Chapter 4 – Geometric Design Elements Mobility
{"Image DocumentName": "Chapter 4 \u2013 Geometric Design Elements Mobility", "Image ImageDescription": "Facility Type. Performance Measure. Definition. Geometric Design Elements. Basic Relationship. Potential Performance Tradeoffs. Segment. Average Travel Time. The mean amount of time it takes a roader user to travel from one point to another point along a roadway segment. Number of travel lanes. Increased vehicle lanes decrease average travel time for autos and increases vehicle speed. Degrades quality of service for pedestrians and bicyclists. Degrade mobility for pedestrians and bicyclists. Higher vehicle speeds are associated with higher severity crashes. Inferred speed. The maximum speed for which all critical design- speed-related criteria are met at a particular location. Horizontal alignment, vertical alignment, and cross- section. Higher inferred speeds associated with higher free flow speeds and higher mobility. Higher vehicle speeds are also associated with higher severity crashes. Two-Lane Segment. Average percent time spent following. The average percent of total travel time that vehicles must travel in platoons behind slower vehicles due to an inability to pass. Horizontal and vertical alignment, sight distance, Type and location of auxiliary lanes. Increased opportunities to pass slow moving vehicles reduces percent time spent following, providing a passing lane can reduce crashes. Increase vehicle speeds, increase potential for higher severity crashes.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}