1,554 Works

Rheological Response of Asphalts

David L. Allen
The rheological response of asphalt cements to shearing stresses is presented. The behavioral characteristics were measured using a rotating coaxial cylinder viscometer. Little or no development of theory is presented. The viscoelastic portion of deformation is discussed in terms of the creep function. Plastic deformation is described using the definitions of apparent and plastic viscosities. Curves showing the effects of temperature, stress level and penetration on these two major components of strain are presented and...

Comparative Evaluation of RAYGO 404 Vibratory Roller

Jerry D. Ross, Herbert F. Southgate & Donald C. Newberry
Roller evaluations are rather phenomenological -- that is, one must rely somewhat on observations. Density measurements following each excursion of the compactor may not relate directly to the work done in compressing the layer. When no increase in density is realized, no work is accomplished. Work is defined here in the classical sense. Energy expended without producing an increase in density is wasted. Thereafter, the only way additional classical work can be done on the...

Characteristics of Kentucky Drivers

Kenneth R. Agent
The characteristics of the driver population in Kentucky were examined and related to their driving record. Also, the characteristics of high-risk drivers were determined and compared to the driver population. Accident records and responses to a questionnaire distributed to a random sample of the driver population and to high-risk drivers were the data source for the study. Frequency of accidents was found to be much higher among males than it was among females and was...

Warrants for Left-Turn Signal Phasing

Kenneth R. Agent & Robert C. Deen
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...

Road Rater and Benkelman Beam Pavement Deflections

Gary W. Sharpe & Herbert F. Southgate
The Benkelman beam has been one of the most commonly used methods of measuring surface deflections of a highway pavement. A Benkelman beam is based on a simple lever-arm principle and uses dial guages to measure surface deflection under an applied load. In 1971, the Commonwealth of Kentucky purchased a Road Rater for use by the Department of Transportation, Division of Research. The Road Rater applies a sinusoidal force to the pavement at a fixed...

Use of Economic Analyses and Dynamic Programming in the Selection of Projects for Resurfacing

Charles V. Zegeer, Kenneth R. Agent & Rolands L. Rizenbergs
The objective of this study was to develop a dynamic programming procedure using economic analyses to assist in optimizing expenditures in the pavement resurfacing program in Kentucky. Benefit relationships were determined from expected accident reduction, improved comfort, time savings, 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. Over $8.4 million of additional user...

Cost-Effectiveness of Lane and Shoulder Widening of Rural, Two-Lane Roads in Kentucky

Charles V. Zegeer & Jesse G. Mayes
The purpose of the study was to determine the cost-effectiveness of widening lanes and shoulders on rural, two-lane roads. Information concerning geometries, accidents, and traffic volumes was obtained for over 15,000 miles (25,000 km) of roads. Reductions in accident rates occurred as lane and shoulder widths increased. Run-off-road and opposite direction accidents were the primary accident types associated with narrow lanes and shoulders. Reductions in accidents ranged from 10 to 39 percent for lane widening...

Analysis of Tandem Axleloads by Elastic Theory

Herbert F. Southgate, Robert C. Deen & James H. Havens
AASHO Road Test tandem axleloads were analyzed to determine the magnitude of the tandem axleload that causes the same damage as the 18-kip (80-kN) single axleload. The procedure is outlined and is the same used to analyze single axleloads. The essential findings were as follows: 1. One repetition of a 34-kip ( 151-kN) tandem axleload appears to cause the same damage as one repetition of an 18-kip (80-kN) single axleload. 2. The relationships of log...

Traffic Conflicts, Erratic Maneuvers, and Near-Miss Accidents:

Charles V. Zegeer
Definitions are given for the various types of traffic conflicts, erratic maneuvers, and near-miss accidents. The General Motors technique for observation of traffic conflicts is summarized. Procedures used by several highway agencies for collecting conflict data are also detailed. Criteria which have been used to identify hazardous intersections using traffic conflict data are summarized. Methods and examples of evaluating safety improvements are detailed. Relationships between conflicts and accidents found by others were given. The procedure...

Computerized Analysis of Stress-Strain Consolidation Data

E. Gregory McNulty
A computerized, mathematical algorithm is described and presented for analyzing the semilogarithmic stress-strain (time-independent) properties of standard, controlled-gradient, and controlled-rate-of-strain consolidation tests. This algorithm is an automation of manual graphical procedures currently used in engineering practice to obtain stress-strain information necessary for use in time-independent settlement analysis. The Casagrande and Schmertmann constructions are analytically represented to determine the preconsolidation stress and the in situ, compressibility coefficients of compression and expansion. Values for each of these...

Surface Dynamics Profilometer and Quarter-Car Simulator:

James L. Burchett, Rolands L. Rizenbergs & Thomas A. Moore
A Surface Dynamics Profilometer was acquired in December 1968. The SD Profilometer was designed to rapidly and accurately measure the profile of the surface over which it is driven. A Quarter-Car Simulator was obtained in 1970. The simulator, a special purpose analog computer, was designed to process road profiles measured with the SD Profilometer. This processing involves analog simulation of a simplified vehicle. Factors and variables associated with the devices and calibration and test procedures...

Flexible Pavement Designs to Support Various Vehicle Configurations

Robert C. Deen & Herbert F. Southgate
Pavement designers are often asked if pavements can be designed to carry and support the unusually heavy loads which have been known to use portions of the highway system. In some instances, for example, haul roads leading to highway or other construction projects or haul roads associated with mining, heavy loads have become commonplace and extra-legal. Within limitations of engineering experience, there appears to be no reason why pavements cannot be designed for these heavy...

Propagation of Traffic Noise

Kenneth R. Agent & Charles V. Zegeer
The effects of various traffic, ground cover, and geometric conditions on traffic noise propagation were evaluated in this study. There were two general methods of data collection. The first used as many as four sound-level meters and graphic-level recorders to take simultaneous recordings of the traffic stream; the second method involved a constant noise source using a random noise generator. The L10 noise level reduction per doubling of distance increased substantially when the traffic volume...

Evaluation of the Traffic Noise Prediction Procedure

Kenneth R. Agent & Charles V. Zegeer
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...

Problem Identification for Highway Safety Plan

Jerry G. Pigman, Kenneth R. Agent & Tom Creasey
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 fifth in a series of annual reports which have been included as the problem identification portion of Kentucky's Annual Highway Safety Plan. In the past, the approach to problem identification has...

\"Before\" Evaluation of Economic Growth Center Developmental Highway

Joseph T. Farmer & Jerry G. Pigman
Before-and-after impact studies were selected as the means of determining the effect of reconstructing a 4.813-mile (7.744-kilometer) section of KY 55 between Campbellsville and Lebanon. The area, though still depressed in terms of per capita income and employment, has many resources available for growth. The study area is predominantly an agriculturally-oriented economy. However, manufacturing employment has increased in recent years, mainly because of industrial sites made available by local industrial commissions. Overall, social services appear...

\"Before\" Evaluation of Economic Growth Center Developmental Highway

Joseph T. Farmer & Jerry G. Pigman
Before-and-after impact studies were selected as the means of determining the effect of reconstructing a 4.886 mile (7.862 kilometer) section of US 25E between Corbin and Barbourville. A comprehensive analysis of the "before" statistics revealed the area designated as a potential growth center suffered from social and economic mediocrity. Many characteristics considered essential for economic prosperity are lacking. Per capita income and educational achievement levels are lower than statewide averages. Transportation is dependent upon highways...

Subject Listing of Research Reports

The Safety Barrier Dilemma

James H. Havens, Don L. Cornette & William M. Seymour
"Ran-off-the-road" fatal accidents currently account for approximately 65 percent of all freeway fatalities (1). Accordingly, ever-increasing emphasis has been given to the development of effective safety barrier systems, from guardrails to earth berms to median barriers to energy absorbing barriers and mires. However, highway designers have also recognized that safety barriers are hazards in themselves, misfits in the highway environment, and that they are items to be eliminated wherever possible. In a study of fatal...

Bridges:

James H. Havens & Robert C. Deen
Repeated stressing of metals above certain limits induces inter- and intra-crystalline dislocations and cleavages and eventually cracks which propagate to failure. Some authorities consider crack propagation to be a separate and discrete stage in the failure process. The internal damage is insidiously cumulative and irreversible. This phenomenon was recognized as early as 1829 and was termed fatigue as early as 1839(1). From the beginning of fatigue testing (Wohler, 1858-1870), results have been reported as S-N,...

Statewide Survey of Skid Resistances of Pavements

Rolands L. Rizenbergs, James L. Burchett, Larry A. Warren & William M. Sampson
Since 1969, when a research-type, skid-test trailer was acquired, U.S. routes were surveyed in 1970 and 1971, and the interstate and toll road systems were surveyed in 1971. The data were used for research purposes and have been reported. The interstate and toll road systems were surveyed again for research purposes in 1974. Since October 1974, surveys have been performed under a highway safety project grant. All primary and principal secondary roads, involving 4,612 miles...

Transverse, Pavement Markings for Speed Control and Accident Reduction

Kenneth R. Agent
Transverse pavement markings were placed ahead of a sharp curve having a high-accident history. Speed and accident studies were conducted before and after. The markings were placed so that drivers otherwise failing to reduce speeds while approaching the curve would see transverse lines on the pavement at an increasing rate. The spacing of lines was intended to create an illusion of acceleration which would cause the driver to slow. The results indicated that pavement markings...

Pavement Roughness In Kentucky

Gary W. Sharpe, David H. Cain, Herbert F. Southgate, James H. Havens & Robert C. Deen
Over two hundred pavement sections in Kentucky have been periodically measured for pavement roughness over a period of several years. This pavement service-life historical data can be used to assess quality of construction, pavement service-life, present and anticipated pavement condition. Road users perception of ride quality can be related to these measurements. Response-type road roughness measuring systems have been used to collect roughness measurements and correlation studies have been performed to relate measurements from current...

A Rock Evaluation Schema for Transporting Planning in Kentucky

C. D. Tockstein & M. W. Palmer
The initial goal was to devise an engineering classification system for intact rock samples based on simple index tests which could be used to categorize Kentucky surface and near-surface rock types and assist Kentucky Department of Transportation personnel in planning for transportation facilities. While conducting the literature survey, several facts become apparent: a large number of rock classification systems, geologic and technical, general and specific, already existed; an equally large number of index tests had...

Analysis of Weekday, Weekend, and Holiday Accident Frequencies

Jerry G. Pigman, Rolands L. Rizenbergs & Donald R. Herd
On rural roads, the largest number of accidents have occurred on Saturdays, Fridays, and Sundays, respectively. Tuesdays generally had the lowest number of accidents. The highest accident rates for two-lane roads were on Sundays and Saturdays, and the rates for expressways (interstates and toll roads) were the highest on Sundays. Accident rates on weekends were substantially higher than on weekdays. Rates of fatal and all accidents were lower during holiday periods than during weekends not...

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