Something is worrying me about Overwatch. I have noticed that after I've been playing for a while the mod keeps giving me messages like '15689 vehicles have been removed'. That is the largest number I have seen, but it is frequently in the thousands. Is this normal? Surely there can't have been that number of cars in the world! I am worried that something has gotten corrupted, or that some other mod is messing things up. I am patched to level 1.67 and am using v121 of Overwatch.

I'm afraid that is perfectly normal. I've seen and heard of routine cleanups approaching 30,000 vehicles. They aren't necessarily cars, though. The mechanism that produces limos for those in the performance career, among others, and snack/ice cream trucks is known to get stuck in loops and that's what most of those could be.

The way to stop the incessant unnecessary vehicles from spawning in the first place is to use Traffic to disallow the issuance of free cars to sims who do not own one or cannot find theirs, thus forcing them to use taxis or other means of getting around, to limit the food trucks to sensible numbers, and to disallow the performance limos entirely.

To disallow other kinds of limos, I would recommend Nonamena's No Limos Careers Plus mod.
http://www.simlogical.com/ContentUpload ... loads/1581

They can both be used together, Traffic and Nona's mod. I haven't seen OW cleanup more than 4 or 5 vehicles on its overnight run in ages, with both of those in place.

Oh, and although not related to vehicular cleanup, I would recommend updating OW to v122. There's a lot of good stuff in the newer version.

I'll upgrade to v122 then, and do what you suggest with Traffic. And I'll check out Nonamena's mod too. Thanks for clearing that up, it's been bothering me for a while now. Glad it's not a sign of anything more serious.