Synthesis of Safety for Traffic Operations - Transports Canada

Synthesis of Safety for Traffic Operations March 2003
Signal-controlled:
where:
N = 0.032452 ADT main 0.503 ADT side 0.224 e 0.063X1 e 0.622X2 e -0.200X3 e -0.310X4 e -0.130X5 e -0.053X6 e -0.115X7 e -0.225X8 e -0.130X9
X1 = 1 if pre-timed signal; 0 otherwise
X2 = 1 if fully-actuated signal; 0 otherwise
X3 = 0 if two-phase signal; 1 otherwise
X4 = 1 if no access control on main road; 0 otherwise
X5 = 1 if 3 or less lanes on the side road; 0 otherwise
X6 = Average lane width on main road (metres)
X7 = 0 if no free flow right turn from main road; 1 otherwise
X8 = 1 if 3 or less lanes on the main road; 0 otherwise
X9 = 1 if 4 or 5 lanes on the main road; 0 otherwise
Harwood et al (2000)
Minnesota, California, and Michigan
Rural intersections with four, two-lane approaches
Stop-control:
where:
N = exp(-9.34 + 0.60ln ADT main + 0.61ln ADT side + 0.13ND – 0.0054SKEW)
N = annual number of crashes
ADT main = Average daily traffic on the main road
ADT side = Average daily traffic on the minor road
ND = number of driveways on the major road legs within 76 metres of the intersection
SKEW = intersection angle (degrees) expressed as one-half of the angle to the right minus one-half of the angle to
the left for the angles between the major road leg in the direction of increasing stations and the right and
left legs, respectively. 6
6 In most instances SKEW is computed as the absolute value of the angle of intersection minus 90 degrees.
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