Explain equation for Change Interval
y = t + v / 2a + 64.4G
Where: y = length of yellow interval (sec)
t = driver perception/reaction time (1.0 sec generally used)
v = velocity of approaching vehicle (fps)
a = deceleration rate (10 fps2 generally used)
G = grade of approach (percent/100)
If G is positive percent or upgrade, use '+' symbol
If G is negative percent or downhill, use '-' symbol