"All of these things collectively created just a huge problem on the supply side,'' Laskoski said.

Rising prices have also brought gasoline thefts.

In Roseville, Calif., police are seeking two people suspected of stealing 750 gallons of gasoline from a Shell station, Police Sgt. Jeff Kool said. He said thieves somehow defeated the gasoline pump's meter controls and filled external tanks in a pickup during visits in the early-morning hours over three days.

"With prices in the upper $4 a gallon, gasoline is obviously more valuable,'' Kool said. "It's a criminal opportunity.''