DOCSLIB.ORG

Evaluation of Concrete Pavements with Tied Shoulders Or Widened Lanes Bert E

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Evaluation of Concrete Pavements with Tied Shoulders Or Widened Lanes Bert E 39 19. K. Y. Kung. A New Method in Correlation Study of vision of Pavements. Proc., 3rd International Con­ Pavement Deflection and Cracking. Proc., 2nd In­ ference on Structural Design of Asphalt Pavements, ternational Conference on Structural Design of 1972, pp. 1188-1205. Asphalt Pavements, 1967, pp. 1037-1046. 20. P. H. Leger and P. Autret. The Use of Deflection Publication of this paper sponsored by Committee on Pavement Condi­ Measurements for the Structural Design and Super- tion Evaluation. Evaluation of Concrete Pavements With Tied Shoulders or Widened Lanes Bert E. Colley, Claire G. Ball, and Pichet Arriyavat, Portland Cement Association Field and laboratory pavements were instrumented and load tested to reducing pavement performance, Because of this prob­ evaluate the effect of widened lanes, concrete shoulders, and slab thick­ lem, several states have installed costly longitudinal ness on measured strains and deflectfons. Eight slabs were tested in the and transverse drainage systems. Thus, concrete field and two in the laboratory. Pavement slabs were 203, 229, or 254 shoulders and widened lanes have the potential for curing mm (8, 9, or 10 in) thick. Other major design variables included the width of lane widening, the presence or absence of dowels or of a con­ many drainage problems as well as providing additional crete shoulder, joint spacing, and the type of shoulder joint construc­ slab strength. tion. Generally, there was good agreement between measured strains and Many design features contribute to pavement life. values calculated by using Westergaard's theoretical equations. Concrete The effect of some of these features can be evaluated shoulders were effective in reducing the magnitude of measured strains analytically. For example, analytical tools can be used and deflections. A chart is presented to show the allowable reduction in to determine the effect of pavement thickness or subbase thickness of the outer lane of the main-line pavement when there is a tied concrete shoulder. Lane widening of about 406 mm (16 in) was as strength on pavement life, Thus, when analytical pro­ structurally effective as a concrete shoulder in reducing edge strains cedures are available, the engineer can combine a knowl­ and deflections. However, it should be remembered that a concrete edge of pavement life with data on construction and shoulder provides the added advantage of draining runoff fartlier from maintenance cost to provide the most economical design, the pavement edge. Because of the possibility of load encroachments on Analytical tools often are unavailable or require the a widened lane, it is recommended that lanes be widened by a minimum use of unknown or unverified coefficients. For example, of 0.46 m (1.5 ft) plus any additional width required to avoid encroach­ ment. Under the conditions considered, tied-butt, tied and keyed, and tied shoulders reduce load deflections and stresses, but keyed-joint constructions were equally effective in reducing load-induced the amount of the reduction is a function of the unknown pavement strains and deflections. continuity across the joint between the pavement edge and the shoulder, In these cases, the most direct method of evaluating design features is a planned series Existing pavements represent a major investment of of field data measurements extended by laboratory tests highway funds. A road can seldom be abandoned or re­ and analytical procedures. This paper reports on a placed. Every year many kilometers of pavements re­ project that incorporated these features. The principal quire rehabilitation to cope with increased traffic. Over­ objective of the project was to determine the effect of lays are built for the purpose of restoring pavement widened lanes, tied concrete shoulders, and slab thick­ serviceability and improving structural capacity, but ness on measured strains and deflections. Field and this practice is expensive and alternative solutions are laboratory pavements were instrumented, and measure­ needed. ments of load strains and deflections were obtained. The One alternative to resurfacing is the use of a widened measured data were then analyzed to determine the ef­ lane or a paved concrete shoulder. This type of con­ fects of the variables on pavement life. struction could be used not only to strengthen existing pavements but also to strengthen new pavements and thus PAVEMENT TEST SECTIONS defer rehabilitation. Another approach for the design of new pavements that include a tied concrete shoulder Field measurements were obtained on four experimental would be to reduce the thickness of the outer lane of the pavement projects located in the state of Minnesota. All main-line pavement. fieldwork was done under a contract between the Min­ In addition to strengthening a pavement, concrete nesota Department of Transportation and the Portland shoulders and lane widening provide a benefit not ob­ Cement Association (PCA). tained by resurfacing in that runoff water is drained far­ Project 1 is a roadway 8.23 m (27 ft) wide that con­ ther away from the wheel paths of traffic. A recent study sists of a 4.57-m (15-ft) wide inside lane, a 3.66-m for the Federal Highway Administration (1) determined (12-ft) wide outside lane, and a 3.05-m (10-ft) wide out­ that accumulation of water in the joint betWeen an asphalt side tied and keyed concrete shoulder. Shoulders are tied shoulder and a concrete pavement was a major factor in at 762-mm (30-in) spacing by no. 5 tie bars 762 mm 40 long. Shoulder thickness is 152 mm (6 in), The pave­ concrete 2.74 m (9 ft) in length were cast at each end of ment is composed of plain concrete slabs 229 mm (9 in) the slab. The untied and keyed construction was tested thick that have skewed joints at a repeated random spac­ in a slab 4.57 m (15 ft) long that had one doweled and ing of 3.96, 4.88, 4.27, and 5.79 m (13, 16, 14, and 19 one undoweled transverse joint. ft). Dowel bars were placed only in the 3 .66-m outside traffic lane. Dowels are no. 8 round bars spaced at INSTRUMENTATION 305 mm (12 in) on centers; the first dowel is located 152 mm (6 in) in from the pavement edge. Panels selected All pavement test sections were instrumented to mea­ for testing were located at stations 539+16 and 540+10. sure load-induced strains and deflections. 1n addition, Project 2 is a roadway 8.23 m (27 ft) wide with a field sections were imitrumentf')d to mea!mre air and slab 3.05-m (10-ft) wide outside tied and keyed concrete temperatures and slab curling (a change in the vertical shoulder, Dowel size and location are the same as for profile of the slab that results from changes in slab tem­ project 1. The pavement thickness is 203 mm (8 in). perature). Panels selected for testing were located at stations 519+80 and 521+81. Type and Location Project 3 is a roadway 8.23 m (27 ft) wide with a 4.57-m (15-ft) wide inside lane and a 3 ,66-m (12-ft) wide Figure 1 shows locations of strain and deflection instru­ outside lane, The pavement is composed of reinforced mentation used on field pavement slabs that included both concrete slabs 229 mm (9 in) thick that have skewed a widened lane and a tied concrete shoulder. Curl mea­ joints at a spacing of 8.23 m. Dowel bars were placed surements were obtained at deflectometer locations, and only in the 3,66-m portion of main-line pavement in both temperatures were measured in instrumented test traffic lanes. The dowels are no. 8 round bars spaced blocks. Test blocks were placed in the subbase adjacent 305 mm (12 in) on centers. Panels selected for testing to the pavement at least 12 h before load testing. Air were located at stations 985+53 and 987+11. temperatures were monitored by a thermocouple that Project 4 is a roadway 7 ,62 m (25 ft) wide with a was shaded from the direct sun. Details on types of in­ 3.66-m (12-ft) wide inside lane and a 3,96-m (13-ft) wide strumentation, methods of installation, and monitoring outside lane. The pavement is composed of plain con­ equipment used are given elsewhere (~). crete slabs 203 mm (8 in) thick that have skewed joints at a repeated random spacing of 3.96, 4,88, 4.27, and Monitoring Equipment 5.79 m (13, 16, 14, and 19 ft), Dowel bars were placed only in the inner 3.66 m of the 3.96-m outside traffic Data were monitored by equipment housed in a mobile lane. The dowels are no. 8 round bars spaced 305 mm instrument van. The equipment consisted of 38 channels (12 in) on centers. Panels selected for testing were of heat stylus recorders, a 14-channel magnetic tape located at stations 870+64 and 872+21. recorder, a 50-channel temperature recorder, a porta­ Projects 1, 2, and 3 are located on TH-90 between ble strain indicator, and a portable temperature re­ Albert Lea and Fairmont, Minnesota. Project 4 is lo­ corder. cated on TH-14 near Rochester, Minnesota. None of the projects had been opened to traffic before testing. TEST PROCEDURES Two test sites were selected on each project for in­ strwnentation and data recording. Sites were located Trucks used to apply load to field pavement slabs were within 60.96 m (200 ft) of each other to facilitate load supplied by the Minnesota Department of Transportation. testing and data acquisition. Care was taken to ensure The trucks were an 89-kN (20 000-lb) single-axle, a 151- that the sites selected were representative of the project kN (34 000-lb) tandem-axle, and a 187-kN (42 000-lb) and were similar in joint opening, The field test pave­ tandem-axle, Before testing, axle weights were checked ments were 203 or 229 mm (8 or 9 in) thick and either and loads were adjusted to obtain uniform distribution to had or did not have a tied and keyed concrete shoulder the rear wheels.
Load more

Recommended publications
  • 2. Basic Roadway Improvements the Street System Provides the Basic Network for Bicycle Travel
    Figure 2-1: Many low-volume resi- YES dential streets need only the most basic improve- ments to make them more ridable. 2. Basic Roadway Improvements The street system provides the basic network for bicycle travel. Other ele- ments (e.g., bike lanes and paths) supplement this system. To make most streets work for bicyclists, basic improvements may be needed. Such things as safe railroad crossings, traffic signals that work for bicyclists, and street networks that connect benefit bicyclists and make more bicycle trips possible and likely. 2.1 Roadway types While the most basic improvements are appropriate for all categories of street, some improvements are most appropriate for certain categories. In a typical community, streets types range from quiet residential streets, to minor collector streets, to major arterials, and highways or expressways. Figure 2-2: Long blocks and a lack 2.1.1 Residential streets of connectivity On quiet residential streets with little traffic and slow speeds (fig. 2-1), make trips longer bicyclists and motorists can generally co-exist with little difficulty. Such and discourage streets seldom need bike lanes. Only the most basic improvements may bicycling for pur- poseful trips. be required, for instance: • bicycle-safe drainage grates • proper sight distance at intersections • smooth pavement and proper maintenance One additional factor that may need attention is connectivity. Providing bicycle linkages between residential streets and nearby commercial areas or adjacent neighborhoods can significantly improve bicycling conditions. In many communi- 2-1 Wisconsin Bicycle Facility Design Handbook ties, newer parts of town tend to have dis- Figure 2-3: Bicycle- continuous street networks that require bicy- pedestrian connec- clists, pedestrians, and motorists to travel a tions like that long distance to get to a nearby destination shown can provide (fig.
    [Show full text]
  • Module 6. Hov Treatments
    Manual TABLE OF CONTENTS Module 6. TABLE OF CONTENTS MODULE 6. HOV TREATMENTS TABLE OF CONTENTS 6.1 INTRODUCTION ............................................ 6-5 TREATMENTS ..................................................... 6-6 MODULE OBJECTIVES ............................................. 6-6 MODULE SCOPE ................................................... 6-7 6.2 DESIGN PROCESS .......................................... 6-7 IDENTIFY PROBLEMS/NEEDS ....................................... 6-7 IDENTIFICATION OF PARTNERS .................................... 6-8 CONSENSUS BUILDING ........................................... 6-10 ESTABLISH GOALS AND OBJECTIVES ............................... 6-10 ESTABLISH PERFORMANCE CRITERIA / MOES ....................... 6-10 DEFINE FUNCTIONAL REQUIREMENTS ............................. 6-11 IDENTIFY AND SCREEN TECHNOLOGY ............................. 6-11 System Planning ................................................. 6-13 IMPLEMENTATION ............................................... 6-15 EVALUATION .................................................... 6-16 6.3 TECHNIQUES AND TECHNOLOGIES .................. 6-18 HOV FACILITIES ................................................. 6-18 Operational Considerations ......................................... 6-18 HOV Roadway Operations ...................................... 6-20 Operating Efficiency .......................................... 6-20 Considerations for 2+ Versus 3+ Occupancy Requirement ............. 6-20 Hours of Operations ..........................................
    [Show full text]
  • Literature Review- Resource Guide for Separating Bicyclists from Traffic
    Literature Review Resource Guide for Separating Bicyclists from Traffic July 2018 0 U.S. Department of Transportation Federal Highway Administration NOTICE This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. This report does not constitute a standard, specification, or regulation. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document. Technical Report Documentation Page 1. REPORT NO. 2. GOVERNMENT ACCESSION NO. 3. RECIPIENT'S CATALOG NO. FHWA-SA-18-030 4. TITLE AND SUBTITLE 5. REPORT DATE Literature Review: Resource Guide for Separating Bicyclists from Traffic 2018 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) 8. PERFORMING ORGANIZATION Bill Schultheiss, Rebecca Sanders, Belinda Judelman, and Jesse Boudart (TDG); REPORT NO. Lauren Blackburn (VHB); Kristen Brookshire, Krista Nordback, and Libby Thomas (HSRC); Dick Van Veen and Mary Embry (MobyCON). 9. PERFORMING ORGANIZATION NAME & ADDRESS 10. WORK UNIT NO. Toole Design Group, LLC VHB 11. CONTRACT OR GRANT NO. 8484 Georgia Avenue, Suite 800 8300 Boone Boulevard, Suite 300 DTFH61-16-D-00005 Silver Spring, MD 20910 Vienna, VA 22182 12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD Federal Highway Administration Office of Safety 1200 New Jersey Ave., SE Washington, DC 20590 14. SPONSORING AGENCY CODE FHWA 15. SUPPLEMENTARY NOTES The Task Order Contracting Officer's Representative (TOCOR) for this task was Tamara Redmon.
    [Show full text]
  • Pedestrian and Bicycle Infrastructure Network Data Catalog
    Pedestrian and Bicycle Infrastructure Network Data Catalog Created by Institute for Transportation Research and Education Bicycle and Pedestrian Program For North Carolina Department of Transportation Division of Bicycle and Pedestrian Transportation January 21, 2016 JANUARY 2016 PBIN DATA CATALOG PBIN Data Catalog Each dataset provides a consistent set of attribute fields on existing bicycle, pedestrian, and shared-use path data for use in asset management as well as proposed data for use in planning and project development by PGI awarded communities. Where applicable, fields or attributes marked with an asterisk (*) are required data for NCDOT Planning Grant Initiative (PGI) communities to collect and/or update as a condition of award. PGI communities should consider including additional fields or attributes from the Data Catalog when inventorying focus areas or corridors, as identified through the plan development process. The data catalog is broken up into three sections: 1. BICYCLE ASSETS The Bike_Fac_Linear feature class includes polyline data on existing and proposed facilities such as bike lanes, bike routes, bicycle boulevards, and paved shoulders. It also includes information on surface condition, facility width, slope, and rumble strips. The Bike_Fac_Point feature class includes polyline data on existing and proposed facilities such as bike parking, crossing improvement, bike boxes, bike share kiosks, and bike detection loops. It also includes information on bicycle-oriented signage and hazardous grates. It also includes information on surface condition, facility width, slope, and rumble strips. The Ped_Fac_Linear feature class includes polyline data on existing and proposed facilities such as sidewalks and other types of footpaths. It includes information on material, facility width, buffer, buffer width and slope.
    [Show full text]
  • FHWA Bikeway Selection Guide
    BIKEWAY SELECTION GUIDE FEBRUARY 2019 1. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED February 2019 Final Report 4. TITLE AND SUBTITLE 5a. FUNDING NUMBERS Bikeway Selection Guide NA 6. AUTHORS 5b. CONTRACT NUMBER Schultheiss, Bill; Goodman, Dan; Blackburn, Lauren; DTFH61-16-D-00005 Wood, Adam; Reed, Dan; Elbech, Mary 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION VHB, 940 Main Campus Drive, Suite 500 REPORT NUMBER Raleigh, NC 27606 NA Toole Design Group, 8484 Georgia Avenue, Suite 800 Silver Spring, MD 20910 Mobycon - North America, Durham, NC 9. SPONSORING/MONITORING AGENCY NAME(S) 10. SPONSORING/MONITORING AND ADDRESS(ES) AGENCY REPORT NUMBER Tamara Redmon FHWA-SA-18-077 Project Manager, Office of Safety Federal Highway Administration 1200 New Jersey Avenue SE Washington DC 20590 11. SUPPLEMENTARY NOTES 12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE This document is available to the public on the FHWA website at: NA https://safety.fhwa.dot.gov/ped_bike 13. ABSTRACT This document is a resource to help transportation practitioners consider and make informed decisions about trade- offs relating to the selection of bikeway types. This report highlights linkages between the bikeway selection process and the transportation planning process. This guide presents these factors and considerations in a practical process- oriented way. It draws on research where available and emphasizes engineering judgment, design flexibility, documentation, and experimentation. 14. SUBJECT TERMS 15. NUMBER OF PAGES Bike, bicycle, bikeway, multimodal, networks, 52 active transportation, low stress networks 16. PRICE CODE NA 17. SECURITY 18. SECURITY 19. SECURITY 20.
    [Show full text]
  • A Guide for HOT Lane Development FHWA
    U.S. Department of Transportation Federal Highway Administration A Guide for HOT LANE DEVELOPMENT A Guide for HOT LANE DEVELOPMENT BY WITH IN PARTNERSHIP WITH U.S. Department of Transportation Federal Highway Administration PRINCIPAL AUTHORS Benjamin G. Perez, AICP PB CONSULT Gian-Claudia Sciara, AICP PARSONS BRINCKERHOFF WITH CONTRIBUTIONS FROM T. Brent Baker Stephanie MacLachlin PB CONSULT PB CONSULT Kiran Bhatt Carol C. Martsolf KT ANALYTICS PARSONS BRINCKERHOFF James S. Bourgart Hameed Merchant PARSONS BRINCKERHOFF HOUSTON METRO James R. Brown John Muscatell PARSONS BRINCKERHOFF COLORADO DEPARTMENT OF TRANSPORTATION Ginger Daniels John O’Laughlin TEXAS TRANSPORTATION INSTITUTE PARSONS BRINCKERHOFF Heather Dugan Bruce Podwal COLORADO DEPARTMENT OF TRANSPORTATION PARSONS BRINCKERHOFF Charles Fuhs Robert Poole PARSONS BRINCKERHOFF REASON PUBLIC POLICY INSTITUTE Ira J. Hirschman David Pope PB CONSULT PARSONS BRINCKERHOFF David Kaplan Al Schaufler SAN DIEGO ASSOCIATION OF GOVERNMENTS PARSONS BRINCKERHOFF Hal Kassoff Peter Samuel PARSONS BRINCKERHOFF TOLL ROADS NEWSLETTER Kim Kawada William Stockton SAN DIEGO ASSOCIATION OF GOVERNMENTS TEXAS TRANSPORTATION INSTITUTE Tim Kelly Myron Swisher HOUSTON METRO COLORADO DEPARTMENT OF TRANSPORTATION Stephen Lockwood Sally Wegmann PB CONSULT TEXAS DEPARTMENT OF TRANSPORTATION Chapter 1 Hot Lane Concept And Rationale........................................................................2 1.1 HOT lanes Defined .................................................................................................2
    [Show full text]
  • Contruction of Concrete Shoulders
    Construction of Concrete Shoulders Ralph L. D uncan Field Engineer, Bureau of Construction Illinois Division of Highways Springfield, Illinois INTRODUCTION Illinois has constructed concrete shoulders on portions of three con­ tracts. During the 1963-1964 construction season, our contracts per­ mitted the contractor the option of the type of stabilizing agent to use with a gravel or crushed stone material to produce a stabilized shoulder. We had progressed to this high type shoulder as have most highway departments in order to try to reduce maintenance problems, eliminate drop-offs at pavement edges, and provide a year-round safe recovery and emergency stopping areas. W e have on the Illinois highway system earth shoulders, gravel shoulders, crushed stone shoulders, cement aggre­ gate mixtures (or CAM ) shoulders, bituminous aggregate mixtures (or BAM) shoulders, and pozzolanic mixtures (or PA M ) shoulders. None of these shoulders have proven to be trouble-free. FIRST CONCRETE SHOULDERS IN ILLINOIS—1965 In the spring of 1965, a contractor requested the division of high­ ways to consider a proposal to place Portland cement concrete shoulders in place of the options provided in the contract. After consideration by the division, it was decided to permit this change in plans. W e hoped to determine the extent of any construction problems and by observation, in future years, to see what maintenance problems might develop. This first construction of Portland cement concrete shoulders is located just north of East Peoria on U.S. 150 between Interstate 74 and Illinois 87. The project is approximately five miles long. The roadway begins at the urban limits of East Peoria and varies from a 4-foot concrete median to a 40-foot depressed median as it leaves the urban area.
    [Show full text]
  • Appendix a Bicycle and Trail Design Guidelines
    Riverton Active Transportation Master Plan Appendix A Bicycle and Trail Design Guidelines 2015 PREPARED BY: Alta Planning + Design 8 Broadway Salt Lake City, UT 84111 DRAFT Appendix A: Bicycle and Trail Design Guidelines Contents Introduction ....................................................................................................................................................................................1 Design Needs of Pedestrians ....................................................................................................................................................4 Design Needs of Bicyclists ..........................................................................................................................................................6 Bicycle Facility Selection Guidelines .......................................................................................................................................9 Facility Classification ....................................................................................................................................................................... 10 Facility Continua ................................................................................................................................................................................ 11 Bicycle Facility Contextual Guidance ........................................................................................................................................ 12 Shared Roadways ..........................................................................................................................................................................13
    [Show full text]
  • Access Control
    Access Control Appendix D US 54 /400 Study Area Proposed Access Management Code City of Andover, KS D1 Table of Contents Section 1: Purpose D3 Section 2: Applicability D4 Section 3: Conformance with Plans, Regulations, and Statutes D5 Section 4: Conflicts and Revisions D5 Section 5: Functional Classification for Access Management D5 Section 6: Access Control Recommendations D8 Section 7: Medians D12 Section 8: Street and Connection Spacing Requirements D13 Section 9: Auxiliary Lanes D14 Section 10: Land Development Access Guidelines D16 Section 11: Circulation and Unified Access D17 Section 12: Driveway Connection Geometry D18 Section 13: Outparcels and Shopping Center Access D22 Section 14: Redevelopment Application D23 Section 15: Traffic Impact Study Requirements D23 Section 16: Review / Exceptions Process D29 Section 17: Glossary D31 D2 Section 1: Purpose The Transportation Research Board Access Management Manual 2003 defines access management as “the systematic control of the location, spacing, design, and operations of driveways, median opening, interchanges, and street connections to a roadway.” Along the US 54/US-400 Corridor, access management techniques are recommended to plan for appropriate access located along future roadways and undeveloped areas. When properly executed, good access management techniques help preserve transportation systems by reducing the number of access points in developed or undeveloped areas while still providing “reasonable access”. Common access related issues which could degrade the street system are: • Driveways or side streets in close proximity to major intersections • Driveways or side streets spaced too close together • Lack of left-turn lanes to store turning vehicles • Deceleration of turning traffic in through lanes • Traffic signals too close together Why Access Management Is Important Access management balances traffic safety and efficiency with reasonable property access.
    [Show full text]
  • Simulation and Experimental Analyses of Microscopic Traffic
    applied sciences Article Simulation and Experimental Analyses of Microscopic Traffic Characteristics under a Contraflow Strategy Leyu Wei 1, Jinliang Xu 1,*, Tian Lei 1,2, Menghui Li 1,3 , Xingliang Liu 1 and Haoru Li 1 1 School of Highway, Chang’an University, Xi’an 710064, China 2 Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin 78712, USA 3 China Harbour Engineering Company Limited, No. 9 Chunxiu Road, Dongcheng District, Beijing 100027, China * Correspondence: [email protected]; Tel.: +86-029-13709208917 Received: 28 April 2019; Accepted: 25 June 2019; Published: 29 June 2019 Featured Application: This work contributes to improving the effectiveness of the contraflow road traffic strategy for mass evacuation in the aftermath of a natural or anthropogenic disaster. Abstract: Contraflow is a common traffic strategy used to improve the capacity of outbound roads during mass evacuation. Previous studies have focused on the contraflow network configuration, travel time, and number of evacuated vehicles on a macroscopic level. Only a few researchers have considered microscopic factors, such as the contraflow characteristics and moving bottlenecks caused by coaches and trucks. In this study, the effects of the contraflow strategy were investigated through field experiments and traffic simulations. Traffic data were collected from highway segments where trucks were forbidden under regular and contraflow conditions for analysis of the traffic characteristics and the effects of coach moving bottlenecks. The results demonstrate that the capacity and flow speed of contraflow lanes are lower than normal lanes, owing to the narrow cross sections and unfamiliar driving environment. The moving bottlenecks also reduced the speed of passenger car platoons by approximately 5–20 km/h.
    [Show full text]
  • Safety Evaluation of Centerline Plus Shoulder Rumble Strips
    Safety Evaluation of Centerline Plus Shoulder Rumble Strips PUBLICATION NO. FHWA-HRT-15-048 JUNE 2015 Research, Development, and Technology Turner-Fairbank Highway Research Center 6300 Georgetown Pike McLean, VA 22101-2296 FOREWORD The research documented in this report was conducted as part of the Federal Highway Administration (FHWA) Evaluation of Low-Cost Safety Improvements Pooled Fund Study (ELCSI–PFS). The FHWA established this pooled fund study in 2005 to conduct research on the effectiveness of the safety improvements identified by the National Cooperative Highway Research Program Report 500 Guides as part of the implementation of the American Association of State Highway and Transportation Officials Strategic Highway Safety Plan. The ELCSI-PFS studies provide a crash modification factor (CMF) and benefit-cost (B/C) economic analysis for each of the targeted safety strategies identified as priorities by the pooled fund member states. The combined application of centerline and shoulder rumble strips evaluated under this pooled fund study is intended to reduce the frequency of crashes by alerting drivers that they are about to leave the travelled lane. Geometric, traffic, and crash data were obtained at treated two-lane rural road locations in Kentucky, Missouri, and Pennsylvania. The results of this evaluation show that head-on, run-off-road, and sideswipe-opposite-direction crashes were significantly reduced, and application of centerline and shoulder rumble strips also has potential to reduce crash severity for all types of crashes. Monique R. Evans, P.E. Director, Office of Safety Research and Development Notice This document is disseminated under the sponsorship of the U.S.
    [Show full text]
  • Residential Street Standards & Neighborhood Traffic Control
    Residential Street Standards & Neighborhood Traffic Control: A Survey of Cities' Practices and Public Officials' Attitudes Eran Ben-Joseph Institute of Urban and Regional Planning University of California at Berkeley Abstract The failure of the local street system to provide livability and safety in the residential environment can be seen in the application of neighborhood traffic management programs by local authorities to mitigate traffic problems. In order to further identify the extent of the conflict associated with "livability" and geometrical design of residential street, the following issues are examined: (1) Existing and proposed residential streets standards and regulations as practiced by various cities and their evaluation by public and city officials. (2) Traffic problems associated with residential streets and their mitigation through traffic management and control programs. Data are collected from Public Works and Traffic Engineering Departments of 56 Californian cities and 19 cities nation-wide. The findings show that most cities are still adhering to published street standards as recommended by different professional and federal organizations. Although some city officials see the need to amend certain aspects of their regulations and create a more flexible framework for street design, most of them believe that the current practice is satisfactory. Yet, the extant of residents' complaints about traffic problems on their streets might indicate an inconsistency between professional practice, as manifested in street design, and its actual performance as experienced by the residents. This can also be seen in the application of traffic control devices used by local authorities to mitigate these problems of which the most common are the installation of speed humps and 4-way stop signs.
    [Show full text]