I also just thought of this. My son is the ultimate backseat driver. He loves to tell me to GOOOOO.. when the stoplight turns green and Stop Mom when its red. I think I can incorporate that into the Freeze game too.

My daughter does this, a lot so we have to be very careful. This is actually very common in the ASD world. We have tried everything but nothing seems to work, so we got a harness that my daughter has to wear when she is out. It is kind of like a big dog harness with a leash but it works. I will say we do get a lot of strange looks from people but we just ignore it because it is better than letting her get loose and get hit by a car. They are not very expensive and they are quality products. I have put a few links here so you can check them out.

http://childharness.ca/index.html

http://www.lucasworks.org/child-harness.html

This may help. Play games like FREEZE, or GO and STOP, etc. so he learns to make himself stop when he's told to stop.

My two year old just started the running to, and he's diagnosed with autism as well, so yea i'm going to start it to

I have the same concerns. Mine will just bolt from me. He refuses to hold my hand. If I 'make' him he will lay down on the pavement, then jump up and run.
I'm going to start with the advice above and start the Freeze game-now.
Thank you for your question and the great answers!!