Sounds like the Mac problem that started with the High Sierra update. There is a long post here about users experiencing the same issues. This post from says they are working on it, but it's been quite a while since that was posted, with no updates since. If you read through all the posts, there are a few other suggestions, all with limited success (lower settings to low/minimum resolution, turn off automatic graphics switching, run in virtual machine, increase memory, use external monitor, use gfxCardStatus utility to force use of non-Intel GPU) but basically EA is "working on it" and no estimate on when it will be fixed.
Please add your details and subscribe to the Simcity Crash OSX 10.13 thread Hopefully, there will be some word from them.