Treatment of curves

Curves that require the driver to slow down considerably before entering them, in order to safely navigate the turn, are described as geometrically substandard and may need some form of treatment. In some cases, when the sharpness of the curvature is not clear to the approaching driver (eg inadequate warning or delineation), the driver is forced to brake within the curve and / or travel a larger radius by encroaching into the opposing lane. Such sudden corrective actions increase the risk of loss of control, and crashing off the road, or into an oncoming vehicle.

The treatment of geometrically substandard horizontal curves includes a number of elements including:

• requirements for signing a curve;
  • what treatments you would need including:
    • signs;
    • a hierarchy of signs available for use;
    • values of advisory speeds; and
    • other appropriate delineation;
• good installation practice; and
• other geometric and alignment considerations.