Engineering Commons^™

Modification Of Kentucky’S Adequacy-Rating Techniques, Charles V. Zegeer, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

The purpose of this study was to evaluate Kentucky's adequacy-rating methods and procedures and to recommend improvements. The rating procedures used by planning engineers in the highway districts were found to be reliable and consistent. Kentucky's methods were found to be superior to methods used in most states, but several changes are recommended. Additions include credits for accident analysis for urban and rural sections, traffic control devices for urban areas, and traffic safety features for bridges. Skid resistance evaluation was changed from a subjective rating to a measured value. Points assigned to the various rating elements have been revised, and …

Acoustic Emission, Fatigue, And Crack Propagation, Theodore Hopwood Ii

Kentucky Transportation Center Research Report

Acoustic emission was used in conjunction with tensile tests to evaluate the condition of structural steel specimens subject to various tensile fatigue lives. The results indicate that the acoustic emissions detected were the result of plastic deformation. There was no apparent relationship between fatigue history of the steel specimens and the amount of plastic deformation they can accommodate.

Further tests revealed that acoustic emission has the physical capability of detecting cracks on large structural steel members. This may prove beneficial for the comprehensive testing of steel bridges.

Development Of Warrants For Left-Turn Phasing, Kenneth R. Agent

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 analysis concerning gap acceptance, computer simulation, capacity, and benefit-cost ratios were also performed.

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

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 …

Freeze-And-Thaw Of Concretes And Aggregates, 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. The effects of air entrainment upon freeze-thaw resistance were demonstrated.

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 popouts in concrete were monitored and are presented along with accompanying theoretical considerations.

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.

Pedestrian Accidents In Kentucky, Charles V. Zegeer, Robert C. Deen

Kentucky Transportation Center Research Report

When a pedestrian is hit by a motor vehicle, he is usually injured or killed; there is no protective cushion to absorb the impact. The high concentration of pedestrians in urban areas, coupled with heavy vehicle traffic, often results in large numbers of pedestrian accidents. In rural areas, there are considerably fewer pedestrians but traffic speeds are higher and, therefore, accidents are more often fatal.

Pedestrian fatalities have increased in the United States from about 7,800 in 1960 to approximately 10,500 in 1973 (1). There are 120,000 pedestrian accidents each year. Total traffic accidents in the US number about …

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 …

Constant-Rate-Of-Strain And Controlled-Gradient Consolidation Testing, C. Thomas Gorman

Kentucky Transportation Center Research Report

Controlled-gradient (CG), constant-rate-of-strain (CRS), and conventional incremental-loading (STD) consolidation testing are compared and evaluated. Undisturbed samples representing three soils common to Kentucky were used in the testing program. Settlements estimated by each testing technique were compared with settlement records from one of the sites. Results of 15 CG, 14 CRS, and 32 STD consolidation tests are shown. No significant differences were noted in values obtained from the three types of consolidation tests. Feasibility of the new test methods for routine testing is briefly discussed and recommendations were made for refinements in testing procedures.

A Survey Of Use Of Left-Turn-On-Red, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objectives of this survey were to determine the extent that a left turn on a red traffic signal (LTOR) has been used across the country and to learn how effective it has been. Responses were received from 43 of the 55 cities surveyed. Of the cities responding, 22 have either had past experience with LTOR or have recently enacted an ordinance which will allow LTOR in the future. Most LTOR laws limit its use to intersections of two one-way streets. A much higher percentage of cities in the western United States have laws permitting LTOR than cities in the …

The Socioeconomic Impact Of The Mountain Parkway And Ky 15, Joseph T. Farmer

Kentucky Transportation Center Research Report

A study of socioeconomic variables in a nine-county region in Eastern Kentucky was undertaken to determine whether significant growth had occurred since the opening of the Mountain Parkway and reconstruction of KY 15. It was hypothesized that these roads have acted as catalysts with available resources to promote a better quality of life.

Study revealed that, while income levels and business sales have enjoyed substantial increases, overall quality of life is still poor. Educational facilities are inadequate; economic diversification in business types is limited; coal is still the main stimulant for income and employment. However, outmigration of persons from the …

Evaluation Of Thermoplastic Pavement-Striping Materials (Louisville And Jefferson County), Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

Approximately 1,406,100 linear feet (428,579 m) of hot-sprayed thermoplastic stripe was applied to roadways in Louisville and Jefferson County in the summer of 1973. Visual observations of appearance, durability, and night visibility were conducted according to ASTM D 713-69, the standard method for conducting road service tests on traffic paint. Attempts to conduct photometer measurements of the thermoplastic striping were unsuccessful. Visual observations made during rainy, nighttime conditions were also unsuccessful because very little difference was noticeable among the various sections.

The evaluation showed that the thermoplastic stripes performed considerably better on bituminous concrete pavements than on portland cement concrete …

Accidents On Rural, Two-Lane Roads And Their Relation To Pavement Friction [Apr. 1976], Rolands L. Rizenbergs, James L. Burchett, Larry A. Warren

Kentucky Transportation Center Research Report

Friction measurements were made with a skid trailer at 40 mph (18 m/s) on 1460 miles (2350 km) of rural, two-lane roads (US routes) in Kentucky. Maintenance sections or subsections were treated as test sections. Accident experience, friction measurements, traffic volumes, and other available data were obtained for each. Various expressions of wet-pavement accidents and pavement friction were related and analyzed. Averaging methods were used in developing trends and minimizing scatter. A moving average for progressively-ordered sets of ten test sections and test sections grouped by Skid Numbers and Peak Slip Numbers yielded more definite results. The expression of accident …

The D-Cracking Phenomenon: A Case Study For Pavement Rehabilitation, James H. Havens

Kentucky Transportation Center Research Report

No abstract provided.

Characteristics Of Traffic Streams On Rural, Multilane Highways, Jerry G. Pigman, Jesse G. Mayes

Kentucky Transportation Center Research Report

The purpose of this study was to develop a data base and interrelationships for traffic characteristics on rural, multilane highways. Primary emphasis was placed on factors influencing lane distribution. Other characteristics investigated were vehicle speeds, vehicle classifications, volumes, time distributions of flow, and noise emitted by vehicle type and weight. Most analyses were based on traffic characteristics data collected in the summer of 1973. Analyses of 1968 and 1975 traffic characteristics data were compared with 1973 data for the purpose of investigating unusual trends over the various time periods. The 1968 and 1973 surveys produced similar results; however, some changes …

Guardrail Performance: An Analysis Of Accident Records, Kenneth R. Agent

Kentucky Transportation Center Research Report

Accident records involving guardrails were analyzed and summarized.

Guardrail-related accidents comprised a significant percentage of interstate and parkway accidents, particularly those resulting in fatalities. Guardrail involvement in accidents was much less on primary and secondary highways than on interstates and parkways.

The severity of guardrail-related accidents was higher than the average severity of all accidents. The severity of guardrail-related accidents was higher on the primary and secondary system than on the interstate and parkway system.

Guardrails have not been very successful in redirecting vehicles parallel to traffic. The largest number of severe injuries involved vehicles vaulting over the guardrail Increased …

A Soils Data System For Kentucky, Dwight Spradling

Kentucky Transportation Center Research Report

This report discusses the development of a computerized soils data system which facilitates collection, centralized storage, and retrieval of soils data developed by engineers and scientists for projects in Kentucky. Without such a system, much soils data are essentially lost after each project is completed. This system will provide data that can conveniently be used for developing preliminary sources of information for site investigation, for preparing regional soil maps, for land use planning, and for studying new and existing empirical relationships involving soil properties and characteristics.

Various types of data systems, the design of the system to include software and …

A High-Accident Spot-Improvement Program, Kenneth R. Agent, John A. Deacon, Robert C. Deen

Kentucky Transportation Center Research Report

As a result of an extensive before-and-after accident study, the high-accident location, spot-improvement program in Kentucky, although not a costly program, was found to have significantly decreased the number of motor vehicle accidents. Favorable benefit-cost ratios indicated that the cost of the program has represented a good investment in comparison with the resultant savings in accident costs. The spot-improvement program had little effect on average accident severity as measured by a severity index. Detailed analysis of available accident data showed that, for studies of the type reported, the 12-month period immediately prior to the date of identification of a high-accident …

Evaluation Of Paint-Stripe Beads, Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objectives of this phase of the overall "Roadway Delineation" study were to evaluate the luminosity and durability of several types of glass beads and one type of plastic bead used with paint stripes and to determine their effectiveness during rainy, nighttime conditions. Eleven types of beads were evaluated. They were applied at rates approximating 4, 5, and 6 pounds per gallon (479, 599, and 719 kg/m3). Photometer and visual observations extended to about 9 months after application of test stripes.

Pedestrian Accidents In Kentucky, Charles V. Zegeer, Robert C. Deen

Kentucky Transportation Center Research Report

Pedestrian accident data in Kentucky were analyzed for 1972 and 1973 on a rural, urban, and statewide basis. Results showed that about 1500 pedestrian accidents occur in Kentucky each year. About 30 percent of the pedestrian accidents in rural areas and four percent in urban areas are fatal. Although about 78 percent of Kentucky's pedestrian accidents occur in urban areas, over 62 percent of the pedestrian fatalities occur in rural areas. Specific characteristics of pedestrian accidents were identified and related to human, environmental, and time factors. Highway and street improvements and safety measures generally considered to be effective in minimizing …

Identification Of Hazardous Locations On City Streets, Charles V. Zegeer

Kentucky Transportation Center Research Report

The purpose of this study was to develop an effective method for identifying hazardous locations in Kentucky cities (over 2,500 population). Methods used in 45 other states were reviewed. Accident information for 69 of the 97 cities over 2,500 population was used to develop criteria for an identification method.

A Number Method was selected for initial identification of midblocks and intersections on arterial-collector streets and on urban freeways. Rate-Quality Control Methods were included in the form of a critical rate factor computed for each location. A set of critical rate curves was constructed for easy determination of critical locations. A …

A Guide To Preparing Research Reports And Technical Talks, Robert C. Deen

Kentucky Transportation Center Research Report

This manual has been prepared to provide guidance to writers of technical reports which are to be issued by the Division of Research, Kentucky Bureau of Highways. Concepts of technical report writing are presented. Specific instructions concerning the preparation and submission of reports for review are also presented. Appendices included provide rules for grammar, punctuation, etc. which cause engineer-writers particular problems.

Effects Of Water On Slope Stability, Tommy C. Hopkins, David L. Allen, Robert C. Deen

Kentucky Transportation Center Research Report

A brief state-of-the-art review of the effects of water on slope stability and the techniques for analysis is presented. The effective stress principle and basic considerations of slope stability, including design factors of safety, are discussed briefly. The derivations and effects of seepage forces and rapid drawdown on effective stress are also presented. Various conditions of external loading produce changes in effective stress. These changes are discussed and limiting conditions which should be analyzed are mentioned.

Limitations of total stress analyses are discussed in detail. It appears that, for soils having a liquidity index of 0.36 or greater (normally consolidated), …

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

Kentucky Transportation Center Research Report

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 can be an effective speed-control measure and reduce accidents. At the single site studied, the obedience of drivers to this type of hazard warning was …

Loads On Box Culverts Under High Embankments: Positive Projection, Without Imperfect Trench, Rick L. Russ

Kentucky Transportation Center Research Report

This report describes the instrumentation and measurements of settlements and pressures on two box culverts in Clark County, Kentucky, designed without the imperfect trench -- one for yielding and one for unyielding foundation conditions. The structures were primarily instrumented for comparison with three structures previously constructed in McCreary County, which were designed using the imperfect trench method. Pressures on the two structures in Clark County generally exceed the product of the unit weight of the overlying material and its height. The pressures on the culverts in McCreary County appear to be lower than expected -- indicating that the imperfect trench …

First-Year Effects Of The Energy Crisis On Traffic In Kentucky (Rural Highways), Kenneth R. Agent, Donald R. Herd, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

The Arab oil embargo in mid-October 1973 curtailed availability of gasoline. Fuel conservation measures resulted in reduced travel and decreased traffic speeds. On March 1, 1974, posted speed was set at 55 mph (88 km/h) on rural highways in Kentucky. Traffic volumes, speeds, and accidents for the rural highway during the period known as the "energy crisis" and its after effects were compared to the corresponding period a year earlier.

Traffic volumes began to decline in December 1973 and continued through September 1974. Total travel in the 12 months through November 1974 decreased by 2.3 percent; traffic increased by five …

The Effectiveness Of School Signs With Flashing Beacons In Reducing Vehicle Speeds, Charles V. Zegeer

Kentucky Transportation Center Research Report

A detailed study of signs with flashers in school zones was conducted to determine their effectiveness in reducing the speeds of vehicles during times of pedestrian activity. Field investigations were conducted at all of the 120 flasher locations in Highway Districts 6, 7, and 9. About 14 percent of the flashers were inoperative. Such problems as non-uniform signing, hidden flashers, deteriorating signs and pavement markings, and poor sight distances were also found.

Speed studies were conducted at 48 locations. Average speed reductions were only 3.6 mph (1.6 m/s) during flashing periods. Signs and flashers at high-speed (55-mph (25-m/s)) locations increased …

Accidents Associated With Highway Bridges, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of this study was to identify those principal features of bridges which may be related to accident frequency and severity and to provide some further insights toward highway safety. Accident data from interstate and parkway (toll) routes and from primary and secondary systems were compiled and summarized. The major findings were:

1. Bridge-related accidents, particularly involving severe accidents, were significant percentages of the total accident experience on interstates and parkways.
2. There were fewer bridges per mile on the primary and secondary highway system and a lower percentage of bridge related accidents than on interstates and parkways.
3. The severity of …

First-Year Effects Of The Energy Crisis On Traffic In Kentucky (Rural Highways) [May 1975], Kenneth R. Agent, Donald R. Herd, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

The Arab oil embargo in mid-October 1973 curtailed availability of gasoline. Fuel conservation measures resulted in reduced travel and decreased traffic speeds. On March 1, 1974, posted speed was set at 55 mph (24.6 m/s) on rural highways in Kentucky. Traffic volumes, speeds, and accidents for the rural highway during the period known as the "energy crisis" and its after effects were compared to the corresponding period a year earlier.

Traffic volumes began to decline in December 1973 and continued through September 1974. Total travel in the 12 months through November 1974 decreased by 2.3 percent; traffic increased by five …