Tanker Rollover Prevention

In this video, we’re going to review vehicle safety and some important ways you can avoid a vehicle rollover.

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What causes a rollover?

So, what causes a rollover? Well, the most common answer we often hear is driving too fast for road and weather conditions. While that statement is certainly true, it’s not the only reason. In this video, we want to go beyond that typical answer and look at other factors that contribute to rollovers. After watching this video, you'll learn how rollovers happen, why they happen, and how you can avoid them.

Where do rollovers occur :

Rollovers today can happen almost anywhere. Most people believe vehicle rollovers only happen during turns such as exit and entrance ramps, but believe it or not, rollovers occur more frequently when traveling on straight roadways. Experts speculate it’s because we’re less focused when traveling on a straight road than when turning. Knowing this, it’s important that you maintain your focus when driving, no matter the road condition. Some of the most common factors that contribute to rollovers include vehicle design, load effects, road conditions, and driver behavior.

Vehicle Design:

Let's start with the design and performance of our fleet. Whether you are driving a pumper, hybrid, stakebed, or proflush truck, a pumper truckthe first thing you must know is that all of our trucks designed with a mounted waste/water tank have standard pumper truck has a high center of gravity. The center of gravity is the place on your truck where it is completely balanced in all directions. Knowing a truck has a high center of gravity means it will lean when it enters a turn. How much it leans depends on the vehicle speed, the sharpness of the turn, and the unit’s overall center of gravity.

When the truck starts to lean, it's center of gravity begins to shift towards the outside of the curve. As it does this, the liquid in the tank moves sideways. This is called sloshing. If this happens too suddenly and too strongly, the vehicle will roll over.

Load Effects:

Next, let’s discuss load effects. Drivers who’ve rolled over a truck in the past will tell you their load shifted. They'll often say the load shift caused the rollover, but the load, especially a liquid load will always shift. That’s because it's responding to the way you, as the driver, are handling the vehicle. Additionally, if you suddenly hit the brakes hard, the liquid will rush forward, causing what is known as a surge. So, what's the key word here… suddenly. If you do things more slowly, you reduce the risk of problems.

The amount of load you're carrying will also affect how your vehicle handles. With a tank full of liquid, one wrong move can mean a rollover. The most important thing you can do to keep the vehicle and the load under control is to manage your speed. This includes managing your speed to adapt to driving conditions. When the road and the weather call for it, always slow down. 

Pay Attention to Load Levels:

Throughout the day, it’s important that you pay attention to your load levels. As difficult as it can be to drive a truck full of liquid, partial loads are even more challenging because there's more room for the liquid to move. Over 94% of rollovers occur in trucks with a partial load. Liquid slosh and surge are a big factor in those rollovers. Slosh and surge are caused by speed, by turning radius, by sudden braking or taking off, by sudden maneuvers, and by load distribution.

Pre-Trip Inspections :

Vehicle maintenance issues can also play a role in tanker rollovers. Things like poor brake performance, a damaged suspension, and under inflated tires could all contribute to a rollover. The good news is most of these can be eliminated with an adequate pre trip inspection. If you have any questions about your vehicle, tell someone in maintenance or dispatch. Never leave the yard with a vehicle that you aren't confident will perform safely. A pre-trip inspection only takes a few extra minutes and it could save your life.

Roadway Conditions :

Now let's review potential roadway factors. These include sharp curves, steep downhill grades, soft shoulders, berms, mounds and curbs, narrow driveway entrances or exits, and limited visibility areas that can reduce eye time for turns or hills. Remember, you're the professional on the roads you travel. If there's a road design condition that makes you feel uneasy, reported it to dispatch.

Speed Limits

It’s nearly impossible to discuss highway factors without first talking about the speed limit. Do you see this sign here? Unlike other cars on the road, this sign is NOT for you. It's for passenger cars traveling in good weather. Fleet safety experts say that when you enter a curve with a sign posted like this, you should drop your speed at least 10 miles per hour below what you see pictured here.

Downhill grades

We all know that long downhill grades often lead to excessive speed. Knowing this, it’s important to remember that the only acceptable time to deal with downhill grades is before you start going down them. Remember, the larger the vehicle, the slower the driver often thinks they’re moving. Never rely on your feel to estimate your speed. Always check your speedometer before you enter downhill grades.

Shoulder Conditions:

When driving on narrow roadways or rural roadways, always be aware of the shoulder conditions of the road. Dropping off onto a soft shoulder may cause the outside wheels to sink and trip the whole unit on its side.  

It’s important to also note that an improper recovery from drifting off on to a shoulder could also lead to a reverse tripping condition. Let's say you go off the roadway and you try to bring the truck back onto the roadway too quickly and at too fast of a speed. This could trip the vehicle when the tires hit the shoulder berm or the pavement on the return.                               

Wide Intersections:

When approaching a wide intersection, always proceed with caution. In these scenarios, you should always slow down and treat it as a narrow intersection. With a standard truck and trailer, you're often taught to square the turn at slow speeds to reduce the impact of off-tracking, but loads with a high center of gravity need to be driven differently through intersection turns. You should always round the turn to make sure the vehicle doesn't have a sudden change in direction. Cutting short on a turn is one of the most common errors.

Driver Behavior :

Okay, we've discussed vehicle design, load effects, and highway factors. Now we come to the last area, and in many ways, it’s the most important. It's you, the driver. You're the one that controls your vehicle. Make sure you know it's like the back of your hand. Begin your day by conducting a thorough pre trip inspection. Learn as much as you can from dispatch and from other drivers about road and weather conditions. Remember, a safe journey depends on your actions. Always drive defensively and avoid unsafe behaviors such as speeding, talking on the phone, texting, complacency, or fatigue. These unsafe behaviors can cause your vehicle to drift of the road. If that should ever happen, always avoid oversteering or overcorrecting as this will greatly increases your risk of rollover.  

In Review…

Well there you have it, rollovers happen all too often in the liquid waste industry. They can be severe, they can be destructive, and they can be deadly.

The good news though, is most rollovers are caused by driving too fast and that is one thing that's entirely under your control. The bottom line is simple, rollover crashes are preventable, and you are often the key to eliminating them.