RECENT REVIVAL
As part of the Moving Ahead for Progress in the 21st Century Act in 2012, the NHTSA allowed automakers to equip vehicles with seat belt interlocks as a way to meet federal safety requirements. These interlocks might prevent the vehicle from starting if an occupant does not wear their seat belt, but can also cut off another feature such as the entertainment system. The legislation also allows the NHTSA to have seat belt reminders last longer than the current limit of eight seconds.
The NHTSA hasn't yet strengthened its requirements on seat belt reminders or seat belt interlocks, but some manufacturers have expressed interest in the technology. In 2013, the agency denied a petition from BMW asking to use a seat belt interlock system to meet some safety requirements. BMW argued that the technology would help reduce its vehicles' weight and make them more spacious, but the NHTSA said further research was needed to determine whether the devices would be effective in increasing seat belt use.
General Motors became the first automaker to offer a seat belt interlock system, although the technology was only available on certain 2015 models sold to fleets rather than mainstream vehicles available for purchase. GM's Seat Belt Assurance System, which was present on the Cruze vehicles used in the IIHS study, prevents the driver from shifting the vehicle into gear for 30 seconds after ignition or when parked unless the front seat occupants are wearing their seat belts.
Every state but New Hampshire requires front seat vehicle occupants to wear their seat belts. However, the number of unrestrained people killed in crashes increased 4.6 percent to 10,428 in 2016. This accounted for about 43 percent of all fatalities in passenger vehicles and large trucks.
Some people choose not to wear a seat belt due to discomfort or the belief that it is unnecessary for short trips, while others occasionally forget to put it on. IIHS estimates that drivers and front seat occupants who use a lap and shoulder belt reduce their risk of a fatal injury by 45 percent in a car and 60 percent in a pickup truck, SUV, or van.
IIHS estimates that gearshift interlocks could increase seat belt use by 16 percent in the United States and save at least 718 lives each year. Researchers also estimate that another 358 lives a year could be saved if the interlocks could not be bypassed.
"Interlocks should be intrusive enough to get the attention of unbelted drivers and front passengers, but at the same time they shouldn't aggravate the vast majority of people who always use belts," said Kidd.