Can you get a 'failure to stop ticket' dismissed if you have a witness?

I was at a 3 way intersection and a car was starting to turn left as i was coming to the stop sign. I slowed down and stopped. About a half block down a cop pulled me over. My friend was in the car and she says she will testify that I stopped, my question is , is it worth it? does anyone but the cop ever win? it was about 10:40 at night and pitch black ,if that makes any difference.