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3 CHAPTER ONE INTRODUCTION BACKGROUND sites. These websites were accessed and the pertinent pave- ment marking information for the various areas of interest to Most of the 50 states and many local governments have this synthesis was obtained and inventoried. The information developed their own designs, detailed layout schemes (typi- that was important, but was not provided, was then requested cal drawings), and associated practices for pavement mark- from all 50 states. These requests resulted in additional infor- ings. These designs, layout details, and practices are usually mation being obtained, either by means of hard-copy docu- more specific than the requirements of the national Manual ments or through the identification of website addresses that on Uniform Traffic Control Devices (MUTCD) (2003). The had not previously been visited. MUTCD provides general guidance and/or minimum or max- imum dimensions for certain markings, spacing of markings, Information was also sought from a number of large combinations of markings, and patterns. Among the more cities and counties to obtain a sense of the policies and prac- detailed designs, layout details, and associated practices that tices that are specific to urban situations. Information was are found in many of the state and local documents are: obtained and used in this synthesis from four local govern- mental agencies: · Methods of delineating turn lane channelization, · Patterns and spacing of lane-use turn arrows and ONLY · City of Charlotte, North Carolina word markings, · City of Los Angeles, California · Patterns and spacing of crosswalk markings and stop · City of New York, New York lines, · City of Tucson/Pima County, Arizona. · Patterns and spacing of turn arrows in two-way left-turn lanes, · Patterns and dimensions of chevrons and diagonal lines, Throughout this synthesis, the term "design standards" is · Methods of delineating climbing and passing lanes, and used generically to refer to all of the various types of poli- · Methods of delineating entrance ramp and exit ramp cies and practices regarding pavement marking layouts that gores. are published by the agencies represented herein. As can be seen in the bibliography, these documents have a wide vari- The purpose of this synthesis was to identify variations in ety of actual titles, including design standards, traffic man- pavement marking designs, practices, and policies of each uals, standard designs, standard plans, design details, typi- state department of transportation (DOT) and agencies in the cal drawings, standard construction drawings, design District of Columbia, Puerto Rico, and several large cities and manuals, state MUTCDs, and supplement to the MUTCD. counties. From the information contained in this synthesis, However, in this synthesis, for clarity and convenience, all common and differing practices and ranges of typical place- of these various publication titles are generically referred to ment dimensions can be identified. This compilation and as design standards. synthesis of information (which has been unavailable to date) will be highly valuable to FHWA and to the National Com- To provide maximum clarity, the terms upstream and mittee on Uniform Traffic Control Devices as these organi- downstream are frequently used in this synthesis to de- zations consider the need for revisions to Part 3 of the MUTCD scribe the pavement marking layout policies and practices. to add more specificity to the national standards for pavement For example, when the phrase "the end of the lane line sep- markings and, where appropriate, to codify the most com- arating the turn lane from the through lane" is used, the mon policies, practices, and applications of pavement mark- reader could interpret this to be the end of the lane line at ings. In addition, state and local government agencies can use the stop line or the end of the lane line in the turn lane taper this information to determine the most common policies and area. However, if the reader keeps in mind that traffic practices in each area of interest as they develop or revise always flows from upstream to downstream, the phrase their pavement marking design standards. "the downstream end of the lane line separating the turn lane from the through lane" can only be interpreted to be Many state DOTs, the District of Columbia, and Puerto the end at the stop line. Figure 1 illustrates the meanings of Rico provide information on pavement markings, and sup- the terms "upstream" and "downstream" as used in this plements to the national and state MUTCDs on their web- synthesis.