reporter: southern california is home to the nation s highest gas prices, nearly $2 a gallon higher than a year ago opinion are you really getting 87 miles to the gallon? yeah. i m getting well over 80 miles per gallon. reporter: wayne gerdis is serious about making his tank go further. about 60% further than what the e.p.a. says his plug-in prius hybrid should be getting. this is very much a slow and steady approach to driving. yeah. you ve hit it with that. reporter: we are on interstate 5 outside san diego. what does 55 miles per hour mean to you? reporter: it means you re going a lot slower than everybody else on the road. that s okay. they re not buying my gas. reporter: he says always follow the speed limit. speed kills fuel economy. it does. there s no way around it. reporter: gerdis is one of the nation s leading hyper-milests. some try to reduce drag, drop weight, even draft behind semis.