Cash and his bike

So we got Cash a new bike and he loves it! Wants to ride all the time, though he has fallen over a few times and I think that is getting to him. But hopefully he can shake it off. I on the other hand am a nervous wreck because he doesn't seem to understand the concept of cars in the rode and when I say or (yell) get over to the right- I mean it! A car is coming and I need you to stay to the curb.