Home arrow Traffic and Safety arrow What Causes Car Accidents?
What Causes Car Accidents?

What Causes Car Accidents?

The dictionary defines accident as "an unexpected and undesirable event, a mishap unforeseen and without apparent cause." Strictly speaking, most accidents are not accidents at all: they are collisions that could and should have been avoided. So, what causes them, and how can you avoid them?

Four factors contribute to the vast majority of collisions. In ascending order they are:

  1. Equipment Failure

  2. Roadway Design

  3. Poor Roadway Maintenance

  4. Driver Behavior

Over 95% of motor vehicle accidents (MVAs, in the USA, or Road Traffic Accidents, RTAs, in Europe) involve some degree of driver behavior combined with one of the other three factors. Drivers always try to blame road conditions, equipment failure, or other drivers for those accidents. When the facts are truthfully presented, however, the behavior of the implicated driver is usually the primary cause. Most are caused by excessive speed or aggressive driver behavior.

  1. Equipment Failure - Manufacturers are required by law to design and engineer cars that meet a minimum safety standard. Computers, combined with companies' extensive research and development, have produced safe vehicles that are easy and safe to drive. The most cited types of equipment failure are loss of brakes, tire blowouts or tread separation, and steering/suspension failure. With the exception of the recent rash of Firestone light-truck tire failures, combined totals for all reported equipment failure accounts for less than 5% of all motor vehicle accidents.

    • Brakes - Modern dual-circuit brake systems have made total brake failure an unlikely event. If one side of the circuit fails, the other side is usually sufficient to stop a vehicle. Disc brakes, found on the front wheels of virtually every modern vehicle, are significantly more effective than the older drum braking systems, which can fade when hot. ABS (Anti Blockier System) or anti-lock brakes prevent the wheels from locking up during emergency braking maneuvers, allowing modern vehicles to avoid many accidents that previously would have occurred.
    • Tires - Today's radial tires are significantly safer than the bias-ply tires of 25 years ago. They still, however, need attention regularly. Under inflation, the most frequent cause of tire failure is considered the main culprit in the recent Firestone tire-failure fatalities. Uneven or worn-out tires are the next most serious problem and can also lead to tire failure. Uneven wear is caused by improperly balanced tires, or misaligned or broken suspensions. Remember, all that keeps you connected to the roadway is your tires. If you don't check your own, have your mechanic check them every 5,000 miles.
    • Steering & Suspension - Your suspension keeps your tires in contact with the roadway in a stable and predictable manner. Your steering enables you to go around road obstacles and avoid potential accidents. Even a safe, well-trained driver is helpless in the event of a steering or suspension system failure. Such failures are catastrophic, especially at high speeds. Have your suspension and steering systems checked out by a mechanic every 10,000 miles.
    • With regular component inspections by trained individuals, equipment failures can be virtually eliminated.
  2. Roadway Design - Motorists may blame roadway design for accidents, but it's rarely the cause. Consultants such as the Texas Transportation Institute have spent years getting road barriers, utility poles, railroad crossings, and guardrails to their current high level of safety. Civil engineers, local governments, and law enforcement agencies all contribute to the design of safe road layouts and traffic management systems. State and federal governments provide guidelines to their construction, with design flexibility to suit local conditions. Roadways are designed by engineers with special consideration given to the following:

    • Hazard Visibility - Permanent roadway hazards consist of intersections, merging lanes, bends, crests, school zones, and livestock or pedestrian crossings. Temporary hazards include road construction, parked or disabled vehicles, accidents, traffic jams, and wild animals (especially deer).
    • Roadway Surfaces - Engineers can use different surfaces (for example, grooved pavement) depending on the environment, traffic speed, traffic volume, and location of the roadway (noise barriers). Roadway markings let drivers know about their ability to pass safely (dotted & double lines), the location of the roadway in inclement weather (reflective cats-eyes & stakes), and where road surface ends and the shoulder begins.
    • Traffic Control Devices - Traffic light signals, speed limit signs, yield and stop signs, school & pedestrian crossings, turning lanes, police surveillance cameras, and traffic circles or roundabouts.
    • Behavioral Control Devices - Built-in obstacles that limit the ability of a vehicle to travel, including crash barrels, speed bumps, pedestrian islands, raised medians, high curbing, guard rails, and concrete barriers.
    • Traffic Flow - Interstate highways remain the safest roads because their flow of traffic is in one direction. One-way streets ease traffic congestion in city centers as well. Rural two-lane roadways are statistically the most dangerous because of a high incidence of deadly head-on collisions and the difficulty impatient drivers’ face while overtaking slower vehicles.
    • Roadway Identification Signs - enable someone without a detailed map to travel from one place to another. They give advance notice of intersections, destinations, hazards, route numbers, mileage estimates, street names, and points of interest.
    • Weather - inclement conditions can aggravate existing hazards and sometimes create new road surfaces (ice & snow).
  3. Poor Maintenance - Roadway maintenance contributes to some motor vehicle accidents, but not to the extent that drivers use it as an excuse. Unfortunately maintenance schedules and procedures vary greatly from city to city and state to state, so nationwide standards don't exist. Below we outline some potential roadway maintenance shortcomings that you should be aware of.

    • Debris on the roadway can be a problem, and is the responsibility of local highway departments.
    • Faded road signs, and signs obscured by foliage, occasionally contribute to accidents. If you know of any offending signs, contact your local police department to see if they can get the problem remedied.
    • Potholes cause a small number of accidents (primarily tire & suspension failures), but the accidents usually occur at low speeds and don't cause many injuries. Call the police to get large dangerous holes attended to. Some Northern US cities have pothole complaint lines that are active during the winter and spring.
    • Roadway construction is an oft-mentioned reason for accidents. Again the blame usually rests on aggressive drivers who are unwilling to merge or slow down when approaching a construction zone. In most states, fines are doubled in work zones, making it expensive as well as unsafe to speed. Stop-and-go traffic requires thoughtful, alert driving to avoid a collision with the car in front of you. Too often we worry that someone will cut in front of us in a traffic jam. The real problem is that drivers forget about the vehicle directly in front, rear-ending it while looking in their rearview mirror or daydreaming. Leave plenty of room between your car and the one directly in front of you. Our 3 second rule applies to traffic jams as well. If a few people cut in front of you, let them.
    • Salting & Sanding - Many wintertime accidents are blamed on inadequate salting or sanding of icy roadways, but as so often, the real culprit is usually excessive speed. And salting only works if the ambient temperature stays above the middle teens. Recent environmental concerns have curbed widespread salting in recent years so less effective materials like clay, sand, and soot have replaced it in some areas. The fact remains that if highways are icy, speed needs to be reduced whether the roadway is salted or not.
  4. Driver Behavior - Humans tend to blame somebody or something else when a mistake or accident occurs. A recent European study concluded that 80% of drivers involved in motor vehicle accidents believed that the other party could have done something to prevent the accident. A miniscule 5% admitted that they were the only one at fault. Surveys consistently reveal that the majority consider themselves more skillful and safer than the average driver. Some mistakes occur when a driver becomes distracted, perhaps by a cell phone call or a spilled cup of coffee. Very few accidents result from an 'Act of God,' like a tree falling on a vehicle.

Speed Kills - The faster the speed of a vehicle, the greater the risk of an accident. The forces experienced by the human body in a collision increase exponentially as the speed increases. Smart Motorist recommends that drivers observe our 3 second rule in everyday traffic, no matter what your speed. Most people agree that going 100 mph is foolhardy and will lead to disaster. The problem is that exceeding the speed limit by only 5 mph in the wrong place can be just as dangerous. Traffic engineers and local governments have determined the maximum speeds allowable for safe travel on the nation's roadways. Speeding is a deliberate and calculated behavior where the driver knows the risk but ignores the danger. Fully 90% of all licensed drivers speed at some point in their driving career; 75% admit to committing this offense regularly.

Consider this example: a pedestrian walks out in front of a car. If the car is traveling at just 30 mph, and the driver brakes when the pedestrian is 45 feet away, there will be enough space in which to stop without hitting the pedestrian. Increase the vehicle speed by just 5 mph and the situation changes dramatically. At 35 mph, with the pedestrian 45 feet away and the driver braking at the same point, the car will be traveling at 18 mph when it hits the pedestrian. An impact at 18 mph can seriously injure or even kill the pedestrian.

Who are the bad drivers? They are young, middle-aged, and old; men and women; they drive luxury cars, sports cars, SUVs and family cars. Almost every qualified driver I know admits to some type of risky driving behavior, most commonly speeding.

Aggressive Drivers - As we've described, modern cars are manufactured to very safe standards, and the environment they're driven in is engineered to minimize the injuries suffered during an accident. The most difficult area to change is aggressive driver behavior and selfish attitudes. A 1995 study by the Automobile Association in Great Britain found that 88% of the respondents reported at least one of the behaviors listed below directed at them (in order of descending frequency):

  • Aggressive tailgating
  • Lights flashed at them because the other motorist was annoyed
  • Aggressive or rude gestures
  • Deliberate obstruction -- preventing them from moving their vehicle
  • Verbal abuse
  • Physical assault

The same group was then asked about aggressive behavior they had displayed towards other drivers. 40% indicated that they had never behaved aggressively towards another driver. A further 60% of the survey respondents admitted to one or more of the following behaviors (listed in order of descending frequency):

  • Flashed lights at another motorist because they were annoyed with them
  • Gave aggressive or rude gestures
  • Gave verbal abuse
  • Aggressively tailgated another motorist
  • Deliberately obstructed or prevented another from moving their vehicle
  • Physically assaulted another motorist (one positive response)

These behaviors are probably under-reported, since most people are not willing to admit to the more serious actions, even if no penalty exists. The majority of these incidents happened during the daylight hours (70%), on a main road (not freeway or divided highway).

NYS Police characterize aggressive driving by the following traffic violations:

  • Excessive speed
  • Frequent or unsafe lane changes
  • Failure to signal
  • Tailgating
  • Failure to yield the right of way
  • Disregarding traffic controls
  • Impaired driving

The NYS State Police point out that there is a difference between aggressive driving and "road rage." Road Rage behaviors, such as using the vehicle as a weapon or physically assaulting a driver or their vehicle, are not aggressive driving. They are criminal offenses, and there are laws in place to address these violent crimes.

 
Comments
John Vance  - Lack of road signs kill |2008-04-14 10:52:16
Navigating in street is simplified as GPS devices are being used nowadays. But a lack of proper street names in city areas can also lead to dangerous, unintentional behavior in busy streets. This is an issue which should be overcome with with standards developed for the placing of road signs with topology taken into account as all street vary with types of visibility problems. Otherwsie this reveiw on road safety has some plusses, but failt to mention if we drive a 5 mph we ca nstill kill someone. Me I'm staying at home when that idea hits the road safety people.
Adam |2008-06-26 06:48:22
Do some research, speed doesn't cause accident, people with poor driving skills and people not paying attention cause accents. Exceeding the speed limit simply makes the government, police department, and depending where you live the insurance company more money. Wait, who has the most influence on traffic laws and fines... all three who benefit from people exceeding the speed limit, what a surprise. Remember what cars were like when the standards for current speed limits were set up, I don't I wasn't born yet but I think it would be safe to say I can go a little faster in a modern car then I could in one of those, makes u think huh? you web site needs some revisions, i bet its funded by insurance companies huh? big surprise
Anonymous |2008-07-04 02:43:59
I agree with Adam. Another thing that causes accidents is people going the wrong speeds. If everyone is traveling 115 (km/h) on a highway and you're going 95, you're the most dangerous driver out there.
Bill  - speed doesn't cause accidents? |2008-07-24 00:40:33
Sounds good to me.Make the driving tests 4 times as hard.No one with less than 5 years driving expeirience should be allowed on the roads to insure adequate driving skills.Then the roads should be safe for those that want to drive whatever speed they want because there would be far less drivers on the road to challenge your driving skills.



Speeding is for selfish people that don't give a crap about anyone else on the road.
Steve |2008-08-11 19:55:53
The "wrong" speed is really a "significantly differently" speed. However, while it may cause more accidents, the greater damage is done at higher speeds. The slower vehicle frequently is the cause of the accident, but is not involved in the car-nage. So the best scenario is a freeway with every car maintaining the speed limit, conditions permitting.
nat |2008-09-01 05:38:01
Thats the stupidest idea to make the tests 4 times as hard. Try more education not making the test harder.
Christina |2008-10-15 11:41:30
i agree with nat boys just have the need for spped you all need to realise that if you stick to the limit and know how to dirve then everyone will be safe.
Dennis C. Ryan, Illinois  - motorist, 44 years, delivery driver, 25 years |2008-11-10 22:42:01
Speeders don't gain much, but lose a lot.
Quick to pass you, they end up just ahead of you at the next red light. Their driving style is hard on their nerves, hard on gas mileage, hard on brakes, and hard on vehicle maintenance. At the end of a day, they saved 15 minutes to a half-hour over the time they would have spent driving at the speed limit. Add to this the risk of tickets or accidents, and they gain NOTHING. If they got onto the road when they should have, instaed of hitting the"snooze" button for an extra 15 minutes in bed, no speeding would be necessary.
Does It Matter  - Yes |2008-11-14 05:17:56
If you consider how many accidents occur because of speed and momentary inattentiveness, then you can understand why we have speed limits. Unless your a UFO driver from mars, you probably should obey speed limits no matter how long it has been there. One, if you crash anyway you won't end up as mangled. Two, you're late to something driving 20 mph faster doesn't get you from home to work 5 highway miles away much faster. Three, there are jobs people have that take into account how people drive in an area and how the roads are, so they set the limit to keep people from getting hurt. So all in all, speed limits are to help keep people safer. No one is an acception, we all drive at different skill levels, but that doesn't mean nothing can happen to you.
speed  - Speed isn't the problem. |2008-11-27 00:01:12
The Autobahn is much safer than US highways and there isn't a speed limit. Speed in itself isn't dangerous. Going significantly faster or slower than the prevailing flow of traffic is what is dangerous. As far as saving time goes, during urban commutes, the time savings is negligible. On a 500 mile road trip going 75 vs 55 mph will save you almost 2.5 hours.

Speed limits are about revenue. Plain and simple.
Ron |2008-12-18 17:57:51
Speeding doesn't make you a worse driver look at the autobon for example, drivers can drive as fast as they want. How often is there an accident there. When a driver drives fast a driver becomes more cautious and watches the road much closer and the other vehicles around. Meaning there would be less accidents, if anything in my opinion drivers that drive too slow cause accidents because then people get anxious and mad and decide to pass at inappropriate spots i would also have to agree with everthing Adam said before me.
OCSD Deputy  - Distracted drivers |2009-02-15 21:14:58
The biggest threat to the driving public is the motorist who isn't paying attention to the task at hand -- operating a 3,000 pound projectile moving at 65mph. Every day I see dozens of female motorists gabbing away on cell phones, completely oblivious to the world around them. My traffic unit issues over 150 citations a week for this but the problem continues unabated.

These individuals are responsible for the overwhelming majority of rear-end collisions, and occasionally cause a serious wreck with life-threatening injuries.
Samantha Oliphant  - Thanks |2009-02-23 21:43:57
Thank you so much your sited help me with a research paper and it helped alot.
therese nash  - thanks |2009-03-22 09:01:26
thanks your website helped me alot with a school project
wiaam  - wlazibi |2009-04-18 16:57:06
i think speed its one of the causes of accidents
JT  - in response to OCSD Deputy |2009-04-26 02:22:37
Funny that you single females out as unsafe motorists. Statistics show that males have more traffic accidents than femals...
Amanda  - teenage student |2009-05-18 12:53:52
i think that if you want to make the driving test harder ya'll are all ridiculous.. i promise you right now if you make the driving test harder all the adults who drive would be totally screwed because your driving skills are not wonderful.. speeding is a leading cause of crashes, but want to pull out other reasons... inattention.. adults talk on their phones when driving more than us kids do.... DUIs its all adults right there.. i aint saying kids dont but heyy ya'll are worse.. when we are drunk we dnt always get behind a wheel and some of us are responsible and take keys.. i havent heard of adults taking any keys here lately.. hmmmm.. and DISOBEYING TRAFFIC SIGNALS.. apparently when your older u decide i've been driving for years and you dnt think u'll wrect so you go on, you hurry all that dumb stuff.. NEWS FLASH!!!!!!!!!!!!!!!!! the sogns were put there for old ppl too!!!
Meerkat Milo  - THANKS |2009-05-24 15:17:21
You saved my life from the school P.E department. Ty.
Selim - teenage student  - re:teenage student |2009-08-09 17:06:29
See though, it's not necessarily the test that would be harder, it's the fact that the laws\regulations\techniques have changed since way-back-when. plus, there's a #### load more people on the road now than then that would make everything more difficult.
Bryan Holland  - Groups like this cause accidents |2009-08-25 01:06:08
Where to start... Speeding does not cause acciidents! It reduces your time to react to a hazard. The only reason why people have accidents is at least one driver is not paying attention and/or is under-skilled. All of these other factors are either mitigating or agravating factors. What a bunch of idiots.
Jonathan  - Road too good |2009-08-27 00:49:45
The roads in Africa are much better than they use to be, hence drivers are going too fast.

Solution:

Revert back to stones and dirt road so driver slows to avoid bursting tyre.

or build system of reducing and braking speed at intervals.
Norman  - drunk and drive |2009-09-02 16:54:53
Most issue that causes accidents on our roads is the behavior of drivers.They are drinking beers while driving ,that particular driver result indrunk and losses control on the roads.Me as atransport manager I request that according to AARTO if a driver fund drunk must be arrested instead of giving him or her fine.Im tellimg you this law will be approved soon.
Ali Gulet  - speed kills |2009-10-04 12:57:25
Speed is adeliberate and calculated behavior where the driver knows the risk but ignores so speed lastly leads to loss of life, time and wealth than gain so before you speed think about this losses. Thanks
Megan  - thanks |2009-10-05 02:05:25
thanks for all this information, helped with a school project. i hope this gets the message out to people to stop speeding!!
It Gurl  - Slow the hell down.... |2009-10-12 06:05:36
Most accidents ARE caused by speeding. Knowing how to drive and to manuever your vehicle are not skills. Those are things you learn when taking the drivers tests. But SPEEDING is a skill. Anyone can speed but it takes a skilled person to do so without hurting himself or anyone else around him. Which is usually unheard of..so if u think u can speed becoz ur skilled well think again...but don't go out and try it...u just might not be as skilled as you thought...Follow the speed limit...its best to drive slow and enjoy the ride while it lasts anyways...life is too short..why make it shorter???
Baby Talia  - Jackson |2009-10-13 12:54:57
I think that they should go to church and save their soul instead of being in the world get spiritual.
Person  - lolz |2009-10-29 23:47:07
they spelt behavior wrong lots of times
wheng  - for me |2009-11-04 02:32:23
drunk driving is the most common cause of car accidents.whereas most drivers losses their concentration on the road when they are drunk......
Alex Patras  - speeding |2009-12-27 09:42:13
Officially speeding causes 3 percent of automobile accidents in Britain. Speeding is not nearly as dangerous as people think, and the speed limits are so ridiculously low in America. The Autobahn is a tribute to this fact and you are more than welcome to look up death rates and fatality numbers as much as you want. If you intend on speeding you should just be aware of how your car performs that is all. Cars cause accidents through poor performance. And having a race mentality causes accidents as well. You are not racing anyone your just speeding.
Rob  - The Money pit verses real road safety |2010-01-18 02:42:36
Be very careful what you wish for folks! I live in a State in which we now have ... wait for it

a 25Kph speed limit in certain suburban environments.

That is the ultimate end game for the logic that says "road safety is only possible through the reduction in force" that is the proper term BTW for "speed" which interestingly enough is a relative term and correctly does not really exist.

The real solution is a mix of sound driver education, sensible speed limits and realistic enforcement. Was it Mark Twains favourite saying that there are "lies Dam lies and Statistics" well beware of those peddling simple statements like "95% of all accidents involve speeding" ... what the hell I have yet to see two stationary cars manage to collide!

Actually it is not speed that kills it is massive changes in velocity that does the job ask any fighter pilot what he feels under 8g! Same for you in the car that decelerates from 100 down to 0 in 10 feet!

So the real issue is how do we make the road safer let us try and stick to that outcome and we will all likely not have to bury one of our children which has to be the most awful of outcomes that comes out of this debate so much more often that it need.
arap elkana kipruto  - overspeeding |2010-01-18 13:01:05
any one moment when your conscience tell you "come on what are doing" think twice and slow down
Le  - drunk driving |2010-01-23 08:05:34
it causes a lot of accident due to drivers who are drunk........when those drivers met accident they blame other people.
Jill  - Go Dennis!! |2010-02-11 21:01:01
I fully agree with Dennis C. Ryan's comments. Way to put my thoughts into words, Dennis!!
Write comment
Name:
Title:
Please input the anti-spam code that you can read in the image.
 
< Prev   Next >