Engineering Commons^™

Evaluation Of Reversible Lanes (Nicholasville Road; Lexington, Ky), Kenneth R. Agent, Jon D. Clark

Kentucky Transportation Center Research Report

The study involved an evaluation of reversibIe lanes as a method of increasing traffic flow. A unique feature of the system was allowing Ieft turns during the period of reversible flow, which meant that the left-turn lanes had to be moved and the signal displays shifted during operation and without interrupting traffic flow. The evaluation involved a comparison of data taken before and after installation of the reversible lanes. Types of data included delays, volumes, accidents, speeds, traffic conflicts, fuel consumption, and environmental factors.

Installation of the reversible lanes resulted in a significant savings in travel time in the peak …

Safety Improvement Program For Toll Roads, Jerry G. Pigman, Kenneth R. Agent, Joseph D. Crabtree

Kentucky Transportation Center Research Report

This report presents proposed safety improvements for Kentucky's toll roads. The primary methods of identifying needed improvements were an accident analysis and a field inventory. The accident analysis identified specific high-accident spots and sections. Also, accident rates were calculated for each toll road, and the types of accidents which had occurred in the 3-year period were summarized. A separate 10-year analysis of fatal accidents was made. The field inventory was used to identify roadway features which are now substandard and in need of upgrading. Also, high-accident spots and sections were investigated in the field. The benefits and costs for each …

Computerized Analysis Of Moisture-Density Data, E. Gregory Mcnulty

Kentucky Transportation Center Research Report

A mathematical algorithm is described and presented for estimating optimum moisture content and maximum dry density from moisture-density data obtained from ASTM Standard Test Methods D 698 and D 1557, which are often, even though incorrectly, referred to as the Standard Proctor Test and Modified Proctor Test, respectively. However, the algorithm can be used to analyze moisture-density data obtained by non-standard procedures. The algorithm is written in Fortran IV for use with the IBM 370/165 computer and Calcomp 663 drum plotter. Documentation of this computer program includes detailed input instructions, coding sheets, flow chart, variable descriptions, example problem, example …

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 …

Effect Of Interrupted Flow On Traffic Noise, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

The objectives of this study were to investigate the effect interrupted traffic flow has on traffic noise and to determine an applicable adjustment factor. No attempt was made to develop a specific equation to predict noise levels at interrupted flow locations.

The basic method of analysis consisted of comparing the field data taken at intersections to determine if the measured noise levels changed as a function of distance from the intersection. Results showed that interrupted flow conditions did not cause an increase in the L₁₀ and L_eq noise levels. Data taken before and after the installation of traffic …

An Analysis Of Bicycle-Related Motor Vehicle Accidents In Lexington, Ky, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

A 1978 report dealt with an analysis of statewide bicycle-related, motor-vehicle accidents in Kentucky. In this study, a more detailed analysis of one city (Lexington) was performed. Accidents in a seven-year period were analyzed to make a detailed summary of several years of accident data, compare the Lexington accident summaries with statewide statistics, identify high-accident locations, and recommend accident countermeasures.

The number of bicycle accidents in Lexington has increased in recent years; however, the bicycle accident rate for Lexington was lower than that found for many other major cities in Kentucky. The largest number of bicycle accidents involved male cyclists …

Propagation Of Traffic Noise, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

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 method consisted of using 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 L_1.0 noise level reduction per doubling of distance was found to increase substantially when the traffic volume was less than 1,000 vehicles per hour. Wind speed and direction were found to have a large effect …

Problem Identification For Highway Safety Plan, Jerry G. Pigman, Kenneth R. Agent, Joseph D. Crabtree

Kentucky Transportation Center Research Report

To comply with Section 402, Title 23 of the United States Code, each state is required to prepare an annual highway safety program. Kentucky's program, which includes identification, programming, budgeting, and evaluation of highway safety projects, is intended to have a positive impact on the reduction of traffic accidents. The first step in the program, problem identification, requires systematic, statistical analyses of accident records. In-depth analyses of accident data were performed, and 29 problem areas were investigated. Accident rates were found for counties and cities in the following categories: total accidents; fatal accidents; accidents by driver age and sex; and …

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 …

Bicycle-Motor Vehicle Accidents In Kentucky, Kenneth R. Agent, Charles V. Zegeer, Robert C. Deen

Kentucky Transportation Center Research Report

The purpose of this study was to determine the characteristics associated with bicycle related, motor-vehicle accidents in Kentucky. It was found that cyclists 10 to 14 years of age were involved in the largest number of motor-vehicle related accidents. Males were involved in four times as many accidents a s females. Most accidents occurred in urban areas, mostly on residential streets. The majority of accidents resulted from errors by the cyclists. The most common type was the right-angle accident, but the leading types varied with cyclist's age. Several factors were related to age and accident severity. The accidents were summarized …

Evaluation Of The Fhwa Highway Traffic Noise Prediction Procedure (Snap 1) [Jan. 1980], Kenneth R. Agent

Kentucky Transportation Center Research Report

Traffic noise prediction procedures are used in the design of new highways to determine if noise is limited to specific levels. A previous study evaluated the procedure outlined in NCHRP Report 117 and developed a correction factor which was incorporated into Kentucky's noise prediction procedure. This adjusted NCHRP 117 procedure has been used in Kentucky for the past several years. The Federal Highway Administration has developed a new procedure to predict traffic noise levels. The objective of this study was to evaluate the new prediction procedure, designated as SNAP 1.

Comparisons of measured and predicted noise levels showed that predictions …

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

Kentucky Transportation Center Research Report

No abstract provided.

Rutting Models For Asphaltic Concrete And Dense-Graded Aggregate From Repeated-Load Tests, David L. Allen, Robert C. Deen

Kentucky Transportation Center Research Report

The development of models to predict rutting in the asphaltic concrete and dense-graded aggregate layers of flexible pavements is reported. The models were developed from data obtained from repeated-load triaxial tests. Details of equipment and methodology are reported.

An asphaltic concrete base mixture was tested at temperatures of 45 F, 77 F, and 100 F. Longitudinal stress levels of 20 psi, 50 psi, and 80 psi were used. The tests were performed unconfined. Most of the specimens were tested to 10,000 cycles of loading. Three sequences of loading were used.

It is noted that temperature and stress level are extremely …

The Effect Of Truck Design On Pavement Performance, Robert C. Deen, Herbert F. Southgate, Jesse G. Mayes

Kentucky Transportation Center Research Report

When work is done on some materials systems, their internal geometric states are altered in such a way that they have the potential to "give back" work when the force is removed and the system returns to its original configuration. This stored energy is called strain energy. Strain energy density (strain energy per unit volume) is a function of the Young's modulus of elasticity and Poisson's ratio and the nine strain (or stress) components; but it is independent of the coordinate system. Material properties are input into the Chevron N-layer computer program to calculate the strain components.

Having calculated the …

Evaluation Of Triaxial Testing Equipment And Methodologies Of Three Agencies, Tommy C. Hopkins, David L. Allen

Kentucky Transportation Center Research Report

To obtain reliable and consistent shear strength results, which are essential in the design of earth structures, from triaxial tests, careful attention, skill, and judgement must be given to testing procedures and equipment make-up. There are many sources of potential errors in the test, especially when pore pressures are monitored. Consequently, a question inevitably arises concerning tbe quality of triaxial test results obtained by different geotechnical laboratories. The intent of this study was to initiate and help establish a triaxial testing forum whereby any geotechnical laboratory engaged in triaxial testing can check the quality of their triaxial results, and therefore, …

Corrective Measures For Unstable Bridge-Approach Embankment Us 68, Licking River, Blue Licks, E. Gregory Mcnulty

Kentucky Transportation Center Research Report

In January 1979, an in-depth investigation of the unstable bridge-approach embankment, Figure 1, on US 68 over the Licking River in the north central portion of Nicholas County (MP 91-68-B0027) was begun by the Division of Research. This investigation was a continuation of a project initiated by the Division of Materials in 1967. This site is approximately 0.3 miles (0.5 km) north of Stony Creek Road and approximately 7.5 miles (12.0 km) north of Carlisle and 0.8 miles (1.3 km) southwest of Blue Licks Battlefield State Park. The bridge is a three-span, continuous, welded plate girder structure with span lengths …

Seasonal Variations In The Skid Resistance Of Pavements In Kentucky, James L. Burchett, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

Frequent measurements of skid resistance were made on 20 pavements in common use in Kentucky. Tests were conducted from November 1969 through 1973. Principal analysis involved relating changes in skid resistance to day of the year and relating skid resistance to temperature at the time of test, to average antecedent temperatures, and to average rainfall.

Seasonal variations exhibited an annual sinusoidal cycle. The changes in sand-asphalt and bituminous concrete surfaces under higher volumes of traffic were about 12 skid numbers. The changes in portland cement concrete and bituminous concrete under lower volumes of traffic were about 5 skid numbers. The …

Truck Design And Usage And Highway Pavement Performance, Robert C. Deen, Herbert F. Southgate

Kentucky Transportation Center Research Report

When the term highway pavement is used, most people think of the moderate to thick systems on which their vehicles travel on intermediate- or high-type roadways. These pavement systems are typically constructed of bituminous concrete or portland cement concrete. This is not to say that low-volume roads do not have a pavement system; however, in case of low-volume roads, the pavement system usually consists of unbound aggregates, sod, soil materials, or at the most very thin or moderate applications of a binding material. It is the high-type pavement systems to which the comments in this paper will be addressed specifically. …

Cracking In Concrete Pavement, Robert C. Deen, James H. Havens, Assaf S. Rahal, Wm. Vernon Azevedo

Kentucky Transportation Center Research Report

Cracking of portland cement concrete pavements is a common, even expected, occurrence. To minimize potentially detrimental effects, it is necessary to understand mechanisms that might be used to explain such behavior so that measures may be developed and implemented to control the occurrence of such cracking. Several "theories" are discussed that might provide the mechanisms of pavement cracking. An alternate meachanism, based on fatigue loading of the concrete by temperature expansions-contrations, for the development of so-called D-cracking is offered.

Cost-Effectiveness Of Lane And Shoulder Widening Of Rural, Two-Lane Roads In Kentucky, Charles V. Zegeer, Jesse G. Mayes

Kentucky Transportation Center Research Report

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 and 6 to 21 percent for shoulder widening. Priority listings were prepared for 531 projects based on critical rate factor. Priority listings were also prepared …

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

Kentucky Transportation Center Research Report

Warrants for the installation of separate left-turn lanes were developed. Literature was reviewed, and policies and practices in other states were surveyed. Accident analyses of locations with and without separate left-turn lanes were conducted. Computer simulation was used to determine the relationship between and among traffic delay and load factor and traffic volume, percent left-turns, cycle length, and cycle split. The relationship between left-turn accidents and conflicts was investigated.

Warrants were developed involving the following three general areas: (1) accident experience, (2) volumes (based on delay), and (3) traffic conflicts.

Statewide Survey Of Skid Resistances Of Pavements (1978), Rolands L. Rizenbergs, James L. Burchett

Kentucky Transportation Center Research Report

Statewide survey of skid resistances continued in 1978 with the testing of 2,943 miles (4,736 km) of state primary roads and 2,405 miles (3,870 km) of state secondary roads. About 10 percent of both the state primary mileage and the state secondary mileage had an average skid number of 28 or less. These pavements, in pariticular, should be considered for de-slicking.

In 1977 and 1978, 35 percent of the mileage of rural, state-maintained roads in Kentucky were surveyed. These roads carried 87 percent of all traffic on rural, state-maintained roads.

Delineation Of Stop-Sign Approaches, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of this study was to use new types of delineation at a stop approach to determine if drivers could be made more aware of the "Stop" situation ahead. The treatments involved post delineators, raised markers, and transverse striping placed at various spacings in advance of the "Stop" signs. Speeds were measured 200 feet (61 m) and 1,200 feet (366 m) in advance of the "Stop" sign. Brakelight distances were also recorded.

The various delineations provided significant reductions in speeds. Post delineators in combination with transverse stripes were the most effective. No significant difference was found between results obtained …

Raised Pavement Markers At High-Hazard Locations, Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

Even though a large number of potentially hazardous locations exist on rural, two-lane roads, guidelines have not been developed for use of raised pavement markers under night and during adverse weather conditions. The purpose of this study was to evaluate the use of raised markers at a sharp curve and narrow bridge in Kentucky. Visual observations, speed data, encroachment data, and accident data were used to evaluate the effectiveness of the markers.

Extensive visual observations of the sharp curve and narrow bridge in this study have provided data to support recommendations for improved delineation at similar sites on rural, two-lane …

Kentucky Culvert Study: An Engineering Review Of Policies And Practices Related To Procurement Of Culvert And Sewer Pipe, Byrd, Tallamy, Macdonald And Lewis

Kentucky Transportation Center Research Report

Objectives: This study was undertaken to provide the Kentucky Department of Transportation (KyDOT) with 1 ) information concerning the present state-of-the-art in the selection of culvert pipes with reference to the problem of drainage water from coal mines, shales and other excavations which may be highly acidic; and 2 ) recommendations on alternative materials and/or special treatments for pipes in areas of acid drain water.

Methodology: The study consisted of a review of the literature from selected highway agencies including Kentucky, a review of culvert pipe selection practices in other states and discussions with persons knowledgeable about pipe materials.

Findings: …

Road Rater And Benkelman Beam Pavement Deflections, Gary W. Sharpe, Herbert F. Southgate

Kentucky Transportation Center Research Report

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 frequency; surface wave velocities are measured and electronically integrated to obtain surface deflections, Since 1971, work has progressed toward the development of a pavement evaluation …

Problem Identification For Highway Safety Plan, Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

To comply with Section 402, Title 23 of the United States Code, each state is required to prepare a annual highway safety program. Kentucky's program, which includes identification, programming, budgeting, and evaluation of highway safety projects, is intended to have a positive impact on the reduction of traffic accidents. The first step in the program, problem identification, requires systematic, statistical analyses of accident records. In-depth analyses of accident data were performed, and 25 problem areas were investigated. Accident rates were found for counties and cities in the following categories: total accidents, fatal accidents, accidents by driver age and sex, and …

An Evaluation Of Permissive Left-Turn Phasing, Kenneth R. Agent

Kentucky Transportation Center Research Report

In this study, exclusive left-turn phasing was replaced with permissive left-turn phasing at four trial intersections. Delay and accident studies were done before and after the trial installations. Also, a questionnaire was issued to determine public opinion concerning the signals.

The use of permissive-turn phasing resulted in a 50-percent reduction in left-turn delay and a 24-percent reduction in total delay compared to exclusive phasing. The permissive left-turn phasing did result in an increase in left-turn accidents. Other accident types, such as rear-end accidents, did not change. The number of left-turn accidents decreased as drivers became more familiar with the signals. …