Chicagos dan ryan expressway provides a unique laboratory for many traffic studies not previously undertaken. A 6 1/2- mi section uses collector-distributor roadways to minimize weaving and expedite traffic flow. Two separate roadways, one local and one express, are available for travel in each direction. Two-lane transfer roadways allow access between local and express lanes, or vice-versa, at six locations. Because this was the first such facility in the chicago area, it was appropriate to conduct a rather comprehensive study to ascertain the efficiency of its operation, particularly at transfer roadways. Time-lapse ground photography was used at two typical locations and an analysis was made of volumes, speeds, distributions, vehicle classifications, lane changes, transfer travel patterns, and hazardous maneuvers. As a result of the initial study, application of several control measures appeared to warrant further investigation. The effects of pavement markings and signs on traffic operation at transfer roadways are also discussed. New lane markings and signs were installed on the basis of analysis of the before study findings. Time-lapse ground photography was used to evaluate the effect of these changes. An additional study was made of the channelization /by use of rubber cones/ of the transfer roadway traffic into one lane.
Abstract