There appear to be two kinds of motorists in California: those who hate motorcyclists who dart between lanes … and motorcyclists.

California is the only state in the country that allows lane-splitting—also known as white-lining, filtering and lane sharing—where motorcyclists slide between vehicles in adjacent lanes to pass them. That is a little-known fact often ignored by motorists who, frightened by the sudden appearance of a human form clinging to a vehicle streaking inches from their own, gesticulate wildly and curse loudly at the law-abiding cyclist.

Now the state has a manual, produced by the California Highway Patrol, which settles once and for all the rules of the road for “motorcyclists who are competent enough riders to lane split.”

And they know who they are . . . if they read the manual.

They are the ones who know they probably shouldn’t split lanes when traffic is moving faster than 30 miles per hour, although they aren’t expressly forbidden to do so. They know “it is safer to split between the #1 and #2 lanes than between other lanes.” They know they shouldn’t split while another motorcyclist is doing the same thing nearby, and that they ought to back off near exit and entrance ramps. But they also know they can legally do all of this just about anytime, anywhere.

They also should be young.

A recent study published in the journal Injury Prevention found that Baby Boomers in their 50s and 60s are flooding the motorcycle market and emergency wards as a result of their new-found activities. In 1990, 10% of motorcyclists were over 50. The rate rose to 25% by 2003 for this hardy breed of aging enthusiasts, who were three times more likely to be hospitalized and 2.5 times as likely to suffer severe injuries from a crash than their younger biker brethren.

And mostly brothers they are. About 85% of the 1.45 million crashes studied between 2001 and 2008 involved men. Every age group saw increases in accidents during the years studied, but older folks fared far worse. Casualties for those 40 to 59 increased 61%, and rocketed 247% for those 60 and over.  

The study cited less bone strength, more fat, less muscle and a decline in chest wall elasticity as reasons for their increased post-crash woes. There was apparently no mention in the study of failing mental awareness among older folks of the obvious aging process.

Motorcycle fatalities increased 15% in 2011, from 352 in 2010 to 414, according to the state Office of Traffic Safety. A recent survey by the office found that 77.6% of motorcyclists said they lane-split, with 30.9% doing it all the time. Only about 57.3% of all vehicle drivers know than lane-splitting is legal and 7.3% admit they have tried to block a motorcyclist from sneaking by.

–Ken Broder  

To Learn More:

California Highway Patrol Posts Rules for Legal Lane-Splitting by Motorcyclists (by Tony Bizjak, Sacramento Bee)

Older Motorcycle Riders More Likely to Get Badly Hurt (by Kim Painter, USA Today)

Baby-Boomer Motorcyclists Face Highest Accident Risk (Agence France-Presse)

CHP Issues First Guidelines for Motorcyclists Who Lane Split (by Jim Fremgen, Santa Rosa Press Democrat)

Lane Splitting Guidelines (California Highway Patrol)