What Are Mansfield Bars on a Truck?

You’ve likely noticed steel bars marked with bright reflective tape hanging beneath semi-truck trailers when driving on American highways. These critical safety devices, known as Mansfield bars, have saved thousands of lives by preventing one of the most catastrophic types of accidents on our roads: underride collisions, in which passenger vehicles slide underneath commercial trucks during rear-end crashes.

While Mansfield bars provide essential protection, they aren’t foolproof. Their effectiveness depends on proper installation and maintenance. Over time, damage, rust, or poor upkeep can compromise their ability to protect motorists. Drivers play an important role in highway safety by reporting trucks with missing or damaged Mansfield bars, as these safety violations not only put lives at risk but can also be factors in accident liability cases.

The American Story Behind Mansfield Bars

The history of these safety devices is rooted in tragedy. On June 29, 1967, actress Jayne Mansfield lost her life in a terrible accident when her vehicle collided with the rear of a tractor-trailer that had slowed suddenly. While urban legends about her death persist, the reality of the accident led to significant changes in American trucking safety regulations. The National Highway Traffic Safety Administration (NHTSA) recognized the need for underride protection, and thus, the Mansfield bar was born.

Help prevent truck accidents. Report unsafe trucks and contact the truck accident lawyers at Munley Law.

The Dangers of Underride Accidents

Underride accidents are among the most catastrophic types of crashes on American roads. When a passenger vehicle collides with the rear of a commercial truck, the lower height of the car compared to the truck’s trailer creates a unique and deadly hazard. Without proper protection, the vehicle can slide underneath the trailer, causing the truck’s frame to slice through the passenger compartment of the smaller vehicle.

These accidents are particularly devastating because they can:

• Cause severe head and neck trauma when the roof of the passenger vehicle is crushed or sheared off
• Resulting in immediate fatalities due to the direct impact on the truck’s frame
• Lead to passengers being trapped in severely damaged vehicles, complicating rescue efforts
• Cause catastrophic injuries even at relatively low speeds
• Result in multiple-vehicle pileups if other drivers can’t avoid the initial crash

The severity of these accidents is often heightened by:

• Poor visibility conditions, especially at night or in bad weather
• The significant height difference between trucks and passenger vehicles
• The high speed of many highway collisions
• The weight disparity between commercial trucks and passenger vehicles

How Mansfield Bars Protect Motorists

The following represent the most significant ways Mansfield bars protect motorists in semi truck accidents:

• Underride prevention:  Mansfield bars  protect drivers and passengers by keeping them from sliding underneath semi trailers when collisions happen. That said, not all Mansfield bars prevent all small passenger cars from sliding underneath trucks.
• Impact absorption: A Mansfield bar can also serve as an “extra bumper” that absorbs energy during a crash. Proper energy absorption can reduce the severity of injuries victims sustain. On the other hand, as mentioned previously, a collision with a Mansfield bar can result in injury. Safety features meant to protect victims can, in fact, put them at risk in certain unique scenarios.

There’s no doubt that Mansfield bars have saved lives. Still, research shows that the degree to which a Mansfield bar is effective depends quite a bit on the angle of a vehicle striking it. Other factors, such as whether or not trucking companies install Mansfield bars properly when equipping their vehicles with these safety features, can also play a role in their effectiveness. There’s also debate regarding whether Mansfield guards are safer than bumpers and other such safety features in certain vehicles and situations.

Modern Mansfield Bar Requirements

Federal law now requires certain trailers manufactured on or after January 26, 1998, to have proper rear impact guardsthat meet technical standards and other such requirements outlined in two separate laws. Individual states may also have their own rules regarding Mansfield bars.

Mansfield bar laws don’t just touch on the strength and installation of these safety features when addressing technical requirements. The law also states that Mansfield bars must be maintained so it consistently offers the same protection it did when it was first installed on a truck. This may also require regularly inspecting Mansfield bars to confirm they’re in good condition.

Common Mansfield Bar Failures

The fact that a truck is equipped with Mansfield bars doesn’t always mean they will serve their intended purpose. There are various reasons Mansfield bars can fail. Common examples include:

• Design defects: A Mansfield bar might fail because an inherent flaw with its original design prevents it from being effective. Even if it was correctly installed and maintained, a design defect could render a Mansfield bar useless. Or, it could only allow a Mansfield bar to serve as an effective underride guard in certain conditions. Similarly, while the design of a particular Mansfield bar may be sound, it could be ineffective due to an error in the manufacturing process.
• Maintenance issues: Like any component of a large commercial truck, an underride guard can become less effective over time due to a lack of upkeep. Insufficient maintenance is a common cause of Mansfield bar failure.
• Installation problems: Rear safety bars are the same as virtually all other safety features in a motor vehicle. They are most likely to prevent injuries and fatalities when they’re installed correctly. Improper installation is another reason these vital features can fail. Those responsible for installing Mansfield bars must follow all relevant directions, guidance, and standards properly to minimize the risk of injury in a collision.
• Impact resistance limitations: Remember, in most situations, semi trucks only need to be equipped with Mansfield bars that can resist the impact of passenger cars striking them head-on at speeds of 35 mph. Mansfield bars can fail when the impact of a collision is too great for a steel bar to withstand. A Mansfield bar might also be more likely to fail if a previous collision or impact has compromised its strength or integrity.

Injured due to a defective Mansfield bar? Let Munley Law investigate your case.

Underride Accidents: Types and Risks

Underride collisions come in several potential forms. They include:

• Rear underride collisions: These are the most common types of underride accidents. They occur when vehicles strike trucks from behind, sliding underneath trucks as a result. The risk of injury to victims is very severe in this scenario. Decapitation is a real possibility, as is being crushed by the weight of a large commercial truck.
• Side underride incidents: Although less common, vehicles can get caught beneath trucks when approaching from the side. These types of accidents are statistically less likely to cause serious or fatal injuries partially because, depending on which side a vehicle approaches a truck from, the seats primarily at risk during a side underride accident may be empty. That said, some trucks are also equipped with side Mansfield bars for additional protection.
• Multiple vehicle scenarios: There are various ways for an underride accident to involve multiple vehicles. For example, maybe a car slides underneath a truck because a vehicle behind it struck the car, forcing it under the semi trailer.

Ways to limit your chances of being involved in an underride accident include:

• Practicing general safe driving habits, like obeying the speed limit and responding accordingly to the actions of motorists surrounding you
• Maintaining a safe distance from trucks and other vehicles in front of you, so you have time to stop if they brake suddenly
• Keeping your vehicle in good condition and ensuring components like brakes are in good working order

Improving Truck Safety Beyond Mansfield Bars

Mansfield bars gained adoption throughout the trucking industry due to legislation and data about their potential effectiveness. However, they don’t represent the latest and greatest trucking safety technology and features. Consider the following ways to improve truck safety aside from simply equipping them with Mansfield bars and similar features:

• Additional safety features: Rear cameras, adaptive cruise control, and lane departure warnings are all relatively new features that can further guard against a truck wreck causing serious injury.
• New technologies: Various innovative technologies can help trucking companies reduce the odds of accidents involving their fleets occurring. For example, companies can use GPS fleet monitoring to ensure a truck driver isn’t driving when or where they shouldn’t be. Other technologies are designed to monitor a truck driver for signs of driver fatigue or distracted driving. These technologies provide alerts, helping truckers stay in control at the wheel.
• Industry best practices: We by no means know everything there is to know about trucking safety. As agencies like the NHTSA and others continue to study trends, industry best practices are constantly refined and reworked. If new technologies prove effective with the trucking companies willing to experiment with them, it may eventually become standard across the industry to use these technologies and features. Or, the NHTSA or lawmakers might require trucking companies to adopt new standards.

Legal Support After an Underride Accident

If you’ve been injured in an underride truck accident, the expert trucking accident lawyers at Munley Law will fight for your rights to compensation. Our truck crash attorneys have decades of experience litigating truck and 18-wheeler accident cases. Our trucking law credentials are impeccable; we have three attorneys who have been board-certified by the National Board of Trial Advocacy (NBTA) in truck accident law, have won billions in settlements and verdicts for clients, and are considered among the country’s best truck accident law firms.

We’re the only law firm with two lawyers leading the American Association for Justice’s Trucking Law Group. We educate and lecture other lawyers about truck crash negligence, liability, and damages because we are nationally known as truck crash legal experts. More importantly, we care about our clients and treat them with the respect and compassion they deserve.

Contact Munley Law Today to Protect Your Rights After a Truck Accident

Mansfield bars represent one of American trucking history’s most critical safety advances. While not perfect, they’ve saved thousands of lives since their introduction. As technology advances and safety standards evolve, we can expect even better protection on our roads in the future.

Understanding these safety features helps everyone make better decisions on the road. Whether you’re a commercial truck driver responsible for maintaining these safety devices or a passenger vehicle driver sharing the road with large trucks, knowledge about Mansfield bars contributes to safer highways for everyone.