Open-source urban driving simulator

Open-source urban driving simulator needed to build an automated taxi driver. The dream feature-set may include:

* easy import of external AI code
* other agents, such as cars and pedestrians
* simulated programmable traffic and traffic regulations
* relatively realistic physics engine

I had a look at TORCS, which has most of these features, only simulates a racetrack. Any suggestions are highly appreciated.

There's an open source GTA clone. (Maybe there are others, but that's what I found when googling). I don't know how far the project is.

IT should include other cars as well as pedestrians in an urban setup. But it's basically 2D and the physics aren't that well, probably.

There are several open source 3D driving simulators released. For example:

CARLA will do it http://carla.org/ and Udacity https://github.com/udacity/self-driving-car-sim