I try to make a traffic flow with many cars.

I use Bullet Widget as cars,put then on street.try to make them stop at red light.

here's my first try:I shoot traffic signs to cars,red hits to stop,green hits to go.it works,but sometimes cars crash into each other...

test4.mfa

here's my second try:I put detectors on each car,to detect if there is another car in front,but cars never start again...

test3.mfa

which way should I go?and how to make cars start again?

and...is there an easy way to make an Isometric movement?

and sorry for my bad English.