Implementing Surrogate Safety Measures in Driving Simulator and Evaluating the Safety Effects of Simulator-Based Training on Risky Driving Behaviors

Table 1

Description of implementable surrogate safety measures.

Relation with surrounding vehicles	No.	Surrogate safety measure	Unit	Description
Relating to the subject vehicle	1	Accumulated speeding (AS)	kph	The normalized relative area (per unit length) bounded between the speed profile values higher than the speed limit and the speed limit line [28]
	2	Speed uniformity (SU)	kph	The normalized relative area (per unit length) bounded between the speed profile and the average speed line [28]
	3	Speed variation (SV)	kph	The standard deviation of the speed
	4	Acceleration (%)	m/s^2	The acceleration of the subject vehicle
	5	Deceleration (%)	m/s^2	The deceleration of the subject vehicle
	6	Acceleration noise (AN)	m/s^2	The root mean square deviation of the acceleration [29]
	7	Lane deviation	m	The standard deviation of lane position [30]
	8	Yaw rate (%)	°/s	The rotational velocity around the z-axis of the subject vehicle [31]
	9	Lane change (%)	—	The number of lane change manoeuvres completed
Relating to surrounding vehicles	10	Gap distance (%) (GD)	m	The longitudinal distance along a travelled way between one vehicle's leading surface and another vehicle’s trailing surface [32]
	11	Proportion of stopping distance (%) (PSD)	—	The ratio of the distance available for manoeuvring to that of the necessary stopping distance to a projected point of collision [33]
	12	Time-to-collision (%) (TTC)	sec	The time interval required for one vehicle to strike another object if both objects continue on their current paths at their current speed [32]
	13	Modified TTC (%) (MTTC)	sec	The time interval required for one vehicle to strike another object if both objects continue on their current paths at their current speed and acceleration [32]
	14	Deceleration rate to avoid crash (%) (DRAC)	m/s^2	The deceleration required by the following vehicle to come to a timely stop or attain a matching lead vehicle speed to avoid a rear-end crash [34]
	15	Min_Front_GD	m	The minimum value of gap distance (GD) with leading vehicle of current lane in lane-changing situation
	16	Min_Lag_GD	m	The minimum value of gap distance (GD) with lag vehicle of target lane in lane-changing situation
	17	Min_Lead_GD	m	The minimum value of gap distance (GD) with leading vehicle of target lane in lane-changing situation
	18	Min_Front_TTC	sec	The minimum value of time-to-collision (TTC) with leading vehicle of current lane in lane-changing situation
	19	Min_Lag_TTC	sec	The minimum value of time-to-collision (TTC) with lag vehicle of target lane in lane-changing situation
	20	Min_Lead_TTC	sec	The minimum value of time-to-collision (TTC) with leading vehicle of target lane in lane-changing situation