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Every year, thousands of people are injured, disabled, or killed in auto accidents due to unsafe road conditions. We all know the dangers associated with wet or icy pavement, but sometimes accidents happen on a clear, dry day for a surprising reason: the design of the road itself.


If you’ve ever dropped off the edge of the road, you’re familiar with the jolt of adrenaline that shocks you into reacting, jerking your steering wheel and your vehicle back onto the road. For some of us, it’s a quick correction that we can shrug off; for others, it’s a reaction that causes us to overcorrect and lose control. Of the more than 40,000 vehicle accidents that occur every year, 4.5% of them involve oversteering or overcorrecting – some with tragic results.

Roadway design and public safety

Most of us don’t give much thought to how roadways are constructed, just as long as we can travel from Point A to Point B with relative ease. But it is the responsibility of highway departments and paving contractors to build roads that are safe to navigate, and nowhere is this more important than the area of pavement at the edge, often called the shoulder.

The minimum shoulder width for travel lanes is dependent upon the type of roadway and whether it’s located in an urban or rural setting. But whether it’s a 1-foot shoulder along an urban ramp or a 12-foot shoulder adjacent to a freeway traveling through a rural area, the transition from the driving surface to the shoulder area is of critical importance.

Conventional paving methods often result in a road edge that is several inches higher than the adjacent shoulder area and in many cases perpendicular to the shoulder surface. Vehicles that drop off this steep edge are subject to a phenomenon known as “tire scrubbing,” where the inside wall of the right tire rubs along the edge of the pavement. Many times, drivers will oversteer in an attempt to return to the roadway, while maintaining their traveling speed. The combination of these two factors can cause the driver to lose control of the vehicle, veering into oncoming traffic or running off the opposite side of the roadway and overturning or striking a fixed object.

Roadway departure is a factor in more than half of all fatal crashes (download report pdf), particularly where a vertical shoulder drop-off is involved. However, The Federal Highway Administration has developed an effective solution for steep shoulder drop-offs called the Safety Edge (interesting brochure for highway workers about the safety edge). The principle behind the Safety Edge is a sloping surface that eases the transition between the roadway and the shoulder. A simple device (called a shoe) attached to a paving machine extrudes and shapes the pavement edge to a precise 30 degree angle, which eases the transition between the driving surface and the shoulders. Vehicles that encounter a 30 degree slope at the pavement edge are less likely to experience tire scrubbing and their drivers can correct their path back onto the roadway with less chance of oversteering.

How to React if Your Vehicle Encounters a Drop-off

Most driver’s education courses and state driver’s manuals offer instruction and advice on how to avoid common road hazards, including how to react to dropping off the shoulder of the road. It is possible to correct a shoulder drop-off without oversteering by following these steps:

  • Let up on the gas, and don’t slam on your brakes.
  • Maintain a firm grip on the steering wheel; a sudden drop-off may cause the wheel to jerk in your hands, but resist the urge to jerk the wheel back toward the roadway.
  • Apply the brakes lightly and briefly; the goal here is to gradually slow the vehicle.
  • Keep steering the vehicle in a straight line and straddle the pavement edge in order to avoid tire scrubbing.
  • Check for oncoming traffic. Once any oncoming vehicles are out of your vicinity, you can attempt a return onto the pavement at a slower speed. Turn your steering wheel one-quarter turn toward the pavement as you attempt to remount the pavement from the drop-off.

Unsafe Pavement Edge Drop-offs

There are over two million miles of paved roads in the U.S., all under varied administration at local, state, and federal levels.The state of Indiana Department of Transportation (INDOT) requires certain types of road construction to include safety edges and in their book of standards lists approved devices capable of producing these edges.

Unfortunately, there are thousands of miles of roadway nationwide that don’t have this 30 degree slope at their edge, creating an unsafe situation for vehicles that drop off the shoulder. It will likely be many years before all driving surfaces conform to this guideline, as many road departments will only implement it as they repair and resurface roads. This leaves an unsafe pavement edge on many of the roadways we travel each day.

If you or a loved one have been injured in a roadway departure incident, the pavement edge may be an aspect worth examining. An experienced attorney can delve into such details and help you to determine if your legal rights need protection in such a case.

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