There are mods that can do that (literally wipe every simulated traffic off the map) but you can handle traffic pretty easily if you plan ahead.

My last few cities really had no traffic problems at all except for one old main road that I really didn't want to redevelop for some reason.

I'm not sure how that can be a problem. If traffic couldn’t have any effect on your city, then why bother simulating it? The whole point is to make you think ahead and plan the capacity of your road network so that traffic jams are less likely and fixing them is easier.