What Is the FMVSS-116?
FMVSS-116 is a safety standard that was enacted in 1973 by the National Highway Traffic Safety Administration (NHTSA) to regulate the strength of vehicle roofs in rollover crashes. The full name of the regulation is Federal Motor Vehicle Safety Standard No. 116 – Roof Crush Resistance. As a U.S. federal regulation, FMVSS-116 sets forth minimum performance requirements for the roof structures of passenger cars and multipurpose passenger vehicles with a gross vehicle weight rating (GVWR) of 10,000 pounds or less.
The purpose of FMVSS-116 is to reduce deaths and injuries due to roof crush during rollover crashes, which can cause severe head and neck injuries. By regulating the minimum strength requirements for vehicle roofs, FMVSS-116 aims to ensure that roofs provide adequate survival space and impact protection for occupants in the event of a rollover accident. This federal safety standard is an important part of motor vehicle regulations in the United States.
What Does FMVSS-116 Cover?
FMVSS-116 establishes roof crush resistance requirements for passenger vehicles with a gross vehicle weight rating (GVWR) of 10,000 pounds or less (https://www.nhtsa.gov/document/final-rule-federal-motor-vehicle-safety-standards-roof-crush-resistance-phase-reporting-0). This includes most light-duty vehicles on the road today.
Specifically, FMVSS-116 sets performance standards for how much load the roof of a vehicle can withstand before crushing inward by more than 5 inches in a test. This simulates the vehicle being overturned and landing on its roof or a heavy object falling on top of it.
The purpose is to reduce deaths and injuries from roof crush that can occur in rollover crashes or when vehicles are overturned. By improving roof strength, FMVSS-116 aims to provide survival space and head protection for occupants inside the passenger compartment.
So in summary, FMVSS-116 establishes minimum roof crush resistance standards that apply to common passenger vehicles under 10,000 lbs GVWR.
When Was FMVSS-116 Enacted?
FMVSS-116 was first enacted in 1973 as part of the initial Federal Motor Vehicle Safety Standards introduced under the National Traffic and Motor Vehicle Safety Act. This original version of the standard specified performance and equipment requirements for motor vehicle brake fluids in order to reduce failures in the braking system caused by defective or contaminated brake fluid.
A major update to FMVSS-116 came in 2009, as detailed in this Federal Register notice. This update modified the standard to include new test procedures and performance requirements related to brake fluid shelf life, boiling point, viscosity, and corrosion. The changes aimed to improve brake system performance and reduce brake failure incidents.
The current version of FMVSS-116 is from 2016 and incorporates previous amendments up to that point. It specifies requirements for brake fluid in hydraulic brake systems used on motor vehicles with a gross vehicle weight rating of 10,000 pounds or less.
FMVSS-116 Roof Crush Standards
The key component of FMVSS-116 is the roof crush resistance standard that sets requirements for how much force the roof of a vehicle must be able to withstand before collapsing inward. This simulates the crushing force that could be applied to a roof during a rollover crash.
Specifically, FMVSS-116 requires that when a metal plate presses down on one side of a vehicle’s roof with a force equal to 1.5 times the unloaded weight of the vehicle, the roof cannot crush more than 5 inches. For example, for a 4,000 pound vehicle, the test would apply a force of 6,000 pounds. The standard applies to both passenger cars and multipurpose vehicles weighing up to 6,000 pounds gross vehicle weight rating (GVWR).
To test compliance, a vehicle is oriented roof-up on a rigid horizontal surface. Hydraulic rams then apply force through a stiff plate until reaching the required load, held for 5 seconds. Measurements are taken of the roof crush distance relative to the original roof height prior to testing. Vehicles must meet the requirements when tested on both sides of the roof.[1]
This standard is designed to reduce occupant injury and fatalities in rollover crashes, which accounted for over 10,000 deaths in the U.S. in 2017. Strong roof crush resistance helps create survival space and prevent intrusion into the passenger compartment.
FMVSS-116 Compliance Testing
Compliance testing is conducted by the National Highway Traffic Safety Administration (NHTSA) and vehicle manufacturers to ensure vehicles meet the requirements outlined in FMVSS-116. There are specific test procedures that must be followed to evaluate roof strength and measure performance during a rollover crash.
NHTSA has a rollover test fixture that allows a vehicle to be rotated to simulate a rollover event. The vehicle is rotated at a speed of 30 degrees per second until a full 360 degree rotation is completed. Forces are gradually applied to one side of the roof at a rate of 5 inches per minute by a metal plate. This continues until the roof is crushed to the extent where the applied force reaches three times the unloaded weight of the vehicle or 22,240 pounds, whichever is less. The maximum amount of crush is recorded along with the force required to reach that point.
Manufacturers are required to self-certify their vehicles meet the minimum requirements. They conduct their own compliance testing either in-house or through contracted facilities that have the proper equipment and expertise. Some examples of compliance test labs certified by NHTSA include ACT Lab LLC and Calspan Corporation.
Vehicles must demonstrate they do not exceed a maximum of 127 mm (5 inches) of roof crush when subjected to 1.5 times the vehicle’s unloaded weight. Light trucks can have up to 254 mm (10 inches) of crush but no more than 5.9 times the curb weight. This helps validate the structural integrity of the roof system and its ability to withstand forces during rollover crashes.
FMVSS-116 Exemptions
The FMVSS-116 safety standard applies to all passenger vehicles sold in the United States. However, NHTSA has granted some exemptions for certain vehicle types where meeting the roof crush requirements would interfere with the intended design and function of the vehicle.
One exemption is for convertible vehicles, where strengthening the roof would negatively impact the ability to retract the roof. NHTSA has allowed convertibles to meet a less stringent standard of providing protection against 1.5 times the unloaded weight of the vehicle. This exemption acknowledges the engineering challenges for convertible roof designs while still requiring a minimum level of rollover protection.
Law enforcement and emergency vehicles have also been granted exemptions from certain aspects of FMVSS-116. For example, police cars often have equipment mounted on the roof which can interfere with crush resistance. There are also exemptions for vehicles outfitted with temporary emergency lighting bars mounted on the roof. The exemptions require these vehicles to still meet baseline requirements while accounting for their unique intended usage.
Overall, exemptions are only granted in specific cases where compliance would fundamentally conflict with the primary design and function of the vehicle. The exemptions aim to strike a balance between safety and practicality for specialized vehicle types. Most standard passenger vehicles are still required to fully comply with all aspects of FMVSS-116.
FMVSS-116 Controversies
FMVSS-116 has faced criticism and controversy over the years from safety advocates who argue that the standards are inadequate. One major area of criticism relates to the strength requirements for roof crush. When FMVSS-116 was first enacted in 1973, it required that passenger vehicle roofs withstand a force equal to 1.5 times the unloaded vehicle weight. However, critics argued this was insufficient, as rollover crashes often exert forces of 3-6 times the vehicle weight on the roof.
In 2009, NHTSA upgraded FMVSS-116 to require roofs withstand 3 times the unloaded vehicle weight, phased in between 2012 and 2017 depending on vehicle weight [1]. However, advocates argue the standards should require roofs to withstand 4 or 5 times the vehicle weight. Stronger roofs would reduce intrusion into the occupant survival space and prevent ejection, resulting in fewer deaths and injuries.
Another area of controversy relates to FMVSS-116’s limited applicability. The standard only applies to passenger cars, multipurpose passenger vehicles, trucks, and buses with a GVWR of 4,536 kg (10,000 pounds) or less. Critics argue that heavier vehicles, like commercial trucks and school buses, should also be required to meet roof strength requirements.
Overall, while FMVSS-116 has improved vehicle safety, many argue that strengthening the standards further could prevent thousands of additional deaths and injuries from rollover crashes each year. This debate between regulators, industry, and safety advocates is likely to continue as long as rollover crashes remain prevalent.
FMVSS-116 Violations
Notable violations of FMVSS-116 include automakers being fined millions of dollars for safety defects related to roof strength. In 2009, NHTSA fined Toyota $16.375 million for failing to notify the agency about roof strength problems in a timely manner. An investigation found that the roofs of some Toyota models like the Sequoia and RAV4 didn’t meet the FMVSS-116 standard.
In 2014, Nissan was fined $64 million after NHTSA discovered the automaker had been conducting unauthorized testing that compromised FMVSS-116 compliance for certain vehicles. Nissan failed to maintain proper records and notify NHTSA of the improper testing procedures.
Other major manufacturers like Honda, Ford, and Mazda have also faced penalties related to violating FMVSS-116 standards and reporting requirements over the years. The penalties highlight the importance of strict compliance with roof crush regulations to protect vehicle occupants.
The Importance of FMVSS-116
FMVSS-116 is crucial for improving vehicle safety and saving lives. By strengthening roof crush standards, FMVSS-116 enhances rollover protection and reduces the risk of occupant injury or death in the event of a rollover accident. According to research from the National Highway Traffic Safety Administration (NHTSA), rollover crashes account for nearly 35% of all occupant fatalities in light vehicles in the U.S. (Source). By requiring stronger roofs that do not crush as easily, FMVSS-116 aims to prevent roof intrusion into the occupant compartment during rollovers, providing greater survival space.
The updated FMVSS-116 standards in place since 2012 require roofs to withstand loads equivalent to 3.0 times the unloaded vehicle weight, compared to just 1.5 times previously. This doubling of the load requirement has significantly improved roof strength and rollover protection across the automotive industry. According to NHTSA data, the enhanced FMVSS-116 standards are preventing an estimated 135 fatalities annually. In addition, the upgrades are estimated to prevent over 1,900 moderate to severe injuries each year in the U.S. (Source). By enhancing roof crush resistance, FMVSS-116 is playing a key role in reducing rollover deaths and injuries.
The Future of FMVSS-116
FMVSS-116 will likely see updates and changes in the future as automotive technologies continue to advance. Some potential updates and outlooks for FMVSS-116 include:
Potential updates for electric vehicle brake fluids – As more electric vehicles enter the market, FMVSS-116 may need to be updated to account for standards and testing procedures specific to electric vehicle brake fluids rather than traditional hydraulic brake fluids.
New performance requirements – Stricter requirements may be introduced for fade and recovery, corrosion, or boiling points as brake system technologies improve.
Changes to compliance testing – New test procedures could be introduced to evaluate emerging brake technologies like brake-by-wire or regenerative braking systems.
Exemptions for autonomous vehicle technologies – FMVSS-116 rules pertaining to split service brake systems may require exemptions to account for autonomous driving systems with integrated braking.
Overall, changes to FMVSS-116 will be driven by innovations in brake fluids, manufacturing, and autonomous driving capabilities. The standard will need to evolve to ensure vehicle braking system safety keeps pace with emerging technologies. But the overarching goal of FMVSS-116, to regulate brake fluid properties for safe vehicle stopping power, will remain unchanged even as the specifics are updated.