Contains: * Increasing the traffic-carrying capability of urban arterial streets (Berman, J.; Carter, A.A.; p 1-13: The basic objective of the wisconsin avenue study was to estimate how great an increase in the traffic-carrying capability of an existing urban arterial street could be developed within existing right-of-way limits, if all known traffic control techniques could be adapted and if major construction were carried out. The study recognized that as pressure increases to push the capacity levels of our existing streets to greater and greater heights, a real danger exists that these highly developed major arterial routes will no longer adequately serve the adjacent land. It was the hypothesis that these two services can and must be maintained in balance on an arterial such as wisconsin avenue. A variety of data-gathering procedures were employed. First, all available existing data regarding current conditions on the study street were reviewed. Material obtained included data on traffic volumes, traffic accidents, signal system features, existing lighting, and right-of-way locations, as well as historical background material. Field crews conducted a variety of actual field studies. Two of these studies involved use of a test car traveling in the traffic flow. In one case, the car was equipped with a digital traffic impedance analyzer which recorded vehicle speed, travel distance, and time. Frictional events occurring during the trip also could be entered in coded form by an observer. In the other case, the driver's tension level was continuously recorded by means of a galvanic skin resistance recorder. The remaining field studies were conducted manually. Included were a series of intersection capacity studies, special studies of traffic interference at problem locations, parking regulation and usage investigations, studies of speed distributions, studies of vehicle occupancy, state-of-registration checks, and accumulation of physical feature and land-use data. A special study was also made of police power and planning controls which relate to this problem, to determine whether or not suggested street improvements could be legally implemented.); * Application of police power and planning controls to arterial streets (Stanhagen, W.H.; Mullins, J.J.; p. 14-28: Ways are explored in which police power regulations, access control provisions, and land use and planning controls can be used to help solve an arterial problem. Suggestions are made for applying these measures to the internal and external causes of deterioration in an effort to halt it, and to develop the maximum effectiveness of an arterial street. A number of suggestions are included: (1) restricting midblock left turns, (2) closing driveways, (3) barricading cross streets, (4) making the street a 'rush hour freeway,' (5) adequate parking and loading zones for new structures, and (6) use of zoning to equate urban land use and transportation facilities.) * Tension responses of drivers generated on urban streets (Michaels, R.M.; p. 29-44: The present study was an attemp to relate driver tension responses to those events in traffic which caused an overt change in speed or lateral location of a test vehicle. In order to measure tension responses the galvanic skin reflex (gsr) was employed, and measurements were made continuously during each trip along two urban streets. Traffic events influencing the test vehicle were determined independently by an observer and recorded on the gsr record. The traffic events were restricted to eight possible interferences, which accounted for 95 percent of all agents causing a change in test vehicle speed and placement. Ten driver subjects were used on the two test routes. Runs were made during five time periods, including peak, offpeak, and night. Each subject drove the test route 25 times, distributed over a two-week period. The results indicated that traffic events occurred, depending upon the street, at a rate of one every 21 to 35 seconds. Of these, 85 percent generated a measurable gsr response. Depending upon the street, the majority of responses were caused by other vehicles in the traffic stream, accounting for 60 percent or more of all events. The events which generated the greatest mean tension response were those involving a maximum difference in speed between the object and test vehicle. Thus, turning maneuvers and crossing and merging were most tension inducing. The least stress inducing events were related to fixed objects in the environment, such as parked vehicles or islands. This ordering was statistically reliable among the subjects. Using the magnitude of gsr response per unit of time as an over-all measure of driver tension, it was possible to compare the two test routes. It was found that the route subjectively preferred by drivers induced an average of 40 percent less tension response per minute than did the other route. An analysis of variance showed that these differences between routes were statistically significant. The results of this study indicate that a road generates tension in drivers inversely with the predictability of the interferences and directly with the complexity of the traffic situation with which they must deal. In addition, the magnitude of tension response is directly related to the rate at which decisions are forced upon the driver by the traffic. /author/.); * Capacity of traffic signals and traffic signal timing (Bellis, W.R.; p. 45-67: For a busy street charts have been developed which show: (1) probabilities for the number of vehicles per hour, and (2) capacity of traffic signals and signal timing for (1) passenger cars at 45 to 55 mph, 35 to 45 mph, 25 to 35 mph, and 15 to 25 mph, (2) trucks at 45 to 55 mph, and (3) combined speeds and vehicle types.); * Report of committes on highway capacity (p. 45-70).
Abstract