7.6 Preview Sight Distance and Grade Perception at Vertical Curves Preview sight distance measures the motorist sight distance required under the assumption they base their behaviors on a preview of the road surface and other cues that lie downstream. The concept...
5.12 Influence of Speed on Sight Distance When operating speeds are much faster than design speed, increasing sight distance to account for higher vehicle speeds can be a good option. Table 5.8 summarizes how different aspects of a road’s design influences operating...
5.8 Determining When to Use Decision Sight Distance Decision sight distance is longer than stopping sight distance. Its use is appropriate in road environments where motorists (a) make complex or instantaneous decisions, (b) have difficulty perceiving information, or...
5.6 Determining Intersection Sight Distance Drivers must have a clear view of an entire intersection so they can see traffic control devices and see far enough upstream or downstream along an intersecting road to identify acceptable gaps in cross traffic before...
5.4 Determining Stopping Sight Distance Stopping sight distance is the distance a motorist traveling at a particular speed needs to stop their vehicle once they detect an object on the road. To determine stopping sight distance, use actual operating speeds if they are...
5.2 Key Components of Sight Distance Formally, sight distance is the length of road a vehicle travels before the driver completes a maneuver in response to an element, hazard, or condition that requires a change in the vehicles speed and/or path. Sight distance...
