Measuring the Effect of Passengers on the Safety of Older Drivers

Older drivers cause a disproportionate number of traffic crashes. With the continued increase in the number of older drivers there is significant motivation to further understand the many factors causing these high crash rates. The proposed research will determine whether including or avoiding different passengers groups in the vehicle could improve the safety records of older drivers. One can hypothesize that passengers might represent either a distraction or an advantage (e.g., "extra" helpful eyes on the road and traffic). No significant research on the effect of passengers exists for older drivers. Because the number of teenage passengers in a vehicle has been shown to negatively impact young driver safety in several research studies, limitations on the number of passengers a young driver can carry has become a key component in many state graduated driver licensing systems. In contrast, our previous preliminary research has shown that adult passengers may have a positive effect on older driver safety (Padlo et al. 2006). The proposed study will make use of the quasi-induced exposure methodology. The effect of the number, age and gender of passengers on the crash-causing propensity of older drivers will be evaluated. Five years of data from 3 states will be used in the disaggregate analysis; making the results of this research appropriate for potential nationwide countermeasure development. It has been well documented that the aging process generally reduces one's capability to operate an automobile safely. Older drivers face a variety of physical barriers to safe continued automobile use and show high crash involvement ratios. In certain traffic conditions, older drivers have been found at fault in a disproportionate number of crashes compared to other age groups. Although it is speculated that older drivers often practice compensatory driving practices (driving slower, avoiding inclement weather), the types of crashes in which older drivers are most frequently involved are consistent with declines in visual skills. In the last few decades, the professional community has been increasingly concerned with the traffic safety of older drivers as senior citizens are the fastest growing segment of the population in the United States. Countermeasures to improve older driver safety have included driver license re-testing, new technologies, and education to improve the older driver's choice to drive or not drive. The number of passengers in a vehicle has been shown to impact young driver safety in several research studies. Research by the authors of this proposal has shown that the presence of additional young people as passengers increases the crash propensity of the young drivers, while the presence of adult passengers decreases this propensity. The influence of the number of passengers in a vehicle is so significant for young drivers that limitations on the number of passengers a young driver can carry have become a key component in the graduated driver licensing systems that have proliferated across the states. No research on the impact of passengers exists for older drivers. It is possible that the number and age of passengers may pose problems or perhaps provide helpful assistance for the older drivers. Preliminary research, undertaken with Kentucky and Connecticut crash data, showed an improved safety effect of passengers for some older drivers but not others. While it is unlikely a reverse system of graduated licensing could be established for older drivers, creating the knowledge base for how vehicle occupants affect older driver safety would allow further education countermeasures to improve older driver decision making. For example, perhaps wide promotion of the idea of "Drive with a Buddy" would change the driving habits of older drivers. The objective of this research is to evaluate the effect of the number, age and gender of passengers on the crash propensity of older drivers using the quasi-induced exposure technique and 5 years of data from 3 states (Maine, Connecticut and Kentucky). The overall relative impact of passengers on older drivers will be compared to other adults. Furthermore, disaggregate analysis will be undertaken with the older driver crash records to determine if the impact of passenger groups varies by older driver age and gender, as well as driving circumstances such as day versus night, road type and rural versus urban locations. Single and multiple vehicle crashes will be considered separately and cross state comparisons will be made.


    • English


    • Status: Completed
    • Contract Numbers:



    • Sponsor Organizations:

      Research and Innovative Technology Administration

      Department of Transportation
      1200 New Jersey Avneue, SE
      Washington, DC  United States  20590
    • Performing Organizations:

      UVM Transportation Center

      University of Vermont
      210 Colchester Avenue
      Burlington, VT  United States  05405
    • Principal Investigators:

      Aultman-Hall, Lisa

    • Start Date: 20060901
    • Expected Completion Date: 0
    • Actual Completion Date: 20070831
    • Source Data: RiP Project 19605

    Subject/Index Terms

    Filing Info

    • Accession Number: 01466333
    • Record Type: Research project
    • Source Agency: New England University Transportation Center
    • Contract Numbers: DTRS99-G-0001, UVMR19-11
    • Files: UTC, RiP, USDOT
    • Created Date: Jan 3 2013 3:14PM