Transportation Engineering Commons^™

Use Of Economic Analyses And Dynamic Programming In The Selection Of Projects For Resurfacing, Charles V. Zegeer, Kenneth R. Agent, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

The objective of this paper was to develop a dynamic programming procedure using economic analyses to assist in optimizing expenditures in pavement resurfacing programs. Benefit relationships were determined from expected accident reduction, improved comfort, time saving, fuel savings, and maintenance savings. The only cost input to the program was the resurfacing cost of each project.

Dynamic programming was adapted to the selection of projects for resurfacing in Kentucky. Over $8.4 million of additional user benefits would have been realized in 1976 if dynamic programming had been used in selecting projects. The benefit-cost ratio of sections selected for resurfacing by the …

The Effect Of Lane And Shoulder Widths On Accident Reductions On Rural, Two-Lane Roads, Charles V. Zegeer, Robert C. Deen, Jesse G. Mayes

Kentucky Transportation Center Research Report

The purpose of the study was to determine the effect of lane and shoulder widths on accident benefits for rural, two-lane roads and also to determine the expected cost effectiveness of widening lanes and shoulders. Information concerning geometries, accidents, and traffic volumes was obtained for over 25,000 km (15,000 miles) of roads.

Run-off-road and opposite-direction accidents were the only accident types found to be associated with narrow lanes and shoulders. Wide lanes had accident rates 10 to 39 percent lower than for narrow lanes. Wide shoulders (up to 2.7 m (9 feet)) were associated with the lower accident rates. Criteria …

The Operation Of An Electrical Heating System For Bridge Decks, Wm. Vernon Azevedo, Robert C. Deen, James H. Havens

Kentucky Transportation Center Research Report

The 9th-Street interchange with I 64 in Louisville, Kentucky, was designed and constructed with an automated electrical heating system for snow and ice removal. This report summarizes the operation of the heating system during the first four years. The system was capable of keeping the interchange free of ice and snow accumulation. The average daily slab temperature fell below 0°C (32° F) only on a few occasions. The average cost of electrical power for heating the interchange was $883 per day.

Interpretation Of Dynamic Pavement Deflections, Gary W. Sharpe, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

In 1977, a methodology was .developed to evaluate pavement performance using dynamic (Road Rater) deflections. Since then, additional research has resulted in modifications ill the procedures. This paper presents the procedures presently used to evaluate flexible pavement structures. Background information is included on various procedures used by others. A sample set of data is presented and evaluated. A discussion is included on how the analyses of dynamic pavement deflections can be used to design overlays and in pavement management.

The Need For A Schema For The Classification Of Transitional (Shale) Materials, Robert C. Deen

Kentucky Transportation Center Research Report

The need for comprehensive information on the characteristics and behavior of earth materials has been recognized for many years, perhaps for as long as significant construction has taken place in and on the surface of the earth. In recent years, however, the magnitude and complexity of engineered construction has greatly increased, resulting in a corresponding increase in the need for information on the engineering properties of soil and rock materials for use in site selection, design, construction, and maintenance of major structures. Probably the most pressing need for such data is for use in preliminary considerations of site selection and …

Modulus And Damping Of Asphaltic Concrete Using The Resonant Column, David L. Allen, Robert C. Deen

Kentucky Transportation Center Research Report

When analyzing flexible pavements or predicting their behavior by such means as elastic-layered theory or by finite elements, it is necessary to know the parameters that govern the behavior of the pavement components. One of the most important factors to consider is the modulus of the asphalt bound layers.

In the past two decades, one method that has seen increasing use in the determination of the moduli of engineering materials (particularly soils) is the resonant column. However, its use in determining the moduli cf asphaltic concrete has not been widespread or well documented. In this study, which was part of …

Traffic Accidents: Day Versus Night, Donald R. Herd, Kenneth R. Agent, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

A comparison of accidents during daylight and darkness was made for both rural and urban roads. Accident rates on all types of rural roads were higher during darkness than during daylight. Critical accident rates during darkness for various types of roads were calculated. In urban areas, a larger percentage of accidents occurred on wet pavements during darkness than during daylight, but there were no significant differences for rural roads. No significant difference was found between average speeds during conditions of daylight and darkness. On rural roads, imposition of the 24.6-m/s (55-mph) speed limit resulted in a reduction in accident rates …

Analysis Of Weekday, Weekend, And Holiday Accident Frequencies, Jerry G. Pigman, Rolands L. Rizenbergs, Donald R. Herd

Kentucky Transportation Center Research Report

Trends in recent years have indicated that a significant percentage of weekend traffic is recreational and that the proportion of weekend trips is increasing. The "energy crisis" in late 1973, and the associated reduction in speed limit on March 1, 1974, affected weekend travel. A previous study by the Division of Research revealed that significant reductions in the number and rates of highway accidents, fatalities, and injuries coincided with the period of time generally referred to as the "energy crisis". Lower speeds were considered to be a primary factor in the reduction of accidents. An alteration in weekend and holiday …

Highway Research, James H. Havens

Kentucky Transportation Center Research Report

The Division of Research is responsible for:

1. Developing and carrying out a comprehensive research program on all aspects of transportation engineering and operations.
2. Maintaining lateral communication and coordination with other segments of the Department of Transportation regarding the development and conduct of research studies and special investigations of various operational and engineering problems.
3. Maintaining relations and cooperating with universities, professional organizations, and other transportation agencies; evaluating and reporting the research experiences of those agencies; and utilizing their findings directly or with further research for the benefit of the Kentucky Department of Transportation.
4. Maintaining an up-to-date library of research findings on …

Transverse Pavement Markings For Speed Control And Accident Reduction, Kenneth R. Agent

Kentucky Transportation Center Research Report

Pavement markings were placed ahead of a high-accident location (a sharp curve). Speed and accident studies were conducted before and after. The markings were placed so that drivers otherwise failing to reduce speed would see the markings at an increasing rate. The spacing of lines was intended to create an illusion of acceleration which would cause the driver to slow. Speed is perceived by the visual senses; drivers sense forces resulting from changes in speed but relate and associate speed to the visual field. In laboratory experiments, it has been shown that a driver's perception of speed can be varied …

Occurrences Of Expansive Limestone In Kentucky, Ralph G. Coy, James H. Havens

Kentucky Transportation Center Research Report

No abstract provided.

Priority Programming For Highway Reconstruction, Charles V. Zegeer, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

An adequacy-rating procedure was developed for use in priority programming for highway reconstruction. The procedure makes use of 15 roadway and traffic elements to rate highway sections in urban and rural areas based on 100 points. Condition elements (35 points) include a subjective rating of highway foundation, pavement surface, drainage, and maintenance economy. Safety elements (35 points) are stopping sight distance, highway alignment, skid resistance, accident experience, and traffic control devices. Service elements (30 points) include shoulder width, passing opportunity, rideability, surface width, volume/capacity ratio, and average speed.

Some of the advantages of the new procedure include computerized analysis of …

Seatbelt Usage In Kentucky [Nov. 1978], Kenneth R. Agent, Michael Barclay, Robert C. Deen

Kentucky Transportation Center Research Report

In this report, the effectiveness and usage of seatbelts in Kentucky and factors affecting usage are examined and identified. Data were obtained from three sources: field observations, accident reports, and a questionnaire.

Kentucky drivers and passengers were found to have lower seatbelt usage rates (slightly under 10 percent) than drivers and passengers in other states. The accident data showed that the chances of being killed or severely injured is greatly reduced by wearing a seatbelt. Seatbelts reduced the chance of being killed by a factor of six and the chance of being severely injured by a factor of two. Several …

Pavement Evaluation Using Dynamic Deflections, Gary W. Sharpe, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

Dynamic test deflections have been duplicated by elastic theory using the Chevron N-layered computer program. Dynamic surface deflections obtained using the Road Rater have been used in conjunction with elastic theory to analyze pavement behavior. A procedure has been developed to use field measured Road Rater deflections to estimate the elastic moduli of the foundation material and to determine the equivalent thicknesses of new material which approximate the behavior of the structure. The estimated moduli and (or) equivalent thicknesses may be used as inputs to design overlay thicknesses. An analysis of the deflections of the first three sensors of the …

Warrants For Left-Turn Signal Phasing, Kenneth R. Agent, Robert C. Deen

Kentucky Transportation Center Research Report

Warrants for the installation of left-turn phasing were developed. A review of literature was conducted along with a survey of the policies of other states. Field data of delays and conflicts were taken before and after installation of exclusive left-turn signalization. Left-turn delay studies were conducted at intersections with varying volume conditions. Analysis of the effect on accidents of adding a left-turn phase was made. The relationship between left-turn accidents and conflicts was investigated. Other types of analyses concerning gap acceptance, capacity, and benefit-cost ratios were also performed.

It was found that exclusive left-turn phasing significantly reduced left-turn accidents and …

A Rational Thickness Design System For Asphaltic Concrete Overlays, Herbert F. Southgate, Gary W. Sharpe, Robert C. Deen

Kentucky Transportation Center Research Report

A method of designing asphaltic concrete overlays has been developed making use of (1) Kentucky's proposed design curves, (2) an estimate of future traffic and the associated fatigue (five procedures are presented according to types of information available), (3) strength of subgrade on subject project (laboratory CBR tests or results of dynamic in-place tests such as the Road Rater), and (4) present condition of the existing pavement (from dynamic in-place tests, roughness measurements, or present serviceability index). Deterioration was expressed as reduced thicknesses of new-quality materials producing the same measured dynamic deflections. The total thickness for the predicted traffic minus …

Simulation Of Travel Patterns For Small Urban Areas, Jerry G. Pigman, Robert C. Deen

Kentucky Transportation Center Research Report

The objective of this study was to develop models which would simulate internal-external trips and external-external (through) trips. Regression analysis and cross-classification of data were tested in an attempt to predict the number of internal-external trips and the percentage of through trips. Regression analysis was used in the development of a through-trip distribution model. Grouping data for analysis created some problems; however, trial-and-error evaluation enabled selection of variables which produced reasonable results. Variables found to be most significant in the development of internal-external models were population and employment. For through-trip models, variables used were population, functional classification, AADT at the …

Green-Extension Systems At High-Speed Intersections [Sept. 1978], Charles V. Zegeer, Robert C. Deen

Kentucky Transportation Center Research Report

The purpose of this study was to determine the effectiveness of green-extension systems (GES) for reducing the dilemma-zone problem associated with the amber phase of traffic signals at high-speed intersections. Reactions of 2,100 drivers were noted during the amber phase at nine intersections, and the dilemma-zone distances with respect to the stop bar were determined.

Before-and-after studies made at three green-extension sites showed a 54-percent reduction in total accidents and a 75-percent reduction in rear-end accidents after GES installation. Accident severity was unaffected.

Conflict, volume, delay, and speed data were taken before and after GES installation at two sites. A …

Acoustic Emission And Fatigue Characteristics Of Typical Bridge Steels, Theodore Hopwood Ii, James H. Havens

Kentucky Transportation Center Research Report

Acoustic emission monitoring was used during tensile tests of low-carbon structural steels to determine the physical characteristics of the acoustic emission phenomena. Results indicate that acoustic emissions are caused by micro-plastic deformation processes (i.e., dislocation motion).

A series of axial-fatigue tests was performed on several types of structural steels, some of which had extensive service in bridges. There was no apparent relation between specimen load histories and subsequent performance in fatigue tests. Tensile tests of specimens subjected to extensive fatigue testing, at stresses below the yield strength of the material, revealed no major difference in mechanical properties or acoustic emission …

Green-Extension Systems At High-Speed Intersections [Apr. 1978], Charles V. Zegeer, Robert C. Deen

Kentucky Transportation Center Research Report

The purpose of this study was to determine the effectiveness of green-extension systems (GES) for reducing the dilemma-zone problem associated with the amber phase of traffic signals at high-speed intersections. Reactions of 2,100 drivers were noted during the amber phase at nine Intersections, and the dilemma-zone distances with respect to the stop bar were determined.

Heating Bridge Decks By Electrical Resistance, James H. Havens, Wm. Vernon Azevedo, Assaf S. Rahal, Robert C. Deen

Kentucky Transportation Center Research Report

The 9th-Street interchange was designed and constructed with an automated electrical heating system for snow and ice removal. This report describes the heating system, its construction, and initial operation. The heating system was capable of keeping the interchange free of ice and snow accumulation. The average daily slab temperature fell below 0°C (32°F) on only one occasion. The average cost of electrical power for heating the interchange was $1,075 per day.

Analysis Of Time-Independent Consolidation Data, E. Gregory Mcnulty, Tommy C. Hopkins, C. Thomas Gorman

Kentucky Transportation Center Research Report

The one-dimensional laboratory consolidation test developed by Terzaghi permits deformation and drainage only in the vertical direction. The stress-strain characteristics of data obtained from this test are normally studied using a semilogarithmic graphical representation, that is, vertical strain or void ratio is plotted as a function of the logarithm of effective stress. Such a representation permits an analysis of the stress history and compressibility characteristics of soils. Knowledge of these material characteristics is of great practical value in the prediction of settlement associated with loading where the effects of lateral consolidation may be neglected.

Analysis Of Time-Dependent Consolidation Data, E. Gregory Mcnulty, C. Thomas Gorman, Tommy C. Hopkins

Kentucky Transportation Center Research Report

No abstract provided.

A Possible Explanation Of Concrete Pop-Outs, James H. Havens, Robert C. Deen

Kentucky Transportation Center Research Report

This report summarizes several years of research relating to damage to concrete and aggregates undergoing freezing and thawing. Basic principles involving freezing and attendant pressures are considered. Application of these principles to the evaluation of concrete was accomplished in experiments on concrete having low and high air contents.

Freeze-thaw characteristics of saturated aggregates relative to physical properties such as porosity, absorption, and bulk specific gravity were studied by submerging individual particles in pre-chilled mercury. Pressures associated with pop-outs in concrete were monitored and are presented along with accompanying theoretical considerations.

Kentucky Research: A Flexible Pavement Design And Management System, Herbert F. Southgate, Robert C. Deen, James H. Havens, William B. Drake

Kentucky Transportation Center Research Report

Various strategies for designing pavement structures are discussed. Initial full-life design, stage designs and planned extensions of service life, final design, surface renewals for deslicking, no-defect designs for high-type high-volume facilities, and allowable-defect designs are considered. Economics enter in terms of salvage value of existing pavements and alternate designs using different proportions of materials within the structure.

The elastic model represented in Chevron's n-layered computer program is the basis for theoretical relationships. Ranges of values are given for input variables such as Young's moduli, Poisson's ratio, thicknesses for layers, tire pressure, and load. The Kentucky CBR is related to modulus …

Effect Of Pavement Texture On Traffic Noise, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

Noise from highway vehicles emanates primarily from engine exhausts, tire-pavement interaction) gears, and rattles. Studies have shown that at high speeds tires become the dominant generators of noise. Measurements on different road surfaces have produced different noise-versus-speed relationships (1). This led to the road surface adjustment used in the noise prediction procedure developed in NCHRP Report 117 (2). This adjustment called for a 5 dBA reduction for smooth surfaces (very smooth, seal-coated asphalt pavement) and a 5 dBA increase for rough surfaces (rough asphalt pavement with voids 1/2 inch (12 mm) or larger in diameter and grooved concrete). …

Highway Accidents At Bridges, Kenneth R. Agent, Robert C. Deen

Kentucky Transportation Center Research Report

Grade-separation structures (bridges) at interchanges, crossroads, over streams, railroads, etc., which are intended to provide greater convenience and safety, otherwise involve features which either obstruct the range of free travel or serve as containment barriers. The objective of this study was to identify those principal features of bridges and appurtenances which may be related to accident frequency and severity and to provide some further insights toward highway safety.

Speed Reduction In School Zones, Charles V. Zegeer, James H. Havens, Robert C. Deen

Kentucky Transportation Center Research Report

The use of flashing beacons together with signing has become somewhat standard throughout the country to alert drivers to the presence of school children and to regulate vehicle speed in school zones. Yellow beacons, usually two flashing alternately, may be used with both warning signs and regulatory signs. The only regulatory signs related to school zones are speed-limit signs. Both hazard identification beacons and speed-limit sign beacons are intended to operate only during hours when the warning and speed regulations are in effect. The effectiveness of signs and flashing lights in reducing speeds in school zones has been questioned.

The …

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 …

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 …