Determining the preventability of motor vehicle crashes

Crashes involving motor vehicles are often preventable regardless of whether the driver was not held legally responsible. Drivers must operate their vehicles defensively to avoid situations likely to result in crashes. This report will outline many situations where a driver may be able to avoid an incident by taking necessary precautions.


A preventable crash is one in which the driver failed to exercise every reasonable precaution to prevent the crash. This is irrespective of the extent of property damage and/or personal injury, to whom it occurred, or the location of the incident. Crash, as used in this report, is any motor vehicle related incident that results in a fatality, injury, or property damage. Currently, multiple terms are used to describe a mishap involving a motor vehicle, including crash, incident, and collision. Rather than try to blend these terms, the description ‘crash’ will be used in this report.

In order to avoid being involved in a preventable crash, it is necessary for a driver to understand the concept of and practice defensive driving. Defensive driving is driving to prevent crashes despite the incorrect actions of others or adverse driving conditions, such as weather, traffic, lighting, vehicle or road condition, or the driver's physical or mental state.

This report will outline many situations where a driver may be able to avoid becoming involved in an incident by taking necessary precautions.

Determining preventability

Where feasible, a crash review board (CRB) should be formed. The CRB is a peer group panel consisting of management representatives and drivers. The purpose of the CRB is to evaluate crashes with the purpose of improving the safety of operations. The number of representatives on the board will depend on the size of the business, but should always be an odd number to avoid “tie” situations. Members can include department representatives from management, dispatch, maintenance, drivers, and safety.

The CRB should convene as soon as possible after the facts of the incident have been verified. The CRB’s decision should provide a clear explanation of findings and what can be done to improve the operation (e.g., if the crash was preventable by the driver, if the driver needs training, if a change in the way vehicles are equipped is necessary, or if maintenance procedures need to be modified).

The following examples should assist in the determination of types of crashes which are preventable.


Practically all backing crashes are preventable. A driver is not relieved of responsibility to back safely when a signaler is involved in the maneuver. A signaler cannot control the movement of the vehicle; therefore, a driver must verify all clearances.

Crash avoidance maneuvers

Many crashes, such as overturning, jackknifing, or running off the road, may result from emergency action by the driver to avoid a crash. Examination of events prior to the incident may reveal speed too fast for conditions or other factors. The driver's actions, prior to involvement, should be examined for possible errors or lack of defensive driving practice.


Virtually all crashes caused by driver distraction are preventable. Using a cell phone, eating, adjusting entertainment devices, and other distracting activities are the decision of the driver.

Fixed objects

Crashes with fixed objects are preventable. They usually involve failure to check or properly judge clearances. New routes, strange delivery points, resurfaced pavements under viaducts, inclined entrances to docks, marquees projecting over a traveled section or road, and similar situations are not valid reasons for excusing a driver from being at fault. A driver must be constantly on the lookout for such conditions and make the necessary allowances.


It is the responsibility of all drivers to approach, enter, and cross intersections prepared to avoid crashes that might occur through the actions of other drivers. Complex traffic movement, blind intersections, or failure of the other driver to conform to the law or traffic control devices will not automatically determine a crash to not be preventable. Intersection crashes may be preventable even though the driver has not violated any traffic regulations. Failure to take precautionary measures prior to entering the intersection is a factor to be studied in making a decision. When a driver crosses an intersection and the obvious actions of the other driver indicate possible involvement, either by reason of speeding excessively, crossing the lane in turning, or coming from behind a blind spot, the resultant crash should be considered preventable.


It is extremely important to check the action of a driver involved in a head-on or sideswipe crash with a vehicle approaching from the opposite direction. The exact location of vehicles prior to and at the point of impact must be carefully verified. Even though an opposing vehicle enters a driver's traffic lane, it may be possible for the driver to avoid the crash by slowing down, stopping, or moving to the right. Failing to signal the opposing driver, by flashing the headlights or sounding the horn, should also be considered.


Unconventional parking locations, including double parking and failure to put out warning devices, generally constitute evidence for judging a crash preventable. Roll-away crashes from a parked position normally should be classified preventable. A properly parked vehicle should be locked, with the engine off, parking brake set, manual transmission in lowest gear, multi-speed axle in low range, and wheels blocked or turned toward a curb to prevent vehicle movement.

Passenger crashes

Passenger crashes in any type of vehicle are preventable when they are caused by the faulty operation of the vehicle. Even when an incident does not involve a crash of the vehicle, it must be considered preventable when a driver stops, turns, or accelerates abruptly. Emergency action by the driver to avoid a crash that results in passenger injury should be checked to determine if proper driving prior to the emergency would have eliminated the need for the evasive maneuver.


Failure to pass safely indicates faulty judgment and possible failure of the driver to consider one or more of the important factors that must be observed before attempting the maneuver. Unusual actions of the driver being passed or of oncoming traffic might appear to exonerate a driver involved in a passing crash. However, the entire passing maneuver is voluntary and the driver's responsibility. Crashes from sideswipes and cut-offs, involving a driver being passed, are preventable if the driver fails to yield to the passing vehicle by slowing down or moving to the right where possible.


Traffic regulations and court decisions generally favor the pedestrian hit by a moving vehicle. An unusual route of a pedestrian at mid-block or from between parked vehicles does not necessarily relieve a driver from taking precautions to prevent such crashes. Whether speed limits are posted or the area is placarded with warning signs, speed too fast for conditions may be involved. School zones, shopping areas, residential streets, and other areas with increased pedestrian traffic must be traveled at reduced speeds, appropriate to the situation. Bicycles, motor scooters, and similar equipment are generally operated by young and inexperienced operators. The driver who fails to reduce speed when this type of equipment is operated within sight-distance has failed to take the necessary precautions to prevent a crash. Keeping within posted speed limits is not taking the proper precaution when unusual conditions call for voluntary reduction of speed.

Private property

When a driver is expected to make deliveries at unusual locations (e.g., construction sites) or on driveways not built to support the weight of the vehicle, it is the driver's responsibility to discuss the operation with the proper authorities and to obtain permission prior to entering the area.


Damage to the vehicle, cargo, or other property, or injury to persons, such as from loose objects falling from the vehicle, loose tarpaulins or chains, and doors swinging open, is preventable when the driver's action or failure to act are evidenced. Cargo damage, resulting from unsafe vehicle operation, is preventable by drivers.

Vehicle ahead

Regardless of the abrupt or unexpected stop of the vehicle ahead, a driver can prevent a crash by maintaining a safe following distance at all times. This includes being prepared for possible obstructions on the highway, either in plain view, or hidden by the crest of a hill or a curve of a roadway. Overdriving headlights at night is a common cause of this type of crash. Night speed should not be greater than that which will permit the vehicle to come to a stop within the forward distance illuminated by the vehicle's headlights.

Vehicle behind

Investigation often discloses that drivers risk being struck from behind by failing to maintain a margin of safety in their own following distance. Crashes involving the rear of the vehicle, that are preceded by a rollback, an abrupt stop at a grade crossing or when a traffic signal changes, or when the driver fails to signal a turn at an intersection, should be considered preventable. Failure to slow down gradually should also result in the crash being considered preventable.


Defensive drivers make no driving errors themselves and allow for the lack of skill or improper driving practices of other drivers. They adjust their own driving to compensate for unusual weather, road and traffic conditions, and recognize the need for caution in situations conducive to crash involvement.

It is impossible to describe in detail the many ways a driver might prevent a crash without being primarily or legally responsible. The crash situations outlined in this report are examples of those most frequently represented.

COPYRIGHT ©2015, ISO Services, Inc.

This material is provided for informational purposes only and does not provide any coverage or guarantee loss prevention. The examples in this material are provided as hypothetical and for illustration purposes only. The Hanover Insurance Company and its affiliates and subsidiaries (“The Hanover”) specifically disclaim any warranty or representation that acceptance of any recommendations contained herein will make any premises, or operation safe or in compliance with any law or regulation. By providing this information to you. The Hanover does not assume (and specifically disclaims) any duty, undertaking or responsibility to you. The decision to accept or implement any recommendation(s) or advice contained in this material must be made by you.

LC FEB 2019-081
171-1161 (12/18)