The next right

June 16, 2008

While the roadway of tomorrow isn’t here just yet, the rules of the roadway of tomorrow are getting closer. Thanks to the work of scores of road safety experts around the nation, the first updates to the Manual on Uniform Traffic Control Devices (MUTCD) since 2003 are en route.

While the roadway of tomorrow isn’t here just yet, the rules of the roadway of tomorrow are getting closer. Thanks to the work of scores of road safety experts around the nation, the first updates to the Manual on Uniform Traffic Control Devices (MUTCD) since 2003 are en route.

Traffic-control devices affected by MUTCD standards and guidance include signs, signals, pavement markings and other features that instruct the traveling public as they use America’s surface transportation system, the backbone of our nation’s economy. More directly, the public road system gives Americans their freedom—more specifically, personal mobility. The movement of people, goods and services is critical to our national quality of life.

Serving such a critical role requires a uniform set of cues to travelers so that those devices appear the same no matter where people travel throughout the U.S. The developers of the MUTCD have recognized this need since the 1930s, and the principles guiding its creation and subsequent evolution have remained the same. Effective traffic-control devices must fulfill an operational need, convey a clear meaning and command attention and respect by the traveler.

Although the MUTCD has been the national standard for designing and installing traffic-control devices for over 70 years, it is a dynamic, ever-changing document that has kept pace with an equally dynamic roadscape. From technological advances like Wi-Fi access and improved retroreflective sheeting for road signs to changes in the way Americans travel, and the special needs and security concerns of travelers, the MUTCD remains as vibrant and forward-looking as ever.

The Federal Highway Administration (FHWA) has issued a Notice of Proposed Amendments that will lead to a new 2009 edition of the MUTCD. The proposed changes are open for public review comment until July 31. A final rule adopting a new MUTCD edition is expected in early 2009.

More able to read

As the number of older drivers on our roads continues to grow, a variety of sign improvements included in the proposed 2009 edition will improve safety and convenience for older drivers and, more broadly, drivers of all ages. Improvements in letter height to improve legibility of sign wording, and even advances in retroreflective sheeting to make signs more visible from greater distances, address some of the developing needs of America’s older drivers. Similarly, increases in the sizes of some regulatory and warning signs also have been proposed, particularly when used on multilane arterial roads.

Street signs also will be affected because, research showed, using all uppercase letters for names of places, streets and highways were less effective than a combination of lowercase letters with an initial uppercase letter. Mixed-case sign legends for destinations have significant legibility and recognition-distance benefits versus all uppercase letters.

Several new sign types are proposed in the new edition for toll plazas, which are growing in number nationally.

Due to increased concern about intersection safety over the last decade, the new edition will contain more detailed information on effective signing for roundabouts. New information will be included in the MUTCD to provide for pavement markings as well as regulatory, warning and guide signs at roundabouts. The use of jughandles as a means of improving intersection safety also is climbing, making appropriate regulatory and guide signs at jughandles all the more critical because of their unique roadway geometry requiring left turns and U-turns to be made via a right turn, either in advance of or beyond the intersection.

Display purposes

Because of the importance of electronic display changeable message signs (CMS) as a means of enhancing traffic operations, the FHWA has proposed to add a completely new section of uniform provisions for CMS design and application. Information will be included on how to develop effective message content, as well as the maximum amount of information that should be displayed, the number of messages and display time for each and minimum letter heights and brightness levels for optimum legibility during daytime and nighttime conditions. These provisions would apply to both permanent and portable installations of CMS.

Walk and arrow

For many years, some engineers have had concerns that drivers turning left on a permissive circular green signal indication might inadvertently mistake it as implying the left turn has the right-of-way over opposing traffic. Research showed that the flashing yellow arrow (FYA) is the best overall alternative to the circular green as the permissive signal display for a left-turn movement. The FYA has a high level of understanding and correct response by left-turn drivers and a lower fail-critical rate than the circular green, and the FYA display in a separate signal face for the left-turn movement offers more versatility in field application. For these reasons, the optional use of a flashing yellow arrow indication for left-turn movements during permissive turn intervals has been proposed to be added in the 2009 edition.

Additionally, as pedestrian traffic increases, the duration of the time for pedestrian clearance after the Walk signal is proposed to increase. The calculation for the recommended walking speed would be changed from 4 ft per second to 3.5 ft per second (except where extended push-button presses or passive pedestrian detection has been installed for slower pedestrians to request additional crossing time). Also, the total of the walk interval and pedestrian clearance time should be sufficient to allow a pedestrian to walk from the pedestrian detector to the opposite edge of the traveled way at a speed of 3 ft per second. These changes are proposed to be made to accommodate the increasing numbers of pedestrians, including slower-walking individuals and wheelchair users.

To provide enhanced pedestrian safety and convenience, the FHWA proposes to change the existing option of using pedestrian countdown displays to a requirement for use with all new installations of pedestrian signals, except for very narrow streets where the duration of the pedestrian change interval (the flashing Don’t Walk symbol) is less than three seconds. This proposed change is based on a comprehensive multi­year research study in San Francisco that showed substantial reduction in the number of pedestrian-vehicle crashes where the countdowns were installed.

Only temporary

Proposed updates in the next edition of the MUTCD also would improve temporary traffic-control measures. For instance, provisions of 23 CFR 634 (originally published in the Federal Register on Nov. 24, 2006) regarding the use of high-visibility safety apparel by workers and flaggers within the public right-of-way will be included. Currently, federal regulations require this on all federal-aid streets and highways. Including them in the MUTCD will make them apply to all roads open to public travel regardless of federal-aid status.

Automated flagger assistance devices (AFADs), optional tools that enable flaggers to be positioned out of the lane of traffic and control road users through temporary traffic-control zones, are also proposed to be included in a new section of the MUTCD. A statement that flaggers should use a Stop/Slow paddle, flag or an AFAD to control road users—and not the use of hand movements alone—also is proposed.

Nearly 43,000 lives are lost each year on America’s roadways, many on rural roads. By ensuring a more uniform system of the devices that communicate essential messages to road users, and by capitalizing on technological advances and exhaustive research, motorists will be safer on the roads than ever before. Though the best safety device is a conscientious driver, the new information proposed for the 2009 edition of the MUTCD will do much to improve the safety for the traveling public as a whole.

For more information, visit the MUTCD online at http://mutcd.fhwa

About The Author: Kalla is the MUTCD team leader for the Federal Highway Administration, Washington, D.C.

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