Higher gas prices may be driving more people to use two-wheeled forms of transportation rather than four.

But some law enforcers say that is also translating into more accidents involving bicycles and motorcycles this summer.

Some of the accidents in Utah so far have been serious.

• In June, 16-year-old Ryan Fullmer was hit by a car while riding his motorcycle and dragged underneath. He suffered two broken legs and a crushed elbow.

• On June 22, four people were injured when a 19-year-old motorcyclist riding at a high rate of speed lost control and crashed into a crowd that was socializing in front of a house.

• On June 14, a 48-year-old man was killed when his motorcycle crashed into a Utah Highway Patrol patrol car that had stopped to assist another motorcyclist who had crashed near the I-80/I-215 interchange.

• Also on June 14, a motorcyclist was critically injured when he careened his bike in front of another vehicle.

• A 12-year-old West Jordan boy was killed May 28 when he lost control of his bicycle and crossed into the path of an oncoming vehicle.

In Sandy, the number of bike and motorcycle accidents doubled in June compared to last year. There were three auto-motorcycle and one auto-bike accidents in Sandy in June of 2007. This year, there were seven auto-motorcycle and two auto-bike accidents, said Sandy Police Sgt. Victor Quezada.

Similarly, the total number of accidents involving an automobile and either a bike or motorcycle, jumped from five in May of 2007 to eight this year.

The Utah State Tax Commission, which oversees the Division of Motor Vehicles, said as of March 1, there were 64,376 registered street motorcycles in Utah compared to 56,146 at the same time last year. Those numbers do not include the estimated 80,000 registered off-road motorcycles in the state.

Law enforcers can't say definitively if higher gas prices are the root cause of more bikes being on the road, but note it's very likely a contributor.

The number of auto-motorcycle accidents in the Salt Lake County Sheriff Office's jurisdiction also doubled from May and June of 2007 to 2008, jumping from eight to 17.

Interestingly, however, the number of auto-bicycle accidents during that same time dropped from 13 to 10, according to the sheriff's office.

Still, sheriff's Lt. Paul Jaroscak said motorcycle riders and bicyclists especially need to be visible on the road by doing such things as wearing reflective clothing.

"Bicyclists and motorcyclists need to take an active roll in their own safety. It's no consolation to be right but dead," he said.

In West Valley, there were two auto-bike and two auto-motorcycle accidents in May of 2007. In May of this year, there were four auto-bicycle accidents and five auto-motorcycle collisions.