Theoretical Study of Safe Braking Line at Signalized Intersection

Signalized intersection is an area where most of the drivers have a difficulty in
deciding either to run through the intersection or decelerate their vehicles and stop
before the stop line. The goal of this study was therefore to determine the safe braking
line at signalized intersection by using the concept of stopping sight distance. The 377
samples of actual approaching speed of vehicles were collected through the site
observation at one signalized intersection in Tronoh, Perak. Statistical analysis showed
that the observed 15
th and 85th percentile speed at the intersection were 66.2 km/hr and
88.5 km/hr with a mean and standard deviation of 77.5km/h and 9.99km/hr. The ChiSquare goodness-of-fit test was conducted, and the results shows that the distribution
of the approaching speed at Tronoh’s intersection was normally distribute with a
probability of 14.4%. From the study, it shows that the safe braking line from the
stopping line at signalized intersection is between 97m for lower speed limit to 152m
for the upper speed limit.