Introducing novel statistical-based method of screening and combining currently well-known surrogate safety measures

ABSTRACT

Until now various surrogate safety measures (SSM) have been developed and research in this area is ongoing. However, it is unclear which indicators are able to reflect danger more accurately. This paper proposes a novel method of performance comparison by taking the advantage of statistical analyses of SSMs data. This analytical approach is inspired by the dominant behavior of drivers in car-following scenarios. Afterward, those indicators that previously identified as eligible are merged using a recently developed safety indicator, named collision probability (CP). The proposed method is applied to microscopic traffic data collected from the I-80 freeway in Next Generation Simulation (NGSIM) project. The results indicated that the proposed framework helps screen SSMs and calculate the probability of rear-end collisions using a combination of the selected SSMs. The results might be helpful for improving the precision and accuracy of in-vehicle collision avoidance warning system and safety evaluations without crash data.

KEYWORDS:

• Safety
• surrogate measure
• microscopic data
• collision avoidance

Nomenclature

$X_i$	=	Position of the vehicle i in horizontal direction
$V_i$	=	Speed of the vehicle i in horizontal direction
$l_i$	=	Length of the vehicle i
$t$	=	Time instant
$T$	=	Duration of car-following
$\mu$	=	Friction factor
$\mathrm{\Delta }t$	=	Reaction time
g	=	Acceleration due to gravity
MADR	=	Maximum deceleration rate to avoid collision
L	=	The leading vehicle
F	=	The following vehicle
TTC	=	Time-to-Collision
TTC*	=	Critical threshold for TTC
MTTC	=	Modified TTC
GTTC	=	General TTC
TET	=	Time-Exposed TTC
TIT	=	Time-Integrated TTC
CMT	=	Comprehensive measure based on TTC
TTCD	=	TTC with disturbance
GT	=	Gap Time
DRAC	=	Deceleration Rate to Avoid Collision
PSD	=	Proportion of Stopping Distance
RECP	=	Rear-End Collision Probability
DSS	=	Difference between space distance and stopping distance

Availability of data

The data that support the findings of this study are available in http://ngsim.fhwa.dot.gov.

Disclosure statement

No potential conflict of interest was reported by the authors.