This place has a pay station before you enter and then you pull up your car into the tunnel. There was a young gentleman that helped me with the pay station, and another that prepped my car (birds bombed my car earlier in the week) with the power washer.
You stay in the car, and the tunnel itself does the satisfactory job. There isn't anyone drying your car at the end, so if dry water stains bother you, bring a towel. There are do-it-yourself vacuum machines once you exit the wash (towards the front of the car wash) where you can use cash to convert them to vacuum tokens.