16.6 Rumble Strips Rumble strips are raised or grooved indentations on the shoulder or median. When a vehicle departs its lane and travels over rumble strips, motorists hear an audible alert and experience a vibrating sensation that warns their vehicle has departed...
9.2 Perceptual and Physical Elements to Support Rural-Urban Transitions When motorists driving at a high speed enter an area with lower speed limits, they tend to underestimate their speed and not adjust it downward enough. The design of transition zones needs to...
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....
