Joseph D. Crabtree

Analysis of Saturation Flow at Signalized Intersections

The accuracy of saturation flow values is of prime importance when determining the capacity of signalized intersections. The objective of this study was to collect a large sample of field measurements so that reliable saturation flow values could be obtained and the factors affecting saturation flow could be identified. The results identified several factors which had significant influence on saturation flow. A formula was recommended for use in estimating an appropriate saturation flow value for a specific lane on an approach to an intersection. Adjustment factors were applied to a base saturation flow value. Adjustments werec·developed for the follmoing factors; location in city, city population, vehicle type and turning maneuver, gradient, width of lane, turning radius (jar right-turning vehicles), pedestrian activity, type of lane, speed limit, and light condition.

Problem Identification for Highway Safety Plan (FY 1982)

An annual highway safety program is proposed each year for the State of Kentucky in order to comply with Section 402, Title 23 of the United States code. This program includes the identification, programming, budgeting, and evaluation of safety projects. This report is the fourth in a series of annual reports which have been included as the problem identification portion of Kentuckys Annual Highway Safety Plan.

Child Restraint Usage in Kentucky (Pre-Legislation)

16. Abstract In an attempt to increase child restraint usage, a law was enacted by the 1982 Kentucky Legislature requiring use of child restraints for children forty inches or less in height. To evaluate the effectiveness of this law, a usage survey had to be completed before the law became effective. Objectives of this study were to determine statewide child restraint usage and statistics relating to improper usage. Seatbelt usage of drivers was also analyzed.

A Needs Assessment and Technology Evaluation for Roadside Identification of Commercial Vehicles

The Roadside Identification Feasibility Study was undertaken to identify methods of unique identification of commercial vehicles at the roadside for slow and high-speed electronic screening purposes. It was designed to be a comprehensive look at the technologies, focused on the needs of the Federal Highway Administrations Office of Motor Carrier and Highway Safety (FHWA/OMCHS) and the States

IMPACTS OF THE EXTENDED-WEIGHT COAL HAUL ROAD SYSTEM (INTERIM REPORT)

The Extended-Weight Coal Haul Road System, created by Kentucky`s Legislature in 1986, consists of all roads which carry over 50,000 tons of coal in a calendar year. Trucks hauling coal on this system are authorized to exceed normal weight limits through the payment of an annual decal fee. A research study was initiated in July of 1992 to analyze the impacts of the extended-weight system. This interim report prepared after one year of a three-year study, describes the analyses performed thus far and presents preliminary findings, recommendations, and a discussion of future work. Analyses in this report are based on: historical data on coal production and transportation; data from coal decal applications; interviews of legislators, transportation officials, coal company representatives, and coal trucking representatives: newspaper articles; vehicle classification data; a pavement cost analysis; and accident data. Preliminary conclusions include: (1) The extended-weight system has apparently been somewhat successful in accomplishing the primary objectives: to enhance the competitiveness and economic viability of Kentucky`s coal industry and to eliminate the perceived need for cal haulers to violate the law in order to be competitive; (2) Overall accident rates are no higher on the extended-weight system than on other comparable routes, but themorexa0» fatal accident rate is significantly higher on the extended-weight system; (3) The coal-decal fee structure results in a net annual loss in Road Fund revenue of approximately

Survey of Effectiveness of Transportation Services

2 million; (4) Forty percent of the revenue from decal sales is allocated to the counties, although less than ten percent of the extended-weight system in county-maintained; (5) The heavier weights of coal-decal trucks add approximately

ANALYSIS OF LOST TIMES AT SIGNALIZED INTERSECTIONS

9 million annually to pavement overlay costs and increase other highway costs. (6) Road users throughout the state are subsidizing the movement of Kentucky coal by underwriting the increased costs.«xa0less

Evaluation of Electronic Truck Monitoring

The objective of this study was to measure the effectiveness of transportation services by means of a public opinion survey. Results from the mail survey were intended to provide administrators with quantitative measures so that emphasis would be based on the public. s perception of specific programs. Questionnaires were mailed to a random sample of 800 licensed drivers in each of Kentuckys 12 highway districts for a total of 9,600 statewide. The total response rate was 51 percent for all districts, with 49 percent considered to be usable responses. Results from the survey showed that 82 percent of the respondents were satisfied or very satisfied with the overall transportation system. Respondents were generally satisfied with overall maintenance (67 percent).Statewide, the least problems occurred with poor traffic signs and the greatest problem was rough roads. The interstate system was the most appreciated aspect of the transportation system and the most frequently mentioned driver complaint was poor road maintenance. Of those expressing an opinion, 25 percent indicated highways were worse in Kentucky than other states and 22 percent felt conditions were better. Drivers felt that government spending should increase for rough railroad crossings, road maintenance, and road reconstruction. The strongest support concerning specific laws and regulations was for a motorcycle helmet law and least support was for mandatory retesting of drivers. When comparing the 1980 and 1984 surveys, satisfaction with the overall transportation system remained the same. A general decline was noted for those dis sa tis~~etwHhn~~~~~;n~ e~; ~g~i;!~~~=~.;~ r~;;l~~ in favor of a seat belt law increased from

Accident Rates by Vehicle Type

When determining the capacity of a signalized intersection, knowledge of certain traffic parameters is necessary. The previous investigation conducted under this study dealt with an analysis of saturation flow values. The objective of this investigation was to determine appropriate values to use for lost times at signalized intersections. The lost times at the beginning and ending of the phases were analyzed, as well as lost times during the phase due to the interference of pedestrians, local buses, and opposing traffic for left turns. Factors affecting those lost time values were identified. The lost time values, along with the previously identified saturation flow values, permit the calculation of capacity at signalized intersections and may be used as input when using computer models to simulate and optimize signal systems. Base values of 1.40 and 1.67 were found for beginning and ending lost time, respectively. Formulas were given that considered the effect of several factors on beginning and ending lost times. Case studies illustrating the use of those formulas are given. (Author)

Safety Improvement Program for Toll Roads

This study study is an outgrowth of a previous study to analyze and document the monitoring systems in place for motor carrier operations in Kentucky. Through an evaluation process which considered various options for improving the efficiency of truck operations in Kentucky a recommendation was made to implement a test of automatic vehicle identification (AVI) and mainline weigh-in-motion (WIM) equipment. The advantages and disadvantages of electronic monitoring equipment especially regarding reliability, accuracy, and benefits/costs, have been demonstrated through the field tests conducted as part of this study.