diff --git a/src/composables/announcer.ts b/src/composables/announcer.ts
index 4b45efb..18b017b 100644
--- a/src/composables/announcer.ts
+++ b/src/composables/announcer.ts
@@ -81,7 +81,7 @@ function useAnnouncer() {
   // Get names of intersecting roads by looking up each road individually
   function getRoadNames(intersectionFeature: SoundscapeFeature): Promise<Set<string>> {
     return Promise.all(
-      intersectionFeature.osm_ids.map((id: number) => cache.getFeatureByOsmId(String(id)))
+      intersectionFeature.osm_ids.map(id => cache.getFeatureByOsmId(id))
     ).then(
       (roads) =>
         new Set(
diff --git a/src/state/cache.ts b/src/state/cache.ts
index 38d1a2c..ebb6ec4 100644
--- a/src/state/cache.ts
+++ b/src/state/cache.ts
@@ -241,7 +241,7 @@ export const cache = {
     };
   },
 
-  getFeatureByOsmId: async function(osm_id: string): Promise<SoundscapeFeature | null> {
+  getFeatureByOsmId: async function(osm_id: number): Promise<SoundscapeFeature | null> {
     // Returns at most one feature, matching a single OSM ID (i.e. a road, not
     // intersectionss involving that road).
     return new Promise(async (resolve, reject) => {