8 Ball In The Wind

Saturday, April 15, 2017

Motorcycles Face Different Dangers On The Road Than Cars

In my last post, I spoke of the differences between motorcycles and other motor vehicles.  Motorcycles and cars differ in some very fundamental ways.  Some highway features may not affect a car at all, or even attract the attention of the highway engineers, can have disastrous effects on a motorcycle.  That is one reason why motorcyclists are involved in such a disproportionate amount of crashes and injuries.  If a car should lose control and go into a skid, that car isn't likely to turn onto its side easily, a motorcycle is very likely to do so.  Skidding out of control on a motorcycle, and the subsequent and probable roll over and slide are a collision that a modern car is not likely to experience.  But a motorcyclist is likely to do.  Unlike cars, or perhaps to a vastly greater degree than cars, motorcycles are affected by any roadway variation that could affect stability (gravel, broken/patched/irregular road surfaces, grooved pavement, rumble strips, recessed lane markers, dips, bumps, etc.).  While these variations may have no affect on an automobile or other motor vehicle, they can easily be a danger to motorcycles.  Leading to motorcyclists having such a high ratio of single vehicle crashes.

In an automobile, the basic protection concept is to enclose the occupant inside the vehicle while preventing intrusion from outside.  Generally allowing the occupants to decelerate in a relatively safe manner inside, protected from the highway environment.  Virtually the only time an automobile passenger is exposed to the highway environment, is if they are somehow ejected from the vehicle during a crash.  Whereas motorcyclists are constantly exposed to the environment.  With nothing to protect them except for their clothing.

Even though the differences in protective strategies between automobiles and motorcycles, highway systems are overwhelmingly focused and designed with the use of motor vehicles other than motorcycles in mind.  This is why the road surface and design of some 'safety' features can be a factor in some crashes.

The dip on the inside of a tight turn can in some situations lead to a stability problem for the motorcycle or its load.  This can lead to a crash while cornering.  Even though there was nothing to collide with or avoid that caused the crash.  Automobiles tend not to be affected by this sort of dip in the highway grade within the turn.

While cars have little or no issue with something as simple as a paint stripe on the highway, they can be an issue for motorcyclists.  Remember, a motorcycle only rides on about two inches of tire surface, and the difference in traction of a paint stripe can be a factor in a crash.  Especially if the bike is already trying to brake and maneuver to avoid a crash.  If the roadway is wet, the painted surface can be much slicker than the regular pavement.  Even while just changing lanes on a wet roadway motorcyclists may notice the difference in traction, an automobile won't.

Another road traction issue can be found where the road is paved in a decorative fashion with irregular pavement such as cobblestones.  These can have a serious adverse affect on the traction a motorcycle may have.  Again, when this sort of road surface is wet, the traction can be reduced even further.  A motorcycle needing to make a sudden braking action, or a turn, can easily lose traction.  This loss of traction can lead to the bike 'going down' and sliding along the irregular surface.  Which can lead to further injuries to the motorcyclist.

Automobiles passing over gravel, wet leaves, or other such debris on the roadway may have some traction issues, but they almost always have two other wheels on the pavement.  Motorcycles passing over this same type of debris have no other tires on the pavement.  Motorcycles are much more susceptible to a complete loss of traction in this type of situation.  Especially when the debris is in a curve, or at an intersection where the motorcyclist is making a turn.

With automobile occupants safely (or moderately so) enclosed within their crumple zone and air bag protected passenger compartment in a crash, motorcyclists aren't, and they experience impacts in a much different manner.  Obeying Newton's 1st Law of Motion, in a crash a motorcyclist will continue moving forward at the same speed they were traveling, while at the same time they are falling down at a speed of between 10 and 15 mph.  The downward velocity is usually low enough to only cause minor injury, but it is the forward velocity that can result in much more serious injuries (yet it is only the downward velocity that helmets are meant to withstand, but that is a discussion for another time).  A motorcyclist losing traction and stability on the roadway at say 45 mph, will impact the roadway surface with a downward force of about 10-15 mph, but if that motorcyclist strikes the guardrail or the jersey barrier, that impact will be at nearly the full speed the motorcycle was traveling.  That same impact in a car will be mitigated by the use of crumple zones, air bags, and seat belts.  Thus the occupant of a car in a similar accident will probably have a much lower level of injuries than the motorcyclist.  However, if the barrier is a cable barrier, it will stop the automobile with a less intense impact, but will act as a cheese slicer to a motorcyclists body when striking it at speed.

Roadside obstacles (fire hydrants, light poles, bus stop shelters, trees, etc.) tend to be a severe injury hazard for motorcyclists.  Because motorcyclists are not enclosed within the protective body of a car, motorcyclists tend to slide along the pavement.  With the obstacles mentioned previously right adjacent to the pavement, these obstacles can result in serious if not fatal injury to a motorcyclist.

One last highway design factor that works well in preventing automobiles and even motorcycles from leaving the roadway are the low barriers along many bridges and overpasses.  While they do a good job of preventing the motorcycle from going over the barrier, the rider can often pass right over the barrier and certain fatal fall to the surface below.  

Although government agencies have crash tested automobiles, and even buses against guardrails for decades.  The roadways and freeways use the data from those test to design the roadways and freeways.  But no such tests have ever been undertaken with motorcyclists that I have been able to uncover.  When the engineers design and build the roadways, motorcycles are looked upon the same as cars, trucks, and buses.  They aren't, and because of this, reducing the number of motorcycle fatalities and injuries on the highways will be difficult.  While there are many causes of motorcycle crashes and fatalities, the loss of stability and control of a motorcycle due to road conditions and the dangerous effects of some highway design features will continue to be a factor in the high percentage of motorcyclists involved in fatal crashes on our roadways.  If the State of Washington is to have a chance to actually reach the Governor's 'Target Zero' goal of no highway deaths or serious injuries by 2030, then we must look towards taking into account the special requirements for protection of motorcyclists.  Otherwise there will be no great reduction, and motorcyclists will continue to account for 14% of all highway fatalities.

Catch ya on the road sometime...

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