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Table 3 Objective driving behavior variables and definitions used in the Longitudinal Research on Aging Drivers (LongROAD) study

From: Longitudinal Research on Aging Drivers (LongROAD): study design and methods

Name Definition
Year Calendar year
Month Calendar month
Subject no. Participant identification number
Days driving Total number of days in month with at least one trip
Trips Total number of trips in month
Miles Total number of miles driven in month
Miles per trip Total number of miles driven in month divided by total number of trips in month
Total trip minutes Total minutes of driving in month
Minutes per trip Total driving minutes in month divided by total number of trips in month
Trip chains Number of trip chains in month (Note: chain is a series of trips starting and ending at home)
Minutes per chain Total driving minutes for chains divided by the number of trip chains in month
Miles per chain Total miles of chains in month divided by total number of trips chains in month
No. trips at night Number of trips during which at least 80% of trip was during nighttime in month (Nighttime was defined as civil twilight or a solar angle greater than 96 deg)
% trips at night Percent of all trips at nighttime
No. trips during day Number of trips in month not classified as nighttime
% trips during day Percent of trips in month not classified as nighttime
No. trips in AM peak Number of trips in month during 7–9 AM on weekdays
% trips in AM peak Percent of trips in month during 7–9 AM on weekdays
No. trips in PM peak Number of trips in month during 4–6 PM on weekdays
% trips in PM peak Percent of trips in month during 4–6 PM on weekdays
No. trips on high speed roads Number of trips in month where 20% of distance travelled was at a speed of 60 MPH or greater
% trip on high speed roads Percent of trips in month where 20% of distance travelled was at a speed of 60 MPH or greater
No. trips <15 miles of home Number of trips traveled in month within 15 miles of home
% trips <15 miles of home Percent of trips traveled in month within 15 miles of home
No. trips <25 miles of home Number of trips traveled in month within 25 miles of home
% trips <25 miles of home Percent of trips traveled in month within 25 miles of home
No. left turns Number of left turns made in month
No. right turns Number of right turns made in month
Right to left turn ratio Ratio of all right-hand to left-hand turning events for a driver in a month
No. high deceleration events Number of events with deceleration ≥0.4 g in a month (hard braking, near crash)
No. speeding events Number speeding events in month (speed ≥80 MPH sustained for at least 8 s)
  1. Trip is defined as a non-zero distance between vehicle engine on-to-off time