Motorcycle design safety: Design alternatives and products liability
Every motorcycle manufacturer has known for decades of the safety importance of including a headlight system which provides important visual cues to other motorists to minimize cross-over collisions.
Riding a motorcycle can be risky. Sadly, motorcycle riders are 28 times more likely to lose their lives in a fatal driving crash compared with other motorists on the road. See NHTSA Traffic Safety Facts 2020, DOT HS 813306.
At least 82,528 motorcyclists were reported injured in 2020. A total of 468 injuries occurred per 100 million vehicle miles traveled over the course of that year. A total of 5,579 were killed in fatal traffic accidents. This was the highest number of motorcycle accident deaths since the Fatality Analysis Reporting System was first started in 1975.
Motorcycle accidents accounted for 14% of all traffic deaths, despite the fact that only 3% of all registered vehicles are motorcycles. Motorcycle crashes also account for 18% of all occupant fatalities and 4% of all injuries to vehicle occupants. 2,143 of these deaths occurred when not wearing a helmet. Accident reports indicate that about a third of fatal motorcycle accidents (34%) involve a motorist traveling above the speed limit.
Speed plus poor braking performance is a major factor in many crashes. Thirty-five percent of motorcycle fatalities happen at an intersection.
Because of their small size and poor lighting configurations, motorcyclists are often not clearly seen or opposing drivers turning in intersections underestimate how fast a motorcyclist is approaching. Low motorcycle conspicuity, or the inability of the motorcyclist to be seen by other road users, is thought to be an important factor associated with risk of motorcycle crashes. This may result from several factors, including size of motorcycle, low luminance or contrast with the background environment, and insufficient braking.
These statistics shed light on the risk motorcyclists face, as well as the engineering safety features essential to reduce this carnage.
Designs for Safety: Solving the Carnage on Our Highways
Product design safety hierarchy is predicated on the reliability of the control mechanism and its effect on either the hazard and exposure. For example, if a hazard is eliminated by the product’s design there is no danger. If a guard (or additional design features) is relied upon to prevent exposure to the hazard, the danger is reduced. Both hazard elimination and guarding place the emphasis of safety control on the design and reduces reliance on the user.
The primary hazards associated with riding a motorcycle relate to other vehicle operators failing to see or failing to appreciate the speed with which a cyclist approaches them (conspicuity issues) and the motorcyclist’s accident avoidance—braking—skills. Once these hazards are identified, design solutions must be found. Decades ago, in 1981, “the Hurt Report” funded by the U.S. Department of Transportation (DOT) observed, and concluded that:
Motorcycle accidents are a very special and severe problem. The fatalities due to motorcycle accidents are approaching 5,000 per year, and have the prospect of further increase unless effective countermeasures are instituted. At present time, motorcycle accidents account for approximately 10% of the total traffic accident fatalities, but the motorcycle is only 1-2% of the vehicle population on the street in traffic.
Other vehicle violation of the motorcycle right-of way is a predominating factor in the 900 on scene, in-depth, accident cases; 50.9% of all those accidents are attributable to the driver of the other vehicle involved in the accident. This fact is especially clear when the multiple-vehicle collision data show that 64.9% of those accidents are due to the actions of the driver of the other vehicle. The typical accident in this category is portrayed by the automobile in traffic turning left into the path of the oncoming motorcycle. In such an accident, the culpability is exclusively due to the action of the driver of the automobile. The greatest part of this accident cause factor is related to the failure of the automobile driver to “see” the oncoming motorcycle, or to “see it in time” to avoid the collision.
These observations and conclusions have been restated in studies funded by private industry, safety organizations and government agencies every decade since the publication of the Hurt Report. In 2013, the Insurance Institute for Highway Safety (IIHS) echoed these recommendations, writing: [See Teoh, Effects of Motorcycle Braking Systems on Motorcycle Fatal Crash Rates: An Update (IIHS, May 2013)].
Improper braking is a major factor in motorcycle crashes. Improper braking, particularly over-braking and resulting loss of control, was identified as a major pre-crash factor in a 1981 in-depth study of the causes of motorcycle crashes and again, 20 years later, in the motorcycle accident in-depth study (MAIDS; Association of European Motorcycle Manufacturers, 2004). Braked motorcycles lost stability in 43% of the crashes studied by Roll et al. (2009).
Operating the brakes on most motorcycles is much more complicated than on four-wheel vehicles. Most motorcycles have separate controls for the front and rear brakes, with the front brake usually controlled by a lever on the right handlebar and the rear brake controlled by a pedal operated by the rider’s right foot. During braking, a rider must decide how much force to apply to each control. As with other types of vehicles, much more deceleration can be obtained from braking the front wheel than from braking the rear wheel.
Motorcycles are inherently less stable than four-wheel vehicles and rely on riders’ skills to remain upright during demanding maneuvers such as hard braking. Braking too hard and locking a wheel creates an unstable situation. Locking the front wheel is particularly dangerous, with falling down being almost certain. A locked rear wheel is more controllable, but still can lead to loss of control with a concurrent steering input, as in an emergency avoidance maneuver. In such situations, riders concerned about wheel lock may be reluctant to apply full force to the brakes, particularly the front brake, resulting in braking that is not adequate to avoid or mitigate impact …
To address the issue of under-braking (especially of the front wheel), manufacturers have developed braking systems that essentially link the actions of the front and rear brake controls. These systems, referred to collectively as combined braking systems (CBS), apply braking force to both wheels when either control is engaged. The degree to which braking force is applied to the front wheel, for example, when the pedal for the rear brake is depressed varies by system, but the concept is the same. CBS has been shown to reduce stopping distances of experienced riders on closed test tracks (Green, 2006) and would be expected to be beneficial in situations in which a rider under-brakes or does not brake the front wheel. With CBS, however, it is still possible to lock a wheel during hard braking.
Antilock braking systems (ABS) have been adapted and tuned for motorcycles to help riders solve this dilemma. Like ABS systems on other types of vehicles, motorcycle ABS systems monitor wheel speed and reduce brake pressure if imminent wheel lock is detected. Brake pressure is then increased, and the system evaluates and adjusts brake pressure many times per second if necessary. These systems allow riders to apply brakes fully in an emergency without fear of wheel lock. ABS and CBS are not necessarily related; either or both can be implemented on a motorcycle.
ABS has shown strong benefits for motorcyclists. Studies conducted on closed test tracks have demonstrated that ABS improves braking performance of both novice and experienced riders (Vavryn and Winkelbauer, 2004) and in a variety of situations (Green, 2006).
Headlight Design Defects: Conspicuity
The issue related to the design of motorcycles to minimize crashes because other motorists either fail to recognize approaching bikes or fail to appreciate the speed of approaching motorcycles is decades old. However, the industry’s reactions have been minimal. The biggest change in design occurred in the late 1970s when manufacturers—at the behest of researchers—created an auto-on headlight mechanism; like cars, when the motorcycle engine is turned on, the headlight is illuminated. However, very little attention has been paid to other design features recommended to enhance visibility/detection—and for this reason, the frequency of crashes has not changed very much. Motorists continue to report not “seeing” motorcycles or they continue to claim that “I saw the bike but thought it was far enough away to make my turn.”
Conspicuity
The published studies on this design-related-crash issue have reached these conclusions: Motorcycle rider conspicuity and crash related injury: case-control study, Dec. 2003, University of Auckland, New Zealand.
⦁ Multiple headlights configured in a certain fashion enhance day and nighttime conspicuity. ⦁ High-beam headlight usage in daytime enhances conspicuity. ⦁ LED headlight usage enhances conspicuity.
While researchers continue to squabble over the “societal value” of added headlight systems to address the perplexing complaint that “I did not see the motorcycle”, they all agree that alternative lighting treatments provide safety benefit because they reduce the likelihood of left turn accidents with on-coming motorcycles. This benefit is the product of enhanced driver recognition of the speed of on-coming motorcycles. Nov. 2011, NHTSA Motorcycle Conspicuity and The Effect of Auxiliary Forward Lighting, DOT HS 811 507.
Motorcycle Braking Systems: Dangers and Solutions
Although motorcycles have sufficient braking power and traction to stop in as short a distance as a typical car, braking a motorcycle poses unique hazards and requires greater operator skill than stopping a car. Braking is the most difficult skill for a motorcyclist to master. It is difficult because most motorcycles have two separate brake-control systems, one for the front wheel and one for the rear wheel. As the front brake is applied, weight transfers to the front tire, which causes available traction to vary as weight shifts, requiring the rider to adjust pressure on each brake control in a maximum-performance stop. In many instances, a motorcyclist will over-brake the rear and under-brake the front, even though weight transfer means the front brake must do the majority of the braking. Over-braking can either cause loss of steering control. If the rear wheel is locked, the rider typically loses directional control. If the front wheel locks, the rider is likely to crash due to loss of stability.
Two solutions have been developed to address these risks: anti-lock brake systems (ABS) and combined brake systems (CBS).
What Is CBS and ABS?
When you’re driving down the road in your car and apply your brakes, the brakes on all four wheels get applied simultaneously. That’s important because otherwise the car would react non-uniformly to braking. Addressing the risk of non-uniform braking, CBS was developed. CBS is a mechanical system that causes both brakes to get applied almost simultaneously when just one of the two brakes are applied. This system alone significantly reduces the dangers associated with applying just one brake. ABS is an electronic/mechanical system that is activated on hard braking to prevent wheel-lock up and skidding. In 2012 the EU announced a mandatory regulation requiring ABS on every new 2016 MY motorcycle with an engine larger than 125 cubic centimeters. Unfortunately, no such requirement exists in the U.S. and even as of 2020, a large percentage of motorcycles sold here were not equipped with ABS or CBS. As it turned out, foreign and domestic manufacturers took their time before creating commonality of design between the vehicles marketed in Europe and the U.S. Fortunately, today in 2023, the majority of new motorcycles are equipped with either independent ABS or ABS with CBS. In 2022, the IIHS recounted that the majority of new vehicles now include ABS, but unfortunately, the additon of CBS has not followed.
Whenever a motorcycle crash occurs, it is essential to consider the vehicle’s conspicuity, and “stopping power.” Often, motorcycle collisions are the result of one circumstance or the other. And, in todays’ product market, there is no technical excuse for the absence of safety systems to address these issues.
Conclusions
Every motorcycle manufacturer has known for decades of the safety importance of including a headlight system which provides important visual cues to other motorists to minimize cross-over collisions. Likewise, the industry has been well aware of the improvement in braking obtained by the use of CBS and ABS brake systems. The delay in equipping every motorcycle sold in the US with these systems is inexcusable.
Larry E. Coben, a shareholder at Anapol Weiss, handles products liability cases at the firm. Contact him at lcoben@anapolweiss.com.