Thanks for the comments. Unfortunately, it kills performance if stuck cars constantly check for new paths. I tried to strike a good balance between quickly-adapting AI and performance.
Also, one might argue that quickly adapting to new routes is somewhat unrealistic. Drivers that have set out to work already have their routes in mind (or programmed into GPS). Yes, people certainly take other routes when stuck in traffic - but they usually don't do it instantly.
I haven't played so much time. Right, it may kill the performance, but maybe it should check new route only if car stuck - this means, that not moving for some time, but have other free path/road to go. So it will check for path for first stuck car and move it, then next time for next one. The last one - will wait, but after some time all cars can go. Additional one or few cars (if many tracks changes for last day) won't need additional performance. Now it is impossible to check new solutions without stopping the source point.
