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Articles 5041 - 5070 of 5920

Full-Text Articles in Civil and Environmental Engineering

Analysis Of Weekday, Weekend, And Holiday Accident Frequencies, Jerry G. Pigman, Rolands L. Rizenbergs, Donald R. Herd Nov 1978

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

Kentucky Transportation Center Research Report

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 involving holidays. Holiday periods had fewer accidents per day than weekends but had more accidents per day than weekdays. Traffic during holidays, however, was significantly …


Statewide Survey Of Skid Resistances Of Pavements [Nov. 1978], Rolands L. Rizenbergs, James L. Burchett Nov 1978

Statewide Survey Of Skid Resistances Of Pavements [Nov. 1978], Rolands L. Rizenbergs, James L. Burchett

Kentucky Transportation Center Research Report

In 1969, 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 highway safety project grants (interaccounted to 108, subsection OSKID). Primary and principal secondary roads, involving 4,613 miles (7,427 km), were surveyed in 1975. A second skid tester, a survey-type, was acquired in April 1976; and survey-testing of major, rural collector roads continued …


Pavement Evaluation Using Dynamic Deflections, Gary W. Sharpe, Herbert F. Southgate, Robert C. Deen Nov 1978

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 Oct 1978

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 Oct 1978

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 Oct 1978

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 Sep 1978

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 …


Evaluation Of Paint Stripe Beads, Jerry G. Pigman, Kenneth R. Agent Sep 1978

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

Kentucky Transportation Center Research Report

This report presents another phase of a study on evaluation of paint stripes and glass beads. The results from the previous phases of this study indicated that large-scale, experimental evaluation of a 1.65 refractive-index bead and a large-gradation, 1.52 refractive-index bead was warranted. Poor embedment of beads, however, precluded the evaluation because the quick-drying paint used did not allow beads to be properly embedded. After progressive thinning of the paint with solvent, adequate bead embedment was obtained. Drying time, of course, was longer.

Attempts were made to obtain good embedment without extending the drying time. This included testing of a …


Pavement Evaluation Using Road Rater Deflections, Gary W. Sharpe, Herbert F. Southgate, Robert C. Deen Aug 1978

Pavement Evaluation Using Road Rater 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 …


Determination Of Rutting In Asphaltic Concrete Pavements: Field Instrumentation And Laboratory Characterizations, David L. Allen Aug 1978

Determination Of Rutting In Asphaltic Concrete Pavements: Field Instrumentation And Laboratory Characterizations, David L. Allen

Kentucky Transportation Center Research Report

This report describes a number of gages developed to measure the location and magnitude of ruts. These were installed in a newly constructed asphaltic concrete pavement. They measure lateral deflections and transient and permanent vertical deflections. Some preliminary vertical deflections are reported. An investigation of materials is also reported. The asphalt concrete base, dense-graded aggregate base, and subgrade material were characterized by (1) shear strength (triaxial tests), (2) rheologic behavior (creep tests), (3) permanent deformation characteristics (repeated-load and creep tests), (4) Young's modulus (resonant column tests), and (5) resilient properties (repeated-load tests). Empirical functions were formulated to describe the permanent …


Characteristics Of Bicycle-Related, Motor Vehicle Accidents In Kentucky, Kenneth R. Agent, Charles V. Zegeer Jul 1978

Characteristics Of Bicycle-Related, Motor Vehicle Accidents In Kentucky, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

The purpose of this study was to determine the characteristics associated with bicycle-related, motor vehicle accidents. Bicycle-related, motor vehicle accidents in Kentucky were analyzed.

A sample of injury-producing bicycle accidents was also analyzed. 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 as 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 …


Seasonal Variations In The Skid Resistance Of Pavements In Kentucky, James L. Burchett Jul 1978

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

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 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 lowest …


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

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.


Acoustic Emission And Fatigue Characteristics Of Typical Bridge Steels, Theodore Hopwood Ii, James H. Havens Apr 1978

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 …


Development Of Procedures For Preparation Of The Interstate Safety Improvement Program, Jerry G. Pigman, Kenneth R. Agent, Charles V. Zegeer Feb 1978

Development Of Procedures For Preparation Of The Interstate Safety Improvement Program, Jerry G. Pigman, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

This report summarizes background information and presents the development of procedures for preparing and updating the lnterstate Safety Improvement Program. There are two major sections: (1) development of procedures for identifying safety needs and (2) development of procedures for prioritizing safety needs. Related to the identification of needs are eleven subsections which are based on historical data, inventories of existing facilities, and analysis of current data. Several accident surveillance procedures were used to identify sites, sections, and elements of the roadway which warrant improvements. Procedures for prioritizing safety needs are based on summaries of data from two reports by the …


Simulation Of External-Internal And Through Trips For Small Urban Areas, Jerry G. Pigman Feb 1978

Simulation Of External-Internal And Through Trips For Small Urban Areas, Jerry G. Pigman

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 …


Heating Bridge Decks By Electrical Resistance, James H. Havens, Wm. Vernon Azevedo, Assaf S. Rahal, Robert C. Deen Feb 1978

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.


Bay Area Rapid Transit (Bart) Advertisment, [Circa 1978], Bay Area Rapid Transit Jan 1978

Bay Area Rapid Transit (Bart) Advertisment, [Circa 1978], Bay Area Rapid Transit

Mayor Moscone

Clippings about BART Advertisment


Analysis Of Time-Independent Consolidation Data, E. Gregory Mcnulty, Tommy C. Hopkins, C. Thomas Gorman Jan 1978

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.


Development Of A Traffic Conflict Procedure For Kentucky, Charles V. Zegeer Jan 1978

Development Of A Traffic Conflict Procedure For Kentucky, Charles V. Zegeer

Kentucky Transportation Center Research Report

The objective of this report was to develop a procedure for the collection and use of traffic conflict data. Data were collected at five intersections to determine characteristics of conflicts. Observer reliability was found to be excellent. Traffic volumes accounted for only about 30 percent of the variation in numbers of conflicts. At one intersection, repeatability of conflict numbers, rates, and types was found to be very good. A total of 6,535 conflicts and 2,957 benign weaves were observed at the test sites.

Based on the data, recommendations were made for collecting data during three peak hours at each site. …


Heating The 9th Street Interchange: Construction And Initial Operation, Wm. Vernon Azevedo, Assaf S. Rahal, James H. Havens Jan 1978

Heating The 9th Street Interchange: Construction And Initial Operation, Wm. Vernon Azevedo, Assaf S. Rahal, James H. Havens

Kentucky Transportation Center Research Report

The 9th-Street interchange was designed and constructed with an automated, electrical heating system for snow and fee 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 32°F (0°C) on only one occasion. The average cost of electrical power for heating the interchange was $905 per day.


Analysis Of Time-Dependent Consolidation Data, E. Gregory Mcnulty, C. Thomas Gorman, Tommy C. Hopkins Jan 1978

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

Kentucky Transportation Center Research Report

No abstract provided.


Loads On Box Culverts Under High Embankments: Analysis And Design Considerations, David L. Allen, Rick L. Russ Jan 1978

Loads On Box Culverts Under High Embankments: Analysis And Design Considerations, David L. Allen, Rick L. Russ

Kentucky Transportation Center Research Report

Pressure and design analyses of five reinforced concrete box culverts are presented. Three of the culverts were constructed with the imperfect trench. Measured pressures on the culverts are compared to pressures predicted by the theories of Marston, Spangler, and Castes. Also, comparisons are made between measured pressures and calculated design pressures using AASHTO's Standard Specifications for Highway Bridges, 1.2.2(A). It is noted that the imperfect trench is, apparently, effective in reducing pressures on the top slab. The AASHTO design formulas underestimated the pressure on the top slab of the culverts without the imperfect trench.


Seatbelt Usage In Kentucky [Jan. 1978], Kenneth R. Agent, Michael Barclay Jan 1978

Seatbelt Usage In Kentucky [Jan. 1978], Kenneth R. Agent, Michael Barclay

Kentucky Transportation Center Research Report

In this report, the effectiveness and usage of seatbelts by Kentucky motorists 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. …


Characteristics Of Kentucky Drivers, Kenneth R. Agent Jan 1978

Characteristics Of Kentucky Drivers, Kenneth R. Agent

Kentucky Transportation Center Research Report

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 highest among teenage drivers. However, females had a higher accident rate. Teenage drivers had the highest accident rate. The rate decreased for middle-aged drivers and …


Flexible Pavement Designs To Support Various Vehicle Configurations, Robert C. Deen, Herbert F. Southgate Dec 1977

Flexible Pavement Designs To Support Various Vehicle Configurations, Robert C. Deen, Herbert F. Southgate

Kentucky Transportation Center Research Report

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 loads. Of course, the restrictive factor in implementing such designs may be the excessive costs of construction. Even so, excessive maintenance costs otherwise associated with …


Kentucky’S Pavement Management System, James H. Havens, Eugene B. Drake Nov 1977

Kentucky’S Pavement Management System, James H. Havens, Eugene B. Drake

Kentucky Transportation Center Research Report

Pavement management concepts are discussed, and a method is presented illustrating the required data and its use to accumulate EAL's annually for comparison with the design EAL. This method can be used to determine overlay priorities, overlay design thicknesses, and financing schedules. A discussion of automatic feedback of field data is presented. Pavement condition reports should be analyzed separately to prevent improper adjustments in the design system due to causes of failure other than normal fatigue.

An overlay, whether for extending service life or improving skid resistance, provides an additional structural thickness and will modify the design life.

Preparation of …


The Maine Airport System Plan : Summary Report, Systems Analysis & Research Corp. Nov 1977

The Maine Airport System Plan : Summary Report, Systems Analysis & Research Corp.

Maine Collection

The Maine Airport System Plan : Summary Report

Prepared for Bureau of Planning , Maine Department of Transportation by Systems Analysis & Research Corporation and Howard Needles Tammen & Bergendoff, November 1977.

Contents: Foreword / Overview / Background / Aviation in Maine / Preparation of the Plan / The Plan / Implementation of the Plan / Appendix A - Airport Needs by County / Appendix B - Airport Classifications / Appendix C - Maine's Airports by Map Code Identifier / Appendix D - Technical Supplement Table of Contents / Appendix E - Regional Planning Commissions / Appendix F - Advisory …


Traffic Conflicts, Erratic Maneuvers, And Near-Miss Accidents: State-Of-The-Art, Charles V. Zegeer Nov 1977

Traffic Conflicts, Erratic Maneuvers, And Near-Miss Accidents: State-Of-The-Art, Charles V. Zegeer

Kentucky Transportation Center Research Report

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 for observing traffic conflicts on freeway ramps is described. Definitions are given for erratic maneuvers at lane drops, gore areas, and intersections. Results from studies …


Analysis Of Tandem Axleloads By Elastic Theory, Herbert F. Southgate, Robert C. Deen, James H. Havens Nov 1977

Analysis Of Tandem Axleloads By Elastic Theory, Herbert F. Southgate, Robert C. Deen, James H. Havens

Kentucky Transportation Center Research Report

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 repetitions versus axleload used by Kentucky appear to be equally valid for single and tandem axleloads. 3. The use of superposition principles, and equivalency of …