Traffic Collision
A Honda Accord slammed on the side by another car. The left side is extensively damaged.

A traffic collision, also known as a motor vehicle collision or car crash when cars are involved in the collision, occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other moving or stationary obstruction, such as a tree, pole or building. Traffic collisions often result in injury, disability, death, and property damage as well as financial costs to both society and the individuals involved.


Terminology and Intent

  • Traffic collisions can be classified by types such as head-on, road departure, rear-end, side collisions, and rollovers.
  • Different terms are used to describe vehicle collisions, including road traffic injury, motor vehicle accidents (MVA), and motor vehicle traffic collision (MVTC).
  • The term ‘accident’ is falling out of favor and being replaced by terms like crash or collision.
  • Government departments and organizations recommend using crash or collision instead of accident.
  • Some traffic collisions are caused intentionally, such as vehicular suicide or staged crashes for insurance fraud.
  • Motor vehicles may be used in collisions as part of deliberate efforts to harm others, such as vehicle-ramming attacks or vehicular homicide.

Health Effects

  • Collisions can result in a range of physical injuries, from bruises and contusions to catastrophic injuries, paralysis, and death.
  • The CDC estimates that approximately 100 people die in motor vehicle crashes each day in the United States.
  • Collisions can lead to long-lasting psychological trauma.
  • Psychological trauma may cause fear of driving again and impact individuals’ ability to work, attend school, or fulfill family responsibilities.

Causes and Human Factors

  • Road incidents are caused by various human factors, including failure to adapt to weather conditions, road design, signage, speed limits, lighting conditions, pavement markings, and roadway obstacles.
  • A study found that driver factors contributed to 57% of crashes, combined roadway and driver factors to 27%, combined vehicle and driver factors to 6%, solely roadway factors to 3%, combined roadway, driver, and vehicle factors to 3%, solely vehicle factors to 2%, and combined roadway and vehicle factors to 1%.
  • Vehicle and road modifications are generally more effective in reducing injury severity than behavioral change efforts.
  • Human factors in vehicle collisions include driver behavior, visual and auditory acuity, decision-making ability, and reaction speed.
  • A report based on crash data found that driver error, intoxication, and other human factors contributed to about 93% of crashes.

Leading Contributing Factors for Fatal Crashes

  • Driving too fast for conditions or in excess of the speed limit
  • Operating under the influence
  • Failure to yield right of way
  • Failure to keep within the proper lane
  • Operating a vehicle in a careless manner

Distracted Driving, Driver Attitudes and Behaviors, Demographic Differences, and Impact of Traffic Policies and Road Design

  • Drivers distracted by mobile devices have nearly four times greater risk of crashing.
  • Texting while driving increases the risk of a crash by 23 times.
  • Dialing a phone is the most dangerous distraction, increasing the risk by 12 times.
  • Reading or writing while driving increases the risk by ten times.
  • Distracted driving is a leading cause of crashes.
  • Overconfidence in driving abilities can lead to crashes.
  • Drivers involved in crashes often do not believe they are at fault.
  • Young male drivers are disproportionately involved in collisions.
  • Actuaries set insurance rates based on age, sex, and vehicle choice.
  • Road designs and rules of the road can improve safety.
  • Drink-driving laws, speed limits, and speed enforcement systems help reduce crashes.
  • Some driving tests now include testing drivers’ behavior in emergencies.
  • Hazard perception is an important skill for drivers.
  • Road and environmental factors contribute to about 34% of serious crashes.
  • Investment in safe road infrastructure could reduce road deaths by 13% in the UK.
  • Seat belt use reduces the risk of death by about 45% in collisions.
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