A tip when I comes to road hierarchy. I've found that the biggest factor in determining Sims routes comes down to road speed limit. Not making a road to long can work, but it also can mess up traffic flow. If you want Sims to use a road only locally I suggest either using a district with old Town policy or using tm:pe to lower the speed limit, while making your collectors and arteries have high speed limits. Since Sims take the fastest possible route (not necessarily the shortest) this discourages then from using roads you don't want then to while keeping traffic flow healthy. I find this really helps spread out traffic to different routes while also keeping local roads from acting as collectors. This has worked really well for me and I hope it does for you as well
A tip when I comes to road hierarchy. I've found that the biggest factor in determining Sims routes comes down to road speed limit. Not making a road to long can work, but it also can mess up traffic flow. If you want Sims to use a road only locally I suggest either using a district with old Town policy or using tm:pe to lower the speed limit, while making your collectors and arteries have high speed limits. Since Sims take the fastest possible route (not necessarily the shortest) this discourages then from using roads you don't want then to while keeping traffic flow healthy.
I find this really helps spread out traffic to different routes while also keeping local roads from acting as collectors. This has worked really well for me and I hope it does for you as well