Last time I transferred a fish, I just put them in an old cooler with plenty of water and put them in the back, with a seat belt on, LOL. It worked they did not seem to be any stressed. Depending on how many and how big, find a plastic recipient that has a cap. But then again, make sure it's not for too long, 15 minutes is not a problem at all. If you have someone to drive with, they can just hold the recipient or cooler while you drive so they don't get smashed around. Also try not to speed and drive with care.
Good luck.