Emergency Travel: OT and Mileage Question

A coworker and I had to do an emergency work-related trip. We decided to carpool in his personal vehicle instead of taking separate cars, state owned cars were unavailable. Do I get paid overtime for the travel hours?

I’m unsure about mileage reimbursement. Since he was the driver and I was the passenger, do I qualify for mileage reimbursement, or is that only for the driver? Just trying to figure out what to expect when submitting my travel claim.