SHRP 2 NDS participants were invited to participate in the Cell Phone Records Study (CPRS) when they exited the NDS study. CPRS participants were required to be 18 years old or older at the time they agreed to join the CPRS and to have been enrolled in the NDS for at least 3 months. CPRS participants were compensated. Call and text data were limited to the date, time, duration, and direction (incoming or outgoing). No personally identifiable data were included. AT&T and Verizon provided electronic records for their customers, as authorized by the account holders. Participants with other cell phone carriers were able to provide their own records. Cell phone records were acquired from 620 drivers. The records contain approximately 1.4 million individual call events, approximately 209,000 of which overlap with NDS driving data. Approximately 4.9 million text events were collected, and approximately 274,000 overlap with driving data. The SHRP 2 NDS is the first large-scale study focused on collision prevention (as opposed to injury prevention once a collision occurs) since the Indiana Tri-Level Study (Tri-Level Study of the Causes of Traffic Accidents: Final Report, DOT HS-805 085, U.S. Department of Transportation, May 1979). Vehicle use was recorded continuously during the SHRP 2 NDS. Information on vehicle travel, or exposure, can be extracted at the same level of detail as for safety-related events, such as crashes and near crashes. Hence, the SHRP 2 NDS is the first large-scale study to support detailed estimates of collision risk. Moreover, crashes are a leading cause of nonrecurring congestion, so collision prevention has added benefits in terms of reduced delay, fuel consumption, and emissions. The NDS provides objective information on the role of driver behaviour and performance in traffic collisions and on the interrelationship of the driver with vehicle, roadway, and environmental factors. This report details the methodology used to acquire cell phone use records from a subset of participants in the SHRP 2 Naturalistic Driving Study (NDS) during the time when they were enrolled in the study. The cell phone records were then matched with participants’ NDS driving data to identify the times while they were driving when they may have been using their cell phones. These data will help researchers quickly and accurately identify events of interest in the NDS database related to cell phone use, from which researchers can learn crucial information about driver behaviour and changes in crash risk when drivers choose to use or not to use cell phones. This report provides researchers with essential information about the Cell Phone Records Study (CPRS) data and how the data were collected. It describes the methods used to recruit and enrol CPRS participants, the collaboration with the cell phone carriers, and the processes of obtaining data from the carriers and directly from the participants. It also provides summary information on the data collected and discusses some limitations of the data. (Author/publisher)
Samenvatting