8.4 Overview of Driver Alertness on Long Tangent Sections Drivers can become fatigued, bored, or less attentive on long tangent sections that impose few cognitive or visual demands. Consider using the countermeasures listed below on long tangent sections that prevent...
8.2 Task Analysis of Lane Changes on Tangent Sections In areas where lane changes are likely (e.g., interchanges, entrance and exit ramps, merge/weave sections) avoid incorporating design features that require motorists to read signs or engage in complex decision...
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...
7.4 Design Considerations for Turnouts and Grades Truck escape ramps provide a space for out-of-control trucks to slow down and stop away from through traffic. Table 7.2 lists design guidelines for geometrics and signing. Table 7.2 Guidelines for Geometrics and...
7.2 Design Considerations for Turnouts and Grades Turnouts are widened, unobstructed shoulder areas where slow-moving vehicles can turn out of the through lane so quicker vehicles may pass. They are particularly valuable on two-lane highways in mountainous areas....
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...
