diff --git a/simple_analysis/templates/simple_analysis/simple_analysis.html b/simple_analysis/templates/simple_analysis/simple_analysis.html
index fbfef37..ac1eb34 100644
--- a/simple_analysis/templates/simple_analysis/simple_analysis.html
+++ b/simple_analysis/templates/simple_analysis/simple_analysis.html
@@ -2598,7 +2598,8 @@ function toggleTrafficPanel() {
 function _ensureFlowLayer() {
     if (!SA.map) return null;
     if (!_trafficFlowLayer) {
-        _trafficFlowLayer = L.layerGroup().addTo(SA.map);
+        const svgRenderer = L.svg({padding: 0.5});
+        _trafficFlowLayer = L.layerGroup([], {renderer: svgRenderer}).addTo(SA.map);
     }
     return _trafficFlowLayer;
 }