There is a project being developed to manage cars that will drive by themselves. It's actually working already. And the below is a system to manage how cars will handle by themselves to cross crossings in roads and even avenues with 6 lanes each side!
And that is what CiM should use to handle it's crossings as for now it's a bit messy.
Visit the website and download the videos. What you see are cars going very close to each other but never crashing and almost zero stop at crossings. It's a big flow of cars and no queues. They also have different speeds to simulate small cars, vans, sedans and SVUs.
Autonomous Intersection Management
P.S.: It wouldn't look realistic in CiM, but SURE is a very interesting thing.
Taking the approach to an extreme, you can see what the reservation system enables with 6 lanes in each direction and granularity of 48.
Simulator available. Make your own parameters: http://www.cs.utexas.edu/~aim/oldsim/simulate.cgi