# Initial Maneuver Distance

Written by Jerry Ratzlaff on . Posted in Civil Engineering

Initial maneuver distance, abbreviated as $$d_1$$, is the distance traversed during the perception and reaction time and during the initial acceleration to the point of encroachment on the left lane.

## Initial Maneuver Distance formulas

 $$\large{ d_1 = \frac{ t_1 }{ 0.68 } \; \left( \bar {u} \;-\; m \;+\; \frac{ \bar {a} \; t_1 }{ 2 } \right) }$$ $$\large{ d_1 = 1.47 \; t_1 \; \left( \bar {u} \;-\; m \;+\; \frac{ \bar {a} \; t_1 }{ 2 } \right) }$$

### Where:

$$\large{ d_1 }$$ = initial maneuver distance

$$\large{ \bar {a} }$$ = average acceleration

$$\large{ \bar {u} }$$ = average speed of passing vehicle

$$\large{ m }$$ = difference in speed of passing vehicle and passing vehicle

$$\large{ t_1 }$$ = time of initial maneuver