayMembershipList
 import com.vitorpamplona.amethyst.ui.note.types.RenderRelayRemoveMember
+import com.vitorpamplona.amethyst.ui.note.types.RenderRoadEventConfirmation
+import com.vitorpamplona.amethyst.ui.note.types.RenderRoadEventReport
 import com.vitorpamplona.amethyst.ui.note.types.RenderRootSiteEvent
 import com.vitorpamplona.amethyst.ui.note.types.RenderSoftwareApplication
 import com.vitorpamplona.amethyst.ui.note.types.RenderSoftwareAsset
@@ -250,6 +252,8 @@ import com.vitorpamplona.quartz.experimental.nip82SoftwareApps.application.Softw
 import com.vitorpamplona.quartz.experimental.nip82SoftwareApps.asset.SoftwareAssetEvent
 import com.vitorpamplona.quartz.experimental.nip82SoftwareApps.release.isNip82SoftwareRelease
 import com.vitorpamplona.quartz.experimental.nip95.header.FileStorageHeaderEvent
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.RoadEventConfirmationEvent
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
 import com.vitorpamplona.quartz.experimental.zapPolls.ZapPollEvent
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.tags.geohash.geoHashOrScope
@@ -814,6 +818,10 @@ private fun FullBleedNoteCompose(
                     RenderFundraiser(baseNote, makeItShort = false, accountViewModel, nav)
                 } else if (noteEvent is BirdexEvent) {
                     RenderBirdex(baseNote)
+                } else if (noteEvent is RoadEventReportEvent) {
+                    RenderRoadEventReport(baseNote)
+                } else if (noteEvent is RoadEventConfirmationEvent) {
+                    RenderRoadEventConfirmation(baseNote)
                 } else if (noteEvent is RepostEvent || noteEvent is GenericRepostEvent) {
                     RenderRepost(baseNote, quotesLeft = 3, backgroundColor, accountViewModel, nav)
                 } else if (noteEvent is RelayDiscoveryEvent) {
diff --git a/amethyst/src/main/res/values/strings.xml b/amethyst/src/main/res/values/strings.xml
index 07da4a218b..c768b6b0aa 100644
--- a/amethyst/src/main/res/values/strings.xml
+++ b/amethyst/src/main/res/values/strings.xml
@@ -3441,6 +3441,25 @@
         <item quantity="one">%1$s +%2$d more</item>
         <item quantity="other">%1$s +%2$d more</item>
     </plurals>
+    <!-- Roadstr road event reports (kinds 1315/1316). "Roadstr" is a proper noun, do not translate. -->
+    <string name="road_event_police">Police</string>
+    <string name="road_event_speed_camera">Speed camera</string>
+    <string name="road_event_traffic_jam">Traffic jam</string>
+    <string name="road_event_accident">Accident</string>
+    <string name="road_event_road_closure">Road closure</string>
+    <string name="road_event_construction">Construction</string>
+    <string name="road_event_hazard">Hazard</string>
+    <string name="road_event_road_condition">Road condition</string>
+    <string name="road_event_pothole">Pothole</string>
+    <string name="road_event_fog">Fog</string>
+    <string name="road_event_ice">Ice</string>
+    <string name="road_event_animal">Animal on the road</string>
+    <string name="road_event_other">Road event</string>
+    <string name="road_event_unknown">Road event</string>
+    <string name="road_event_confirmed">Still there</string>
+    <string name="road_event_denied">No longer there</string>
+    <string name="road_event_confirms_report">Confirms a road report</string>
+    <string name="road_event_denies_report">Reports a road event cleared</string>
     <string name="goal_amount_label">Goal amount (sats)</string>
     <string name="goal_amount_placeholder">100000</string>
     <string name="goal_description_label">Describe your goal</string>
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/RoadEventConfirmationEvent.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/RoadEventConfirmationEvent.kt
new file mode 100644
index 0000000000..9259df9d45
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/RoadEventConfirmationEvent.kt
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.confirmation
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadEventStatus
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadReportTag
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
+import com.vitorpamplona.quartz.experimental.roadstr.tags.coordinates
+import com.vitorpamplona.quartz.experimental.roadstr.tags.latitude
+import com.vitorpamplona.quartz.experimental.roadstr.tags.longitude
+import com.vitorpamplona.quartz.experimental.roadstr.tags.roadGeohashes
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintProvider
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.geohashes
+import com.vitorpamplona.quartz.nip31Alts.AltTag
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.nip40Expiration.expiration
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * Roadstr road event confirmation/denial (kind 1316).
+ *
+ * Validates or refutes a previously published [RoadEventReportEvent]. See
+ * <https://github.com/jooray/roadstr>.
+ *
+ * Tags (canonical order):
+ * - `e` — the referenced report event id ([RoadReportTag]).
+ * - `status` — [RoadEventStatus.STILL_THERE] (confirm) or [RoadEventStatus.NO_LONGER_THERE] (deny).
+ * - `g` / `lat` / `lon` — optional copy of the report's location, so confirmations
+ *   are reachable through the same `#g` geohash queries as reports.
+ * - `expiration` — NIP-40 relay garbage-collection window (`created_at + 14 days`).
+ * - `alt` — NIP-31 human-readable fallback.
+ */
+@Immutable
+class RoadEventConfirmationEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig),
+    EventHintProvider {
+    override fun eventHints() = tags.mapNotNull(RoadReportTag::parseAsHint)
+
+    override fun linkedEventIds() = tags.mapNotNull(RoadReportTag::parseId)
+
+    /** The referenced report event id from the first `e` tag. */
+    fun reportId() = tags.roadReport()?.eventId
+
+    fun status() = tags.roadEventStatus()
+
+    fun isConfirmation() = status() == RoadEventStatus.STILL_THERE
+
+    fun isDenial() = status() == RoadEventStatus.NO_LONGER_THERE
+
+    fun geohashes() = tags.geohashes()
+
+    fun latitude() = tags.latitude()
+
+    fun longitude() = tags.longitude()
+
+    fun alt() = tags.firstNotNullOfOrNull(AltTag::parse)
+
+    fun relayExpiration() = tags.expiration()
+
+    companion object {
+        const val KIND = 1316
+        const val ALT_DESCRIPTION = "Roadstr: event confirmation"
+
+        fun build(
+            reportId: HexKey,
+            status: RoadEventStatus,
+            latitude: Double? = null,
+            longitude: Double? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<RoadEventConfirmationEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, "", createdAt) {
+            report(reportId)
+            status(status)
+            if (latitude != null && longitude != null) {
+                roadGeohashes(latitude, longitude)
+                coordinates(latitude, longitude)
+            }
+            expiration(createdAt + RoadEventReportEvent.RELAY_TTL_SECONDS)
+            alt(ALT_DESCRIPTION)
+            initializer()
+        }
+
+        fun build(
+            report: EventHintBundle<RoadEventReportEvent>,
+            status: RoadEventStatus,
+            latitude: Double? = null,
+            longitude: Double? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<RoadEventConfirmationEvent>.() -> Unit = {},
+        ) = build(report.event.id, status, latitude, longitude, createdAt) {
+            report(report)
+            initializer()
+        }
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/TagArrayBuilderExt.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/TagArrayBuilderExt.kt
new file mode 100644
index 0000000000..8d5a0debd7
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/TagArrayBuilderExt.kt
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.confirmation
+
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadEventStatus
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadEventStatusTag
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadReportTag
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
+
+fun TagArrayBuilder<RoadEventConfirmationEvent>.report(reportId: HexKey) = addUnique(RoadReportTag.assemble(reportId, null, null))
+
+fun TagArrayBuilder<RoadEventConfirmationEvent>.report(reportHint: EventHintBundle<RoadEventReportEvent>) = addUnique(RoadReportTag.assemble(reportHint))
+
+fun TagArrayBuilder<RoadEventConfirmationEvent>.status(status: RoadEventStatus) = addUnique(RoadEventStatusTag.assemble(status))
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/TagArrayExt.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/TagArrayExt.kt
new file mode 100644
index 0000000000..6b413829f6
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/TagArrayExt.kt
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.confirmation
+
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadEventStatusTag
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadReportTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+
+fun TagArray.roadReport() = firstNotNullOfOrNull(RoadReportTag::parse)
+
+fun TagArray.roadEventStatus() = firstNotNullOfOrNull(RoadEventStatusTag::parse)
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/tags/RoadEventStatusTag.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/tags/RoadEventStatusTag.kt
new file mode 100644
index 0000000000..87ca3f0f3e
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/tags/RoadEventStatusTag.kt
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+/** Confirmation status carried in the `status` tag of a Roadstr confirmation (kind 1316). */
+enum class RoadEventStatus(
+    val code: String,
+) {
+    STILL_THERE("still_there"),
+    NO_LONGER_THERE("no_longer_there"),
+    ;
+
+    companion object {
+        fun fromCode(code: String?): RoadEventStatus? = entries.firstOrNull { it.code == code }
+    }
+}
+
+/** The `status` tag of a Roadstr confirmation (kind 1316): `still_there` or `no_longer_there`. */
+class RoadEventStatusTag {
+    companion object {
+        const val TAG_NAME = "status"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): RoadEventStatus? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            return RoadEventStatus.fromCode(tag[1])
+        }
+
+        fun assemble(status: RoadEventStatus) = arrayOf(TAG_NAME, status.code)
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/tags/RoadReportTag.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/tags/RoadReportTag.kt
new file mode 100644
index 0000000000..f4c3bd5597
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/confirmation/tags/RoadReportTag.kt
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
+import com.vitorpamplona.quartz.nip01Core.hints.types.EventIdHint
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.RelayUrlNormalizer
+import com.vitorpamplona.quartz.nip01Core.tags.events.GenericETag
+import com.vitorpamplona.quartz.nip19Bech32.entities.NEvent
+import com.vitorpamplona.quartz.utils.arrayOfNotNull
+import com.vitorpamplona.quartz.utils.ensure
+
+/** The `e` tag of a Roadstr confirmation (kind 1316): the referenced report event. */
+@Immutable
+data class RoadReportTag(
+    override val eventId: HexKey,
+) : GenericETag {
+    override var relay: NormalizedRelayUrl? = null
+    override var author: HexKey? = null
+
+    constructor(eventId: HexKey, relayHint: NormalizedRelayUrl? = null, authorPubKeyHex: HexKey? = null) : this(eventId) {
+        this.relay = relayHint
+        this.author = authorPubKeyHex
+    }
+
+    fun toNEvent(): String = NEvent.create(eventId, author, RoadEventReportEvent.KIND, relay)
+
+    override fun toTagArray() = assemble(eventId, relay, author)
+
+    companion object {
+        const val TAG_NAME = "e"
+
+        fun isTagged(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].length == 64
+
+        fun parse(tag: Array<String>): RoadReportTag? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].length == 64) { return null }
+
+            val hint = tag.getOrNull(2)?.let { RelayUrlNormalizer.normalizeOrNull(it) }
+
+            return RoadReportTag(tag[1], hint, tag.getOrNull(3))
+        }
+
+        fun parseId(tag: Array<String>): String? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].length == 64) { return null }
+            return tag[1]
+        }
+
+        fun parseAsHint(tag: Array<String>): EventIdHint? {
+            ensure(tag.has(2)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].length == 64) { return null }
+            ensure(tag[2].isNotEmpty()) { return null }
+
+            val hint = RelayUrlNormalizer.normalizeOrNull(tag[2])
+
+            ensure(hint != null) { return null }
+
+            return EventIdHint(tag[1], hint)
+        }
+
+        fun assemble(
+            eventId: HexKey,
+            relay: NormalizedRelayUrl?,
+            author: HexKey?,
+        ) = arrayOfNotNull(TAG_NAME, eventId, relay?.url, author)
+
+        fun assemble(eventHint: EventHintBundle<RoadEventReportEvent>) = assemble(eventHint.event.id, eventHint.relay, eventHint.event.pubKey)
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/RoadEventReportEvent.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/RoadEventReportEvent.kt
new file mode 100644
index 0000000000..1d7eb8747c
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/RoadEventReportEvent.kt
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.report
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.experimental.roadstr.report.tags.RoadEventType
+import com.vitorpamplona.quartz.experimental.roadstr.tags.coordinates
+import com.vitorpamplona.quartz.experimental.roadstr.tags.latitude
+import com.vitorpamplona.quartz.experimental.roadstr.tags.longitude
+import com.vitorpamplona.quartz.experimental.roadstr.tags.roadGeohashes
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.geohashes
+import com.vitorpamplona.quartz.nip31Alts.AltTag
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.nip40Expiration.expiration
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * Roadstr road event report (kind 1315).
+ *
+ * A driver-published report of a notable road condition (police, accident,
+ * hazard, …) at a specific location. See <https://github.com/jooray/roadstr>.
+ *
+ * Tags (canonical order):
+ * - `t` — the [RoadEventType] code.
+ * - `g` — geohash at precision 4, 5 and 6 (for multi-resolution spatial queries).
+ * - `lat` / `lon` — coordinates as decimal strings with 7 fractional digits.
+ * - `expiration` — NIP-40 relay garbage-collection window, always `created_at + 14 days`.
+ * - `alt` — NIP-31 human-readable fallback.
+ *
+ * The relay-side `expiration` is a fixed 14-day window; clients should instead use
+ * [effectiveExpirationAt] (derived from the event type's TTL) to decide when to
+ * stop displaying a report. The `content` field holds an optional free-text comment.
+ */
+@Immutable
+class RoadEventReportEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig) {
+    /** The parsed [RoadEventType], or null when the `t` tag is missing/unknown. */
+    fun roadEventType() = tags.roadEventType()
+
+    /** The raw event-type code from the first `t` tag (may be outside [RoadEventType]). */
+    fun roadEventTypeCode() = tags.roadEventTypeCode()
+
+    /** All `g` geohash tags, coarse-to-fine as published. */
+    fun geohashes() = tags.geohashes()
+
+    fun latitude() = tags.latitude()
+
+    fun longitude() = tags.longitude()
+
+    fun alt() = tags.firstNotNullOfOrNull(AltTag::parse)
+
+    fun relayExpiration() = tags.expiration()
+
+    /** Client-side effective expiry (`created_at + ` the type's TTL), or null if the type is unknown. */
+    fun effectiveExpirationAt(): Long? = roadEventType()?.let { createdAt + it.effectiveTtlSeconds }
+
+    /** Whether the report should no longer be displayed at [now], per its client-side TTL. */
+    fun isEffectivelyExpired(now: Long = TimeUtils.now()): Boolean = effectiveExpirationAt()?.let { now > it } ?: false
+
+    companion object {
+        const val KIND = 1315
+        const val ALT_PREFIX = "Roadstr: "
+
+        /** Fixed relay-side NIP-40 window (14 days) for both report and confirmation events. */
+        const val RELAY_TTL_SECONDS = 1_209_600L
+
+        fun altDescription(type: RoadEventType) = "$ALT_PREFIX${type.code} report"
+
+        fun build(
+            type: RoadEventType,
+            latitude: Double,
+            longitude: Double,
+            comment: String = "",
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<RoadEventReportEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, comment, createdAt) {
+            roadEventType(type)
+            roadGeohashes(latitude, longitude)
+            coordinates(latitude, longitude)
+            expiration(createdAt + RELAY_TTL_SECONDS)
+            alt(altDescription(type))
+            initializer()
+        }
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/TagArrayBuilderExt.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/TagArrayBuilderExt.kt
new file mode 100644
index 0000000000..ff4713a50a
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/TagArrayBuilderExt.kt
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.report
+
+import com.vitorpamplona.quartz.experimental.roadstr.report.tags.RoadEventType
+import com.vitorpamplona.quartz.experimental.roadstr.report.tags.RoadEventTypeTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+
+fun TagArrayBuilder<RoadEventReportEvent>.roadEventType(type: RoadEventType) = add(RoadEventTypeTag.assemble(type))
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/TagArrayExt.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/TagArrayExt.kt
new file mode 100644
index 0000000000..7f6f40ab1f
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/TagArrayExt.kt
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.report
+
+import com.vitorpamplona.quartz.experimental.roadstr.report.tags.RoadEventTypeTag
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+
+fun TagArray.roadEventType() = firstNotNullOfOrNull(RoadEventTypeTag::parse)
+
+fun TagArray.roadEventTypeCode() = firstNotNullOfOrNull(RoadEventTypeTag::parseCode)
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/tags/RoadEventTypeTag.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/tags/RoadEventTypeTag.kt
new file mode 100644
index 0000000000..48188fe5ca
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/report/tags/RoadEventTypeTag.kt
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.report.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+/**
+ * Road event categories carried in the `t` tag of a Roadstr report (kind 1315).
+ *
+ * Each type also defines a client-side *effective* TTL: the relay-side NIP-40
+ * `expiration` tag is always a fixed 14-day garbage-collection window, but
+ * clients should stop showing a report after [effectiveTtlSeconds] from its
+ * `created_at` (subject to confirmations).
+ */
+enum class RoadEventType(
+    val code: String,
+    val effectiveTtlSeconds: Long,
+) {
+    POLICE("police", 7_200L), // 2 hours
+    SPEED_CAMERA("speed_camera", 2_592_000L), // 30 days
+    TRAFFIC_JAM("traffic_jam", 3_600L), // 1 hour
+    ACCIDENT("accident", 10_800L), // 3 hours
+    ROAD_CLOSURE("road_closure", 604_800L), // 7 days
+    CONSTRUCTION("construction", 604_800L), // 7 days
+    HAZARD("hazard", 14_400L), // 4 hours
+    ROAD_CONDITION("road_condition", 21_600L), // 6 hours
+    POTHOLE("pothole", 604_800L), // 7 days
+    FOG("fog", 10_800L), // 3 hours
+    ICE("ice", 21_600L), // 6 hours
+    ANIMAL("animal", 3_600L), // 1 hour
+    OTHER("other", 7_200L), // 2 hours
+    ;
+
+    companion object {
+        fun fromCode(code: String?): RoadEventType? = entries.firstOrNull { it.code == code }
+    }
+}
+
+/** The `t` tag of a Roadstr report (kind 1315): the [RoadEventType] code. */
+class RoadEventTypeTag {
+    companion object {
+        const val TAG_NAME = "t"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        /** Parses the tag into a known [RoadEventType], or null when missing/unknown. */
+        fun parse(tag: Array<String>): RoadEventType? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            return RoadEventType.fromCode(tag[1])
+        }
+
+        /** Returns the raw `t` value even when it is not a known [RoadEventType]. */
+        fun parseCode(tag: Array<String>): String? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1]
+        }
+
+        fun assemble(type: RoadEventType) = arrayOf(TAG_NAME, type.code)
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/LatitudeTag.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/LatitudeTag.kt
new file mode 100644
index 0000000000..d3c8ab167c
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/LatitudeTag.kt
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+/** The `lat` tag of a Roadstr event: latitude as a decimal string with 7 fractional digits. */
+class LatitudeTag {
+    companion object {
+        const val TAG_NAME = "lat"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): Double? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            return tag[1].toDoubleOrNull()
+        }
+
+        fun assemble(latitude: Double) = arrayOf(TAG_NAME, RoadCoordinate.format(latitude))
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/LongitudeTag.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/LongitudeTag.kt
new file mode 100644
index 0000000000..18880cfebc
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/LongitudeTag.kt
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+/** The `lon` tag of a Roadstr event: longitude as a decimal string with 7 fractional digits. */
+class LongitudeTag {
+    companion object {
+        const val TAG_NAME = "lon"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): Double? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            return tag[1].toDoubleOrNull()
+        }
+
+        fun assemble(longitude: Double) = arrayOf(TAG_NAME, RoadCoordinate.format(longitude))
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/RoadCoordinate.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/RoadCoordinate.kt
new file mode 100644
index 0000000000..193b34e122
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/RoadCoordinate.kt
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.tags
+
+import kotlin.math.abs
+import kotlin.math.round
+
+/**
+ * Formatting for the `lat`/`lon` tag values of Roadstr events. The spec requires
+ * a decimal string with exactly 7 fractional digits (e.g. `48.8566140`), which is
+ * locale-independent here (unlike `String.format`, which is unavailable in
+ * `commonMain` anyway).
+ */
+object RoadCoordinate {
+    private const val SCALE = 10_000_000L // 7 decimal places
+
+    fun format(value: Double): String {
+        val scaled = round(value * SCALE).toLong()
+        val negative = scaled < 0L
+        val absValue = abs(scaled)
+        val intPart = absValue / SCALE
+        val fracPart = (absValue % SCALE).toString().padStart(7, '0')
+        return (if (negative) "-" else "") + intPart + "." + fracPart
+    }
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/TagArrayBuilderExt.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/TagArrayBuilderExt.kt
new file mode 100644
index 0000000000..a124f24cb4
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/TagArrayBuilderExt.kt
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.GeoHash
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.GeoHashTag
+
+/** Adds `lat`/`lon` tags (7-decimal strings) shared by Roadstr reports and confirmations. */
+fun <T : Event> TagArrayBuilder<T>.coordinates(
+    latitude: Double,
+    longitude: Double,
+) = apply {
+    add(LatitudeTag.assemble(latitude))
+    add(LongitudeTag.assemble(longitude))
+}
+
+/** Adds the three `g` geohash tags (precision 4, 5 and 6) derived from [latitude]/[longitude]. */
+fun <T : Event> TagArrayBuilder<T>.roadGeohashes(
+    latitude: Double,
+    longitude: Double,
+) = apply {
+    val geohash6 = GeoHash.encode(latitude, longitude, 6).toString()
+    add(GeoHashTag.assembleSingle(geohash6.substring(0, 4)))
+    add(GeoHashTag.assembleSingle(geohash6.substring(0, 5)))
+    add(GeoHashTag.assembleSingle(geohash6))
+}
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/TagArrayExt.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/TagArrayExt.kt
new file mode 100644
index 0000000000..1368797d18
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/roadstr/tags/TagArrayExt.kt
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+
+fun TagArray.latitude() = firstNotNullOfOrNull(LatitudeTag::parse)
+
+fun TagArray.longitude() = firstNotNullOfOrNull(LongitudeTag::parse)
diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/GeoHash.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/tags/geohash/GeoHash.kt
similarity index 95%
rename from amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/GeoHash.kt
rename to quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/tags/geohash/GeoHash.kt
index 4741b104a5..ac2b320078 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/service/location/GeoHash.kt
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/tags/geohash/GeoHash.kt
@@ -18,13 +18,17 @@
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-package com.vitorpamplona.amethyst.service.location
-
-import android.location.Location
+package com.vitorpamplona.quartz.nip01Core.tags.geohash
 
 /**
  * GeoHash encoding/decoding based on Gustavo Niemeyer's algorithm (2008).
  *
+ * Pure-Kotlin and platform-agnostic (lives in `commonMain`), so any Nostr
+ * protocol code can derive `g` tags from coordinates and walk neighboring cells
+ * without depending on a platform location API. Callers that work with a
+ * platform `Location` type add thin conversion helpers in their own module
+ * (e.g. `amethyst`'s `Location.toGeoHash()` / `GeoHash.toLocation()`).
+ *
  * Bits are interleaved: even-indexed bits (0, 2, 4, ...) = longitude,
  * odd-indexed bits (1, 3, 5, ...) = latitude.
  */
@@ -237,12 +241,6 @@ class GeoHash private constructor(
     val easternNeighbour: GeoHash get() = fromBitArrays(latBits, numLat, mask(lonBits + 1L, numLon), numLon)
     val westernNeighbour: GeoHash get() = fromBitArrays(latBits, numLat, mask(lonBits - 1L, numLon), numLon)
 
-    fun toLocation(): Location =
-        Location("").also {
-            it.latitude = centerLat
-            it.longitude = centerLon
-        }
-
     override fun toString(): String {
         val charCount = significantBits / BITS_PER_CHAR
         val sb = StringBuilder(charCount)
@@ -263,6 +261,4 @@ class GeoHash private constructor(
     override fun hashCode(): Int = 31 * bits.hashCode() + significantBits
 }
 
-fun Location.toGeoHash(charsCount: Int = GeoHash.MAX_CHAR_PRECISION): GeoHash = GeoHash.encode(latitude, longitude, charsCount)
-
 fun String.toGeoHash(): GeoHash? = GeoHash.decode(this)
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt
index 6752dcd986..cdf987c70f 100644
--- a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt
@@ -53,6 +53,8 @@ import com.vitorpamplona.quartz.experimental.nipsOnNostr.NipTextEvent
 import com.vitorpamplona.quartz.experimental.nns.NNSEvent
 import com.vitorpamplona.quartz.experimental.notifications.wake.WakeUpEvent
 import com.vitorpamplona.quartz.experimental.profileGallery.ProfileGalleryEntryEvent
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.RoadEventConfirmationEvent
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
 import com.vitorpamplona.quartz.experimental.zapPolls.ZapPollEvent
 import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageEvent
 import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
@@ -579,6 +581,8 @@ class EventFactory {
                 ReleaseArtifactSetEvent.KIND -> ReleaseArtifactSetEvent(id, pubKey, createdAt, tags, content, sig)
                 RelaySetEvent.KIND -> RelaySetEvent(id, pubKey, createdAt, tags, content, sig)
                 ReportEvent.KIND -> ReportEvent(id, pubKey, createdAt, tags, content, sig)
+                RoadEventConfirmationEvent.KIND -> RoadEventConfirmationEvent(id, pubKey, createdAt, tags, content, sig)
+                RoadEventReportEvent.KIND -> RoadEventReportEvent(id, pubKey, createdAt, tags, content, sig)
                 RootSiteEvent.KIND -> RootSiteEvent(id, pubKey, createdAt, tags, content, sig)
                 RepostEvent.KIND -> RepostEvent(id, pubKey, createdAt, tags, content, sig)
                 RequestToVanishEvent.KIND -> RequestToVanishEvent(id, pubKey, createdAt, tags, content, sig)
diff --git a/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/experimental/roadstr/RoadEventTest.kt b/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/experimental/roadstr/RoadEventTest.kt
new file mode 100644
index 0000000000..16a7f82706
--- /dev/null
+++ b/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/experimental/roadstr/RoadEventTest.kt
@@ -0,0 +1,207 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.experimental.roadstr
+
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.RoadEventConfirmationEvent
+import com.vitorpamplona.quartz.experimental.roadstr.confirmation.tags.RoadEventStatus
+import com.vitorpamplona.quartz.experimental.roadstr.report.RoadEventReportEvent
+import com.vitorpamplona.quartz.experimental.roadstr.report.tags.RoadEventType
+import com.vitorpamplona.quartz.experimental.roadstr.tags.RoadCoordinate
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.tags.geohash.GeoHash
+import com.vitorpamplona.quartz.utils.EventFactory
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+class RoadEventTest {
+    private val reportId = "fcbfc866b657a2fe514b579bcf7ff7700a195731eb6f306efb01529a683f86db"
+
+    private fun sampleReport(): Event =
+        EventFactory.create(
+            id = "a099d4db563041bb289d3704f983fc148fc805860303a4f479a8264dc6a2d7cc",
+            pubKey = "932614571afcbad4d17a191ee281e39eebbb41b93fac8fd87829622aeb112f4d",
+            createdAt = 1_700_000_000L,
+            kind = RoadEventReportEvent.KIND,
+            tags =
+                arrayOf(
+                    arrayOf("t", "police"),
+                    arrayOf("g", "u2ed"),
+                    arrayOf("g", "u2edc"),
+                    arrayOf("g", "u2edcg"),
+                    arrayOf("lat", "48.8566140"),
+                    arrayOf("lon", "2.3522219"),
+                    arrayOf("expiration", "1701209600"),
+                    arrayOf("alt", "Roadstr: police report"),
+                ),
+            content = "",
+            sig = "00".repeat(64),
+        )
+
+    private fun sampleConfirmation(): Event =
+        EventFactory.create(
+            id = "b199d4db563041bb289d3704f983fc148fc805860303a4f479a8264dc6a2d7cc",
+            pubKey = "932614571afcbad4d17a191ee281e39eebbb41b93fac8fd87829622aeb112f4d",
+            createdAt = 1_700_003_600L,
+            kind = RoadEventConfirmationEvent.KIND,
+            tags =
+                arrayOf(
+                    arrayOf("e", reportId),
+                    arrayOf("status", "no_longer_there"),
+                    arrayOf("expiration", "1701213200"),
+                    arrayOf("alt", "Roadstr: event confirmation"),
+                ),
+            content = "",
+            sig = "00".repeat(64),
+        )
+
+    @Test
+    fun factoryParsesReportAndConfirmation() {
+        assertIs<RoadEventReportEvent>(sampleReport())
+        assertIs<RoadEventConfirmationEvent>(sampleConfirmation())
+    }
+
+    @Test
+    fun kindsAreKnown() {
+        assertTrue(EventFactory.isKnownKind(RoadEventReportEvent.KIND))
+        assertTrue(EventFactory.isKnownKind(RoadEventConfirmationEvent.KIND))
+    }
+
+    @Test
+    fun parsesReportFields() {
+        val event = sampleReport()
+        assertIs<RoadEventReportEvent>(event)
+
+        assertEquals(RoadEventType.POLICE, event.roadEventType())
+        assertEquals(listOf("u2ed", "u2edc", "u2edcg"), event.geohashes())
+        assertEquals(48.8566140, event.latitude())
+        assertEquals(2.3522219, event.longitude())
+        assertEquals("Roadstr: police report", event.alt())
+        assertEquals(1701209600L, event.relayExpiration())
+        // police TTL is 2h → created_at + 7200
+        assertEquals(1_700_000_000L + 7_200L, event.effectiveExpirationAt())
+    }
+
+    @Test
+    fun unknownTypeYieldsNullType() {
+        val event =
+            EventFactory.create<Event>(
+                id = "00".repeat(32),
+                pubKey = "00".repeat(32),
+                createdAt = 1_700_000_000L,
+                kind = RoadEventReportEvent.KIND,
+                tags = arrayOf(arrayOf("t", "spaceship")),
+                content = "",
+                sig = "00".repeat(64),
+            )
+        assertIs<RoadEventReportEvent>(event)
+        assertEquals("spaceship", event.roadEventTypeCode())
+        assertNull(event.roadEventType())
+        assertNull(event.effectiveExpirationAt())
+    }
+
+    @Test
+    fun parsesConfirmationFields() {
+        val event = sampleConfirmation()
+        assertIs<RoadEventConfirmationEvent>(event)
+
+        assertEquals(reportId, event.reportId())
+        assertEquals(RoadEventStatus.NO_LONGER_THERE, event.status())
+        assertTrue(event.isDenial())
+        assertTrue(!event.isConfirmation())
+        assertEquals("Roadstr: event confirmation", event.alt())
+    }
+
+    @Test
+    fun buildReportProducesCanonicalTags() {
+        val lat = 48.8566140
+        val lon = 2.3522219
+        val createdAt = 1_700_000_000L
+        val template = RoadEventReportEvent.build(RoadEventType.SPEED_CAMERA, lat, lon, createdAt = createdAt)
+
+        assertEquals(RoadEventReportEvent.KIND, template.kind)
+
+        val expectedG6 = GeoHash.encode(lat, lon, 6).toString()
+        val geohashes = template.tags.filter { it[0] == "g" }.map { it[1] }
+        assertEquals(
+            listOf(expectedG6.substring(0, 4), expectedG6.substring(0, 5), expectedG6),
+            geohashes,
+        )
+
+        assertEquals("speed_camera", template.tags.first { it[0] == "t" }[1])
+        assertEquals("48.8566140", template.tags.first { it[0] == "lat" }[1])
+        assertEquals("2.3522219", template.tags.first { it[0] == "lon" }[1])
+        assertEquals((createdAt + RoadEventReportEvent.RELAY_TTL_SECONDS).toString(), template.tags.first { it[0] == "expiration" }[1])
+        assertEquals("Roadstr: speed_camera report", template.tags.first { it[0] == "alt" }[1])
+    }
+
+    @Test
+    fun buildConfirmationOmitsLocationWhenAbsent() {
+        val template = RoadEventConfirmationEvent.build(reportId, RoadEventStatus.STILL_THERE, createdAt = 1_700_000_000L)
+
+        assertEquals(reportId, template.tags.first { it[0] == "e" }[1])
+        assertEquals("still_there", template.tags.first { it[0] == "status" }[1])
+        assertEquals("Roadstr: event confirmation", template.tags.first { it[0] == "alt" }[1])
+        assertTrue(template.tags.none { it[0] == "g" || it[0] == "lat" || it[0] == "lon" })
+    }
+
+    @Test
+    fun buildConfirmationIncludesLocationWhenProvided() {
+        val lat = 48.8566140
+        val lon = 2.3522219
+        val template = RoadEventConfirmationEvent.build(reportId, RoadEventStatus.STILL_THERE, lat, lon)
+
+        val expectedG6 = GeoHash.encode(lat, lon, 6).toString()
+        assertEquals(expectedG6, template.tags.filter { it[0] == "g" }.last()[1])
+        assertEquals("48.8566140", template.tags.first { it[0] == "lat" }[1])
+    }
+
+    @Test
+    fun roadEventTypeTtls() {
+        assertEquals(7_200L, RoadEventType.POLICE.effectiveTtlSeconds)
+        assertEquals(2_592_000L, RoadEventType.SPEED_CAMERA.effectiveTtlSeconds)
+        assertEquals(3_600L, RoadEventType.TRAFFIC_JAM.effectiveTtlSeconds)
+        assertEquals(604_800L, RoadEventType.POTHOLE.effectiveTtlSeconds)
+        assertEquals(RoadEventType.TRAFFIC_JAM, RoadEventType.fromCode("traffic_jam"))
+        assertNull(RoadEventType.fromCode("nope"))
+    }
+
+    @Test
+    fun coordinateFormattingHasSevenDecimals() {
+        assertEquals("48.8566140", RoadCoordinate.format(48.856614))
+        assertEquals("2.3522219", RoadCoordinate.format(2.3522219))
+        assertEquals("-0.0000010", RoadCoordinate.format(-0.000001))
+        assertEquals("0.0000000", RoadCoordinate.format(0.0))
+        assertEquals("-33.8688000", RoadCoordinate.format(-33.8688))
+    }
+
+    @Test
+    fun geohashEncodeProducesPrefixHierarchy() {
+        val g6 = GeoHash.encode(48.8566140, 2.3522219, 6).toString()
+        val g5 = GeoHash.encode(48.8566140, 2.3522219, 5).toString()
+        assertEquals(6, g6.length)
+        assertEquals(g6.substring(0, 5), g5)
+        // decode round-trips back to a hash with the same prefix
+        assertEquals(g6, GeoHash.decode(g6).toString())
+    }
+}