BIKE LAW 101 – Motorcycle Accident Reconstruction – say WHAT??

magaslogo BUMPER



By, Steven M. Magas[1]

I recently received my copy of that epic tome, “Motorcycle Accident Reconstruction & Litigation,” by Ken Obenski, a well known forensic expert, and lawyer Paul Hill.  As a contributing author to the sister volume, “Bicycle Accident Reconstruction & Litigation” I was curious to see what they had done with the subject relative to motorcycles.  This 1130-page volume discusses the engineering and legal process of reconstructing motorcycle crashes in the sort of wonderful technical detail that only us trial lawyers [and former math majors] could love!  Along the way, Obenski, an experienced rider himself, offers some wonderful insight into common rider errors which lead to self-induced crashes and better tactics for dealing with commonly encountered hazards.


Steering is the thing that sets motorcycles apart from all other vehicles.  As EVERY reader of this magazine knows, they clearly do not steer like cars, but they also do not steer like bicycles, mopeds, trikes, forklifts or even airplanes!  Many of us understand, instinctively or by virtue of taking the MSF class, how to lean and guide our bike through the twisties, but could not begin to analyze the physics of it.  Unfortunately, too often reconstructionists and lawyers, including some construction accident attorney in nyc, find that motorcycle crashes are caused by the operator errors while steering in a crisis.

As I’ve stated in earlier columns, a shocking number of deaths and injuries from motorcycle crashes come in single vehicle accidents.  This results in including injury law attorneys so that the legal complications can be handled. In Ohio last year, 158 motorcyclist operators, and 19 passengers, were killed.  More than half of those crashes were single vehicle crashes.  The motorcycle operator was listed in the police report as being “In Error” in 53% of the crashes[2], leading to 115 deaths and 1,849 injuries.[3] Many [possibly as many as 40%, according to Obenski] of these deaths and injuries relate simply to improper steering.

I like the idea presented in one popular motorcycling magazine that while most riders steer a motorcycle fine in good times, the critical issue is how the “nut that connects the handlebar to the seat” will perform in a crisis![4] This glaring weakness is frequently exposed only after a crash occurs!

Unfortunately, many panicked riders turn INTO, and not AWAY from, a suddenly appearing obstacle.  By turning the handlebars away from the obstacle to try to avoid it, the rider unknowingly counter-steers the bike TOWARDS it.  The concept of counter-steering is covered in some depth in the MSF classes.  Many of us don’t practice it or think about it after “graduation” until a sudden emergency arises!

Turning the bars left and leaning left to get away from a hazard to the right amounts to asserting two “contradictory inputs.”  The bike must obey the laws of physics [which can never be skirted], and will always follow the prevailing input, regardless of the rider’s intent!  The accident reconstructionist will often be told that the bike just “locked up” in such a crash.  Yet, the bike checks out as normal.  When the operator turned the bars “away” from the hazard and tried to lean that way also, “…the gyroscopic effect of the front wheel offers such high resistance to this effort that it will feel as if the steering is ‘locked’” and a crash will ensue.

Imagine now an inexperienced rider, on a big, fast bike, heading into a corner too fast.  Realizing he can’t make the curve, he tries to brake and “steer” harder “into” the curve, but ends up counter-steering his way into a violent crash.

Lesson 1 – Know How To Steer & Panic Steer!


How many times have you heard it?  “I knew I was going to crash, so I just laid it down?”  Well, accident expert Obenski says “Laying a bike down makes absolutely no sense in 99.99% of all emergency situations.”  Why?  The main reason is that once you lay it down you’ve played all your cards – you have absolutely no other options except to accept your fate.  Obenski describes it like this:  “The bike becomes a ballistic object that will slide in a straight line with a drag factor of about 0.5 and, with rare exceptions, cannot recover its normal riding position until it stops.”  If you keep the bike UP, you have options, maneuverability and alternative strategies which almost always make more sense.  Even standing on the pegs and trying to JUMP OVER a crash may be preferred over sliding into it!


Accident reconstructionists and forensic engineers frequently measure and discuss “perception/reaction” times.  This relates to idea that there is a time lag between the brain’s perception that life has gone from “good” to “not good” and a human being’s reaction to that realization.  1.5 seconds is a common “perception/reaction time” used by experts in analyzing daylight accidents.  Thus, it takes a motorcyclist about a second and a half to “perceive” the danger of a guy turning a pick-up truck into her lane, and to “react” by taking some evasive maneuver.  This time becomes critical when analyzing whether the rider could have avoided the crash.

At 60 mph, the motorcyclist travels 132 feet, almost half a football field, in that second and a half![5] If the vehicle is only 90 feet away when it turns left in front of your bike, it was probably physically impossible for you to “perceive” the danger and “react” before hitting it at 60 mph!  Perception/reaction times are unique to each individual and change with age, experience, stress, weather, visibility, intoxication level and more!

Another common problem with inexperienced riders [and some with much experience] is that they are simply not sure what to do in a sudden emergency.  Again, this is discussed at some length in the MSF classes.  However, in reconstructing crashes we know that riders sometimes choose evasive action that “seems” good, but may simply be wrong, as in our counter-steering example above.  Even worse, as Obenski eloquently states, “…sometimes riding a motorcycle is like combat in that the one thing you can be sure will be wrong is indecision!”  In one study, a full ONE-THIRD of riders did NOTHING in a panic situation – they didn’t even apply the brakes![6] You must take action, the right action, to either avoid a crash, or minimize its impact.

Lesson 2 – Learn What To Do When Life Is Not Good and PRACTICE Before Life Changes!


Today’s motorcycles have incredibly powerful front brakes.  That point is drilled into new recruits by the MSF drill sergeants.  Although it’s a lousy idea, the front brake CAN provide 100% of the stopping power, and get the back of the bike off the ground! It’s better, of course, to split the braking between front [70% or so] and back [30% or so].  This is completely opposite the bicycling mantra of maximizing the rear brake in order to avoid being thrown head over handlebars.  Perhaps this is why many new riders tend to overuse the rear brake.  Faulty braking technique is found to be a factor in many motorcycle crashes.

Locking up the brakes is never a good idea since locked tires have “no directional stability.”  Yet, it is an easy thing to do on a motorcycle, particularly the rear brakes.  You should learn, BEFORE a panic situation, how much force you can exert on that rear brake pedal before they lock up.    Once locked, the rear will try to pass the front!  While perhaps mildly disconcerting in a car, this is frequently an unrecoverable event on a bike and can lead to catastrophic results!

As you might expect, bike brake performance is “highly rider-dependent.”  Operating a motorcycle requires far more technical skill than operating a car but many of us never “practice” – we just ride!  Going over those “parking lot” drills from your MSF class from time to time is a GREAT idea!

Lesson 3: Practice, Practice, Practice…


I commute virtually year round.  As I rode home into and out of a series of high intensity storms last night, I tried to keep Obenski’s words in mind.  “As long as acceleration in any axis is kept below the friction coefficient a motorcycle can be driven even on wet ice!”  In other words, slow down, adjust your thinking, and watch out for those areas of the roadway where the “friction coefficient” may be lessened by rain– areas like intersections, where traffic slows, or the center of the lane, where oil drips.  Rain, after a dry spell [like last night’s here in Cincinnati], creates particularly treacherous conditions as the water mixes with the oils and other stuff on top of the pavement to create a slick surface for cars, trucks, busses AND bikes!

This is just the beginning of an extensive forensic analysis of motorcycle accidents I will undertake in these articles.  As one who routinely represents injured motorcyclists, it seems to me that cars, trucks and busses are forever interrupting the right of way of motorcyclists!  Hopefully, this will never happen to you, but, if it does, try to remember one more bit of scientific wisdom from engineer Obenski – “biology generally makes a softer landing point than masonry…”


[1] Steve Magas, The Bike Lawyer, is an avid commuting and touring motorcyclist and an active Ohio trial lawyer who handles motorcycle cases in all of Ohio’s 88 counties!  He can be reached for a FREE Consultation at 513-484-BIKE, or at

[2] Having dealt with MANY police reports that inaccurately parcel out “fault,” I take this number with a grain of salt!

[3] Fortunately, out of almost 600,000 “units” involved in vehicle crashes in 2005, there were only 4,413 motorcycles – just 0.7%.

[4] See, “Countersteering:  Motorcyclists Who Zig” at

[5] 60 mph = 88 feet per second.


Printed from: .
© 2024.

Leave a Comment