What does accessibility in transportation primarily refer to$?$

$($a$)$ The cost of using different modes of transport.

$($b$)$ The environmental impact of various transportation systems, system.

$($d$)$ The speed of the transport

$($a$)11\mathrm{.}2f\frac{V}{se{c}^2}$

$($b$)9\mathrm{.}8f\frac{t}{se{c}^2}$

$($c$)10\mathrm{.}5f\frac{t}{se{c}^2}$

$($d$)12\mathrm{.}0f\frac{t}{se{c}^2}$

What does the formula $S=\frac{{}_b(V_1^2-V_2^2)}{2g({}_b+f_{rl}+-sin{}_g)}$ calculate in the absence of air resistance?

$S=\frac{{}_b(V_1^2-V_2^2)}{2g({}_b+f_{rl}+-sin{}_g)}$

$($b$)$ The theoretical stopping sight distance for a vehicle.

$($c$)$ The maximum speed a vehicle can attain on a given road segment.

$($d$)$ The amount of time needed for a vehicle to come to a complete stop.