Hybrid cars that use both gasoline engines and electric motors are becoming more common on Iowa roads. It’s a trend that’s not likely to run out of gas, according to University of Northern Iowa biology professor Ken Nuss, who says high gas prices will only help hybrids grow in popularity.The Honda Insight and the Toyota Prius are the most visible hybrids on the market. The Insight can seat two while the Prius can seat four, but it gets fewer miles to the gallon. Both run about 20-thousand dollars. Professor Nuss says they’d be a good investment. He says higher gas prices would make the hybrid technology look even better.Plenty of Iowans drive pickups and S-U-Vs and may be reluctant to trade in their big machines for the tiny fuel-efficient vehicles. Nuss says the final selling point might be a comparison of the monthly gasoline bills. Ford, Dodge and G-M are working on plans for S-U-V hybrids as well.