diff --git a/sim/src/lib.rs b/sim/src/lib.rs
index 028182db98..f731720939 100644
--- a/sim/src/lib.rs
+++ b/sim/src/lib.rs
@@ -226,11 +226,15 @@ pub struct SidewalkSpot {
 
 impl SidewalkSpot {
     // Pretty hacky case
-    pub fn deferred_parking_spot(b: BuildingID, goal: DrivingGoal, map: &Map) -> SidewalkSpot {
+    pub fn deferred_parking_spot(
+        start_bldg: BuildingID,
+        goal: DrivingGoal,
+        map: &Map,
+    ) -> SidewalkSpot {
         SidewalkSpot {
-            connection: SidewalkPOI::DeferredParkingSpot(b, goal),
+            connection: SidewalkPOI::DeferredParkingSpot(start_bldg, goal),
             // Dummy value
-            sidewalk_pos: map.get_b(b).front_path.sidewalk,
+            sidewalk_pos: map.get_b(start_bldg).front_path.sidewalk,
         }
     }
 
diff --git a/sim/src/sim.rs b/sim/src/sim.rs
index f6b925c229..1dbe56e7f8 100644
--- a/sim/src/sim.rs
+++ b/sim/src/sim.rs
@@ -760,7 +760,18 @@ impl Sim {
             }
             lines
         } else {
-            self.parking.tooltip_lines(car).unwrap()
+            let mut lines = self.parking.tooltip_lines(car).unwrap();
+            if let Some(b) = self.parking.get_owner_of_car(car) {
+                if let Some((trip, start)) = self.trips.find_trip_using_car(car, b) {
+                    lines.push(format!(
+                        "{} will use this car, sometime after {}",
+                        trip, start
+                    ));
+                } else {
+                    lines.push("Though this car has owner, no trips using it".to_string());
+                }
+            }
+            lines
         }
     }
 
diff --git a/sim/src/trips.rs b/sim/src/trips.rs
index 478237999a..3f74112068 100644
--- a/sim/src/trips.rs
+++ b/sim/src/trips.rs
@@ -493,6 +493,12 @@ impl TripManager {
             end: trip.end.clone(),
         }
     }
+
+    // Return trip start time too
+    pub fn find_trip_using_car(&self, id: CarID, home: BuildingID) -> Option<(TripID, Duration)> {
+        let t = self.trips.iter().find(|t| t.uses_car(id, home))?;
+        Some((t.id, t.spawned_at))
+    }
 }
 
 #[derive(Serialize, Deserialize, PartialEq, Debug)]
@@ -508,6 +514,19 @@ struct Trip {
 }
 
 impl Trip {
+    fn uses_car(&self, id: CarID, home: BuildingID) -> bool {
+        self.legs.iter().any(|l| match l {
+            TripLeg::Walk(_, _, ref walk_to) => match walk_to.connection {
+                SidewalkPOI::DeferredParkingSpot(b, _) => b == home,
+                _ => false,
+            },
+            // No need to look up the contents of a SidewalkPOI::ParkingSpot. If a trip uses a
+            // specific parked car, then there'll be a TripLeg::Drive with it already.
+            TripLeg::Drive(ref vehicle, _) => vehicle.id == id,
+            _ => false,
+        })
+    }
+
     fn is_bus_trip(&self) -> bool {
         self.legs.len() == 1
             && match self.legs[0] {