diff --git a/editor/src/mission/dataviz.rs b/editor/src/mission/dataviz.rs
index 3ab1bc9cf2..5688cb7f5e 100644
--- a/editor/src/mission/dataviz.rs
+++ b/editor/src/mission/dataviz.rs
@@ -27,6 +27,7 @@ struct Tract {
 
     num_bldgs: usize,
     num_parking_spots: usize,
+    total_owned_cars: usize,
 }
 
 impl DataVisualizer {
@@ -67,6 +68,10 @@ impl DataVisualizer {
                 "{} parking spots ",
                 prettyprint_usize(tract.num_parking_spots)
             ));
+            txt.add_line(format!(
+                "{} total owned cars",
+                prettyprint_usize(tract.total_owned_cars)
+            ));
         }
         self.menu.handle_event(ctx, Some(txt));
         ctx.canvas.handle_event(ctx.input);
@@ -189,6 +194,7 @@ fn clip(popdat: &PopDat, ui: &UI, timer: &mut Timer) -> BTreeMap<String, Tract>
                     color: Color::WHITE,
                     num_bldgs,
                     num_parking_spots,
+                    total_owned_cars: tract.total_owned_cars(),
                 },
             );
         }
diff --git a/popdat/src/lib.rs b/popdat/src/lib.rs
index 9f0a2dd1cc..5f99787ad1 100644
--- a/popdat/src/lib.rs
+++ b/popdat/src/lib.rs
@@ -146,3 +146,22 @@ fn group_attribs(mut attribs: BTreeMap<String, String>) -> BTreeMap<String, Esti
         })
         .collect()
 }
+
+impl TractData {
+    // Nontrivial summary
+    pub fn total_owned_cars(&self) -> usize {
+        let mut sum = 0;
+        for (name, est) in &self.household_vehicles {
+            match name.as_str() {
+                "1 vehicle avail." => sum += 1 * est.value,
+                "2 vehicles avail." => sum += 2 * est.value,
+                "3 vehicles avail." => sum += 3 * est.value,
+                // Many more than 4 seems unrealistic
+                "4 or more vehicles avail." => sum += 4 * est.value,
+                "No vehicle avail." | "Total:" => {}
+                _ => panic!("Unknown household_vehicles key {}", name),
+            }
+        }
+        sum
+    }
+}