OPINION - Does Speeding Actually Cause Crashes?

Speed Demon Many drivers believe speeding alone does not actually cause crashes. While not totally inaccurate, this over-simplified phrase does not paint the whole picture. The fact is, very few crashes are caused by one factor alone, and this includes speeding, but downplaying the impact of speeding can prove to be deadly.

Some drivers try to justify a bit of extra speed. Their opinion being it’s safe and of no consequence or, quite frankly, they feel justified by their logic of everybody else does it. Or perhaps once a person has been driving for a few years and maybe had no crashes the thought is its okay to go a few kilometres over the speed limit, right? Ever heard the excuse, “the police don’t give out tickets for just five or 10 km/h over the speed limit?”

This thought process is dangerous as a lot has to do with the laws of physics and reaction times. Let me explain.

There is an old traffic joke that goes, “Physics; the only laws that drivers cannot break” so, if you don’t like what follows, you can blame Newton and all of his science pals. Here are the facts and some real police scenarios to help it all make sense.

Fact number 1

The faster the vehicle is travelling, the further it will take to stop. Without evasive driver action a collision is likely to happen.

A non-scientific perspective would assume that if something is going twice as fast as it was a minute ago, it will be twice as hard to stop, right? But, it doesn’t work like that. If a vehicle’s speed has been doubled a rough rule-of-thumb is a vehicle will take about four times as far to stop under braking. Check out table 1 for stopping distances. Keep in mind the braking distances in this table are for dry roads in good condition.

stopping distance chart

Fact number 2

The faster a car is travelling, the less time a driver will have to react to a hazardous situation.

To actually determine the true stopping distance for a vehicle, you must take into account the time it will take for the driver to perceive a threat, react to that threat and then take evasive action. Very few can use their “best” reactions in an emergency.

Most of us can do well on an actual test of reaction time in a controlled environment. Testing has shown the average reaction time would be 1.5 seconds. For example, when a light flashes or a specific sound is activated we have to press a button. In that situation we have awareness; we know a light is going to come on or a buzzer will activate so we are ready, with our finger on the button and muscles tensed. But real life is different. Real life is not controlled and driver reaction times are much higher. So, if we apply a minimum reaction time of 2.0 seconds in an uncontrolled environment, we can see the distance travelled during that decision phase and subsequently calculate the total stopping distance of a vehicle. (See Table 2)

stopping distance chart + reaction time

You can see the total stopping distance is reliant on the driver’s ability to react in a prompt manner and the capabilities of the vehicle to stop under different road and weather conditions, and this is all based on the primary factor of the initial SPEED of the vehicle.

In addition to the science, there are also several factors which can influence a driver’s perception and response time. These factors can be broken down into two categories:

1) Human Factors

  • Drivers’ ability to perceive a threat
  • Fatigue
  • Alcohol / drug consumption
  • Distractions within the vehicle (passengers, children, eating/drinking, putting on make-up, reading a book or map)
  • Cell Phones (even hands-free phone conversations significantly increase the risk of a serious crash as it will affect your concentration on the task of driving

2) Environmental Factors

  • Road and weather conditions (fog, rain, snow, sleet, etc.)
  • Darkness, direct sunlight
  • View obstructions (other vehicles of different sizes, trees, bushes, buildings, etc.)
  • Visual clutter (too many reflected and illuminated signs, flashing lights, traffic signals)

Today’s driver has a lot to process and complacency or overconfidence can easily set in. Typical quotes I have heard include, “I’ve been driving for thirty years and never had a crash” or “I’ve driven this road a thousand times; I know every bump and twist.” The scary fact is, anybody driving while thinking about anything other than their driving at any moment is a distracted driver.

I get it, nobody is a robot, and nobody can concentrate at 100 per cent for 100 per cent of the time, especially on longer journeys. However, a key difference between unsafe drivers and safer drivers is the safer ones think only about their driving for a much larger proportion of the time, and that takes effort.

Fact number 3

The more extreme evasive action taken by a driver to avoid a collision, the more likely they are to cause a secondary collision or involve other road users in the incident before even reaching the original hazard.

There are three ways to make a vehicle respond to what you are demanding of it; steering, accelerating and braking. Most drivers will place an excessive amount of steering input (swerving) in an emergency. Subsequently, this will cause a car to travel beyond the intended path in order to avoid a hazard. This creates a ripple effect involving other users of the road and, in some unfortunate situations, places your vehicle into oncoming traffic. For example, swerving can sometimes be successful on a racetrack (a somewhat controlled environment) where everyone is ultra-alert and travelling in one direction. The fact is, in the real world there are often vehicles beside you, behind and in front of you and, in the worst case scenario, approaching you. Oh, and don’t forget the bicycles and pedestrians that are also using the shoulders of the roadway!

It takes as little as a quarter turn on the steering wheel to travel from one lane to another at 80 km/h. Add excessive speed to the equation and we are back to the capability of the vehicle and driver’s reaction time to stop before the hazard.

Fact number 4

The faster a vehicle is travelling at the moment of impact, the greater the damage will be, the more serious the injuries and the higher the risk of death.

I’m going to use two real police file examples to explain this one. Tragically these were fatalities I investigated which illustrated the deadly consequences of SPEED.

Scenario 1

It’s a 6:30 a.m. dark, stormy morning with torrential rain pouring down. A driver is travelling on a two-lane road that has a posted speed limit of 50 km/h. The driver suddenly reacts to an elderly pedestrian crossing the road within a marked and lit crosswalk. The driver applies the brakes (evasive action) but slides through the crosswalk striking the pedestrian before the vehicle comes to a stop.

The evidence at scene enabled me to determine the vehicle was travelling at a minimum speed of 75 km/h at the time evasive action was taken. Subsequently, the pedestrian was hit at a vehicle speed of 52 km/h and tragically died as a result of the injuries sustained.

Without changing any parameters prior to the evasive action and assuming the vehicle was travelling at the posted speed limit of 50 km/h when the brakes were applied, the pedestrian would have been hit at a vehicle speed of 23 km/h. Therefore, there was a very strong likely hood the injuries would not have been fatal.

In this scenario, the driver was charged and convicted of the Criminal Code offence of dangerous driving causing death which carries a maximum penalty of 14 years imprisonment.

Scenario 2

At 7:30 p.m. on a clear, dry summer’s evening a vehicle is travelling down a two-lane roadway with a speed limit of 50 km/h. The driver noted a child riding their bicycle along the shoulder of the road going in the same direction as they were. The child suddenly cuts in front of the vehicle. The driver takes action by steering left (swerving) and braking (evasive) but still strikes the child. The driver flees the scene but is arrested a short distance away.

The evidence at scene enabled me to determine the vehicle was travelling at a minimum speed of 80 km/h at the time evasive action was taken, with the child being hit at a vehicle speed of 59 km/h. Again, another tragedy as the child died as a result of the injuries sustained.

Without changing any parameters prior to the evasive action and assuming the vehicle was travelling at the posted speed limit of 50 km/h when the brakes were applied, the vehicle would have stopped 2.44 meters short of hitting the child.

This driver was charged and convicted of the Criminal Code offences of dangerous driving causing death (maximum penalty of 14 years) and hit and run causing death which carries a maximum penalty of imprisonment for life.


Are you still with me? I recognize this has been a long article but I appreciate you reading through. Most people refer to crashes or collisions as an “accident”. That word is never used by collision reconstructionist analysts. The Oxford Dictionary describes an accident as “an undesirable or unfortunate happening that occurs unintentionally and usually results in harm, injury or damage.” If you are speeding then a crash or a collision is anything but an accident. It is actually an intentional act by the driver to break the law.

Now that you know all this, what would your explanation or defense for speeding be? Or even worse what would it be if you caused a fatal crash because you were speeding? Was it somehow an unavoidable “accident” or rather a dangerous choice you made to SPEED?

Sergeant Bruce McCowan is a forensic collision reconstructionist with Ridge Meadows RCMP Traffic Services and kindly gave his permission to reproduce his opinion here.

Not that anybody should be going over what the number on the sign says, but these arguments have been used to lower that number arbitrarily, to the point where 85% of drivers are now non-compliant in the Lower Mainland, since even 1km/h over the limit is considered speeding, despite what the majority of drivers think.

1. It is true that the kinetic energy increases as a square of speed. But lots of modern cars manage to stop with-in 35 meters from 100kmh, not 50m.
In either way this is a false pretense to begin with because stopping is not the sole way to react to a space conflict, and in a lot of cases it is not an effective method of avoiding a collision, that's how highway pile-ups happen. Inability to stop does not lead to a collision in 100% of space conflicts, we don't need to pretend that it does.

2. It is a fallacy to include the 2 second reaction time in the absolute stopping distance table. Its a synthetic number of an average reaction of an average driver at any speed, it includes the long reaction times by the distracted drivers and quick reactions of those who are paying attention. It never indicates the actual reaction time in actual incidents unless by coincidence. Its as useful as a measure of an average body temperature of every patient in the hospital for judging the overall well-being of every patient in the hospital. Its only useful to designate the lowest common denominator reaction time for engineering decisions like traffic light phase times or whether an amber forewarning needs to be installed before a set of hidden traffic lights.

"The average reaction time for humans is 0.25 seconds to a visual stimulus, 0.17 for an audio stimulus, and 0.15 seconds for a touch stimulus."
Higher speed usually means higher adrenaline which means higher reaction time.
But when it comes to road reaction time - its not that simple - if the driver is paying attention and has their "eyes up" - looking far ahead and scanning the horizon and the side hazards this provides additional safety cushion to use the extra time to make a decision on how to avoid an obstacle or to slow down to an appropriate speed to negotiate a passage.

3. True that the vehicle dynamic changes at high speeds due to the build up of the kinetic energy, exaggerating the jerky and panicky control inputs. But its still a fallacy to imply that high speed necessitates an extreme evasion. People panic and get into a collision, but that's not because they were simply going fast, its because they weren't looking ahead, and/or were exceeding their personal and/or vehicle ability at a time when a potential hazard appeared and over-reacted. Doesn't mean that the speed caused the over-reaction when it only contributed to the consequences of an over-reaction.

4. Number one fallacy used to artificially lower the speed limits. It implies that every collision is the driver's fault, thus every driver must travel at speeds that are lower than what the road is capable of to account for these extremely rare occasions, which are not the sole fault of the driver, at an extremely high cost of personal time, albeit stolen in tiny amount from individuals, but when summed up can equate to YEARS of human lifetime lost. If everyone on the North Shore were to slow down from 50km/h to 30km/h at current traffic numbers it would mean 7 years of human lifetime wasted every business day.

Scenario 1: Pedestrian, in the wee hours on a stormy morning. Not a common sight for sure. Driver, likely used to traveling on that road, complacent due to the familiar routine, panics and loses control. First of all, what if the driver didn't do any inputs at all, do we know that the pedestrian would still be affected? Sometimes, not doing anything is the best course of action. Second, pedestrians aren't deer, 75km/h is a common vehicular speed, vehicles commonly travel on roads and we must first look left then right in order to safely cross the street. Sure, the pedestrian is elderly, and has certainly survived long enough to know that, but what if they simply don't care anymore? Is it the driver's sole fault? Is it the fault of the arbitrary speed number when a road user proceeds before looking? Should everyone travel slower to allow for the faults of a few individuals?

"In this scenario, the driver was charged and convicted of the Criminal Code offence of dangerous driving causing death which carries a maximum penalty of 14 years imprisonment."
A glaring admission of statutory discrimination against motor vehicle operators. Show me the criminal code statute that carries a maximum penalty of 14 years imprisonment for pedestrian actions on the road that would cause a car to swerve and kill somebody else?

Scenario 2: A child swerves while traveling on a public street. "Do not allow children to ride in the street until they are 10 years old, are skilled riders, and consistently observe the basic rules of the road." (https://www.healthlinkbc.ca/pregnancy-parenting/keeping-your-child-safe…). Seems like neither the child nor the driver knew what to do, is it the speed's fault? If the driver had space, the driver should have been allowing more space when passing, but regardless the incident is initiated by the poor riding skills, not the speed itself. Should everyone travel slower to allow for the faults of a few individuals?

Engineers are constantly working on making the front ends of cars optimized to offset the damage potential for pedestrians at higher speeds, its an acknowledged car problem. Yet we don't hold every car engineer accountable in each case of pedestrian fatality for not designing a mattress to the front of the car. Why don't we strap mattresses to the front of our cars? Just adding 2 or 3 old mattresses to the front of each car can make a life and death difference for pedestrians in collisions over 50km/h.

In all seriousness - why not ban the use of hard plastics and metals on the front ends of all vehicles, requiring that the first 2 feet of any vehicle are ballistic gel or memory foam before denigrating everyone to die of old age in traffic? Certainly such regulation would be very effective in preventing higher speed pedestrian deaths, much better in efficacy than requiring everyone to drive below their personal ability and the road configuration, while applying extreme prejudice against their actions via monetary penalties and infringement of their property rights.

Conclusion: While I buy the point that the word accident doesn't meet the gravity of a situation in a vehicular collision, the leap of logic that if somebody is speeding they are defacto "at fault" in any collision is simply untrue. It takes two to tango, and when somebody steps on to the road and creates a conflict that leads to a collision with a speeding driver, it does not absolve the responsibility of the initiating party entirely. True that people may have an expectation of another road user's speed when making a decision, and if a collision would not have occurred in a specific case of a decision being made had the other driver not been speeding, this would be a valid point - but only in the circumstances where a collision would not have occurred with-out the speeding. Speeding by a 3rd party is not the reason for another person's poor decision, and does not absolve multilateral responsibility. Its good to keep under the maximum posted limit to avoid unexpected surprises, but driving over the limit which isn't set appropriately does not directly cause drivers to crash eventually.

P.S. Bonus fallacy: - "But everyone is speeding" - "You can't catch all the fish"...
Except that the fish are not being held to an artificial arbitrary standard via laws and fines for being in the water and swimming, we honestly just catch and cook them for food.
Imagine we instead made laws to only eat the speeding fish to make it fair to all the law abiding fish...o_O

If everyone is speeding while regularly completing their journeys safe and secure, it means that the speed limit is wrong, not that everyone deserves to be caught.

It took me awhile to digest the article and the first response.  I found them equally articulate and I think I get both positions.

So here’s me 5 cents (no pennies anymore).

I probably have an unhealthy hatred for speed mongers.  There is cause for the words limit/max under a speed number.  Perhaps feebly, but maybe, just maybe keep some law and order on the roads so people don’t get out of control, which is exactly what they do when they drive too fast.  And while I realize and accept that I have inherited a “risk” of being maimed or killed in an “accident” I fail to accept that anyone else has the audacity to increase that risk so that I don’t even have a chance at survival.  Speed certainly takes that out of the equation.  The scenarios are perfect examples that had the driver been at a speed posted &/or to the conditions, then maybe, just maybe, the victims would have survived.  I get it... speed is not the sole factor of these “accidents” but it certainly plays a humongous role as an aggravating factor and it’s horrific results.  Drivers who speed are impatient, intolerant and are outside their ability to drive excessive speed, they think more of themselves then they do being with others who are just as entitled as they to be using the road.  Frankly, I don’t want to be near anyone who drives like an idiot, they are an “accident” waiting to happen and unfortunately will take innocent people.  Speed mongers always look for reasons to be speeding, flow of traffic, everyone does over 10+, roads are built for speed, this country does it, etc.etc.  No excuse substantiates speeding.  What is the big hurry?  Whatever your answer, it has no rationale, it is not the speed mongers authority to increase my risk of death.  If you want to kill yourself, have at‘er, but you have no business taking me with you! 

So to all those speed mongers who think their sense of entitlement to speed is paramount over all others who want to live and reach their destination....... Slow Down!  

I admit that most of the time I am above the posted limit on the open highway. In larger centres I either go with the flow or do the posted limit.

But as I said I am on a tangent tonight. So here is something to consider.

We live in a democracy or at least we like to tell ourselves we do. So, is not part of a democracy that the laws are made with the agreement of the majority? If as it has been stated that 85% of the people exceed the posted limit indicating that the majority are being dictated to by the minority? Is this really how our society is supposed to work?

I'm not arguing the laws of physics but common sense has to be taken into consideration. After all if we were to restrict the maximum speed of all vehicles to 5 KPH we would probably eliminate most highway fatalities. On the other hand I do not believe we would eliminate all accidents. Look at the number of fender benders in parking lots! As the old saying goes some people cannot chew gum and walk at the same time.

Driving has been a passion of mine my entire life. I fill out ICBC surveys, take tests provided by ICBC and BCAA. I keep myself informed on changes to the motor vehicle act. I study and review statistics provided by other countries. I feel confident that I know most of the rules of the road.

If one checks accident statistics for various countries you will find that most countries that have a lower accident rate than Canada also have higher speed limits on their highways. Metropolitan areas about the same.

Back in the 80's there was a Task force on driving in B.C. I was one of the participants and received reports for several years. At the time I sat down with the owner of a driving school and raised my concerns about driving schools and what I considered their flaws. Several of my concerns were shared by this owner. They know you are not ready but they cannot stop you for trying the test. All they can hope is the examiner will fail you. Unfortunately a high percentage of people that should be failed make it through.

The graduated licencing system in my opinion is a failure. ICBC's own stats show that new drivers that have taken an accredited drivers training program have a higher rate of accidents than those that did not. Before you jump all over me on this statement I posted several months back where you can find the information. It is contained in reviews of the program on the ICBC website.

So I am back with my normal complaint about police officers. Rather than getting out on the road and checking for poor driving habits they revert to the age old adage that speed kills. Yes speed definitely does kill. But rather than always blaming the speeding driver what did the other person do?

A true story going back to the days when impaired driving was the cause of all accidents. And this is where the old saying of lies, damn lies and then there is statistics. A fellow I worked with his son was charged with impaired driving and 100% at fault for the accident he was in. He blew .08 so was legally impaired. What had happened is he was travelling through a green light when another vehicle ran the red light and T-boned his vehicle. In the eyes of the investigating officer this was an impaired driving accident. Running a red light has no consequences if you make sure you hit a vehicle whose driver is either impaired, distracted or not wearing a seat belt.

Going back to the start of this thread "Opinion - Does Speeding Actually Cause Crashes." Most definitely. Should it be blamed for all accidents? Definitely not. Unfortunately when you have a widely held belief that you know everyone is going to believe without question, what is the default? Speeding.

Pathological lying is telling the same story over and over till they believe it themselves. This has been so ingrained in police culture that officers have lost the ability to look for other factors. Maybe just maybe it is time to start looking for another cause. One that will really save lives. Unfortunately I do not believe I will ever see this day as it is far easier to result to the LCD and run with it.

As I said at the start this was a tangent the same as the original post. Now the question to ask yourself should 15% of the people force 85% of the people to follow their way?

One final thought the Coq since raising its speed to 120k does not follow the normal 85% driving over. The speed is now where most drivers feel comfortable.



The issue that is not fully addressed in this discussion is how to deal with the situation where you want to drive at the speed limit, e.g.  at 50 km/h on a road where almost all the other traffic wants to go 65 km/hr or more and there's only one lane in each direction. Several times when studiously keeping to the 50 km/hr limit in this situation, I have been unsafely overtaken by an impatient speeding driver on a section of the road where overtaking was not allowed. I have been advised by experienced instructors that the safest thing to do in this case is to drive at a speed that's slower than the other traffic wants to go but which may be a few km/hr above the speed limit, and of course to increase following distance accordingly. Now in the same situation I do consciously drive at 55 km/hr if conditions are good (good visibility, not raining etc) and there are no potential hazards such as intersections, pedestrians, children, cyclists etc. Since adopting this practice I have not run into the dangerous overtaking problem. I believe that this reduction in hazardous overtaking experiences is not a coincidence.

On the other hand, if driving a larger vehicle like a bus, I will not consciously exceed the limit because the problem with dangerous overtakers is significantly less than when driving a small vehicle.

The challenge to the original poster is this:  What evidence do you have that it's "not OK to go a few km over the speed limit"  in the circumstances as described above?

The figure below supplements the stopping distance charts provided by Sergeant Bruce McCowan. Drivers of light vehicles may find the data to be helpful in determining a minimum safe following distance to maintain when tailgated by a heavy vehicle and in determining a safe strategy to apply when in or approaching a conflict zone used by heavy vehicles.

The following figure is from the Yukon Commercial Vehicle Handbook, which can be found at http://www.hpw.gov.yk.ca/mv/1780.html.

As to the role of speed in causing or contributing to the severity of collisions, I expect the court case for the Humboldt Broncos crash to provide some expert clarification.

Cars of today are capable of higher speeds and stopping distances because of better suspension, tires, handling and braking technology than the cars of 40-60 years ago.  

The problem I see is that the drivers of today are not capable of handling the higher speed. Not knowing how to handle a vehicle in situations, not paying attention, overdriving their capabilities and being alert at all times.

Nearly all vehicles are safe on the road, its the driver behind the wheel. You can drive an overloaded truck from 1/2 ton to semi trailer tractors and still drive it safely.  I've driven  overloaded cube vans when I shouldn't have, but you drive it accordingly. Luckily I never got stopped.   You must have a feel for the vehicles handling characteristics and load.   If you don't have that feel in you, don't drive it.  It's like music, its either in you or its not.


How true. My brother and I were taught by our Dad and one thing we could never do is come home saying we hit the snowbank because the road was slippery or it was an accident. In his mind there was no such thing as an accident, "You were driving beyond your ability". It made no difference to him what the other driver did, it was our fault we screwed up.

And this is where being the younget paid off. I learned from my brothers mistakes. Thus I never got the lecture on screwing up.

Another thing my dad pounded into our young minds is you drive by the seat of your pants. And as Butchart pointed out "If you don't have that feel in you, don't drive. It's like music, it's either in you or it's not."

A good driver is at one with his vehicle. It doesn't make any difference what you are driving if you have the feel of the vehicle you have the feel of the vehicle. This is very noticeable on black ice. I refer to it as feeling the vehicle working. There is a different feel when that traction is just not there. And the people that don't have that feel are the ones you see in the ditch.