Chapter 4 - Elements of Design

4.1. Sight Distance

4.1.4. Decision Sight Distance

Decision sight distance is the sight distance needed by a driver to detect and identify an unexpected condition and initiate and complete a safe avoidance maneuver. Decision sight distance values are substantially greater than those of stopping sight distance.

Decision sight distance should be considered a desirable target for all crest curves. In particular, decision sight distance should be provided on new alignment roadways, interstate mainlines, and any other high-speed limited access facilities.

The use of decision sight distance values less than those specified in the AASHTO Green Book is discouraged by GDOT and shall require a design variance.