cars: halve density and bias traffic toward motorways

config.js

@@ -417,8 +417,11 @@ window.CONFIG = {
         spreadKm: 45,             // gaussian sigma around the motorway network
         spreadFloor: 0.30,        // share that far side roads keep
         speed: 1.0,               // flow speed multiplier
-        density: 0.5,             // vehicle density multiplier
+        density: 0.25,            // vehicle density multiplier
         brightness: 0.78,         // vehicle light intensity (60 % of 1.3)
+        motorwayDensity: 0.95,    // share of the density budget on motorways/trunk
+        sideDensity: 0.35,        // share of the density budget on primary/secondary/tertiary
+        sideDashFactor: 3.2,      // wider spacing on side roads: fewer local cars
         // Time-based traffic profile. Values are multipliers around the
         // configured density. Times are local scene-clock hours.
         timeProfile: {
@@ -441,6 +444,7 @@ window.CONFIG = {
             // timeProfile: { morningGain: 0.8, eveningGain: 1.0, nightReduction: 0.85 }
         }
         // speed: 2.0, density: 0.6, brightness: 1.0
+        // density: 0.25, motorwayDensity: 1.0, sideDensity: 0.25, sideDashFactor: 4.0
     },
 
     // ------------------------------------------------------------------