To help with vehicle stability, the outer edge of a road in a curve is raised with respect to the inner edge. This is called superelevation and is specified as the difference in elevation divided by the width of the road. It needs to be higher for faster speeds and sharper curves. The radius of a curve is the radius of the section of a circle along the middle of the road where the curve is constant. See Figure 111for a drawing of this. Figure E.1E.1E.1: Section of a circle along the middle of a road with radius RRR. In some cases the curve may need a lower speed limit than straight portions of the road. The superelevation shouldn’t be more than about.12.12.12 to keep vehicles from sliding off the road in slippery conditions. Your job is to calculate the maximum speed on a curve given the radius of the curve and the superelevation. The maximum speed is given by this formula: V=/.067V = sqrt{/.067}V=/.067, where VVV is the max speed in miles per hour,RRRis the radius of the curve in feet, andSSS is the superelevation.
To help with vehicle stability, the outer edge of a road in a curve is raised with respect to the inner edge. This is called superelevation and is specified as the difference in elevation divided by the width of the road. It needs to be higher for faster speeds and sharper curves. The radius of a curve is the radius of the section of a circle along the middle of the road where the curve is constant. See Figure 111 for a drawing of this. Figure E.1E.1E.1: Section of a circle along the middle of a road with radius RRR. In some cases the curve may need a lower speed limit than straight portions of the road. The superelevation shouldn’t be more than about .12.12.12 to keep vehicles from sliding off the road in slippery conditions. Your job is to calculate the maximum speed on a curve given the radius of the curve and the superelevation. The maximum speed is given by this formula: V=(R∗(S+.16))/.067V = sqrt{(R ∗ (S + .16))/.067}V=(R∗(S+.16))/.067, where VVV is the max speed in miles per hour, RRR is the radius of the curve in feet, and SSS is the superelevation.
