inside ite SUSTAINABLE TRAFFIC SIGNAL
Transcription
inside ite SUSTAINABLE TRAFFIC SIGNAL
| inside ite SUSTAINABLE TRAFFIC SIGNAL DEVELOPMENT By James R. Helmer, P.E., T.E., PTOE, Gordon Meth, P.E., PTOE, PTP, and Seth D. Young, P.E., PTOE H ow can we make traffic signals “future-proof?” What can we do to minimize the amount of the investment that has to be scrapped as components become obsolete; and how can we build them so they are more easily modified to accommodate new features for all road users? As you plan, design, or construct a transportation project, do you ever ask yourself: Will this project even exist in ten, twenty, or fifty years? The response to that question is the key issue being explored by the ITE Sustainable Traffic Signal Development (STSD) Committee. The purpose of this article is two-fold; first to share the work of the committee and its presentation made at the 2014 ITE Annual Meeting and Exhibit in Seattle, WA, USA, and second, to seek feedback on your agency’s or company’s use of sustainable principles, design, construction methods, materials, innovation, and technology in stages of signal development. Traffic signals have a long history dating back to the 19th century. The reasons for their installation and their designs have gone through many changes. History shows the first traffic signal using colored lights was installed in London, England at the intersection of Bridge and George Streets.1 The pole was approximately 22 feet in height (7 meters), with mechanical semaphore arms indicating “stop” when extended horizontally or “caution” when lowered to a 45-degree angle. The pole contained a gas night light on top to help identify it after darkness, and the semaphore arms were equipped with colored gas lights—red for stop, and green for caution. After testing, the installation was approved by the English Parliament, because it proved superior to the prior method of police (cornermen) blowing whistles and moving their arms and hands to control horse traffic and people crossing on foot. Early efforts of manually and mechanically controlling traffic in the United States also proved unsustainable, as police officers fought the weather elements and risked injury. Figures 1 and 2 show early attempts of U.S. police traffic control. The installation of what is believed to be the first electric traffic signal in the United States in Cleveland, OH, just celebrated its 100-year 14 May 2015 ite j o urn al birthday in 2014.2 However, this signal and other early 20th century installations did not last but a few years in most cases. Even traffic signals built just 50 years ago, if they still exist, likely contain few of their original parts. For example, pedestrian head indications have gone from green and red neon walk-wait messages, to incandescent bulbs utilizing white and orange messages, and now to light-emitting diode (LED) panels with numeric countdowns. Traffic Signals—A Look Forward Installing traffic signals today involves a very complex, time-consuming, and expensive process. Signals have always had the primary purpose of getting people safely through an intersection, whether on horse or foot, riding a bicycle, or driving a vehicle. Often though, signal installations are accompanied by public controversy Institute of Transportation Engineers Traffic Signals—A Look Back The only remaining original part might be the housing. While the purpose for installing the pedestrian signal has not changed, technology advancements, human factors testing, and energy efficiency continue to improve, and thus upgrades are regularly performed and old parts discarded. Today, the traffic signal still performs the same basic function of allocating right of way and providing safety for all users at intersections, but engineers and maintenance teams are constantly retrofitting and upgrading the original components. Because traffic signals are expensive to design, install, and operate, we should make every reasonable effort to ensure each has a long service life. Figure 1. Woman police officer in Washington, DC, USA directing traffic under a hand-rotated umbrella with stop-go signs on top, circa 1918. Figure 2. Detroit, Michigan traffic towers or “crows nests.” The “stop” and “go” instructions were supplemented by red and green illuminations, circa World War I. inside ite | and high emotions if their installation was due to a history of tragic incidents. Every intersection is unique as is the make-up of the users. This is why detailed attention must be given to the traffic mix, prevailing speeds, geography, building setbacks, street and sidewalk widths, visibility obstructions, transit stops, and more. Besides the more common parameters that influence a signal design, there are many new considerations that need due diligence that were not a factor a few decades ago. These issues include, but are not limited to, municipal policies on sustainable procurement, changes in energy supply from alternating current to direct current, vehicle-to-vehicle communications, and self-driving cars. In looking at some examples of sustainable signal development currently being applied, the committee hopes to raise interest and questions about how our profession of signal planners, designers, builders, and operators will respond to a rapidly changing transportation system and smart car development. The committee divided its research of the traffic signal development process into the key focal areas that have a direct effect on the ultimate installation and operation of a traffic signal: Policies, Planning, Design, and Construction. Within each of these areas, examples of sustainable practices and innovation were explored. Policies and Planning Traffic signals are generally the responsibility of public agencies, and before one is considered for installation, it must meet the policy requirements and follow the necessary planning procedures established by that agency. The policy and planning requirements are the initial steps to the development of a traffic signal, yet the establishment of these requirements is often the result of issues encountered in the design, construction, operation, or maintenance of past signal installations. The proliferation of innovation and technology also leads to the adoption of new policies and planning processes. The committee seeks to include several examples of sustainable policies and planning procedures in the information report in order to inform and inspire agencies to adopt similar practices. Sustainable traffic signal policies and directives are requirements an agency may have in place to ensure all traffic signals installed are safe, energy efficient, and accessible to all potential users. These documents can take the form of general plans, master transportation plans, bicycle and pedestrian plans, accessibility guidelines, directives, and signal timing and phasing policies. Looking back, in the September 1927 Annals of the American Academy of Political and Social Science, Burton Marsh noted the following observation: “In brief, an officer while working at his best can use brain power for the handling of traffic at that corner, and brain power efficiently used, is of course, usually better than mechanical control for a single corner.”1 However, with the rapid growth of vehicle ownership in the USA, 8,000 in 1900 to about 8 million in 1920, cities were being challenged to provide police staffing at a fast growing number of intersections requiring control.1 The police commissioner of New York City realized that police traffic control would not be a sustainable practice with such growth, and thus enacted a policy to transition to mechanically controlled signals for intersections. By the late 1920s, New York City had grown to approximately 3,000 mechanically controlled intersections at an annual cost of $1,000,000 USD. The same number of intersections would have required 6,000 police officers at an annual cost of $15,000,000.1,3 Through research and with the help of ITE members and affiliates, the committee has discovered several current, forward thinking examples of sustainable traffic signal policies. An example of a general plan containing sustainable traffic signal recom- About the ITE STSD Committee Formed in early 2013, the ITE Sustainable Traffic Signal Development (STSD) Committee represents a wide range of experts, comprised of engineers, planners, controller and equipment suppliers, lighting experts, accessibility advocates, and other disciplines. The committee first established its Mission Statement: To create and produce an information report for the Institute of Transportation Engineers that explores the most common practices and activities that led up to the operation of traffic signals, and to identify ways to plan, design, and build them in a more sustainable manner. Initially, because there were widespread views on what an STSD was, the committee next established the following definition: A sustainable traffic signal development is one that is planned for, designed, and constructed in such ways that when operational it serves all users, operators, and other stakeholders in a safe, efficient, accessible, equitable, and informative way, without compromising the needs of future generations With its mission and STSD definition in place, the committee began the work of researching, surveying, and interviewing those involved in four developmental stages of traffic signal installations: policies, planning, design, and construction. In each of these stages the committee’s objective was to identify sustainable and innovative practices resulting in longer lasting and less impacting signals that better met the needs of all users. The committee appreciates receiving information about STSD from ITE members and affiliates to help it achieve its mission. We also invite you to contact any of the authors if you have an interest in joining the committee. www.ite.org May 2015 15 | inside ite mendations can be found from San Jose, CA, USA—Envision San Jose, 2040.4 This general plan includes recommendations for the installation of smart street lights, transit signal priority, and adaptive signal controls. The Baltimore, MD, USA Sustainability Plan and Report contains recommendations and goals for all aspects of the community such as education, the economy, and transportation. Adopted in 2009, the plan includes strategies to implement software upgrades for transit signal priority and install countdown pedestrian signals citywide. The plan is supported by an annual report which tracks the progress of the goals and recommendations. The 2013 edition of the report recorded the completion of 751 countdown pedestrian signals.5 Many agencies across North America are mandating designs that improve access and mobility for all users. The California Department of Transportation’s (Caltrans) Traffic Operations Policy Directive No. 09-06 is an example. It requires bicycle and motorcycle detection be provided on all new and modified approaches to traffic-actuated signals in the state.6 This policy reflects sustainability by accommodating the accessibility of all modes of travel. The Maryland State Highway Administration (SHA) has committed to install accessible pedestrian signals (APS) at all pedestrian activated locations by 2016.7 In order to support this commitment the SHA has developed a policy for the installation of APS, which includes prioritization criteria and a systematic installation approach. Policies requiring the replacement of all incandescent traffic signals with LEDs have become commonplace for most North American public agencies, with many using innovative financing programs with loans being paid back through energy savings. The STSD Committee is seeking innovative funding strategies for sustainable traffic signal improvements. 16 May 2015 ite j o urn al In order to investigate the planning stage of the development of traffic signals for sustainable practices, we must take a step back and ask the question, “why are traffic signals installed?” This question can be answered by looking at who requests the traffic signals and for what purpose. The installation of a traffic signal is generally initiated by concerned citizens and local governments, or is the result of crash history, new developments, or capital improvement projects. Most transportation professionals can agree traffic signals are not the solution to all traffic control problems. Alternatives to signalized intersections include education, the installation of roundabouts, and other initiatives. Recurring feedback the STSD Committee received from the ITE community was that the most sustainable practice would be to not install the signal at all. This emphasizes the importance of public education of the advantages and disadvantages of traffic signals in the planning process. A good example of this is the Georgia Department of Transportation’s Traffic Signals Public Information Document.8 Prepared by the ITE Georgia Section Technical Committee Group in 2011, it walks through the installation process and answers frequently asked questions concerning the installation of traffic signals. After a traffic signal has been requested, the next step is the review and approval process. In order for a traffic signal to be approved for installation, it must meet federal, state/provincial, and local requirements. The STSD Committee has begun investigating these processes for more sustainable outcomes. A common initial requirement in the approval process is a traffic engineering study. Traffic engineering studies for intersections with the potential for signalization will include a warrant analysis. Several of the Manual on Uniform Traffic Control Devices (MUTCD) warrants have remained unchanged for decades. Revisions to these warrants, state and province warrants, and international requirements such as the Transportation Association of Canada’s Traffic Signal and Pedestrian Signal Head Warrant Handbook will be considered for sustainable practices. 9 Sustainable traffic engineering studies may also include alternative traffic control and intersection design analysis. An example of this is the roundabout policy for the City of Calgary, Alberta, Canada, which calls for the consideration of roundabouts as the preferred traffic control option where a signal may be warranted.10 Caltrans Operations Traffic Operations Policy Directive 13-02, implemented in 2013, also requires an evaluation of roundabouts on new interchange projects.11 Additional aspects of the traffic signal planning process that are being considered for improved sustainability are the development review process, requirements for temporary and emergency signals, capital improvement projects, and traffic signal removals. The requirement to analyze an existing traffic signal for warrants and phasing when it is impacted by a capital improvement project can be considered a sustainable planning practice. The Alabama Department of Transportation’s Traffic Signal Design Guide and Timing Manual states that a signal warrant analysis be performed for any traffic signal impacted by a federally funded project and if the signal is not warranted, it be considered for removal.12 The STSD Committee believes it has only scratched the surface of sustainable policies and planning processes in place for traffic signals and encourages fellow ITE members and affiliates to share examples from their communities. Design and Construction There are a number of sustainability considerations and issues that one needs to consider when designing traffic signals. Some relate to the impact of the signal as inside ite | with pedestrian modifications.13 Crosswalk lengths should be minimized and run perpendicular to curb faces where possible to minimize the time pedestrians are exposed to moving traffic. Temporary pole placement during roadway construction should also follow ADA requirements. Traffic signal design needs to consider several factors for sustainability. It is recognized that agencies owning traffic signals may assume significant liability when signals fail to function properly. Signal installations should be designed to reduce the number of signal knock-downs by not placing poles in locations that are part of the likely vehicle turning paths of oversized vehicles. Redundant signal heads can help reduce the potential impacts of signal indications being burned out, snow covered, or otherwise obstructed, in addition to enhancing the visibility of signals during normal operation. A maintenance and operations plan should be developed for each new traffic signal. Asset management systems should be employed for major components of traffic signal installation, so that replacements can be programmed, funded, and performed in a preventive manner. One area of criticism with respect to traffic signals has been the fact that traffic signal cabinets have grown larger instead of smaller over time, constraining the space available for pedestrians on the sidewalk as shown in Figure 3. In many respects, this is the impact of legacy analog design of traffic signals. Low power smaller cabinets and components are currently under development and may be widely available in the next few years. The cabinets under development will include the ability to self-diagnose problems with intersections, and send alarms to maintenance personnel. Further reductions in power consumption of signals may allow the use of solar power in the future, allowing signals to operate without needing to be connected to the power grid. Including battery backups, fuel cell, and generator hookups in new signal installations can help prevent the negative consequences of power outages, and free up police from having to direct traffic in these situations. In addition to the basic needs to convey maintenance alarms and operate in a flexible or adaptive traffic signal timing environment, the traffic signal will be a hub of information collection and disbursement Gordon Meth part of the entire transportation system, and some relate to the installation itself. A traffic signal can be a significant source of vehicle delay and vehicle emissions. When designing signal phasing and operations, it is important to remember that the traffic signal will be used 24 hours a day, 7 days a week. Often, we make decisions about operations for the sake of peak period operation instead of the entire week (i.e., 5–20 hours of the 168 hours per week). Further, pedestrians are often delayed at intersections with complicated phasing or long cycle lengths, and this is often overlooked as a potential issue during design. Short cycle lengths and free-float operation in off-peak times can help these issues. In all but the most urban of settings, vehicle detection is commonplace. Vehicle detection helps eliminate unnecessary delay and reduce the delay and emissions impact of a traffic signal. Several alternative technologies for detection exist, and some are better for certain climates. The important factor is, if detection is utilized, a plan must be put into place to maintain and replace the detection devices over time, as the useful lives of alternative detection technologies vary substantially. Whatever technology is used needs to be able to detect bicycles, and preferably distinguish bicycles from other traffic, so that minimum green times can be adjusted when necessary. Historically, push buttons have been used to detect pedestrians. If traffic signal coordination or complicated phases are used, it is helpful to add an LED indicator to the push button, so the pedestrian knows a call has been registered (i.e., similar to an elevator button). When push-buttons are utilized, consideration should be given to utilizing APS and compliance with the Americans with Disabilities Act (ADA) requirements. It is noted at the time of writing, the draft Public Rights of Way Accessibility Guidelines (PROWAG) mandated the use of APS on all new traffic signal installations, and any Figure 3. Type “P” traffic signal cabinet and service cabinet in less than desirable location for pedestrians, Millburn, New Jersey, 2015. www.ite.org May 2015 17 | inside ite in the future. For this reason, traffic signals in the future should be equipped with communications ability, even if the backbone network is not presently available. Modems connected via cell phone, DSL line, copper wire, fiber optic cable, or wireless mesh should be added to all new traffic signal installations, or any modified installations. Specifying readily available traffic signal equipment, such as poles and arms, can help reduce costs and downtime in the event of knock-downs. Using standard signal specifications and pre-approved lists for components can reduce design risks and costs. Specifying life expectancy of materials and using recycled or reusable materials helps minimize waste reduction and often reduces transport costs. Using 3D modelling in the design of traffic signals may enhance and improve designs by better identifying and resolving conflicts, particularly with overhead utilities. 3D models can also allow better analysis of sight lines in areas of vertical or horizontal roadway curvature, or with roadside and overhead structures and vegetation. During the construction of traffic signals, it is important to provide appropriate protection of traffic and pedestrians and provide continued accessibility for all modes. Pedestrian routes need to be accessible during construction. Circuitous pedestrian detours should be avoided, even if this results in having to stage sidewalk and curb ramp construction. Innovation The STSD Committee also seeks innovative practices and solutions that may not be commonly thought of as part of a traffic signal installation. The committee believes public agencies will seek more and more opportunities to provide services not related to traffic control, as part of the infrastructure at an intersection. Examples of these opportunities would be providing extra cables or conduit for cell phone wireless 18 May 2015 ite j o urn al communications antennae, utilizing electricity to heat the concrete under ADA ramps where ice and snow are common, installing air monitoring equipment, and providing surveillance cameras or public announcement systems for public safety. Agencies should be seeking solutions that benefit as many sectors of society as possible, thus making the end solution more sustainable. Using “Universal Design” design principles, wheel chair ramps not only benefit those in wheel chairs, but those with minor disabilities, aging pedestrians who have limited mobility, and parents pushing strollers.14 Thus, applications like heating ramps in areas that have freezing temperatures can be thought of as a universal solution aiding as many users of the signalized intersection as possible. Utility companies often have restrictions in their billing schedules that limit the types of equipment that can be attached to the service meter that feeds a traffic signal. Some utilities limit increases in electrical load to no more than 5 percent over the total load of the traffic signal.15 However, when you consider most signals have had their loads significantly reduced (some by as much as 90 percent) due to the conversion of incandescent lamps to LED indications, there may be more available power that could be used for other applications. Examples include: an ADA accessible electric vehicle charging station installed on-street in the first parking space near the signal, providing lighting and advertising power to an adjacent bus shelter, or allowing advertising kiosks for marketing special events or nearby businesses. Agencies may wish to work with their local electric providers or their regulators to see if traffic signal electrical meters could be used for non-traffic signal equipment. Third parties would likely have an interest to pay a government for the benefit of convenient electrical power to provide service to communications equipment, promote large events, or operate security systems. Since traffic signals are installed at most of the busiest intersections in a city, it is highly likely that private parties through encroachment permits could benefit from an agency that looked at the traffic signal as an innovative opportunity to provide public benefit other than traffic safety. Cabinets will decrease in size, but increase in density as batteries, solar energy, and fuel cells begin to play a greater role in supplying energy to operate the signal. Easy maintenance plug-in modules will reduce the amount of wasted space and wiring connections. Self-driving cars are no longer a dream. States such as Michigan and California have made them legal to operate under special conditions on their highways. Vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications are key to assuring the safety and reliability of autonomous vehicles. Working with auto-manufacturers, traffic signal controller companies are now testing two-way communications between vehicles and signals. As Doug Davenport, CEO of Prospect Silicon Valley, the first nonprofit, Silicon Valley-based technology commercialization catalyst for smart cities says: “Traffic signals of the past have merely been the voice of a traffic system, telling drivers when to stop, start, turn safely... tomorrow’s signals need eyes and ears as they will also need to look and listen to a range of mobile devices in vehicles or carried by pedestrians.”16 He sees the traffic signal as a “vast, untapped market” for municipalities to provide services to its community. Conclusion In this time of increasing costs, rapidly changing technology, and broadening needs for accessibility, it is imperative we “future proof ” new traffic signals as far as possible. The STSD Committee is confident there are more examples of innovation and sustainability currently being deployed in traffic inside ite | signals. The committee welcomes your participation as well as providing examples and your ideas. The committee also seeks examples of sustainable policies, planning documents, design standards, and construction techniques and/or materials, to be shared in its information report. Please help us by taking a few minutes to forward them to the authors of this article. The Committee’s PowerPoint presentation, presented at the 2014 ITE Annual Meeting and Exhibit in Seattle, WA, USA is also available in the ITE Library at library.ite.org. itej 11 References 13 1 Gordon M. Sessions (principal writer). Traffic Devices: Historical Aspects Thereof. Institute of Traffic Engineers, 1971. 2 “Happy 100th Birthday to the Electric Traffic Light,” USA Today. www.usatoday.com/story/ money/cars/2014/08/05/electric-traffic-lightbirthday/13634363/. 3 C.A.B. Halvorson. International Commission on Illumination, Saranac Lake, New York, 1928. 4 Envision San Jose 2040 General Plan. www.sanjoseca.gov/index.aspx?NID=2095/. 5 2013 Annual Sustainability Report. Baltimore Office of Sustainability. www.baltimoresustainability.org/sites/ baltimoresustainability.org/files/AR2013_ FINAL_web_small.pdf/. 6 Traffic Operations Policy Directive No. 09-06. California Department of Transportation (Caltrans). www.google.com/search?source id=navclient&ie=UTF-8&rlz=1T4ADBF_en US281US282&q=caltrans+operations+ policy+09-06/. 7 Maryland State Highway Administration. http://roads.maryland.gov/index. aspx?PageId=26/. 8 Georgia Department of Transportation Traffic Signals Public Information Document. http:// elitepdf.com/by/3.0/au/traffic-signals-publicinformation-document-prepared-for.html/. 9 Transportation Association of Canada Traffic Signals and Pedestrian Head Handbook. 10 12 14 15 16 http://tac-atc.ca/en/bookstore-andresources/bookstore/. Roundabout Guidelines-The City of Calgary, 2011, 2012, 2013. www.calgary.ca/ Transportation/TP/Documents/Safety/ Roundabout-Guidelines.pdf?noredirect=1/. Caltrans Operations Traffic Operations Policy Directive 13-02. www.dot.ca.gov/hq/traffops/ liaisons/ice.html/. Alabama Department of Transportation’s Traffic Signal Design Guide and Timing Manual. www.dot.state.al.us/maweb/frm/ALDOT%20 Traffic%20signal%20Design%20&%20 Timing%20Manual.pdf/. Public Rights of Way Accessibility Guidelines (PROWAG). www.access-board.gov/guidelines-andstandards/streets-sidewalks/public-rightsof-way/. Universal Design. http://en.wikipedia.org/ wiki/Universal_design. Electric Schedule TC-1, Traffic Control Service, January 2015. www.pge.com/tariffs/tm2/ pdf/ELEC_SCHEDS_TC-1.pdf/. Prospect Silicon Valley. http://prospectsv.org/. James R. Helmer, P.E., T.E., PTOE worked 32 years in local government, most recently serving as director of transportation for the city of San Jose, CA, USA. He holds a B.S. and M.S. in transportation from Cal Poly, San Luis Obispo and Mineta Transportation Institute. He currently is sole proprietor of LightMoves, a company focused on sustainable transportation and adaptive lighting solutions. Jim is an ITE Fellow. He can be reached at [email protected]. Gordon Meth, P.E., PTOE, PTP is a senior associate and director of Traffic Engineering for The RBA Group in Parsippany, NJ and Silver Spring, MD. He has both a bachelor’s and master’s degree in civil engineering from the Uni- versity of Waterloo, and a master of business administration from Montclair State University. He has 25 years of experience in traffic engineering and has designed in excess of 200 traffic signal installations. He is a licensed professional engineer in NY, NJ, CT, MD, DE, DC, and Ontario, Canada. He is presently Northeast District Chair for ITE, as well as being part of the executive committees for the Traffic Engineering Council, the Complete Streets Council, and the Sustainability Task Force. Gordon is a Past President of the ITE Metropolitan NY/NJ Section. He also has served on the Transportation Professional Certification Board since 2012. He is an ITE Fellow. He can be reached at [email protected]. Seth D. Young, P.E., PTOE is an associate and senior traffic engineer at STV Incorporated with more than 12 years of experience in transportation planning, analysis, and design. He currently manages a team of engineers specializing in traffic control device design for various U.S. state and local agencies in the Mid-Atlantic region as well as nationwide. Throughout his career, Seth has been responsible for the planning and design of hundreds of traffic signals in Maryland, the District of Columbia, Pennsylvania, New Jersey, Connecticut, and California. These traffic signal designs include innovative techniques and technologies and accommodations for all users such as accessible pedestrian signals and bicycle signals and detection. Earlier in his career, Seth served several years as an on-site project manager at the Maryland State Highway Office of Traffic and Safety, Traffic Engineering Design Division. Seth has a bachelor’s degree in civil engineering from The Pennsylvania State University and is a licensed Professional Engineer in Maryland, Pennsylvania, Virginia, North Carolina, South Carolina, the District of Columbia, Georgia, and Florida. He is also a certified Professional Traffic Operations Engineer. He is a member of ITE. He can be reached at seth. [email protected]. www.ite.org May 2015 19