Date of Award
Master of Science
Civil, Construction, and Environmental Engineering
Iowa started enforcing a graduated driver license (GDL) system on January 1, 1999. The system requires a three-step process for full licensing: Instruction Permit at 14 years of age at the earliest; Intermediate Licensure at 16 years of age at the earliest; and Full Licensure at 17 years of age at the earliest. Under the system, full driving privileges without restriction cannot be obtained until the age of 17. This report will demonstrate the before and after effects the GDL has had on teenage crashes (14 to 18 year olds) by comparing the following unique identifiers, which were found in the Iowa crash records database: crash severity, injury status/severity, number of fatalities, number of injuries, time of crash, rural/urban, first harmful events, light condition, manner of crash/collision, vehicle configuration, total occupants, alcohol test administered, alcohol test results, and driver condition. The analysis of the pre-1999 data shows that 14 to 18 year old drivers had substantially more crashes and violations in those years after 1999. A higher percentage of their crash involvements are due to driver condition, alcohol test administered, alcohol test results, vehicle action, number of occupants in the vehicle, location (rural versus urban), time of day, first harmful events (non-collision and collision), light condition, manner of crash/collision, crash severity, injury status/severity, number of fatalities compared to the number of injuries, and contributing circumstances.
Deborah Lora Witt
Witt, Deborah Lora, "Before and after effects of the Iowa graduated driver licensing program" (2004). Retrospective Theses and Dissertations. 20311.