Passing Sight Distance

PSD $=d1+d2+d3+d4$

$d1=$ distance traveled during $\frac{P}{R}$ time to point where vehicle just enters the left lane

$d1=1\mathrm{.}47t1(s-m+\frac{at1}{2})dotsdots.$ PROOF $!!!!$

where

$t1=$ time for initial maneuver $(sec)$

$s=$ average speed of passing vehicle $($mph$)$

$a=$ acceleration $(mp\frac{h}{s})$

$m=$ difference between speeds of passing and passed vehicle