查看文章

One of the important decisions that highway engineers have to make when designing a nonfreeway arterial highway through a suburban area is whether to provide a continuous two-way left-turn lane (TWLTL) or a nontraversable median. A survey of highway engineers working for state highway agencies revealed that policies regarding the choice of a cross-section vary among different agencies. An analysis of accident data on Tennessee highways and the application of NETSIM software to a few hypothetical scenarios revealed that the selection of a cross-section of one of these alternative designs involves a tradeoff between safety and traffic delay. Based on the findings of the study a set of guidelines was developed for choosing between a TWLTL and a nontraversable median under different scenarios of land use, traffic volume, and driveway density.