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PAVEMENT MARKINGS-- DESIGN AND TYPICAL LAYOUT DETAILS SUMMARY States and many local governments have developed their own designs, detailed layout schemes (typical drawings), and associated practices for pavement markings. These designs, layout details, and practices are usually more specific than the requirements of the national Manual on Uniform Traffic Control Devices (MUTCD). Among the more detailed designs, layout details, and associated practices that are found in many of the state and local documents are the following: · Methods of delineating turn lane channelization, · Patterns and spacing of lane-use turn arrows and ONLY word markings, · Patterns and spacing of crosswalk markings and stop lines, · Patterns and spacing of turn arrows in two-way left-turn lanes, · Patterns and dimensions of chevrons and diagonal lines, · Methods of delineating climbing and passing lanes, and · Methods of delineating entrance ramp and exit ramp gores. This synthesis identifies variations in pavement marking designs, practices, and policies of 48 of the 50 state departments of transportation, the District of Columbia, Puerto Rico, and four large cities. From the information contained in this synthesis, common and differing practices and ranges of typical placement dimensions can be identified. This compilation of information (which has been unavailable to date) will be highly valuable to FHWA and to the National Committee on Uniform Traffic Control Devices as they consider the need for future revisions to Part 3 of the MUTCD to add more specificity to the national standards for pavement markings and, where appropriate, to codify the most common policies, practices, and applications of pavement markings. In addition, state and local government agencies can use the information in this synthesis to determine the most common policies and practices in each area of interest as they develop or revise their pavement marking design standards. This synthesis is not intended to be used by practitioners in the various states as a design guideline when developing pavement marking plans. The information in this synthesis is essentially a "snapshot" of current state and local government policies and practices in the late 2004/early 2005 time frame. Such policies and practices are subject to change and many agencies reported that they were in the process of revising their design standards at the time the information in this synthesis was requested. However, practitioners can visit the websites listed in the bibliography of this synthesis to obtain the latest design standards for the vari- ous agencies that maintain these websites. This synthesis addresses only the information that was found in the various policies and practices regarding pavement marking layouts that are published by the agencies represented herein. Existing pavement markings and the actual implementation of new pavement mark- ings within a particular state might vary from the state's published policies and practices. No attempt has been made to discover or document any variations from the published policies and practices within the geographical areas of the agencies represented in this synthesis. This synthesis does not specifically address the safety aspects or the cost-effectiveness of the agency's various pavement marking layout policies and practices. The report also does not
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2 provide any value judgments regarding whether certain policies and practices of one agency are superior or inferior when compared with the policies and practices of other agencies. Although Part 3 of the MUTCD contains provisions for pavement markings on streets and highways across the United States, it does not require or recommend uniformity for many of the aspects of pavement marking layout that were studied in this synthesis. This flexibility and latitude given to the states and local governments has resulted in a wide variety of poli- cies and practices among the various agencies as documented in this synthesis. Tables 13 in chapter six (Conclusions, pages 4649) show the range of values and the most common pavement marking practices found in the design standards for the various agencies. Table 1 contains information regarding pavement markings at intersections including: · Turn lanes, · Lane lines for dual turn lanes, · Lane line extensions into intersections for dual turn lanes, · Use and type of dotted lines in turn lane tapers, · Left-turn lanes added between through lanes of two-lane highways, · Solid lane lines between through lanes on signalized approaches, · Crosswalks, · Stop lines, and · Right-turn channelizing islands. Table 2 contains information regarding pavement markings between intersections including: · Minimum length of passing zones; · Minimum length of no-passing zones; · Two-way left-turn lanes; · Climbing or passing lanes; · Lane reductions; and · Painted medians, paved shoulders, and approaches to obstructions. Table 3 contains information regarding pavement markings at interchanges including: · Entrance ramp gores and · Exit ramp gores. In some cases, such as the width of a line, road users who travel from one state to another might be unaware of any differences; whereas, in other instances, road users might experi- ence confusion about unfamiliar pavement markings. There is little doubt that states and local government agencies appreciate some degree of flexibility and latitude as they develop and implement their various pavement marking policies and practices. Variations in line widths and sizes of gaps between line segments in broken or dotted lines may be attributable to the economics of construction and maintenance. States with tight budgets might specify narrower lines and longer gaps to save money, whereas states that have larger proportions of older drivers might be inclined to favor wider lines and shorter gaps.