With a long holiday weekend just days away, motorcyclists and drivers will be taking to the highways in record numbers. This means a greater risk of accidents and that all drivers should be extra cautious about keeping their eyes on the road and watching who is traveling around them.
A recent University of California–Berkeley study reveals that lane-splitting, a common motorcycling practice outside the U.S., is a reasonably safe tactic for traveling in congested traffic. Currently, only California allows lane-splitting by motorcyclists, but other states are considering allowing it as well. (Lane-splitting, or "stripe riding," occurs when a two-wheeled vehicle travels between two lanes of traffic moving in the same direction; it is most commonly seen when traffic is slowed or stopped and a motorcycle maneuvers between them at a greater speed.)
Led by Thomas Rice, Ph.D., the Safe Transportation Research & Education Center (SafeTREC) at U.C. Berkeley looked at the incidence of lane-splitting among 5,969 motorcyclists involved in collisions between June 2012 and August 2013. The data was derived from the California Enhanced Motorcycle Data Project with the collaboration of the California Highway Patrol (CHP).
The immediate question determined the prevalence of lane-splitting among those motorcyclists, as well as the interplay of other factors like speeding, time/day of week, helmet use, and types of injuries.
The data revealed that 17% (997 riders) were lane-splitting at the time of the collisions. However, the typical riding behaviors of these motorcyclists were distinct from those who were not lane-splitting. For the most part, lane-splitting motorcyclists were traveling during commuting hours on weekdays, using better-quality helmets, and traveling at lower speeds.
The analysis further revealed that they were less likely to have imbibed alcohol or carried passengers. All told, the results point to the idea that lane-splitting in California is, much like dedicated High Occupancy Vehicle (HOV) lanes and automatic toll pay measures, an effort to shave commuting time.
While injuries to these lane-splitting riders were fewer and tended to be less grave, the researchers found that the difference between the motorcycle's and the traffic's speeds correlated to the possibility of injury. They concluded that differentials of up to 15 mph were not associated with increased injury occurrence—above that speed, however, injuries to the head, torso and extremities were more likely.
Photo: Pelykh Konstantin/Shutterstock
Interest groups like the American Motorcyclist Association and motorcycle-riding clubs look to the research results as affirmation for their position that responsible lane-splitting is a safe and effective motorcycle-riding strategy nationwide which serves to reduce overall traffic congestion. The challenge is convincing the rest of the driving public who see lane-splitting as an unpredictable factor in everyday driving.
Man-on-the-street surveys of California drivers typically spark negative outbursts because many have had the experience of being spooked by motorcyclists suddenly appearing in their lines of sight or encroaching on their lanes—both behaviors adversely affecting the reaction times of drivers and motorcyclists.
It is no surprise that 75% of drivers in a 2012 study by the California Office for Traffic Safety thought lane-splitting was unsafe—almost half of those surveyed also thought the practice was illegal. A majority of them disapprove of lane-splitting and a minority admitted to blocking riders trying to lane-split—a situation reported by 67% of the riders in the same 2012 study.
Clearly, there is a gap in understanding between motorcycle enthusiasts and other motor vehicle drivers, the narrowing of which would certainly help the acceptance of lane-splitting on a national scale. Beyond that, California state regulators and law enforcement need to address institutional ambivalence about the practice of lane-splitting.
Recent efforts to offer guidelines to safe lane-splitting in the online/print publications supplied by the California Department of Motor Vehicles as well as information posted on the CHP's website have been removed due to complaints that publishing strategies was tantamount to state endorsement of the practice. Influenced by the results of the U.C. Berkeley study, the California Assembly is proposing adding lane-splitting guidelines to the Vehicle Code with AB 51. The law would limit the lane-splitting motorcyclist to 50 mph and not to exceed the speed of traffic in adjacent lanes by 15 mph.
A common argument for lane-splitting has been a mechanical one: motorcycles are often powered by air-cooled engines that heat up in stalled traffic, but there are other hazards on the road that also favor maximizing the maneuverability of motorcycles in heavy traffic. Uneven pavement, potholes, debris and the like are more dangerous to riders than to drivers of other vehicle types.
The U.C. Berkeley study also showed that riders who lane-split were less likely to be rear-ended themselves, a prevalent concern among motorcyclists. These realities coupled with the results of the research by Rice and his team show that the case for lane-splitting may just be a life-saving choice.
Rory Murphy is a project engineer at Peter R. Thom and Associates, Inc., a national firm of consulting automotive engineers. He can be contacted at www.prtassoc.com.
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