Those buggers took over my house a few years ago. We were out of town for 10 days, right when the weather starts getting cold. They moved in and took over. We tried trapping and trapping and trapping and it did no good. We finally got a dozen bait stations and let them feast. Took a few weeks and the problem was finally solved.
Now we just keep the bait stations refreshed. We were away again for a couple of weeks recently, and they were back, but a refresh of the bait stations took care of it.
We killed a few squirrels accidentally. We had one of the bait stations outside, and they chewed into it. We notice very few squirrels around here now. Ooops.
Anyway, all that to say, keep a few bait stations around, and refresh them every 2-3 months, and you'll have a lot fewer problems with your vehicles. Not just one or two stations, either, if you live in the country. We keep about a dozen stocked up.
Buy the pails of bait online for the best price. Those dinky packages of Tomcat will make you go bankrupt.