CAPACITIES OF ONE-WAY AND TWO-WAY STREETS WITH SIGNALS AND WITH STOP SIGNS

Studies were conducted of traffic at four intersections while the traffic signals were in normal operation and with two-way stop signs and four-way stop signs used in place of the traffic signals. All four intersections in downtown washington, d. C. Were on a four-lane street, which carries more than 3,200 vehicles per hour during the peak period. A definite value for either practical or possible capacity was determined for each of the three types of intersection control. The effect of one-way and two-way operation on the capacities of both thru and cross streets and the effect of parking on the thru street were also determined. These determinations were based on the magnitude of the delays to traffic as well as on the traffic volumes which were observed. The following conclusions were: (1) with properly coordinated progressive signal control, the practical capacity of the one-way street closely approaches its possible capacity, (2) intersection capacities are greater with progressive signal control than with either type of stop-sign control, (3) possible and practical capacities for cross-street stop-sign control are much lower than with progressive signal control or all-way stop-sign control, (4) the capacity of an intersection at which all traffic is controlled by stop signs approaches that of an intersection with progressive signal control when both streets carry two- way traffic, and (5) the capacity of an intersection will vary greatly with the control and regulation of traffic.