I was useing this mod with the traffic load.
copy msvcr100d, TrafficLoad.asi and TrafficLoad.ini to the MAIN GAME folder where GTAlounhcer and gtaiv.exe are.
Open theTrafficLoad.ini file and change CustomDensity=0 to CustomDensity=1
CarsPerCycle=20 means how many cars you see in some time period, change it to 100 to check if its working
But I can tell you that if more cars (modded cars) you chose to see the more chances of game crashing you have.
There was also another mod that changes the amount of cars but it was not a MOD that force you to put a new file. Just can;t find it. Try this TRRAFFIC LOAD ANYWAY.
And the timcecyc from the LOW ENB makes game loook really nice but you won;t be disappointed with the graphic. You will see no difference only more FPS. Trust me.