Motorcycle Accidents: Distance, Perception, And Reaction Times

I have acted for numerous motorcyclists who have been severely injured as a result of cars colliding with them when the motorcyclist was easily seen and clearly visible.

Many collisions were as a result of a car suddenly turning left into the path of the motorcycle while the motorcycle was lawfully passing the car.  Others were as a result of the car suddenly turning left in front of the motorcycle as the rider passed through an intersection, or suddenly pulling out in front of the motorcycle.  In most of these motorcycle/car collisions, the motorcycle was there to be seen, in broad daylight, with its lights on.

Why does this happen so often? Why do cars regularly pull out in front of motorcyclists, or misjudge how far away the motorcycle is? A recent study sheds some light on this.

Recent research by a Texas Tech University psychologist suggests that the regularity of this problem isn’t necessarily a case of poor driving or carelessness, but may be related to a basic human judgment error caused by the way the brain judges distance and time. The study, conducted by Pat Delucia, coordinator of the Human Factors Psychology Program at Texas Tech University, and published in the professional journal, Current Directions in Psychological Science, says these types of brain miscalculations likely play a crucial role in motorcycle crashes with automobiles.

DeLucia said her results show that small, near objects can appear farther away than larger, farther objects. She studied how the human brain perceives objects, their size and motion and an object’s time to impact.  Her finding that an object’s size affects distance perception may be the basis of car drivers miscalculating motorcyclists’ distance and speed.

The brain uses two visual information cues for judging time to impact, she said. In the first, a moving object is reflected on the eye’s retina. It expands as it approaches the eye, providing the brain accurate information about when the object will hit. This is called an optical invariant.

However, the brain also uses “rules of thumb” as well, such as various “artist” depth cues as a shortcut, she said.

Many times, the brain interprets objects with a larger retinal image as closer. Since motorcycles are smaller than cars, the brain may use this shortcut to judge a smaller motorcycle farther away than it actually is, DeLucia said.

With computer simulations, we had a big, far object and small, near object approaching the viewer, where the small object would hit first,” she said. “We wondered if people would choose the big one, based on the artist depth cue of relative size or choose the smaller one based on the more accurate optical invariant. Unexpectedly, people picked the bigger object again and again. We found people relied on rules of thumb.

This size-arrival effect can lead drivers to misjudge when a vehicle would arrive at an intersection, (or distance away in their rear view mirror), and could be considered a contributing factor in many motorcycle/vehicle accidents.

DeLucia hopes to find funding from the Department of Transportation to create an education program to inform drivers of her findings to reduce the incidents of these types of accidents.


Reaction times for the human brain are estimated at approximately 1.2 to 1.5 seconds, depending on various factors (health, age, time of day etc). This is the time the average human brain will take after seeing a danger, and actually reacting to it, by applying the foot to the brake, or starting evasive action.

If the car is going 80 kmh, it is travelling at about 73 feet per second.  At 80 kmh, the car would travel over 100 feet, before the driver even starts to react. This would be the distance they travel before they even start to apply their foot to the pedal, or start to take evasive action.

So as a car driver, make sure you give lots of leeway to motorcyclists.  They may be closer than you think. Your brain may be playing tricks on you. And to make matters worse, it takes you quite some time, and distance travelled, to react to any sudden danger.

If you ride a bike/motorcycle, the old adage “drive defensively” applies.  Give cars plenty of room, slow down at intersections, and be very careful when passing (briefly hit the horn before, or while you pass, or flash your lights).  Always be ready for the car driver to do the unexpected, even when you think you and your bike can be obviously seen.

Even when you think “the car has lots of time to see me and react”, remember, the car driver’s brain may be playing tricks on them, and they may not have enough time or distance to react and slow down to avoid you.


If you have been in a motorcycle accident, you should also hire lawyer with motorcycle accident experience as soon as possible after the accident, within the first week following the accident if possible.

I know this sounds self-serving, but waiting to hire a lawyer can often be devastating to your case against the other driver.

Delay in retaining a lawyer can lead to the loss of critical evidence at the scene such as skid marks, debris, damage to the vehicles, the testimony of witnesses and other evidence.

Do not rely on the police at the scene to get all the necessary evidence you will need. They often don’t, and whatever evidence they get at the scene, including witness statements, they will not divulge without a court order because of privacy laws.

The motorcycle accident lawyer should hire an accident reconstruction expert immediately to analyze the scene, and the vehicles involved. They should also retain the vehicle’s “black box” for examination by their accident engineer to determine the car’s speed etc, before the vehicle is destroyed or sold by the insurance company as salvage.  The car driver‘s insurance company retains accident reconstruction experts as soon as they are notified of the accident. Often within the first week, or just days after.  You need one as well. You need to have the same evidence as the insurance company.  Without immediate accident engineering evidence you are at a serious disadvantage.

So be aware, drive safe, and be prepared.

About the author:
Paul Mitchell, Q.C. is a partner with the law firm of Pushor Mitchell LLP, in Kelowna BC. He has extensive experience with catastrophic injury claims arising from motorcycle accidents. He is an approved lawyer for AIM (The Association for Injured Motorcyclists, Interior Chapter). Paul’s paralegal, Lynne Holmes, was a founding director of the Interior Chapter of AIM and continues to be closely involved with AIM, currently serving as the Volunteer Visitation Coordinator.

Paul acts for seriously injured clients all over BC and Alberta, and will not act for ICBC, or any other insurance company. He only acts for the injured.

For more information on this article, or for a confidential discussion of your claim, contact Paul Mitchell, Q.C. at 250-869-1115 (direct line), or at [email protected].

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