Contains: TI: TRAVEL TIME- A MEASURE OF SERVICE AND A CRITERION FOR IMPROVEMENT PRIORITIES. AU: Haley-CE; Hall-EM; Johnson-AA SO: Highway Research Record. 1963. NT: No 35, Pp1-17, 5 FIG, 9 TAB AB: It is demonstrated that travel time offers a sound measure of the level of urban traffic service and can be a basic criterion for a major street improvement priority formula. The overall level of service as obtained by peak-hour travel time studies in phoenix, arizona in 1947, 1957 and 1962 are compared. This comparison also related the level of service to population growth, increase in vehicle registration, city size and traffic volumes. Selected route segments are compared for change in average speed, vehicle delay and average daily traffic. In making these comparisons, street improvements that increased capacity are are identified. Examples of these improvements are street widening, intersection widening and provision of left-turn lanes, channelization, and removal of parking. The test formula used assigns major emphasis to delay rate, but also consideres collisions, traffic volume and structural condition of the pavement. The formula was evaluated by comparing the relative priority rating for selected major arterial street segments, as determined by the formula, to judgment rating of individuals. This improvement priority formula is not intended to replace judgement, but could be used as an aid to develop recommended capital improvement priorities for major arterial construction programs. Travel time was felt to be an effective measure of level of service both for individual routes and for urban street and freeway systems TI: AN ECONOMIC EVALUATION OF TRAFFIC MOVEMENT AT VARIOUS SPEEDS. AU: Marcellis-JC SO: Highway Research Record. 1963. NT: No 35, pp 18-40, 28 FIG, 43 REF AB: The purpose of this study was to evaluate economic utility or cost of resources consumed by the highway transportation industry for various speeds of travel in rural and urban areas for passenger cars and commercial vehicles on 2- and 4- lane streets and highways during daytime and nighttime travel. Graphical relationships of economics of vehicle operation, values of time, safety of travel, and their sum, which is defined as the total cost of traffic movement, were drawn for the various conditions. The minimum point on each total cost curve represents that speed at which the cost of traffic movement is minimized. Results indicated that there was a speed which minimized the cost of traffic movement for each of the various conditions considered. This speed was defined as the optimal speed. In rural areas the optimal speed was 50 mph for passenger cars and 41 mph for commercial vehicles. Optimal speeds in urban areas decreased with an increase in number of stops per mile from 41 to 29 mph for passenger cars and from 36 to 25 mph for commercial vehicles with 1 and 8 stops per mile, respectively. The most direct application of the results is likely to be in the establishment of statewide or areawide speed limits where the limit is established so that the mean speed of the vehicles coincides with the optimal speed. /Author/. TI: MULTIVARIATE ANALYSIS OF VEHICULAR SPEEDS. AU: Oppenlander-JC SO: Highway Research Record. 1963. NT: No 35, pp 41-77, 2 FIG, 10 TAB, 20 REF AB: A multivariate analysis study was conducted of vehicular speeds on 2-lane rural highways to gain a better understanding of traffic stream characteristics through the formulation and evaluation of mathematical models describing the time-rate of traffic flow. The concept of traffic flow was founded on the assumption that vehicular speeds are a function of various travel conditions present in and adjacent to the traffic stream. Thus, various types and levels of travel features produce different average spot speeds. The total effect of these resistance variables determines the speed characteristics of a particular highway location. The description of this traffic-flow concept was accomplished through the development of multiple linear regression equations. Two mathematical models were devised to relate mean spot speed as a function of generated factors in one equation and of travel- restriction variables in the other expression. These regression models were restricted by the assumption of linearity in both the variables and the parameters. TI: SAMPLE SIZE DETERMINATION FOR SPOT-SPEED STUDIES AT RURAL, INTERMEDIATE, AND URBAN LOCATIONS. AU: Oppenlander-JC SO: Highway Research Record. 1963. NT: No 35, pp 78-80, 2 TAB, 3 REF AB: In the estimation of traffic characteristics by a sampling technique, the design of experiment requires the determination of an adequate and economical sample size. The evaluation of speed characteristics is accomplished by a sampling survey and a statistical analysis. A statistical procedure previously developed for sample size determination made possible the design of a spot-speed study with a sample size that is statistically acceptable. The measure of speed variability can be obtained from the results of previous speed surveys. However, a reliable estimate of standard deviations permits the use of the equation for determining sample size. The findings of the previous investigation were supplemented by analyzing these standard deviations of spot-speeds for 2-and 4-lane highways in rural, intermediate and urban areas. References' applied general statistics, 2nd edition, f. E. Croxton and d.j. cowden, prentice-hall 1955. Sample size requirements for vehicular speed studies, j.c. oppenlander, w.f. bunte and p.l. kadakia, hrb bull. 281, pp 68-86, 1961. Traffic characteristics on illinois highways, illinois division of highways, 1961.
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