It is not uncommon to see a truck that has rolled over on its side. This is an occurrence that happens more than it should and it is a terrifying event for everyone involved. Heavy duty loaded trucks are most likely to roll over because they have a higher center of gravity than other vehicles. This means that the point on the truck and trailer where everything is perfectly balanced is up high.
There are many reasons that a truck can turn over. Some of the factors that lead to a truck rolling over can be attributed to 3 things:
- Highway factors
- Vehicle maintenance
- Driver errors
Being aware of all of the factors that can contribute to a truck rolling over is the first step to preventing one before it happens.
Highway factors
The highway conditions provide a lot of reasons for many rollover events. A common misconception is that a rollovers happen while on the on-ramp or off-ramp when the driver is trying to merge. However, most rollovers happen on straight stretches on the highway when the driver is less alert and aware.
Sharp curves
Sharp curves become more dangerous with more speed. If a turn it taken too fast the load will want to continue moving straight ahead and this effect will cause a rollover.
According the the FMCSA, road signs that indicate how much speed to take around a turn are intended for cars in good weather conditions. It is recommend that when a truck is approaching a curve, that is goes 10 mph under what the sign says for maximum safety.
Steep grades
Steep grades are always a problem for truck drivers. Trucks naturally what to speed up when going downhill and with an 80,000 lb load, getting it to slow down is difficult. Picking up speed while on a steep grade with a loaded truck is a recipe for a turnover.
When approaching a steep grade it is important to be traveling the speed that you want before you start the grade. This will save the amount of force your brakes need to apply to slow down.
Soft shoulders
Soft shoulders can lead to tripping. Tripping occurs when one side of your trailer axle drops below the other side suddenly which results in a rollover. Similarly, when trailer axles makes it back to the road and jump off of the curb, the reaction from the driver can put the truck in a position to rollover on the other side. This is known as reverse tripping.
When turning in a truck pulling a trailer the path that the trailer axle follows is different than what the drive axles will follow. Trailer axles can follow a path that is up to 5 ft off from the drive axle path depending on the configuration.
When making turns to get on to on-ramps or off-ramps, making sure that you have about 5 feet of space between the steer axle and the curb will help your trailer avoid climbing the curve and tripping.
Vehicle Maintenance
Proper vehicle maintenance should always be a top priority for every carrier and driver. Performing pre-trip inspections before ever driving a truck should be the most important task a driver makes. A failure to check the most critical components of a truck and trailer will greatly increase the likelihood of a rollover when the truck is loaded.
Vehicle maintenance is one of the most heavily enforced parts of the FMCSAs BASIC categories. The type of accidents that can happen with poor vehicle maintenance can be catastrophic and a rollover is no different.
Brake performance
If brakes are not in a great working condition then slowing the truck down to make a turn will be harder. Many rollovers happen when a truck cannot slow down fast enough and the speed of the truck takes over.
Trucks need to be able to approach turns at a safe speed and the brakes is the only way that can happen. If a truck is going down a steep grade it is important to get the truck to a safe speed before even starting down the grade.
Suspension damage
The suspension system can play a big part in a rollover. A damaged suspension system will prevent your axles from being able to adjust and absorb bumps in the road. If an axle climbs a curb on a damaged suspension then the effect on the truck will be intensified.
When driving a truck you want avoid anything situation that will cause sharp or sudden movements while loaded. With loads up to 80,000lbs at high speeds any sudden movements are exaggerated and can become difficult to manage.
Tire pressure
Proper tire pressure is always critical when driving a truck. When a tire is low, it makes the other tires bare more of the weight and can cause the truck or trailer to lean. This will shift the center of gravity for the load to the side and increase the possibility of a rollover
Blowouts also can occur when tire pressures are low and open up the opportunity for driver error and an over correction situation. Depending on which tire experiences a blowout can have a big impact on the possibility of a rollover.
Load dynamics
How a load is situated on the truck and trailer can change your equipment's center of gravity. Loading to much on the back of the trailer can affect the trucks handling. Loading more on one side of the trailer can make overturning on that side higher.
It is important to load from the front to back on the trailer and from the middle out so that the loads center of gravity is as low and even as possible. Using the proper load securement methods to tying down loads so that they don't move in transit is also critical.
When hauling liquids, it is important to understand how the fluid moves when braking, accelerating and turning. Liquids will slosh around during transport and these loads operate very differently from loads that are strapped down.
Driver errors
Most rollover events happen because of driver error. This can be for any number of reasons whether it's driving to fast, over correcting, braking or becoming distracted.
At the end of the day everything that happens to the truck is the responsibility of the driver. Making sure that everything is in working order and that you are focused and alert will put you in the best position to avoid a rollover.
Braking
Braking to aggressively or not soon enough can lead to the truck turning over. Just like how driving with poor brakes can be bad, not properly using your brakes is just as dangerous.
If you are hauling liquids, then harsh braking events will cause the fluids to slam into the front of the trailer and can affect how you are able to steer. It is important to give yourself plenty of space to slow down gradually.
Turning radius
Your turning radius also has an effect on how your trucks center of gravity will react. If you are making sharp turns too fast the truck can turn over. Making wide turns with little acceleration and slow speeds are best.
Speed
Speed always plays a role in rollovers. Slow and steady always wins the race when it comes to trucking.
Sudden maneuvering or over correcting
Keeping calm during surprise situations will help keep you from over correcting. Sudden movements in a truck react very differently than in a car or small passenger vehicle. Panic braking or jarring can have unintended consequences. You want to always be alert so you are not caught off guard and put in a position to make sudden movements.
Unsafe behaviors
It is important as a driver to always be fully alert. If you are feeling tired or fatigued it is best to get off of the road and rest. Distracted or fatigued driving leads to surprise situations which can lead to over reacting and eventually a rollover.
Unsafe driving is also taken very seriously by DOT and FMCSA. It is another of the FMCSAs BASIC categories that DOT heavily enforces. Unsafe driving includes texting, talking on the phone, eating, speeding, driving fatigued or any event that takes the drivers focus off of the road.
