Lane-splitting — the act of a motorcycle passing alongside a slow-moving vehicle in the same lane — could become legal in California and across the country.

Although it’s already “tolerated” California, the practice has stirred controversy throughout the nation, where most of the other 49 states frown upon it or legislate against it.  But recent studies indicate that lane-splitting may actually be safer for motorcycle drivers.

The Logic of Lane-Splitting

When most people think of lane-splitting, they think of loud racing bikes roaring past their car and nearly taking out their side view mirrors. What these anecdotal experiences lack in hard facts they make up for in vividness.

Indeed, the whole purpose of legislating lane-splitting is to establish parameters to study the practice further. The type of lane-splitting under consideration is quite specific and has to do with safety, as well as practicality. Motorcycles are frequently rear-ended in heavy traffic as a result of careless motorists. What could be a fender bender for a car turns into a spillout for a motorcycle, and these motorcycle accidents could cause severe injuries.

Disallowing lane-splitting also exacerbates congestion, making bad traffic even worse. Air-cooled motorcycles — which are the vast majority of models — could overheat in such conditions, leading to stranded drivers or the aforementioned rear fender tap.

Lane-Splitting by the Numbers- Is it Safe?

The majority of those opposed to lane-splitting cite vivid anecdotes rather than facts.

“There’s many opinions about it and very little data,” Chris Cochran, spokesman for the California Office of Traffic Safety, told The Washington Post. His office conducted one of the few studies on the practice, and his findings were in line with what motorcyclists had been saying for years. “Out of that study came the data that lane-splitting in and of itself — when done in what we refer to as in a safe and prudent manner — is no more dangerous than regular motorcycle-riding.”

The study, conducted in partnership with the UC Berkeley, found that 17 percent of motorcycle accidents from June 2012 to August 2013 occurred while the driver was lane-splitting. However, these accidents were markedly different from most other motorcycle accidents.

“Compared with other motorcyclists, the report read, “lane-splitting motorcyclists were more often riding on weekdays and during commute hours, were using better helmets, and were traveling at lower speeds. Lane-splitting riders were also less likely to have been using alcohol and less likely to have been carrying a passenger.”

These conditions lead to far fewer injuries from motorcycle accidents. Lane-splitters were nearly half as likely to suffer head injuries or fatalities, and significantly less likely to suffer torso, extremity or neck injuries.

Lane-Splitting Safety Guidelines

The California Highway Patrol briefly provided guidelines for safe lane-splitting before taking down the document because it was viewed as condoning the practice. Their poster can still be found here, and it advises riders to:

• Only lane-split when traffic is moving 30 mph or less
• Never travel more than 10 mph faster than traffic
• Avoid lane-splitting on right-hand lanes near on ramps or exits
• Recognize that car drivers who purposefully attempt to impede or injure lane-splitting riders are committing illegal acts

Lane-Splitting: Coming to a City Near You?

If AB-51 is signed into law, it would be the first step towards formally codifying lane-splitting in the country. Many legislatures and citizens will no doubt have a visceral reaction to the practice, but with more studies like the CA OTS, reason may have to prevail over emotion. Until then, drive safely and watch out for our two-wheeled friends on the road.