How bad is the parking at your school?
When I was at ASU there were always girls walking into class late and complaining about parking, waiting in line to pay for it, etc.
My program was 95% male, so if it happened with the guys, it was much less common.
Batteries inside a car running the air conditioning are one thing, but if you drive 15,000 miles a year, and average 50 MPH, you are spending three hundred hours a year driving, although I would expect double that.
What about the other eight hours of summer heat each day?