a_{d_req} - curve speed warning time

time when the curve speed warning starts which is greater than or equal to the minimum allowed curve speed warning time tcsw ≥ tcsw_min
NOTE 1 to entry: The tCSW, Swarn, and Vcurrent has the following relationship: tcsw = Swarn /Vcurrent
NOTE 2 to entry: The value of tCSW is selected by the manufacturer.

Application Area: Vehicle/roadway warning and control systems