Bike Gangs?

My town has a problem, gangs of kids on bikes (most of them 13-17) started terrorizing the streets. What they do is they surround your car, force you out, bit you up and rob you. Of course the police is doing nothing, so the question among everybody is what to do in that situation, just locked yourself in your car and call the police from your cell-phone (though some people that have done that had gotten their windows smashed) or just drive away risking to hit some of the kids. What would you do? I am not sure yet