Estimating the Effect of Passengers in Fatal and Non-fatal Crashes Involving Teen Drivers

Previous studies have shown that young drivers’ risk of fatal crash involvement is elevated when passengers are present in the vehicle. However, this finding has been observed mainly in studies of fatal crashes; studies that have examined non-fatal crashes have found weaker associations. For example, a naturalistic study which measured the driving exposure and crash involvement of the same individuals found no association between the presence of passengers and teen driver crash risk after controlling for other factors. This discrepancy could potentially be attributable to uncontrolled confounding or bias in studies that have examined passenger presence in fatal crashes and in government travel surveys to calculate crash rates. This study seeks to investigate the relationship between the presence of passengers and a driver’s crash risk using an innovative statistical method that does not rely on direct measurement of driving exposure. The crash incidence ratio (CIR) quantifies the association of a risk factor with crash involvement using only crash data (not relying on driving exposure data). The CIR is a measure of prevalence of some factor of interest (e.g., passengers) in crashes of a group of interest (e.g., teens) relative to among all drivers in crashes. This method does not rely on the assumptions inherent in studies that compute exposure-based crash rates using separate sources of data for crashes and for driving exposure, yet it can be applied to the large samples available in crash databases rather than only the much smaller samples available in naturalistic driving studies. This study will compute the CIR using data from the 2016 Fatality Analysis Reporting System (FARS) database and the Crash Report Sampling System (CRSS) to investigate all crashes, including those that are fatal and non-fatal. Additional analysis will be performed to investigate the association of passenger presence with death or injuries of the drivers themselves, the passenger, and other road users such as occupants of other vehicles, and non-motorists. Additionally, the CIR will also be obtained for drivers in speeding involved crashes and nighttime crashes. Presence of passengers. The CIR for the presence of passengers decreases with the age of the driver. This implies that the prevalence of them carrying a passenger decreases in fatal crashes, as drivers get older. Following a similar trend as the presence of passengers, when a fatality involving a teen driver occurs, the CIR odds of it being a speeding-related crash is highest compared to all other age groups. Similarly, this trend declines with age of the driver. Teen drivers may need additional training in their ability to drive safely especially when a passenger is in their vehicle. Likewise, additional analysis showed that speeding demonstrated a particular problem area for teen drivers. Interestingly, nighttime driving appears most dangerous among 25-29-year-old drivers, perhaps owing, in part, to drinking and driving.

  • Supplemental Notes:
    • This paper was sponsored by TRB committee ANB30 Standing Committee on Operator Education and Regulation.
  • Corporate Authors:

    Transportation Research Board

  • Authors:
    • Villavicencio, Leon
    • Svancara, Austin
    • Kim, Woon
    • Kelley-Baker, Tara
    • Tefft, Brian C
  • Conference:
  • Date: 2019


  • English

Media Info

  • Media Type: Digital/other
  • Features: References;
  • Pagination: 4p

Subject/Index Terms

Filing Info

  • Accession Number: 01697715
  • Record Type: Publication
  • Report/Paper Numbers: 19-04311
  • Files: TRIS, TRB, ATRI
  • Created Date: Mar 1 2019 3:51PM