There's potential in the mechanics here, I think this could turn into a really cool mix of Crazy Taxi and Pacman, with more obstacles/roadblocks so the player is both route planning based on speed/the geography of the roads and avoiding hazards that slow them down. Also, as a siren noise might get repetitive if it is on the whole time, but turning it into a usable mechanic and toy that can make cars move out the way could really add another layer. I think it's fun, well done :)