Analyzing the Effect of Driver Age on Operating Speed and Acceleration Noise: On-Board Second-by-Second Driving Data

The objective of this research was to characterize the second-by-second driving style of older drivers to account accurately for differences in lead-vehicle operations for different subgroups of drivers. The project focused on differences by age and used field data collected with in-vehicle instrumentation on a predefined route. The sample set included 19 individuals older than age 70 and 16 individuals between the ages of 21 and 35 years. Trends and differences in unconstrained speed and acceleration noise— including interactions with intersection departures, posted speed limits, grade, and horizontal curvature—were explored. The speeds of younger drivers were up to 3 mph greater than those of older drivers; variations were also attributable to geometric roadway characteristics. Most notably, the speed of younger drivers was influenced 64.5% more than the speed of older drivers by the curvature change rate in 35 mph zones. Older drivers were influenced 87% more than younger drivers by grade in 25 mph zones. Results reinforced the importance and feasibility of accounting for driver style in traffic simulation and emissions modeling and emphasized that age and geometric features were valuable factors for defining typology. Large robust data sets of driving behavior are needed to calibrate models of lead-vehicle behavior.