Car use is an increasingly serious problem in many modern cities because of polluting emissions, noise, accidents and congestion. To examine this issue, this paper analyzes the individual choice between taking the car and using alternative transport modes (e.g. walking, cycling, taking the bus etc...) in the presence of cars' negative impacts on alternative transport modes. Using a simple evolutionary model, we show the existence of suboptimal Nash equilibria characterized by the widespread use of cars and discuss the effects of simple transport policies that reduce cars' negative impacts on alternative transport modes.