Transportation Engineering

Superelevation

The cross slope given to a roadway on a horizontal curve to counter the outward pull on vehicles.

On a horizontal curve, superelevation e and side friction f together supply the centripetal force: e + f = V²/(15R) with V in mph and R in feet. For a design speed and a maximum superelevation, that sets the minimum radius.

Maximum rates are capped by what slow or stopped vehicles can tolerate on ice, which is why rural highways allow more superelevation than urban streets.

How much of the FE Civil exam is Transportation Engineering?