The California Highway Patrol and the Department of Motor Vehicles and Department of Traffic Safety have released the first ever set of written guidelines regarding “lane splitting”, a practice which allows motorcycle riders to legally pass vehicles in adjacent lanes by driving between them. California is the only state that allows for lane splitting, however, officials highly discourage the practice. Up to this point, there have not been any written laws or guidelines on how to safely execute this practice. For the rest of the United States, the practice is either outright prohibited or considered unauthorized. While vehicle code in California states that lane splitting is legal as long it is done in a “safe and prudent manner”, the question of what is considered to be a “safe and prudent manner” has arisen. The new guidelines state that motorcyclists can ride between two cars if there is enough room, but should not go more than 10 MPH faster than the vehicle they are passing. Motorcyclists should also not attempt to lane split at full freeway speeds or is any other traffic that is going faster than 30 MPH.

California Highway Patrol said that one reason for the guidelines is to get people to slow down. There is nothing in the California Vehicle Code that specifically prohibits lane splitting, but many people are not aware that the practice is legal. In fact, a survey last year found that half of California drivers thought the maneuver was illegal. Another recent survey found that 87% of California motorcycle riders say they lane split and that 7% of drivers say that they have actually tried to stop a motorcyclist from lane splitting. Further, even though lane splitting is legal, a motorcyclist could still be found to be partially responsible in the case of an accident if the officer on the scene determines their actions to be unsafe.

Because it is often not evaluated as a potential cause of an accident in many motorcycle accident reports, statistical information regarding lane splitting is limited. Instead, California Highway Patrol usually looks at excessive speed, unsafe lane changes and improper passing, and following too closely, all considered to be characteristics of lane splitting. In 2005, 397 motorcyclist fatalities and injuries out of the 9,472 incidents were found to be a result of these characteristics. One could also look at the statistics of the United Kingdom, where lane splitting is also allowed, to get an idea of the prevalence of motorcycle accidents caused the practice. A study in 2004 found that lane splitting was responsible for about five percent of accidents that occurred.

As the number of motorcycle riders in California goes up, the number of motorcycle accidents goes up as well. In 2010, there were more than 9,600 injured in motorcycle accidents, up twenty-five percent since 2000. In 2008, there were 537 fatalities in California resulting from a crash, a 175% increase over the span of ten years. These statistics show that both motorcyclists and motorists always need to be alert and attentive when driving on the road in order to reduce injuries and fatalities related to lane splitting. California Highway Patrol has suggested motorcycle riders remember the four “R’s” while lane splitting, be responsible, reasonable, respectful, and always be aware of all road conditions.