Mansfield Bar On Trucks: Are They Effective?

Mansfield Bars on Trucks 

Trucking companies and truck owners install Mansfield bars to cover the high clearance of semi-trucks and large vehicles. Mansfield bar manufacturers market the feature as an additional protection that prevents passenger cars from sliding underneath trucks in the event of a crash.

Although the Mansfield Bars on Trucks proved successful after the initial crash tests, further studies showed its effectiveness largely depends on the impact angle. Similarly, a change in trajectory vastly decreases the success rate.

A Mansfield bar is not as effective as bumpers, meaning it can’t absorb energy as bumpers do to prevent injuries. The height is also a limitation and may not protect all passenger vehicles and motorcycles.

Consult a trusted Baltimore truck accident lawyer for legal support if you’ve sustained injuries in an accident involving a negligent truck driver.

What Is a Mansfield Bar?

Mansfield bars are metal features underneath semi-trucks and other large vehicles. They’re also called underride guards. They prevent cars from sliding underneath trucks to prevent severe or fatal car accident injuries.

Most semi-trucks don’t have low bumpers, so there is no barrier to stop passenger cars from sliding beneath the truck. The lack of low bumpers also means little protection to absorb the impact of rear-end collisions.

Mansfield bars instill an extra layer of protection in semi-trucks and other large vehicles. They are mandated for specific large commercial vehicles and can absorb the extent of impact during rear-end collisions between passenger cars and semi-trucks.

The Tragic Origin of the Mansfield Bar 

In response to a rising number of deaths and injuries caused by passenger cars crashing beneath semi trucks and trailers, the federal government instituted a few regulations. Certain large vehicles were mandated to install underride guards, later named Mansfield Bars, in the future to prevent injuries and deaths.

The first regulations for underride guards were passed in 1953, with subsequent updates to include modern vehicles without bumpers.

Originally known as underride guards, Mansfield Bars gained its new name ten years later following a tragic accident that resulted in several deaths. 

In June of 1967, a famous actress, Jayne Mansfield, and her children, driver, and lawyer were involved in an accident due to foggy weather that decreased driver visibility. The lack of visibility blinded Mansfield’s driver’s vision, colliding with a semi-trailer.

The collision sheared off the roof, killing Mansfield, the lawyer, and the driver, with her three children in the back seat surviving the incident. The tragedy re-awakened the interest regarding underride guards and their importance.

The safety feature changed its name to Mansfield Bars, as experts believe if the semi-trailer had underride guards, Jayne Mansfield, her driver, and her lawyer may have survived the crash.

Mansfield Bars on Trucks Today

Two changes have been made to the original 1953 safety standards for underride guard bars or Mansfield rules: first in 1998 and, more recently, in 2022, when the National Highway Traffic Safety Administration (NHTSA) upgraded the underride system.

NHTSA increased the required strength of Mansfield Bars to reduce potential injuries and property damage of passenger vehicles that collide with underride guards at 35mph. Truck companies must comply with the NHTSA requirements for underride guards.

Trucking companies are also responsible for inspecting the efficacy of Mansfield bars on their vehicles. Transportation companies should also keep up with changes to NHTSA regulations and make changes to Mansfield bars as necessary.

Are Mansfield Bars Effective?

The original concept of Mansfield Bars is to protect passenger vehicles that might otherwise slide beneath semi trucks and sustain severe injuries or death. Even so, the current underride guard regulations may only protect some drivers.

The effectiveness of Mansfield bars is still up for discussion. For instance, no rule requires installing side Mansfield bars on semi-trucks and large vehicles. Therefore, if a side-impact collision occurs, nothing stops a passenger vehicle from riding underneath the car.

Although Mansfield bars supplement the strength of bumpers, they lack the original qualities of bumpers. For instance, underride guards do not absorb energy like a front bumper, nor do they ensure vehicle occupants do not sustain injuries in case of a rear-end collision.

Although Mansfield Bars can protect vehicle occupants from severe injuries, they can also cause substantial damage to other vehicles. 

Lastly, an underride guard can break your windshield depending on your vehicle’s height. If you’re not wearing a seatbelt at the time of the accident, you can suffer an impact with a Mansfield Bar, which can cause severe or fatal injuries.

The consensus is that while underride bars may prevent certain accidents and the severity of some injuries, they don’t offer complete protection. In addition to NHTSA guidelines, trucking companies can install Mansfield Bars with better absorbent qualities to enhance road safety.

Mansfield Bars: Associated Risks

While underride guards offer enhanced protection in a collision with passenger vehicles, the danger they pose to other road users depends on the operators. For instance, driver fatigue, distracted driving, and speeding are the leading causes of semi-truck accidents.

Although Mansfield Bars have safety features, they might cause injuries in certain circumstances. Since they are made of steel and located at the eye level of passenger vehicles, they can cause severe injuries upon impact.

An impact with an underride bar can cause several injuries, including broken bones, severe head trauma, or limb amputation. The severity of injuries increases when trucking companies install underride bars at an inappropriate height or when a collision involves a passenger without a seat belt.

If a passenger car hits an underride guard that meets all regulations, the chances of injury decrease. Further, when a vehicle hits a Mansfield Bar at an angle, the chances of injury increase.

Dangers in Mansfield Bars

Despite their intended purpose, these mechanisms come with significant risks that can worsen the severity of truck accidents. Although they can prevent some underride collisions, they are far from perfect, and many risk factors can lead to extreme or even fatal injuries.

Injuries

They are typically made of steel and positioned at approximately eye level (when seated) for occupants of smaller vehicles. This means that when a car strikes the bar, the impact can result in severe damages, including broken bones, head trauma, and, in the worst cases, decapitation. These impairments are often life-threatening and can have long-term consequences for survivors. Even well-constructed bars don’t always prevent such outcomes, as highlighted by the Insurance Institute for Highway Safety (IIHS).

Improper Installation

They must be installed at the proper height and angle to function correctly. If the mechanism is not positioned correctly, it is less likely to prevent underride accidents, significantly increasing the threat of harm or death. Many older trucks or trailers may still be equipped with outdated or poorly placed bars, which fail to provide the necessary protection during a crash. This is why routine security checks are essential for all commercial vehicles.

Angle of Impact

One significant limitation is that they are primarily designed to prevent rear-end collisions, but they offer limited security in angled impacts. If an automobile strikes a truck from the side, the bar may fail to stop it from sliding underneath, which might lead to potentially fatal consequences. This vulnerability is particularly concerning on highways like I-95 or I-83, where high-speed lane changes can result in vehicles hitting trucks at sharp angles.

Speed

Their effectiveness diminishes considerably as the vehicle’s velocity increases. At higher speeds, the force of the impact can exceed the strength of the bar, causing it to collapse and fail to prevent an underride. This is notably concerning on Baltimore’s major highways, where traffic often moves at a high pace. Drivers who impact with the rear of a truck at 40 miles per hour or more are at a much greater chance of harm.

Seatbelt Usage

While wearing a seatbelt is always essential, it becomes even more critical in underride crashes. If passengers are not wearing one, the likelihood of fatal injuries increases dramatically. The belt strap helps keep occupants in place during a collision, but without it, the force of impact may cause them to crash directly with the Mansfield bar or other parts of the vehicle.

Poor Design

Some underride guards are poorly designed or outdated, failing to meet modern protection standards. These inadequately constructed bars may buckle under pressure or fail to absorb enough energy from the impact, leading to catastrophic results. In recent years, safeguarding advocates have called for stricter regulations and improved designs to reduce the risk of incidents.

Inadequate Strength

To be effective, the device must meet specific strength and size requirements. The bars may provide limited protection if these criteria are not met, leaving smaller vehicles vulnerable during a collision. The Federal Motor Carrier Safety Administration (FMCSA) supports stronger underride guards regulations to reduce accidents and fatalities.

Lack of Regulation

Despite advancements in assurance, there are still no federal mandates for side underride guards in the U.S., which leaves vehicles susceptible to sliding underneath the sides of trucks during side-impact collisions. Without these protections, fatalities can still occur, leading safety advocates to demand more comprehensive regulations. The National Truck Equipment Association (NTEA) is actively pushing for higher standards for both rear and side underride guards to enhance security on the roads.

Are Mansfield Bars an Effective Solution to Rollovers?

No, the bars are not designed to prevent rollovers. They are only effective in underride crashes and offer no protection in accidents where a truck can potentially crush smaller vehicles. Motorists should be aware that while these mechanisms play a role in road safety, they do not mitigate the full spectrum of hazards, such as side impacts or trucks tipping over. Practicing safe driving and keeping a safe distance from large trucks is essential for everyone’s well-being.

Injured in a Truck Accident? Get in Touch With Experienced Personal Injury and Trusted Legal Advisors

If you suffered injuries in a truck crash, you likely have extensive losses and wonder about your legal rights. Never wait to seek representation from an experienced attorney from Bob Katz Law, who’ll aggressively fight for a fair settlement value for your losses.

Contact us online or at 410-576-4287 to schedule a consultation.

Timothy J. Capurso

Timothy J. Capurso is chair of the firm’s Personal Injury Practice Group. He concentrates his practice on personal injury cases of all types, focusing on automobile accidents. His background includes litigating personal injury cases from inception through trial and settlement negotiations. 25+ years of experience.

Contact Timothy J. Capruso