I love the concept, I think this has potential to be a released game and a lot of people would really enjoy it (I love cars! having my own fleet running in the background would be awesome)
I do have to agree with some other comments regarding the slow speed of progress. I can especially feel it because we almost fell face first into it (we dialed our speed waaay up after the first playtest, and I'm not even sure we still got it 100% right for the jam). I would love to see all content the game has to offer in a bit of a shorter timespan. Another small nitpick is that the "clunky" steering behavior on the cars doesn't help on that regard (although it is a bit funny once they start going fast boi mode)
please turn this into a full thing! I think you have a nice spin on the idle game formula here