Just wanted to point out a very small bug that I seemed to find. I you have a street connection in an L and have the edge street marked as public transit only, sometimes the cars still use it in a sort of diagonal way, even though visually it looks like they are using it. I suppose the issue comes from the diagonal not actually checking for it. If it's intentional, simply ignore it.
Just going to add this to make it more visual
M S
S
The M square is a street marked public only, the S are streets that are available to cars. Even tough there is no direct connection between the two S, sometimes cars still used them as if they were connected diagonally.
(I'm not sure if I'm giving you enough information to hunt this bug down)
Other than that, nice game. Some OST would be nice and maybe some other types of streets? An ability to move the buildings (whithin a certain range) could also be useful if you have a very unlucky spawn.