Reducing the Risk of Rollover Crashes

Rollover crashes constitute about one-fifth of all fatal crashes, according to the National Highway Traffic Safety Administration (NHTSA) report, “Characteristics of Fatal Rollover Crashes.”

Statistics Tell the Story
Nearly three-fourths of occupants killed in rollover crashes were not using restraints, and slightly less than two-thirds of them were completely ejected from the vehicle. Most fatal rollovers are single-vehicle crashes. Rollover crashes are more likely to result in fatalities than other types of crashes.

NHTSA data indicates that pickups and sport/utility vehicles have the greatest number of fatal crashes. In general, those vehicles with a high center of gravity are most likely to roll over.

Many reports indicate that large-capacity vans (i.e. 15 passenger), such as those used to transport church groups, college athletic teams, and vanpools have a considerably higher risk of rolling over when loaded with passengers. In fact, NHTSA issued a warning after a study revealed that vans are three times more likely to roll over when carrying 10 or more passengers than with lighter loads.

Rollovers can happen to almost any vehicle type. These events are not limited to 15-passenger vans, SUVs, or tractor trailers. Even occasional business drivers who make trips to the post office during the business day could become involved in a rollover.

Fatal rollover crashes are speed-related more often than fatal non-rollover crashes. Some 40 percent of fatal rollover crashes involved excessive speeding. Additionally, nearly 75 percent of fatal rollovers took place where the posted speed limit was 55 miles per hour or higher.

NHTSA data also suggests that more than 90 percent of the vehicles in fatal, single-vehicle rollover crashes were involved in routine driving maneuvers (going straight or negotiating a curve) at the time of the crash.

NHTSA data shows that nearly 85 percent of all rollover-related fatalities are the result of single-vehicle crashes. This further suggests that driver behavior (distraction, inattentiveness, speeding, and impaired driving) plays a significant role in rollover crashes.

What Causes Rollovers?
Rollovers happen because of a combination of factors related to the driver, cargo, conditions, and vehicle design.

Factors include:

• Driver: drowsiness, overcorrection in steering, failure to anticipate slippery conditions, and speeding.
• Conditions: slippery roads, soft shoulders lower than the road surface, drop-offs, cloverleaf ramp designs, and roadway barrier design.
• Vehicle: wheelbase, vehicle weight, distance between wheels on the same axle (track width), and center of gravity affect the likelihood of a rollover crash.
• Cargo: too many passengers in a van. When a large van is fully loaded, its center of gravity shifts up and back, increasing the risk of rollovers, especially in panic maneuvers.

  Reducing Risk and Mitigating Injury — Action Items for Fleet Managers

  Off the Road – Before the Trip

• Familiarize employees with the statistics related to rollovers — how many rollovers occur, what types of vehicles are more prone to these events, and tips to prevent rollovers. Let drivers know your approach to managing the issue of rollovers and ask them for their help in maintaining safety at your company.
• Communicate to drivers the particulars of driving a 15-passenger van. A large van is substantially longer and wider than a car. Therefore, it requires more space and additional reliance on the side-view mirrors for changing lanes, does not respond as well to abrupt steering maneuvers, and requires additional braking time.
• Be especially wary of allowing nonfleet drivers to drive large vans. They may not realize the potential danger to flip over during abrupt steering maneuvers. Instead, designate one or two trained, experienced drivers in the organization to operate these vans.
• Have drivers regularly inspect tires for proper pressure and tread depth.
• Have a mechanic inspect vehicles regularly to find, repair, or replace any worn or broken components. Shock absorbers, springs, and strut mechanisms should be inspected periodically and serviced or replaced based on manufacturer recommendations.
• Understand the crash avoidance and crash protection technologies in the 12- and 15-passenger van models in the fleet.
• Consult the vehicle’s owners manuals to determine the maximum safe load, as well as proper load distribution. If using a roof rack, pay special attention to the manufacturer’s instructions and weight limits. Any load placed on the roof will be above the vehicle’s center of gravity and will increase the vehicle’s likelihood of rolling over.
• Though it may seem obvious, reinforce the need for drivers — and all passengers — to always wear safety belts. Safety belt use has an even greater effect on reducing the deadliness of rollover crashes than in other crashes because so many victims of rollover crashes die as a result of being partially or completely thrown from the vehicle. Add this rule to the fleet safety handbook.

  On the Road – Safe Driving Tips

• Get adequate rest before trips, and never drink and drive — nearly half of all rollover crashes involve alcohol.
• Rain, snow, ice, and even wet leaves can create slippery conditions that compromise vehicle handling.Slow down and allow extra time to react to situations.
• Be extra careful on rural roads that are often narrow and poorly maintained. Stay calm in skids and accident situations, as panic maneuvers often lead to rollovers.
• If the wheels drop off the roadway or pavement, gradually reduce speed and steer back onto the roadway when it is safe.
• When a 15-passenger van is not full, passengers should sit in seats that are in front of the rear axle.