Summary of Vehicle Classification Data

As part of an attempt to calculate accident rates for different vehicle types on various kinds of roads, it was necessary to determine the percentage of each vehicle type in the traffic stream for each type road. This was accomplished by summarizing Kentucky\u27s Vehicle Classification File. The procedure used in summarizing the file and the results of the summary are presented in this report. Vehicle distributions are reported by number of lanes, by functional classification, by administrative classification, by federal-aid system, by hour of day, by day of week, and by month of year. It is believed this report provides the most extensive and accurate data currently available on vehicle type distributions in Kentucky

AN ASSESSMENT AND ANALYSIS OF USING DEDICATED SHORT-RANGE COMMUNICATIONS (DSRC) TECHNOLOGY FOR INCIDENT DETECTION ON RURAL FREEWAYS

This report describes an assessment of using dedicated short-range communications(DSRC) technology to perform travel time monitoring and automated incident detectionon a segment of rural freeway. The assessment used the CORSIM traffic simulation toolto simulate traffic and incidents on a segment of rural freeway. Output data from thesimulation was subjected to post-processing to produce the probe and beacon data thatwould be produced by a DSRC-based system. An incident detection algorithm wasdeveloped, which used a travel time threshold and a counter. Travel times exceeding thethreshold incremented the counter, while travel times below the threshold decrementedthe counter (unless it was at zero). An alarm was generated when the counter reached apre-selected level. This algorithm was tested on selected data files, and the results wereused to identify the best values of the threshold and counter alarm level. Using these best values, the algorithm was then applied to the probe and beacon data todetermine how quickly the system could detect various traffic incidents. The analysisshowed that the system could provide rapid and reliable detection of incidents.During the simulation and analysis, several parameters were varied to observe theirimpacts on the system performance. These parameters included traffic volume, incidentseverity, percentage of vehicles with transponders, spacing of roadside readers, andlocation of the incident relative to the next downstream reader. Each parameter proved tohave a significant effect on the detection time, and the observed impacts were consistentwith logical expectations. In general, the time to detect an incident was reduced inresponse to (1) an increase in traffic volume, (2) an increase in incident severity, (3) anincrease in transponder population, (4) a reduction in reader spacing, and (5) a reductionin distance from incident location to next downstream reader.Preliminary estimates were developed of the costs associated with implementing aDSRC-based traffic monitoring system. The relationship between system cost andsystem performance was explored and illustrated.Recommendations were developed and presented. These included further analysis basedon traffic simulations, followed by a limited field deployment to validate the analysisresults

Highway Sizing

A critical examination is made of the conventional method for highway sizing, that is, determination of lane requirements. Ranked hourly traffic volume distributions, obtained from 1977 Kentucky volume stations are examined to test certain assumptions common to the conventional approach. Several of these distributions have no distinct knee and, for those which do, the knee is most frequently found outside the normally anticipated range. Of equal importance, the knee location can be arbitrarily altered simply by changing the number of highest volume hours that are examining. The fundamental fallacy of the conventional procedure is its focus on a single design hour and its orientation toward conditions experienced by the the highway rather than the user. This can readily be overcome by basing size decisions on an alternate criterion such as the percentage of vehicles that suffer congestion during the design life. An example demonstrating this concept is presented. More significant improvement can be achieved by directly computing the economic efficiency of investment in additional lanes. An example is presented to demonstrate current capabilities for such computations. the example also demonstrates that current procedures do not always yield the mos economical designs and that the most economical highway size is affected by the specific shape of the traffic volume distribution. Use of economic efficiency analysis as a standard tool in evaluating critical sizing decisions is highly recommended

User’s Manual for Dynamic Programming for Highway Safety Improvement Program

The term, dynamic programming, was first used by Bellman to represent the mathematical theory of a multistage decision process. Dynamic programming is applied to allocate expenditures so that maximum benefits result. Three types of applications of dynamic programming are single-stage, multistage, and multistage with a time factor. Single-stage programming is used to evaluate a single project having several alternatives. Multistage programming involves selection of several projects having several alternatives. Multistage dynamic programming with a time factor is used where several projects and alternatives are considered and where various time periods are involved. The Alabama Highway Department did considerable work on the application of dynamic programming to the optimization of budget allocation for the spot-safety- improvement program. Significant modifications were incorporated into the Alabama procedures to make it applicable to the spot-safety-improvement program in Kentucky (3). That procedure was adapted to Kentucky\u27s needs and has been used periodically to select projects for the safety improvement program. Another application of dynamic programming in Kentucky has been for the selection of projects for resurfacing. With hundreds of candidate projects recommended for resurfacing each year, it is difficult to select projects that will yield the greatest benefits to the driving public. Prior to the application of dynamic programming to resurfacing projects, it was necessary to develop reliable means of calculating benefits derived from roadway resurfacing. Further use of the dynamic programming process in Kentucky has been for the development of a means to priority rank safety improvements for interstate and toll road facilities. Separate reports were prepared to document the procedures used for the interstate system and the toll road system. As was the case with other applications of dynamic programming, the major task was determination of benefits expected from each improvement. For both the interstate and toll road programs, all benefits were estimated to be the result of accident reductions associated with the improvements. The program described herein is designed specifically for highway projects. Program development was done in 1974 and several modifications have been made since then. Additional modifications were performed during the preparation of this user\u27s manual to make the program easier to use. A current listing of the program is in Appendix A

Development of a Research Project Tracking System

The Kentucky Transportation Center, in cooperation with the Kentucky Transportation Cabinet, has developed a Research Project Tracking System (RPTS). The RPTS is web-based and includes a database of active (and recently completed) research projects. The system allows authorized users to access and edit the project data, enter new projects into the system, and produce periodic progress reports. It produces a homepage (or dashboard) for each project, and it provides links to key project documents. It also has the capability to track the implementation of research results on a project-by-project basis

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\u27\u27 saturation flow value. Adjustments were developed for the following 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

Child Restraint Usage in Kentucky (Pre-Legislation)

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 statewide child restraint usage rate of 14.4 percent was obtained. Only 44 percent of restraints were coded as used properly. Several factors, such as population, age of child, and driver restraint usage, were related to child restraint usage. The specific restraint brand was noted and a few, such as the Strolee and Bobby Mac, were the most common. The major overall improper usage was failure to tether the restraint as required. A statewide driver restraint usage rate of 4.2 percent was found

Evaluation of Electronic Truck Monitoring

Automatic vehicle identification (AVI) and weigh-in-motion (WIM) equipment were installed at the northbound weigh/enforcement station on 1-65 in Simpson County, Kentucky. The objectives were to determine the reliability and accuracy of the equipment and to determine the benefits/costs for the trucking industry and enforcement agencies. The test site for evaluation of the equipment became operational in July 1991 and the evaluation continued through June 1993. AVI equipment was provided by Amtech Corporation and WIM equipment by International Road Dynamics. Participating motor carriers were United Parcel Service and Averitt Express, with a total of 114 trucks equipped with transponders. The system operated the first year with the AVI and WIM systems serving only the function of verifying the passage of an equipped truck. During the second phase, the AVI/WIM system was moved to a position in advance of the station where equipped trucks could be identified and given a preclearance signal. Overall, it was determined that the electronic equipment could be used to collect data more accurately than through a manual process. However, it was also found that AVI and WlM equipment were not without problems, particularly when interfacing the two types of equipment. Benefits gained were Increased levels of understanding of the reliability of AVI and WIM equipment Improved relationships between motor carriers and enforcement personnel were seen as a benefit. A preliminary evaluation of systemwide application of AVI does not indicate it would be cost-effective unless greater benefits were gained by motor carriers

Alleviation of Fuel Tax Evasion in Kentucky (Interim Report)

Motor fuel tax evasion is a problem of major significance nationwide. In Kentucky, evasion of motor fuel taxes could mean an annual loss of approximately $25 million. This study was initiated to provide Kentucky officials involved with fuel tax collection with the best available information on the problem of fuel tax evasion and the best uses of all resources to alleviate the problem. This interim report concludes the first phase of the study and provides a qualitative look at motor fuel tax evasion in Kentucky. It discusses the fuel tax process in the Commonwealth, how evasion occurs, efforts to alleviate evasion, and preliminary findings and recommendations. Findings include the tact that fuel tax evasion by dishonest dealers places honest dealers at a major competitive disadvantage, as well as contributing to the loss of funds tor highway construction end maintenance. Kentucky is combating evasion through a combination of state and cooperative regional and national efforts. Future research will include examining three basic approaches to developing a quantitative estimate of the magnitude of fuel tax evasion in Kentucky end implementing the most promising of these approaches. Additional research could be conducted on experience gained by other states, average fuel burn rates tor various types of engines and furnaces, and a cost/benefit analysis tor Kentucky\u27s Motor Fuel Tax Audit program to justify additional funds for that program

Accident Rates by Vehicle Type

This report describes the calculation of accident rates for different vehicle types, using vehicle-miles travelled as the measure of exposure. Rates are reported for passenger cars, single-unit trucks, combination trucks, buses, and motorcycles on various highway types. Highway types are broken down by functional classificaion, administrative classification, number of lanes, and rural or urban location. Generally motorcycles had the highest rates and passenger cars had the lowest, although this varied by highway type