Studying one congested stretch of road, the researchers found replacing 10 percent of cars with motorcycles would cut time stuck in traffic by 63 percent—for everyone. Carbon emissions drop by 6 percent, due largely to smoother traffic flow. The study didn’t specifically consider lane splitting, but noted that “when traffic comes to a complete standstill, it can be assumed that all motorcycles drive between two lanes.”
On top of all that, there are safety advantages to lane splitting. Hard to believe—it’s so easy for a driver to hit someone riding by!—but riding between cars rather than in front of and behind them seems to reduce the risk of a deadly collision, specifically from being rear ended.
“Seemingly counter-intuitive, traffic filtering is actually a viable safety technique,” motorcycle safety consultant Steve Guderian wrote in an August 2011 study. It “removes the motorcycle and rider from the danger spot behind a stopped car, and places the motorcycle into the more secure safety envelope that is created between two larger vehicles.” Guderian found that California had significantly fewer motorcyclist fatalities from rear end collisions than other states.