Engineering Commons^™

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 …

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 …

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 …

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

Kentucky Transportation Center Research Report

No abstract provided.

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.