Engineering Commons^™

Optimal Highway Safety Improvement Investments By Dynamic Programming [Dec. 1974], Jerry G. Pigman, Kenneth R. Agent, Jesse G. Mayes, Charles V. Zegeer

Kentucky Transportation Center Research Report

The process of determining which projects to implement under a given budget, and which to defer until later, is central to the planning and management of highway systems. With a limited budget for construction, maintenance, and safety improvements, investments which will produce the optimal benefits must be chosen. This is often impossible to accomplish without the aid of a computer because of the complexity of the problem. Dynamic programming has been tested and verified as an efficient method for selecting priority projects to derive maximum benefits. The applicability of dynamic programming to the safety improvement program is demonstrated in this …

Identification Of Hazardous Rural Highway Locations, John A. Deacon, Charles V. Zegeer, Robert C. Deen

Kentucky Transportation Center Research Report

An effective procedure was determined for identifying hazardous rural highway locations based on accident statistics. Multiple indicators of accident experience that are necessary include the number of fatal accidents, the total number of accidents, the number of effective-property-damage-only accidents, and the accident rate. Critical levels of these four indicators should vary from state to state depending on the nature of the local safety improvement program as well as local traffic and roadway conditions and prevailing attitudes toward highway safety. Specific recommendations are given for use in Kentucky. Critical accident rates are established using quality control procedures.

To identify hazardous highway …

Accidents On Rural Interstate And Parkway Roads And Their Relation To Pavement Friction, Rolands L. Rizenbergs, James L. Burchett, John A. Deacon, Cass T. Napier

Kentucky Transportation Center Research Report

Friction measurements were made with a skid trailer at 70 mph (31 m/s) on 770 miles (1240 km) of rural, four-lane, controlled-access routes on the interstate and parkway systems in Kentucky. Each construction project was treated as a test section. Accident experience, friction measurements, and traffic volumes were obtained for each. Various relationships between wet-weather accidents and skid resistance were analyzed. Averaging methods were used as a means of developing trends and minimizing scatter. A moving average for progressively-ordered sets of five test sections yielded more definite results. The expression of accident occurrence which correlated best with skid and slip …

Evaluation And Modification Of The Traffic Noise Prediction Procedure For Kentucky Highways, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

Approximately 270 noise-level recordings were obtained at 39 highway sites and compared with the noise-level predictions obtained by the procedure outlined in NCHRP Report 117. The measured noise levels were computed in terms of the A-weighted L₁₀ value (level exceeded 10 percent of time) and then compared to the predicted noise levels. A significant discrepancy was found between predicted and measured noise levels; generally, the predicted values exceeded the measured values. Average error per location was 4.8 dBA; the maximum error was 13 dBA. A nomograph was devised to correct the predicted value; this nomograph involves observer-to-roadway distances, truck …

Fatigue Analysis From Strain Gage Data And Probability Analysis, Robert C. Deen, James H. Havens

Kentucky Transportation Center Research Report

The Central Bridge over the Ohio River between Newport, Kentucky, and Cincinnati, Ohio, was completed in 1891 and in 1972-73 was considered to be in danger of fatigue failure. A series of investigations were undertaken to determine the likelihood of failure and to estimate the time of probable failure. During the investigation, a methodology was developed to determine fatigue damage from a probability analysis of traffic data by reconstituting or synthesizing the load (traffic) history of bridges. Strain gage data obtained with Prewitt scratch gages and SR-4 resistivity gages were used to evaluate fatigue damage incurred by the Central Bridge.

Experimental Portland Cement Concrete Shoulders Design And Construction, James H. Havens, Assaf S. Rahal

Kentucky Transportation Center Research Report

Kentucky's first portland cement concrete shoulder project was conceived in 1970 and was inspired by the Portland Cement Association's issue Concrete Shoulders for Safe Modern Highways, Concrete Report, 1970, and FHWA's Informational Memorandum CMPB-17-70, Experimental Project for the Evaluation of Portland Cement Concrete Shoulders Adjacent to Concrete Mainline Pavement; Project Prospectus, National Experimental and Evaluation Program; May 12, 1970. It was expected that at least two states in each region would participate in the national program. A 3.442-mile section of US 31 W, between Radcliff and Tiptop, beginning at the intersection of US 60 and extending southward, …

A Rock Classification Schema, Robert C. Deen, C. D. Tockstein, M. W. Palmer

Kentucky Transportation Center Research Report

The need for engineering data on earth materials for use in site selection, design, construction, and maintenance of major engineering structures is generally accepted. Probably the most pressing need is for such data to use in preliminary considerations of site selection and design alternatives. Maps and(or) surveys giving the areal distribution of earth materials and their characteristics, together with topographic maps available for many areas, would permit much preliminary work on engineering structures to be done without the engineer ever having to leave his office.

Heating The 9th Street Interchange, Louisville, Ky, James H. Havens

Kentucky Transportation Center Research Report

The 9th Street interchange, I 64-2(87)3, was first conceived about 1959. Preliminary design studies began in the early 1960's. Design began about 1964. The idea of heating the ramps was first considered in the early 1960's but was not pursued intently until the final design stage (about 1968). As the design progressed, it became more and more evident that snowing and icing conditions could prevent otherwise normal passage of traffic up and down the ramps. At one point on the structure, a combination of superelevation and grade would produce a 6 1/2 percent slope. The highest ramp or "fly over" …

High-Intensity Reflective Materials For Signs, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

Field observations and laboratory tests and evaluations were conducted on High-Intensity and Engineering Grade materials (Scotchlite), manufactured by the Minnesota Mining and Manufacturing Company, and were compared in regard to reflectivity, durability, and cost.

The High-Intensity Grade materials were found to have outstanding performance characteristics in comparison to Engineering Grade materials. The material significantly enhances sign legibility under low-beam illumination, and accelerated weathering tests showed superior durability.

Optimal Highway Safety Improvement Investments By Dynamic Programming [Aug. 1974], Jerry G. Pigman, Kenneth R. Agent, Jesse G. Mayes, Charles V. Zegeer

Kentucky Transportation Center Research Report

The process of determining which projects to implement under a given budget, and which to defer until later, is central to the planning and management of highway systems. With a limited budget for construction, maintenance, and safety improvements, investments which will produce the optimal benefits must be chosen. This is often impossible to accomplish without the aid of a computer because of the complexity of the problem. Dynamic programming has been tested and verified as an efficient method for selecting priority projects to derive maximum benefits.

There are several approaches to priority programming as it is related to the capital …

Operational Characteristics Of Lane Drops, Don L. Cornette, Robert C. Deen, James H. Havens

Kentucky Transportation Center Research Report

Traffic behavior studies were conducted at seven lane-drop locations, representing three lane-drop classes. These studies consisted of conflict observations (that is, erratic movements and brakelight applications), spot-speed observations, and lane volume counts. Such a study was made before and after each different traffic control device installation in an attempt to determine which device was the most effective in minimizing conflicts at existing lane drops. A study of conflict deviations indicates that no single type of traffic control device studied was significantly effective in reducing erratic movement and brakelight rates at all seven lane-drop locations. Rather, it appears that different traffic …

Before-And-After Analysis Of Safety Improvements On I 75 In Northern Kentucky, Jerry G. Pigman

Kentucky Transportation Center Research Report

In September 1971, the U.S. House of Representatives Subcommittee on Investigations and Oversight met in Covington, Kentucky, to discuss the accident experience and remedial procedures taken to alleviate the frequency of accidents occurring on approximately five miles of I 75 just south of Cincinnati. This section of highway had been and was continuing to be the subject of several safety improvements. The objective of this study was to conduct before-and-after investigations of the effectiveness of the following safety improvement projects: (1) five variable message signs within a two-mile section, (2) a New Jersey-type median barrier wall extending approximately four miles, …

Raised Pavement Markers As A Traffic Control Measure At Lane Drops [No. 418], Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

Raised pavement markers are an effective means of reducing erratic movements at lane-drop locations, particularly under nighttime driving conditions. The cost of raised pavement markers and their installation is nominal (approximately $150 per lane-drop location). It is recommended that raised pavement markers be installed at other lane-drop locations. Markers installed at locations described in this study have not been in place for a sufficient time to determine their durability; however, reports from other states indicate their durability is sufficient to render them economical. If raised pavement markers are installed routinely, steps should be taken to insure they are not damaged …

Porous Sand-Asphalt Mixtures, James H. Havens

Kentucky Transportation Center Research Report

Size is relative. Densely graded sand-asphalts are relatively similar to conventional, bituminous concretes. Porous sand-asphalts possess the same attributes as other porous, bituminous mixtures. Surely, sand-asphalt mixtures, can be designed to be as porous as the so-called, open-graded plantmix seals. Particle shape and texture otherwise define skid-resistance. Stability remains an assurance against scaling. Stability is assured by maximum utilization of filler-bitumen ratio and the stiffness of asphalt cement.