Colliders, triggers and modelling a level

I'm wanting to build a simple traffic simulation focusing on having cars stop at intersections, be aware of the intersection type (t-intersection, four way, no right turn etc) and then choose a random path once the road is clear.

My thought was to first model a basic cityscape and import into Unity. Then, create some prefabs with colliders based on the few key intersection types. I could read a map file at runtime and instantiate the right prefabs at the right intersections. Finally, by using triggers my cars could know when they're approaching an intersection and slow down/check.

Is this a sensible approach? I'm not planning on hundreds of cars or anything and no physics.