Traffic flow and access are thought to be the two main determinants of the safety of a road. When we developing IHSDM for two-lane roads under the rubric of ‘access’, only driveway density are discussed. Intersections, both signalized and unsignalized, treated separately from road segments (that do not include intersections but may include access points, both residential and commercial). When the focus shifts to multilane roads, the design decisions that should come under the rubric “access” may require some rethinking. In a recent report Gluck et al. adopt a broad view of access management. The main division is into Policy (which refers to access codes/spacing zoning/subdivision regulation, purchase of access rights, setbacks for interchanges and intersections) and design (of interchanges, frontage roads, medians, right turns, redesign, traffic control access/driveway design). The report lists the twelve priority techniques: 1 Establish traffic signal spacing criteria. 2 Establish spacing for unsignalized access. 3 Establish corner clearance criteria. 4 Establish access separation distances at interchanges. 5 Install physical (restrictive) continuous median on undivided highway. 6 Replace TWLTL with restrictive median. 7 Install left-turn deceleration lanes. 8 Install continuous TWLTL. 9 Install U-turns as alternative to direct left turns. 10 Install jug-handle and eliminate left turns. 11 Install frontage road to provide access to individual parcels. 12 Locate/relocate the intersection of a frontage road. (Author/publisher)
Abstract