18.2 General Principles for Sign Legends Motorists have trouble seeing and processing signs that have too much content or whose messages are too complex. Sign legends must be concise and worded to maximize the comprehension of information presented. Use text-based...
17.6 Effects of Roadway Factors on Speed Geometric, environmental, and traffic-related variables all influence driving speed under free-flow conditions on tangents. Drivers of free-flowing vehicles can select speeds based on their level of comfort and the appearance...
17.2 Behavioral Framework for Speeding Factors related to the motorist, vehicle, road, and environment influence speeds at which motorists drive. Figure 17.1 reviews factors designers should focus on to select countermeasures that mitigate speeding. It is critical to...
13.12 Determining Work Zone Speed Limits Decisions about work zone speed limits need to account for road geometrics and the location of work zone features (e.g., lane closure tapers, work activity). If possible, keep work zone speed limits within 10 mph of normal...
13.8 Changeable Message Signs The purpose of changeable message signs is to communicate important messages succinctly. Keep display messages to a maximum of two phases. Avoid splitting information across phases, use a consistent format for calendar dates, and make...
