If snow and icy conditions are common, what should the maximum rate of superelevation be limited to?

The maximum rate of superelevation should be limited to 8 percent in regions where snow and icy conditions are prevalent. This limitation is primarily due to safety considerations. In icy conditions, the friction between the tires and the road surface is significantly reduced, which can lead to skidding and loss of control when navigating curves. A superelevation of 8 percent provides a balance that allows for adequate drainage of water while minimizing the risk of vehicles slipping.

If the superelevation is set too high, drivers may have difficulty maintaining control, especially if road conditions are compromised by ice or snow. Keeping the superelevation at 8 percent helps ensure that vehicles can negotiate curves more safely under adverse weather conditions, as it reduces the lateral acceleration forces acting on the vehicle. This consideration is essential in roadway design, particularly in areas that experience winter weather conditions frequently.

In contrast, higher rates of superelevation would increase the likelihood of losing traction on slick surfaces, hence the need for the restriction to the 8 percent maximum in these circumstances.