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Human Factors Research on Seat Belt Interlocks

Project #: 4W4693
Start Date: 09/26/2013
End Date: 12/30/2017

Almost all states in the United States have enacted legislation that mandates the use of seatbelts for adults, and enforcement of mandatory seatbelt laws has greatly increased seatbelt use. Seat belt use has increased from 54 percent in 1994 to more than 86 percent in 2012. Further increases in belt use of front seat occupants to near 100 percent would continue to produce substantial reductions in injury and fatality. However, recent increases in seat belt use have been modest, suggesting there is some need for new seat belt use enforcement.


In-vehicle belt interlock technology is a promising way to promote belt use, since it can monitor belt use and provide immediate feedback whenever an occupant is unbuckled. To date, no field data have been collected or testing has been performed that involves both user and non-user driver populations interacting with the different interlock types.


In this project, the University of Michigan Transportation Institute (UMTRI), General Motors (GM), and WTI will collaborate to perform field operational tests on currently available interlock systems to provide data on the functional approach, the system effectiveness, the consumers’ acceptance, any unintended consequences (e.g., avoidance strategies), and likely cost. The objective of this project is to compare user experience between both belt-user and non-belt-user drivers when interacting with different interlock technologies. In this proposed study, UMTRI will lead the effort, identify current practice on the interlock systems, conduct the field test and interpret the results, while GM, along with other potential OEMs, will provide the use of interlock systems and technical support during the test. Through this project, WTI will perform a review of relevant literature and support the development of survey instruments to assess the usability of the technology, as part of Task 1 and 2 of the overall research effort.


The objective of this project is to compare user experience between both seatbelt-users and non-seatbelt-user drivers when interacting with different interlock technologies.


  • Nic Ward
    Nic Ward


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