UPDATE for 2REAL's FDR Traffic Mod, now including the complete (new) highway loop of FDR Map. Also fixed the glitching/swerving cars, now traffic on all lanes all the time, no crazy lanchanging. Thanks to maximumstar02 for the help on this.
Works with 2REAL's POLICE MOD and SCORE system.
Install: Put the traffic.json and surfaces.ini file in each layouts /data folder of FDR Track.
for ex.: assettocorsa/content/tracks/fdr/fdr/data
Then start the map in practice mode and use traffic tool (2REAL APP) to enjoy FDR with heavy traffic, police chases and score system in Assetto Corsa singleplayer.