MOTORCYCLE SAFETY HAS proven to be a difficult issue to address. Nationally, motorcycle rider fatalities increased each year between 2000 and 2008 even though total traffic fatalities were consistently decreasing after 2002. In 2009, there was finally a sharp decrease in the number of fatal motorcycle crashes in the US, and it is estimated there will be a small decrease in 2010 as well.

Despite the decrease in the number of motorcycle rider fatalities in 2009 and the estimated 2010 projections, the ratio of fatal motorcycle accidents to total vehicle fatal accidents remained approximately the same as it was in 2008. Registration data from the Federal Highway Administration (FHWA) shows that, nationwide, motorcycle registrations account for approximately 3% of the total number of vehicles registered.

Figure 1 provides insight into the scope of this problem. It shows that motorcyclist fatalities remain at 13% of the total number of fatal vehicle accidents, because the number of total fatal vehicle accidents has also continued to decrease. This data also suggests that efforts to address the disproportionately high incidence of motorcyclist fatalities have been difficult to develop and implement. When attempting to develop proactive motorcycle safety efforts, the diversity of riders must be taken into account. Therefore, safety initiatives that are applicable through- out the entire spectrum of the motorcycle- riding community will likely be the most successful efforts.

Potential US safety initiatives can be com- pared to similar developments in other industrialized countries. For example, throughout Europe and Asia, motorcycles are allowed to “traffic filter” ride in the space between vehicles proceeding in the same direction on multi-lane roadways; utilizing unused road- way space to pass stopped or slow moving traffic.

Although it might seem counter-intuitive to some. traffic-filtering has proven to be a viable safety technique that removes the motorcycle and rider from the dangerous spot behind a stopped car, and places them in the more secure position that is created between two larger vehicles. Information from the US National Highway Traffic Safety Administration (NHTSA) suggests that rear-end collisions are the most common type of collision dynamic for all vehicles in the United States. Safety measures that can reduce the incidence of this type of impact would enhance motorcycle safety on American roadways.

In most of the 50 US states, traffic-filtering by motorcycles is not permitted by statute or ordinance. Indeed, it is often actively discouraged through enforcement of associated traffic laws. such as unsafe passing, passing on the right and unsafe speed; too fast for conditions. One exception is the State of California where “lane-sharing”-a term that describes the same technique as Europe’s traffic-filtering-is not expressly prohibited by law. Furthermore, California has one of the largest motorcyclist populations and some of the worst traffic congestion in the nation. Lane-sharing is a common technique practiced by many of the state`s motorcyclists. And while those who do lane-share overwhelmingly regard it as safer, what do the statistics indicate?

Since California is the only state in the US that does not expressly prohibit lane-sharing. a comparison with other states with similar conditions. such as similar riding weather, riding conditions, and/or a large motorcycle riding population, can indicate statistical differences between California and those states regarding rear-end collisions. We` ll use Arizona, Florida and Texas for a comparison. In an effort to standardize the comparison between states. the rear-end fatal crash rate per 100,000 registered motorcycles was assessed. The results are shown in Figure 2.

Figure 2 shows that California does have a lower rate of fatal rear-end motorcycle crashes when compared to these other motorcycling states. This figure also shows that the rate of fatal rear-end collisions in California is also lower than the national rate, which includes many states with a limited riding season and fewer motorcycle riders (which naturally serve to reduce statewide figures).

In general, there are two major rear-end collision situations involving motorcycles. One is where the motorcycle is struck in the rear by another vehicle; the other is where the motorcycle collides into the rear of another vehicle.

Figure 3 looks at these two conditions as a percentage of all probable conditions in which a motorcycle fatality might occur. The chart in figure 3 shows that when compared to Florida and Texas, California has fewer motorcycle deaths involving a motorcycle rear-ending another vehicle and significantly fewer deaths from a motorcycle being rear-ended by another vehicle than all three states and the US as a whole.

The two previous charts have shown that with respect to fatal rear-end collisions involving motorcycles, California has lower numbers than comparable US states.

An additional consideration when looking at rear-end motorcycle fatalities is how California compares with all fatal rear-end collisions.

Figure 4 shows this comparison. This graph shows that the “all vehicle fatal rear-end crashes” percentage is about the same for the three states, and the US percentage is slightly lower. The percentage of motorcycle rear-end impact fatalities compared to all motorcycle fatalities is quite a bit higher than the all vehicle rear-end impact fatality percentage in Florida (12.7% vs. 8.5%), Texas (l().8% vs. 7.5%), and the US as a whole (9.0% vs. 6.2%). However, in California, the percentages (85% vs. 73%) are closer, and they are lower than the comparison states. It could be argued that the lower California percentage is attributable to the practice of lane-sharing.

Moving a motorcycle from behind traffic to a position next to traffic significantly changes the risk to the motorcyclist. All crash situations will comply with physical laws. Comparing the collision dynamics of a rear-end impact to a motorcycle involved in a lane-sharing accident reveals that lane-sharing represents a safer overall situation for motorcyclists. A motor- cycle that is lane-sharing is no longer exposed to the full-force of a rear-end impact. Rather, the dynamic is similar to a side- swipe lane-changing impact, which is an incomplete force con- tact. The motorcycle and the car are basically traveling in the same direction, so any contact between the two is limited to the vectoring motion of the car moving into the adjacent lane. This means there is a less forceful contact to the motorcycle and, by extension, to its rider.

When a motorcycle is stopped behind another vehicle and is impacted from the rear, the motorcycle and rider are exposed to an in-line, full-force contact, where the full amount of the striking vehicle’s kinetic energy or momentum is transferred directly to the motorcycle. Consider a common 5 mph rear- end contact. An average motorcycle, weighing about 550 lbs. is completely stopped when it is struck on the rear-end by an average car, weighing about 2500 lbs., traveling at about 5 mph. In this dynamic, the motorcycle will be accelerated for- ward to a speed of about 4 mph in about one-tenth of a second. The chances are very high that the rider will be launched from the motorcycle in some manner and will often suffer back or spinal injuries. In a lane-sharing crash the rider has a good chance of staying on the motorcycle instead of being thrown to the ground.

Some additional considerations when comparing a rear impact into a motorcycle with a lane change type of contact into a motorcycle;

• In a lane change impact, the rider has a chance to recover and remain upright. This is unlikely in a direct rear-end contact.
• In a lane change impact, the rider has a chance to take evasive action to avoid the contact altogether. This is unlikely in a rear-end impact.
• If the rider does go down in a lane change contact, the potential injuries are not as severe as those in a full-force direct rear-end contact.

In other words, when a motorcycle is lane-sharing, if a crash with a vehicle does occur, the effects of the crash will most likely be less serious to the rider than a direct rear end contact into the motorcycle Motorcycle safety and the reduction of fatal and injury motorcycle collisions is a difficult issue to address for multiple reasons. Effective safety efforts might need to be unorthodox or even creative. In comparison with other countries around the globe, the US is the only industrialized nation that does not commonly allow traffic-filtering or lane-sharing for motorcycle riders. To the contrary, in some states lane-sharing is expressly prohibited.

The only US exception to the traffic- filtering prohibition is California, where lane-sharing is routinely practiced by a high percentage of riders in congested traffic conditions. Yet, despite significant traffic congestion and a higher number of motorcycles on the roadway, with a high number of motorcycles lane- sharing, the statistics show California has one of the lowest rates of rear-end motorcycle collisions.

Similarly, European studies indicate that lane-sharing was a factor in less than 1% to 5% of motorcycle crashes. However, further study will provide more conclusive information regarding the safety benefits of motorcycle lane- sharing in the US.

Rather than a hazardous or reckless behavior, lane-sharing appears to be a viable technique that can positively affect rider safety regardless of the type of motorcycle ridden. Factual information is preferable to emotional reactions, and makes education efforts easier to achieve.

It is important to note that like all driving action, it is possible to lane-share in an unsafe manner, and it is not the purpose of this report to discuss how to safely lane- share. These considerations can be addressed in a study that evaluates lane-sharing as a safety-countermeasure. It is also important to note that any govemental entity that evaluates lane-sharing as a safety measure has the opportunity to also enact reasonable restrictions or per- missions, as well as to conduct a traffic awareness campaign to promote safe lane-sharing.

 

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