Life in Vegas is pretty fast and you can expect that these guys have cars. Vegas is one of the most highly populated cities in New York. The traffic there is high and if those citizens don't know how to obey traffic rules then things will be quite dangerous as there will be lots of accident.
The game is played via mouse and the idea here is to make sure that there will be no accidents. You only advance to the next level once you are able to let all the cars in the level to get through safely. Expect things will be harder as you move forward from level to another level.