Hello, nice pack and overall the city is quite nice to get started with. Thanks for releasing this pack!
I just wanted to add that the overall scale for all your objects is down by around 0.4. I imported a Pontiac Firebird model with correct dimensions and it looked like a huge stone replica in there. I have to scale down every vehicle I need to get it in there and approximate the import scale of the mesh as well as throw wild guesses at wheel collision shape radii, which is a major pain.
In addition to the building collision meshes, I also had to fix the collision for road static meshes with multiple collision shapes for road and side-walks. Now the vehicles behave much more realistically.
Also, there are a bunch of errors regarding some overlapping UVs for a door and NULL static meshes for ‘sky4’ when we build the lighting. I sent these via email but did not receive any response, so I had to post this here. If you can double check before compiling your next pack update, it’ll reduce more rework.
I hope these issues are fixed in your repack. Let me know if you need help with anything. It would be lovely to see a bigger city than this block come alive without any issues! 
Cheers!