
197Slips and Falls
V
v
is the velocity of vehicle (mph) (25 mph)
t
pr
is the perception reaction time (2.5 s)
f is the coecient of friction (.375 for V
v
= 30 mph)
D is the clearance distance from vehicle or pedestrian to nearest rail (15 )
L is the length of vehicle (65 )
W is the distance between outer rails (18 )
d
e
is the distance from driver to front of vehicle (10 )
τ
350 ft
(7.14)
H
170 ft
(7.15)
Moving Vehicle Sight Distance Calculations
For a moving vehicle or pedestrian, the distance along the highway is given by the following
equation:
dVt
V
Hvpr
v
f
e
=++++147
30
2
.
(7.16)
where
V
v
is the vehicle velocity
t
pr
is the perception/reaction time ( ...