ON THE RESERVE CAPACITIES OF PRIORITY JUNCTIONS AND ROUNDABOUTS

The concept of reverse capacity of a whole junction has been used exte nsively in the design of signal-controlled junctions. This concept, ho wever, has not been applied to priority junctions and roundabouts, pro bably because of the complicated demand and supply relationship. When the demands on the approaches to the junction increase, the capacities of those non-priority approaches reduce at different rates. This make s the calculation of reserve capacity of the whole junction not a stra ightforward task. Using the definition of reserve capacity of a whole junction in Allsop (1972; Transpn Res. 6, 245-255), explicit formulae for the estimation of reserve capacities of priority junctions and rou ndabouts are derived in this paper. Numerical examples are given to il lustrate the usefulness of these formulae. Copyright 1996 (C) Elsevier Science Ltd