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SECTION V--DESCRIPTION OF STRATEGIES Cooper River bridge, additional funding was obtained for a lane for pedestrians and future work activities so a lane would not have to be closed to perform work. Another example is the provision for adequate space to allow positive barriers to be placed between traffic and the work area. Physical barriers are discussed further under Strategy 19.1 C2. Many DOTs have developed guidelines on how many lanes will be required to be maintained during construction based on facility type or traffic volumes. Ohio DOT has developed a "Permitted Lane Closure Map" for its network of freeways and expressways. This map highlights the number of lanes that are present and the number of these lanes that can be closed without exceeding a maximum allowable queue length. North Carolina DOT uses established work zone capacity values for rural, suburban, and urban facility types in assessing work zone operational requirements. This maintaining information can be used to determine the effect that lane closures and other work zone traffic control will have on capacity and delay. The information will help agency staff who plan roadways to be able to address future work zone needs. Be aware of the long-term vision of roadway corridors. For example, if a four-lane facility is being constructed, but the plan ultimately calls for six lanes, consideration should be given to the future widening project, and the design of that work zone should be considered during development of the four-lane project. The Ohio DOT is developing guidelines on constructing a full-depth shoulder on roadways where work may be planned within a certain time period. Objective 19.1 B--Improve Work Zone Traffic Control Devices Traffic control devices are used to communicate with drivers in advance of and within work zones. It is critical that the devices are understandable and visible and provide useful information. Since work zone conditions vary from typical roadway conditions, it is important to inform the driver of the desired actions and the correct path through the work zone. In addition to use of conventional signing and media outlets, route decision making can be enhanced using ITS to inform drivers of delays and alternative routes. Traffic signs, pavement markings, and work vehicles should be well maintained and visible in both daytime and nighttime conditions. Visibility of workers is also a key issue in work zone safety. 19.1 B1--Implement ITS Strategies to Improve Safety (E) General Description ITS tools--such as traffic monitoring, advanced travel time, delay, and route information-- can improve safety and mobility for travelers in work zones and on the approaches to work zones. This improvement is accomplished through communication with travelers and between elements of the system, which includes agency personnel. The information gathered from the roadway environment is transmitted to agency personnel and road users to allow them to make better safety and mobility decisions. Using ITS in work zones can improve traffic safety by alerting drivers to the presence of the work zone and real-time conditions in the work zone. This advanced notice can warn drivers that they may need to reduce their speed or stop. Because travelers have advanced V-41

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SECTION V--DESCRIPTION OF STRATEGIES information regarding delays in the work zone, as well as information on alternative routes or detours, the drivers can make route choices in advance of the work zone. Thus, mobility is improved. The length of the backup, as well as an estimated travel time, can be communicated to travelers. ITS can be used to convey work zone speed limit information, as well as messages on increased enforcement or higher fines in the work zone. With the data collected by a system, agency personnel can better respond to incidents and relay messages to the public as needed. Detection of accidents can allow faster action by appropriate emergency response personnel, and this faster action can in turn minimize the impacts of accidents on traffic flow, including potential for secondary crashes. Messages conveying the location of an accident can be relayed to travelers quickly. ITS can be used for functions that typically have been performed manually. It is possible to incur lower project costs by using ITS to automate transfer of information to agency personnel and travelers. Remote sensors collect data on traffic volume, speed, and/or queues and relay this information to a central control center. The data are processed and communicated to transportation agency staff and travelers. Agency staff are able to override messages relayed to the public if adjustments are needed. Portable system elements may be appropriate for rural or short-term installations. New ITS technologies are developing at a fast pace. Some of the more common technologies applied to work zones are shown in Exhibit V-9. Several systems have a specific focus on improving safety in work zones and are described in further detail in the FHWA's Intelligent Transportation Systems in Work Zones (FHWA, 2002): Dynamic message signs advise drivers of slower downstream speeds and travel times. This technology has been effective in reducing speeds in congested flow conditions, but not during uncongested flow. The technology can offer the road users information that may minimize frustration and associated aggressive driving. A highway advisory radio broadcasts advisory messages to drivers. A sign (dynamic or fixed message) informs drivers of the correct radio station, and messages regarding traffic delays, detours, road closures, and other travel conditions in the area can be broadcast. EXHIBIT V-9 Example System Components for Use in Work Zones ITS Components for Data Collection and Processing: Central controller/sensors Closed circuit television cameras Remote sensors ITS Components for Communication with Travelers: Dynamic/changeable message signs (portable or fixed) Internet Highway advisory radio Telephone information line In-vehicle navigation systems V-42

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SECTION V--DESCRIPTION OF STRATEGIES A citizens band radio channel broadcasts advisory messages. A survey showed that a majority of truckers, whom the system targets, hear the message and think it is a worthwhile method of communicating. Portable signs define the length of a dynamic no-passing zone based on the length of a traffic queue. As a queue lengthens, the next upstream "DO NOT PASS" sign lights up. This is a regulatory (and therefore enforceable) sign. A portable trailer measures vehicle speeds and displays the speeds for the driver. In a study based on a limited amount of data, this system was shown to reduce speeds and variations in speeds in the work zones where deployed and, on occasion, downstream of the work zone (Maze et al., 2000). Variable work zone speed limits reduce speed limits when workers are present. This strategy is experimental; therefore, the effectiveness of it in reducing crashes is unknown. A work zone speed limit may vary depending on whether workers are present or on other factors; therefore, the speed limit may vary in long work zones. Legislative authority may be needed for an agency to implement this strategy. Appendix 2 discusses variable speed limits in more detail. Speed warning systems communicate average downstream speeds to drivers on variable message signs. This technology warns drivers that they may soon need to slow down or stop. Web cameras provide real-time visual traffic condition information. Video cameras used to monitor traffic can provide images to be broadcast on a website or on television stations. Traffic reporters can use these images, and drivers can check the website for an update on traffic conditions before beginning their travel. Illinois DOT has instituted a program of speed-monitoring cameras in work zones similar to other applications (e.g., red-light running cameras). ITS strategies are generally more applicable to larger projects on high-volume facilities over long construction periods. Such projects are in one sense beyond the focus of the SHSP. However, in the context of an agency changing its practices and methods for all projects moving forward, the strategies are appropriate. EXHIBIT V-10 Strategy Attributes for Implementing ITS Strategies to Improve Safety (E) Attribute Description Technical Attributes Target ITS strategies target crashes related to congestion caused by work zones-- speeding, aggressive driving, and unexpected conditions--as well as crashes that may be related to driver confusion or lack of information, such as last-minute correction of navigation errors (i.e., swerving). Related crash types include rear-end crashes, side swipes, or head-on crashes. ITS strategies warn drivers of the potential need to decelerate or stop and provide drivers with alternative route information. V-43

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-10 (Continued) Strategy Attributes for Implementing ITS Strategies to Improve Safety (E) Attribute Description The types of work zones that may be appropriate for ITS applications include: High-volume roadways where delays may be common or where detours will be used, Work zones that may involve changes in travel patterns, and Work zones where high speeds are expected or have been experienced. Long-term projects are more ideal situations for ITS use, since the system costs will be more easily justified. Any situation that necessitates communication with drivers while they are in or approaching the work zone may be appropriate for ITS applications. ITS systems are more likely to be used to improve mobility in urban work zones and to improve safety in rural work zones. Expected Effectiveness The complex and individual nature of work zones creates difficulty in evaluating the effectiveness of specific technologies and applying the estimated safety improvements to other projects. Although no studies conclusively prove that ITS technologies reduce work-zone-related crashes, anecdotal information from a variety of work zones on which ITS strategies were used suggests that the crash rates were lower than expected. A reduction in volume through a work zone should reduce the crash experience of that work zone, and use of ITS to provide information on downstream traffic conditions and alternative routes can help divert traffic from the work zone to other routes, thereby lowering exposure and reducing crashes. The FHWA report Intelligent Transportation Systems in Work Zones: A Cross Cutting Study (2002) states that the New Mexico State Highway and Transportation Department reported a smaller increase in crashes (7 percent) than expected during the rebuilding of the I-40 and I-25 interchange, as compared with the crash experience before the construction project began. Secondary crashes were reduced as well, and this is thought to be due to a reduction in the time to clear incidents. A PI&E campaign, increased enforcement, and ITS were likely the main contributors to an initial 32-percent decrease in crashes during the first 3 months of construction. Other projects reported in the FHWA study experienced low numbers of crashes as well. Wisconsin DOT evaluated the accuracy of travel time messages for a work zone displayed on variable message signs. Traffic flow data were collected using roadside sensors, and this information was used to estimate travel times. Variable message signs were placed in locations where drivers had the opportunity to exit the freeway under construction (or not to enter it) if they chose. A comparison of these calculated times with actual travel time data showed that the travel times displayed on the variable message signs were relatively accurate. The difference between actual and predicted travel times was 2 to 3 minutes, on average. Fewer injury crashes were experienced on this section of the freeway after the travel time messages were put into use than in the control section of the roadway (a similar work zone in the opposite direction of travel). (These data were collected for approximately 2 months and the results should be used with caution.) (Notbohm et al., 2001). It is also expected that drivers in congested conditions will experience less frustration and be less inclined to take aggressive action if informed about the length of the congestion, in terms of both time and distance. Emergency response times and, potentially, crash survivability may also be improved when ITS strategies are used to detect incidents and determine the appropriate types of responders. V-44

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-10 (Continued) Strategy Attributes for Implementing ITS Strategies to Improve Safety (E) Attribute Description Keys to Success Keys to success are related to planning and administration of the system to be implemented and technical details related to information provided to travelers and agency personnel. As a system is being developed, the transportation agency implementing the system should coordinate with other stakeholders, such as emergency responders. One issue to consider is how information will be shared with police and emergency medical providers so that resources are used appropriately and efficiently when incidents occur. The public is another key stakeholder to consider during planning, and a PI&E campaign should inform the public of the technologies that will be used and their benefits, as well as the information that will be provided by the ITS. Throughout the project, accurate information is needed (FHWA, 2002). A plan for handling problems with the system components will need to be developed with consideration for placing staff on-call during nonbusiness hours to handle problems. The reliability of the communications system should be confirmed before implementation. The schedule will need to include some time for startup of the system, which includes activities such as calibration of traffic detectors and accounting for traffic scenarios that may not have been initially programmed into the system. Periodic--possibly daily--checks on system performance will need to be performed (FHWA, 2002). It is important that variable message signs information be provided to travelers far enough in advance of the back of the queue for them to be able to take alternative routes. The advance warning signs should also be appropriately spaced so that drivers do not encounter a queue before they reach the sign warning them of the queue. A portable system remotely operated by cell phone may be more appropriate for a rural work zone, where a traffic command center would not be available or needed. Portable systems are applicable in situations where a system is needed for a relatively short time (such as for a planned event). These systems can work with sensors and without the need for an operator. Providing accurate and up-to-date information to drivers is important as well. Should drivers repeatedly find information to be old or inaccurate, they will learn to disregard the information. Adequate planning is needed for the system, especially larger complex ones, since the system will need to be customized for the specific situation (such as setting up web cameras). Contractors will often lease the system from a vendor, so time and planning are needed to allow for this. Having a separate contract for the ITS portion of the project can allow the planning for and implementation of the system to proceed separately from the construction contract to ensure that the system is in place before construction begins. Potential Difficulties Costs associated with the purchase or lease of ITS components can be significant. Agencies should make efforts to reduce difficulties with system components during startup and initial periods of system use. Comprehensive testing of the system should be performed. Lack of cell phone coverage may limit the applicability of systems intended for use in rural areas in which sign messages are controlled by cell phones. V-45

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-10 (Continued) Strategy Attributes for Implementing ITS Strategies to Improve Safety (E) Attribute Description Typical weather conditions that may be expected during the duration of the work should be considered when choosing systems that detect traffic queues or incidents. For example, video detection of incidents may be hampered during periods of heavy fog. Appropriate Measures A key process measure is the number of projects on which ITS technology is used. and Data The types of systems and quantities of each, as well as system malfunctions, should be used to measure the implementation process. Key safety effectiveness measures include crash frequency and severity, by type of crash. It is important to consider crashes related to the presence of the work zone, as well as to identify crashes related to traffic diversion to an alternative route. These might include congestion-related crashes on the detour routes, such as rear-end crashes. Crash frequency and severity data are needed to evaluate the construction operation for safety effectiveness. Traffic volume data are needed to represent exposure, including changes in volumes on alternative routes during the construction. Changes in traffic volume in the work zone can be used to determine the exposure of traffic to the work zone and the exposure of workers to traffic. Delay data are needed to determine the operational impacts of the project on traffic flow. Citations in the work zone may be an appropriate surrogate measure of safety. Changes in the number of citations for speed violations, from before construction to during construction, can be used to evaluate possible changes in the level of safety. Associated Needs The deployment of specific ITS equipment may require skills not present among the personnel of the highway agency. Therefore, private contractors may be needed to implement and/or maintain the system. Organizational and Institutional Attributes Organizational, Coordination with other agencies--such as emergency response providers, local Institutional and jurisdictions, and land users adjacent to the work zone that may be affected by the Policy Issues project--should be a part of the planning process, and this coordination should continue throughout the project. Some education may be required so that personnel from these other agencies are aware of how the ITS work zone system works. Stakeholders with incident management responsibilities should have a significant role in determining how the system is used for and affects emergency response. New policies and procedures may be required to guide the application of ITS technologies in the jurisdiction. Issues Affecting Agencies should not need to spend significant effort to begin using ITS on Implementation Time construction projects. It may be desirable to establish a procedure for comparing the costs of various systems with the benefits. Much of the equipment needed may not be available and would need to be ordered in advance of a project. This would add to the initial implementation time. If an ITS contractor/consultant is required for a construction project, it may require additional time to finalize a contract. It may be desirable to install already-planned permanent or long-term ITS before a construction project begins. In such a case, a separate system would not be needed during construction. This would also be a good time to update an existing system. Installing the ITS technology before the construction begins can either increase V-46

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-10 (Continued) Strategy Attributes for Implementing ITS Strategies to Improve Safety (E) Attribute Description implementation time (if the installation was scheduled to occur some time after the construction project) or decrease implementation time (if the system is nearly ready to be installed and does not need to be added to the construction contract). PI&E campaigns for the construction project should include an element to make travelers aware of the ITS technologies being used. In some cases, the ITS technologies will need to be fully operational before construction can begin, and this will need to be planned into the implementation time for individual projects. Costs Involved Establishing procedures for including ITS in work zones will be of minimal cost. ITS components can be purchased or leased, and the cost will depend on the complexity of the system and the individual technologies included in the system. The FHWA (2002) reports that ITS work zone systems cost less than 1 to 10 percent of the total project cost for the construction projects highlighted in the document. An analysis of over 100 planned ITS projects in Nebraska led to development of benefit/cost (B/C) ratios for the system deployments. The systems studied were planned for permanent use, rather than work zones. The projects were expected to have an average B/C ratio of 1.5. Types of ITS programs with the highest expected B/C ratios were tourism and traveler information systems, commercial vehicle operation systems, and traveler safety and security systems (McCoy et al., 1998). Training and Other Agency design staff will need to be trained on what technologies are available and in Personnel Needs what situations they are applicable and appropriate. If support of the ITS components is not included in the vendor's contract, agency personnel will most likely need to be trained by the vendor so that they can operate and maintain the system. Legislative Needs None identified. Other Key Attributes Compatibility of Most technologies that fall into the broad category of ITS are compatible with other Different Strategies strategies discussed in this guide and may enhance the effectiveness of other strategies. Other Key Attributes In addition to lessening the impact of the work zone on road users, cooperation with to a Particular Strategy stakeholders such as the public and emergency response providers can improve relations with these groups and improve the confidence that these groups have in agency personnel and programs. Examples of these benefits are documented by FHWA (2002). Agencies should consult legal personnel to determine whether certain data, such as camera images, should be archived. Key References Carlson, P.J., M. Fontaine, H.G. Hawkins, K. Murphy, and D. Brown, "Evaluation of Speed Trailers at High-Speed Temporary Work Zones." Paper No. 00-1475. Transportation Research Board, Compendium of Papers CD-ROM, Washington, D.C. 2000. Colorado DOT, TDM Toolkit. 2002. http://www.dot.state.co.us/CommuterChoice/ TDM/TDM.htm. V-47

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SECTION V--DESCRIPTION OF STRATEGIES Federal Highway Administration, Intelligent Transportation Systems in Work Zones: A Cross Cutting Study. Report No. FHWA-OP-02-025. Washington, D.C. 2002. http://www.itsdocs.fhwa.dot.gov/JPODOCS/REPTS_TE/13600.html. Federal Highway Administration, ITS Operations Resource Guide. 2003. http://www.itsdocs.fhwa.dot.gov//JPODOCS/catalog/frame_sec6_zones.htm. Federal Highway Administration, Mitigating Traffic Congestion--The Role of Demand-Side Strategies. Washington, D.C. 2004. http://ops.fhwa.dot.gov/publications/mitig_traf_cong/ index.htm. Fontaine, M.D., "Guidelines for the Application of Portable Work Zone Intelligent Transportation Systems." Paper No. 03-2700. Transportation Research Board, Compendium of Papers CD-ROM, Washington, D.C. 2003. King, T. W., C.C. Sun, and M.R. Virkler, "Evaluation of a Freeway Work Zone Speed Advisory System Using Multiple Measures." Paper No. 04-2401. Transportation Research Board, Compendium of Papers CD-ROM, Washington, D.C. 2004. McCoy, P.T., S.L. Gaber, J.A. Gaber, and W.D. Tobin, Nebraska Intelligent Transportation Systems Statewide Strategic Plan. Nebraska Department of Roads. Lincoln, Nebraska. FHWA-NE-99-P511. 1998. Maze, T., A. Kamyab, and S. Schrock, "Evaluation of Work Zone Speed Reduction Measures." Iowa State University Center for Transportation Research and Education. Ames, Iowa. April 2000. Notbohm, T. , A. Drakopoulos, and A. Horowitz, Smart Work Zone Deployment Initiative Summer 2001 Travel Time Prediction System. 2001. http://www.eng.mu.edu/~drakopoa/ web_documents/TIPS/Tipswisconsin.pdf. Information on Current Knowledge Regarding Agencies or Organizations That Are Implementing This Strategy The FHWA report Intelligent Transportation Systems in Work Zones: A Cross Cutting Study (2002) describes construction projects that used ITS in the work zones to successfully provide real-time travel information to travelers, reduce delay, and reduce time to clear incidents. 19.1 B2--Improve Visibility of Work Zone Traffic Control Devices (T) General Description Visibility of traffic control devices can be limited by poor retroreflectivity, obstructions, sight distance, weather conditions, wear, and other factors. Lack of visibility of traffic control devices can contribute to crashes in work zones. Providing adequate visibility of traffic control devices aids in drivers' advance perception of the travel path through the work zone, especially at night. Poor visibility of signs and markings may result in drivers unintentionally violating the intended message of a regulatory or directional sign. Also, drivers' attention may be focused on other objects in the work zone or work activities in an adjacent lane rather than on signing. The visibility of signs, markings (including raised V-48

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SECTION V--DESCRIPTION OF STRATEGIES pavement markers), and channelizing devices may also be affected by degradation of the reflectivity of the device, the interference of physical objects (e.g., equipment, other vehicles, dirt, or road sludge), atmospheric conditions (e.g., fog), and darkness. Maintenance of traffic control devices is important to the visibility of the devices. If visibility of traffic control devices is considered to be a potential factor in crashes that have occurred, field reviews may be regularly performed, especially at night, to determine if part of a device's message is obscured, obliterated, or blocked, as well as to check the retroreflectivity of the device. In addition to potentially restricting driver sight lines, signs not associated with the driving task and a large numbers of appurtenances in the vicinity of a work zone can impose a high workload on drivers. The need for numerous traffic control devices in work zones, combined with the presence of existing signs and devices, plus background clutter created by advertising signs, street lighting, and so forth often make it difficult to select and locate temporary traffic control devices to ensure adequate visibility in work zones. It is therefore essential to adhere to the Manual on Uniform Traffic Control Devices (MUTCD) guidance to ensure that all work zone traffic control devices are properly selected, designed, and located to provide adequate visibility and driver comprehension. An analysis of driver information workload may be needed to identify potential problem areas. State agencies are encouraged to adopt their own visibility standards for work zone traffic control devices. The standards would apply not only to signs and pavement markings, but also to barricades and channelizing devices such as cones and barrels. The American Traffic Safety Services Association (ATSSA) has recommended guidelines for the condition of temporary traffic control devices, and many states follow these or equivalent standards (available online at http://www.atssa.com/resources/statepolicies.asp). In addition, FHWA is developing standards for retroreflectivity. Frequent inspections are needed to ensure that an agency's visibility standards are met in work zones. Agencies are encouraged to require that a person certified in development and implementation of traffic control plans oversee the traffic control in work zones. It is important to follow up with contractors to make sure traffic control supervisors are being used on projects where this is recommended or required. It may be desirable to have more than one supervisor, possibly at least one on the contractor's staff and one from the highway agency staff, to be able to monitor more of the time when the work zone is active, especially when work is occurring for long periods (such as 24-hour operations). The recent FHWA rule on work zone safety and mobility requires contractors and state highway agencies to designate a trained person to be responsible for "implementing a transportation management plan and other safety and mobility aspects of the project." Beginning in January of 2005, South Carolina DOT has required all construction work bids to have a certified work zone traffic control supervisor. Certification is obtained during a 3-day training course. Nighttime visibility is an important consideration when determining appropriate traffic control devices to use in a work zone. Drivers and pedestrians at nighttime tend to be less alert and are more often driving under the influence of alcohol or drugs than during daytime. "A significant problem with night work, then, is that drivers need more visibility at a time when conditions reduce visibility" (Bryden and Mace, 2002, NCHRP Report 476). The clues that drivers are able to pick up from the roadway environment that help them steer their vehicles along the appropriate path are not as evident at night, and reliance on signs and markings increases. Increased conspicuity of signs and markings provides more V-49

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SECTION V--DESCRIPTION OF STRATEGIES information to drivers at a greater distance, and this is especially important at night. NCHRP Report 476 and NCHRP Report 498 should be consulted for additional information about nighttime visibility of traffic control devices. Older drivers are particularly susceptible to involvement in work zone crashes due to their often increased difficulty in responding to situations that violate driver expectancy and due to their significantly decreased visual acuity, especially in periods of reduced visibility such as night and poor weather. Decreased visual and other functional capabilities compound the issues related to the unique nature of every work zone. The older driver guide in this NCHRP Report 500 series (Volume 9) should be consulted for additional information on improving work zones to accommodate older drivers. In addition, the FHWA Older Driver Highway Design Handbook (1998, available at http://www.fhwa.dot.gov/tfhrc/safety/ pubs/older/home/index.htm) should be consulted to ensure that improvements to visibility of traffic control devices will be appropriate for older drivers. Also, see Appendix 3 for a brief summary of some research on traffic sign visibility, performed by the United States Sign Council, with emphasis on the mounting height. Methods for improving visibility of signs, pavement markings, and channelizing devices include: Implement visibility (i.e., retroreflectivity) standards (or ATSSA condition guidelines or the equivalent). Upgrade sign sheeting materials. Use of highly reflective or fluorescent sign sheeting can provide improved visibility for work zone signs. Use fluorescent orange sign sheeting where low-light conditions are expected during the work zone operation. Fluorescent sheeting does not provide much additional value during bright daylight or nighttime conditions and therefore may not be appropriate for work zones that are set up and taken down daily. Provide larger signs on high-speed roadways where clutter is not a concern. Where sign density is higher (such as on urban roadways), temporary signs need to fit in with existing traffic control and cannot block other devices. Larger letter height and stroke width can help increase visibility as well. Crash experience on a roadway can be used to determine if larger signs may be appropriate for a work zone on that roadway. Provide redundancy in signs on high-speed rural roadways and for critical signs. Increase sign spacing on high-speed roadways to allow more time for drivers to process the information on the signs and to prepare for the required maneuver. Provide artificial lighting on work zone signs. Provide flags and/or warning lights on work zone signs. Increase the size of channelizing devices. Decrease the spacing of channelizing devices. Avoid using Type III barricades near intersections and ramps, except for full road closures (where Type III barricades are required). Other channelizing devices, such as Type II barricades, drums, and vertical panels, especially if closely spaced, can provide equivalent path guidance to drivers without blocking sight lines. V-50

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-11 Positive Guidance: Excellent Temporary Marking and Channelizing Devices Install highly reflective temporary pavement markings to delineate intended travel paths; a material with high visibility in both dry and wet conditions is ideal. A wet reflective tape product is available that provides increased visibility in wet conditions. Refer to the section entitled "Information on Current Knowledge Regarding Agencies or Organizations That Are Implementing This Strategy" for one agency's experience with this product. Ensure adequate visibility of signs and markings on detour routes. Improvements need to be made as appropriate to accommodate increased volumes of traffic anticipated due to diversions from the work zone. Improve the display of sign messages through changes in colors, contrast, pictorial or text messages, font style, letter height, and stroke width. Reduction of glare from signs and adjusting mounting height and location relative to travel way as appropriate can improve visibility of signs. Another aspect of visibility of traffic control devices relates to the obliteration of temporary markings when the control plan changes in a work zone. Construction and maintenance may be done in stages so that vehicles are directed over different paths at various stages of work. When the paths change, the temporary and permanent markings that are present for a V-51

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SECTION V--DESCRIPTION OF STRATEGIES Flag trees (T): Flag trees are high-level devices that provide additional warning that flaggers are present. They may be less effective in urban or congested areas than in rural areas due to visual clutter of the background. However, flag trees in urban areas may be more visible than flaggers since they can be taller than flaggers and more easily seen over taller vehicles. Flag trees may not be feasible for mobile or short-term work where frequent moving of the trees is needed. Additional advance warning of flagger presence (E): Centerline cones may be placed upstream of a flagger station to alert drivers to the presence of a flagger in the roadway. This may not be ideal on narrow roadways or where drivers may be confused by the cones and may drive on the left side of them (NYSDOT, 2005). Flashing stop/slow paddles (E): Another method for increasing flagger visibility is to use stop/slow paddles with flashing lights. The paddles have high-intensity lights on the "stop" side that flaggers can activate when needed (i.e., when it appears that a driver has not noticed the flagger and sign). Alerting a driver to the presence of a flagger and sign should increase the chances of the driver stopping or slowing and avoiding crashes. Information on states' experiences with flashing paddles can be found on the FHWA website at http://www.fhwa.dot.gov/winter/roadsvr/ byproduct.htm (listed under "flashing stop/slow paddle"). High-visibility apparel (T): Flaggers generally stand facing traffic, but this is not always true for workers performing other tasks. Therefore, they need to be visible from all directions in any position (stooping, facing away from traffic, and so on). This means that since it is unpredictable which part of the body will need to be visible to traffic and other construction personnel, there is a great need for a worker's entire body to be visible. At night, flaggers are often illuminated by headlights and therefore can be made more visible with retroreflective clothing, but other workers not directly exposed to traffic cannot rely on retroreflectivity. Light-colored clothing, in addition to retroreflective vests and hard hats, should be worn to make workers visible under both headlights and more diffused work lighting (Bryden and Mace, 2002). Encircling hard hats with high-visibility tape will help improve visibility of workers as they are positioned sideways with respect to oncoming traffic and as they therefore have a smaller cross section of high-visibility apparel facing traffic. The American National Standard for High-Visibility Safety Apparel (ANSI/ISEA 107- 2004) established three levels, or conspicuity classes, of high-visibility apparel for workers. This is a consensus standard developed by ISEA through ANSI and is not currently included in the latest version of the MUTCD. The level of apparel a worker needs to wear (per these standards) is dependent upon the type of work, vehicular traffic, hazards, and other activities in the work zone. Class 3 apparel is the most visible in a wide range of weather and lighting conditions and is appropriate for use where traffic speeds are 50 mph or greater. Additional discussion of the classes of apparel is available on the Center for Disease Control and Prevention website at http://www.cdc.gov/elcosh/docs/d0600/d000627/d000627.html. In order for workers to be visible against the background of construction equipment and vehicles, clothing with a striped pattern, rather than a solid color, may provide additional V-56

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-14 Highly Visible Flagger at Night--Apparel, Temporary Lighting visibility (Bryden and Mace, 2002). Use of yellow-green colors in worker apparel may help improve worker visibility against a background of orange construction equipment, signs, and barricades. Fluorescent apparel can enhance visibility during dawn and dusk. Varying apparel colors by season to ensure that workers stand out against the foliage background is suggested by Pratt et al. (2001). For example, South Carolina DOT does not use yellow-green apparel because workers wearing that color do not stand out well against the pine forest background commonly found in the state. Visibility of Work Zone Vehicles Improvements to visibility of work zone vehicles include: Use more visible paint colors, conspicuity tape, or retroreflective materials or backup alarms to increase road user and worker awareness of work zone vehicles (T): Increased visibility of work vehicles will provide road users with more warning that vehicles either are present or may be entering the traffic lanes. Use backup alarms or video cameras to increase worker awareness of work zone vehicles and driver awareness of other workers (T): Backup alarms are used to alert people in the vicinity of a vehicle that it is backing up. These alarms are sometimes objectionable to residents in the vicinity of a work zone, and an alternative can be an observer who signals to a vehicle operator when it is safe to proceed in reverse. Video cameras can be used to provide the view behind the vehicle as the operator is backing up. Use advance warning vehicles to alert drivers to the presence of a work zone (T): The AASHTO 2002 Roadside Design Guide discusses appropriate use of advance warning vehicles (shadow and barrier vehicles) and truck-mounted attenuators. Advance warning vehicles should be equipped with warning lights, such as rotating V-57

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SECTION V--DESCRIPTION OF STRATEGIES beacons or strobe lights. Strobe lights, however, can be fatiguing to workers in nighttime conditions (in addition, strobe lights can trigger seizures in some people with epilepsy). Arrow panels are recommended for use on shadow and barrier vehicles as an effective means of warning drivers that a lane is closed. These panels should be mounted as high as possible on the vehicles and should be as large as possible to provide the most visibility. The arrow panels should be dimmed at night to a maximum of 50 percent of full intensity to avoid glare problems for approaching drivers. Use combinations of warning light colors (T): A combination of colors for warning lights may convey a message of greater hazard warning to drivers. A study of several freeway sites in Texas showed a 5- to 6-mph decrease in speed of vehicles approaching maintenance vehicles with a combination of yellow and blue warning lights at two of five sites. This color combination resulted in an increase in brake usage as well and an even greater increase when red-yellow-blue warning lights were used. Different color lights did not have a significant impact on the tendency of drivers to change lanes as they approached the maintenance vehicle with the warning light. The presence of a law enforcement vehicle was shown to influence drivers to brake more frequently than a TxDOT courtesy patrol vehicle (Ullman, 2000). Warning lights in colors other than yellow should be used only when a specific need exists for these lights and only when permitted by the jurisdiction in which the work zone is located (Bryden, 2003). Nighttime Visibility Nighttime visibility of workers and vehicles is an important consideration when determining whether to perform work during the day or night. Visibility is reduced at night, and there are also concerns related to driver expectancy and the potential for fatigued or otherwise impaired drivers. EXHIBIT V-15 Visible Work Vehicle at Night--Arrow Board, Reflective Signs and Markings, Warning Lights V-58

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SECTION V--DESCRIPTION OF STRATEGIES Retroreflective material on apparel and vehicles will improve their visibility. Strobe lights are highly visible and less costly than incandescent flashing/rotating lights for vehicles, but are believed to be more difficult for drivers to determine both the distance to them and the rate at which the distance is closing. Light bars provide good visibility but may be difficult to be visible from 360 around a large vehicle. Additional guidance on use of warning lights at night is provided by Bryden (2003). For nighttime construction, adequate lighting is necessary to allow workers to complete their tasks efficiently as well as increase the visibility of workers and vehicles. Care should be taken to minimize the glare experienced by both workers and drivers. Consideration of glare-free light balloons is suggested by Pratt et al. (2001). EXHIBIT V-16 Strategy Attributes for Improving Visibility of Work Zone Personnel and Vehicles (Varies) Attribute Description Technical Attributes Target The principal targets are worker and vehicle visibility, which affect crashes that occur when drivers either are not aware of the presence of workers or vehicles or fail to see them due to distractions or reduced visibility. Such crashes would involve either a vehicle striking a worker (whether a flagger or other worker directly exposed to traffic) construction vehicle or a vehicle intruding on the work space. Also, lack of worker or equipment visibility could contribute to a collision between vehicles traveling through the work zone should drivers make erratic maneuvers to avoid a worker or work vehicle that was not seen. These crash types would include rear-end crashes and possibly side-swipe, angle, and head-on crashes, depending on work zone configuration. Work zones of all types would be appropriate sites for improving visibility of workers and vehicles. Expected Effectiveness It can be expected that improvements in visibility will have a positive effect on crash experience. Methods for improving visibility of work zone personnel and vehicles have been evaluated, and treatments such as high-visibility apparel and warning lights have been shown to be effective in improving visibility. While it is difficult to quantify the effectiveness in terms of crash reduction in work zones, it is known that a substantial number of work zone crashes involve vehicles traveling through the work zone that strike a worker or work vehicle/equipment. It is reasonable to expect improved visibility to reduce the number of such crashes. Keys to Success One key to success is to have well-developed agency guidelines for the use of apparel and other methods to improve worker and vehicle visibility. Another key to the success of visibility improvements is frequent inspection of worker clothing, vehicle warning lights, and other enhancements to ensure that the devices are clean, functioning, well maintained, and providing an appropriate level of visibility. Potential Difficulties If high-visibility materials are not maintained properly, the expected benefits may be lost. It is important to ensure that any lighting that improves visibility of workers and equipment does not create glare for drivers passing through the work zone, workers, or drivers of construction vehicles. Appropriate Measures The existence--or development, if necessary--of a clear policy on worker and work and Data vehicle visibility is a primary process measure. Another key process measure is the V-59

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-16 (Continued) Strategy Attributes for Improving Visibility of Work Zone Personnel and Vehicles (Varies) Attribute Description project on which worker and vehicle visibility is improved. The types of improvements and the number of applications of each should be used to measure the implementation process as well. Key safety effectiveness measures include crash frequency and severity, by type of crash. It is important to consider crashes related to visibility of workers and work vehicles in the work zone. Crash frequency and severity data are needed to evaluate the construction operation for safety effectiveness. Traffic volume data are needed to represent exposure. Associated Needs None identified. Organizational and Institutional Attributes Organizational, Highway agencies should review and revise, as appropriate, policies regarding worker Institutional and and vehicle visibility to facilitate appropriate action being taken on routine projects. Policy Issues Good quality control/quality assurance procedures and practices at the project level are also necessary. Nearly any highway agency can implement this strategy, which is applicable to work zones on any facility type in rural, urban, and suburban areas where work occurs either during the day or at night. Complete cooperation of contractors and all field staff is important. Contract provisions should clearly specify the visibility requirements for both personnel and equipment used on the project. Issues Affecting Implementation time will be relatively short for procedures to improve visibility, such as Implementation Time installing markings or lights on vehicles or lighting for the work area, and for workers to begin wearing high-visibility apparel. Costs Involved Costs will be low for most procedures to improve visibility and awareness of the work zone personnel and vehicles. Ongoing maintenance costs should be included in cost considerations. Cost elements will include apparel purchases, painting of vehicles, and installation of appropriate lighting fixtures. Training and Other Visibility of work zone personnel and vehicles should be addressed in highway agency Personnel Needs training concerning work zone safety. Contractors may also need to undergo training that includes discussion of ways to improve worker and vehicle visibility. Legislative Needs Use of different combinations of colored warning lights (such as yellow and blue) may require enabling legislation. Other Key Attributes Compatibility of Actions taken to improve visibility of work zone personnel and workers are compatible Different Strategies with other strategies to improve work zone safety. Key References American Association of State Highway and Transportation Officials, Roadside Design Guide. 3rd Edition. Washington, D.C. 2002. V-60

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SECTION V--DESCRIPTION OF STRATEGIES Bryden, J., Traffic Control Handbook for Mobile Operations at Night: Guidelines for Construction, Maintenance, and Utility Operations. Federal Highway Administration. FHWA-SA-03-036. August 2003. Bryden, J.E., and D. Mace, NCHRP Report 476: Guidelines for Design and Operation of Nighttime Traffic Control for Highway Maintenance and Construction. Transportation Research Board. Washington, D.C. 2002. http://trb.org/news/blurb_detail.asp?id=1023. Federal Highway Administration. Manual on Uniform Traffic Control Devices (MUTCD). Washington, D.C. 2003. Hanscom, F.N., and R.F. Pain, NCHRP Report 337: Service Vehicle Lighting & Traffic Control Systems for Short Term and Moving Operations. Transportation Research Board. Washington, D.C. 1990. Kamyab, A., T. McDonald, and B. Storm, Synthesis of Best Practice for Increasing Protection and Visibility of Highway Maintenance Vehicles. Iowa State University Center for Transportation Research and Education. August 2002. http://www.ctre.iastate.edu/reports/visibility.pdf. NYSDOT, Highway Design Manual. June 24, 2005. http://www.dot.state.ny.us/cmb/ consult/hdmfiles/hdm.html. Pratt, S.G., D.E. Fosbroke, and S.M. Marsh, Building Safer Highway Work Zones: Measures to Prevent Worker Injuries from Vehicles and Equipment. National Institute for Occupational Safety and Health. 2001. http://www.cdc.gov/niosh/2001128.html. Ullman, G.L., "Special Flashing Warning Lights for Construction, Maintenance, and Service Vehicles: Are Amber Beacons Always Enough?" Transportation Research Record 1715. Transportation Research Board. Washington, D.C. 2000. 19.1 B4--Reduce Flaggers' Exposure to Traffic (T) General Description Though many workers are exposed to traffic-related hazards in the work zone, flaggers are in a particularly hazardous position since they are constantly near moving traffic and frequently to two or more different streams of traffic. Many times, however, a two-way, one- lane operation is the only viable traffic control option. Making the flagger more visible (discussed in Strategy 19.1 B3) is one method to improve flagger safety. Additional strategies, discussed in this section, include using signals, remote control flagging systems, and pilot cars. Road closure is an alternative to using flaggers and two-way, one-lane operations and will eliminate crashes where vehicles strike flaggers. Refer to Strategy 19.1 A2 for additional details. Another alternative is use of a temporary roadway that allows for two-way, two-lane operation. Temporary Signals Temporary traffic signals can be used instead of flaggers, thereby reducing the exposure to traffic of the workers who would perform the flagging task. Temporary signals may be considered for work zones where other traffic control options include flaggers, stop or yield V-61

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SECTION V--DESCRIPTION OF STRATEGIES signs, or warning signs or lights. In some situations (such as on low-volume roadways), these other options may be sufficient. Work zone types on which temporary signals may be appropriate include: Pavement and bridge repair, Roadside maintenance, and Emergency repairs. A warrant for the use of temporary signals does not exist, and decisions to use them are generally made on a case-by-case basis. As with the installation of permanent signals, traffic conditions and physical characteristics of the work zone should be examined to determine if use of a signal is appropriate. Portable Signals Portable traffic signals can replace flaggers to allow work zone personnel to perform other critical tasks. In order to avoid fatigue, flaggers need to be relieved periodically, such as every 2 hours. Workers need to be able to perform multiple functions and need to rotate into and out of the flagger task. By automating the task of flagging, workers can be freed to focus on other tasks for longer periods and are removed from direct exposure to traffic at the flagger station. Portable signals are mounted on trailers at both ends of the area where one-way operations occur. Communications between the signals are provided by hard wiring, by a radio frequency transceiver, or by a preset timing. An operator inputs the cycle information, such as minimum and maximum green time, yellow and red intervals, and green extension. The portable nature of the signals on trailers allows for easier setup and removal than stationary signals, making them an appropriate option for projects of relatively short duration. Portable EXHIBIT V-17 Portable Signal System to Reduce Flagger Exposure V-62

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SECTION V--DESCRIPTION OF STRATEGIES signals also may be appropriate for use in long work zones. If temporary signals malfunction and switch to flashing red operation, drivers must be able to see whether there is another vehicle on the opposite approach. Portable signals will more likely be used on operations where workers are present the entire time and where, therefore, flaggers could replace the signals until the signals are repaired. Automated Flagger Assistance Devices An automated flagger assistance device, which is a remote control sign or signal, can be also be used instead of a flagger. These devices typically require only one worker to operate, and this worker does not need to be stationed in the roadway or on the shoulder. The FHWA has issued interim approval for the use of these devices in temporary traffic control zones and provides technical provisions for these devices (see http://mutcd.fhwa.dot.gov/res- memorandum_afads.htm). However, each jurisdiction must receive a specific approval from the FHWA by submitting a written request to the FHWA stating the location where the device will be used and agreement to comply with the terms. Approval for use of these devices must be received from FHWA. There is some concern that drivers will misinterpret the meaning of a remotely controlled stop/slow paddle. It is possible that a driver will stop at the stop sign and then proceed, rather than wait for the slow sign. Additional signing could address this. A brief description of the Minnesota DOT experimental use of such a device is provided on the FHWA Work Zone Mobility and Safety Program website at http://ops.fhwa.dot.gov/ wz/practices/best/view_document.asp?ID=140&from=topindex&Category_ID=124. Minnesota limits the use of these devices to work zones less than 1,000 feet long on low- volume, two-lane roadways. A similar device is a remote controlled red/amber signal that replaces a flagger or is used in coordination with a flagger positioned out of the traffic stream. The system includes a gate that lowers during the red signal. Wisconsin DOT has used a remote flagging device with success; an evaluation is provided in Appendix 4. EXHIBIT V-18 Strategy Attributes for Reducing Flaggers' Exposure to Traffic (T) Attribute Description Technical Attributes Target This strategy targets crashes in which vehicles strike flaggers. Other crash types, such as rear-ends that occur when a driver's view of a flagger is blocked by another vehicle, may also be reduced. This strategy is applicable to any work zone where two-way, one-lane operations are necessary, though some of the alternatives may be more costly than can be warranted on smaller projects. Expected Effectiveness While thorough studies have not yet been performed to show the effectiveness of this strategy, replacing flaggers with temporary or portable signals or remote-controlled signs would be expected to eliminate crashes where vehicles strike flaggers, should V-63

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-18 (Continued) Strategy Attributes for Reducing Flaggers' Exposure to Traffic (T) Attribute Description the flaggers be able to be stationed a distance away from through traffic. It is possible that rear-end crashes may initially increase as drivers become familiar with new devices. Keys to Success If a flagger is replaced with a signal or sign, the traffic control device needs to be installed and used in such a way that it is clear to drivers what action they are supposed to take. In addition to advanced warning signs, supplemental signing at the signal or an arm that lowers during a red phase of a signal (see Appendix 4) to provide this information, a PI&E campaign may be necessary to communicate to drivers how the signal operates and how drivers are expected to proceed through the work zone. This is especially true for the new or experimental systems that are being developed and becoming more frequently used. The devices must be visible to approaching motorists, and at least the minimum amount of sight distance should be provided. Care should be taken to ensure adequate sight distance to the traffic control device on approaches where permanent features, such as horizontal or vertical geometry, or temporary conditions, such as work vehicles and equipment, may restrict the drivers' view of the device. Appropriate timing of the temporary or portable signals is critical to the success of this strategy. Excessive wait time can lead to driver confusion and frustration, possibly resulting in violation of the signal. A maximum reasonable wait time is considered to be 4 minutes (Daniels et al., 2000, and NYSDOT, 2005). Factors to consider when determining signal timing include length of the work zone, traffic volume, approach speed, range of speeds in the work zone, and amount of buffer time between traffic departing the work zone and traffic entering the work zone (Daniels et al., 2000). Driveway and intersections, pedestrians, and parking should also be considered (NYSDOT, 2005). Potential Difficulties It is important to ensure that replacement of flaggers with remote control of two-way traffic on a one-way facility does not present greater safety problems for drivers, due to low visibility of the system or confusion that the new system may create. Design of a signal timing plan, if it does not consider all appropriate factors, can negatively impact traffic flow and safety through the work zone. Conditions at the site should be studied before implementing the signal. In the event of malfunction of a traffic signal or of an automated flagging device, flaggers must take over responsibility of directing traffic immediately. It is possible that work zone personnel would not be immediately aware of the malfunction unless stationed nearby and watching for such situations or unless the system has an alarm to warn workers that there has been a malfunction. Such an issue could result in serious head-on crashes as well as place workers within the area at greater risk to collision. As with traditional manual flagging operations, work zones with driveways or intersections in between the signals or automated flagging devices will present additional challenges to safe handling of the alternating one-way operations. It is preferable to locate the one-way operations so that they do not include intersections and high-volume driveways so that automated flaggers or portable or temporary signals are controlling all the vehicles that enter a work zone. For work zones that involve very short-term, one-way operations or projects with a location that moves frequently, flaggers may be a better choice than temporary or portable signals, since the benefits gained by using portable signals may not be offset by the repeated efforts to set up, take down, and move the signals. V-64

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-18 (Continued) Strategy Attributes for Reducing Flaggers' Exposure to Traffic (T) Attribute Description Appropriate Measures A key process measure is the number of projects on which flaggers are replaced with and Data temporary or portable signal systems or with experimental remote control flagging systems. Documentation of the type of system and the manner in which it is deployed is also needed as part of the process evaluation data collection. Key safety effectiveness measures include crash frequency and severity, by type of crash. It is important to consider crashes involving flaggers in the work zone. Crash frequency and severity data are needed to evaluate the construction operation for safety effectiveness. Traffic volume data are needed to represent exposure. Delay data are needed to determine the operational impacts of the project on traffic flow. Associated Needs A PI&E campaign is an important part of implementing a device for controlling two- way, one-lane operation that may be new or potentially confusing to drivers. Drivers need to know how to respond when they encounter the situation, especially if it is relatively new to an area. It is important to communicate with the public on the use of remote control flagging systems, as these are experimental and it is very likely that a high percentage of drivers will not be familiar with them. Organizational and Institutional Attributes Organizational, Agencies using temporary signals need to determine whether alterations to the Institutional and procedure for adjusting the timing of temporary signals are needed. While temporary Policy Issues signals are in use, agencies will want to establish a procedure for adjusting the settings. It should be determined who will be responsible for determining the changes, and it is important to consider how this will be accomplished during nonbusiness hours if the signal will be operating at night. An agency desiring to use this strategy may need to develop a set of policies and guidelines on the use of the devices. In some cases, legislation may be needed for a control device to be used. Another key issue is the development of operational procedures for these devices to ensure that each setup provides adequate sight distance. Proper signal timing for specific temporary and portable signals should also be determined using established policies or guidelines. Since remote control flagging systems are experimental traffic control devices, FHWA approval may be needed before they can be used. An evaluation plan should be in place as well to assess the effectiveness of the system. Issues Affecting Implementation of temporary or portable signals or remote control flagging systems Implementation Time can be achieved in a relatively short time, once any necessary authorization is received. The "authorization," however, may involve passing legislation, establishing policies and guidelines, and receiving FHWA approvals. In such cases, the time could be extended to beyond a year. Costs Involved The cost of the improvements and devices described above could be amortized over several projects. To implement such measures in all applicable locations would have a significant impact on overall budget and cost of projects. Many agencies will purchase one or more sets of equipment and use these sets on projects where they will provide the greatest benefit. One advantage to having several of these systems is that by freeing a flagger to perform other tasks, efficiency is increased on the project and the number of personnel needed is reduced. Example costs of a temporary signal are provided in Appendix 5. V-65

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SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-18 (Continued) Strategy Attributes for Reducing Flaggers' Exposure to Traffic (T) Attribute Description Training and Other Highway agency personnel (specifically traffic signal engineers) and contractors Personnel Needs should be trained in the process of developing a signal timing plan for temporary and portable signals (including appropriate location of the devices in order to ensure adequate sight distance) and use of the system, as appropriate for the tasks for which the personnel are responsible. Training will also be needed for flaggers who are operating remote control systems and proper procedures for serving this function. Legislative Needs None identified. Other Key Attributes Compatibility of Use of temporary or portable signals or remote control flagging systems is compatible Different Strategies with other strategies discussed in this guide. Key References Bryden, J.E., and D. Mace, NCHRP Report 476: Guidelines for the Design and Operation of Nighttime Traffic Control for Highway Maintenance and Construction. Transportation Research Board. Washington, D.C. 2002. http://trb.org/news/blurb_detail.asp?id=1023. Daniels, G., S. Venglar, and D. Picha, Feasibility of Portable Traffic Signals to Replace Flaggers in Maintenance Operations. Texas Transportation Institute. TTI Report 3926-1. 2000. http://tti.tamu.edu/documents/3926-1.pdf. Federal Highway Administration, Manual on Uniform Traffic Control Devices (MUTCD). Washington, D.C. 2003. McGraw-Hill Construction, "Illinois to Test Flagging Device as Part of Injury Crackdown." Engineering News-Record. The McGraw-Hill Companies, Inc. March 15, 2004. Vol. 252, No. 11. Page 16. http://72.14.207.104/search?q=cache:odfwtpJcUY0J:www.enr.com/ news/safety/archives/040315.asp+Illinois+to+Test+Flagging+Device+as+Part+of+Injury+ Crackdown&hl=en. Notbohm, T., Evaluation Report on RC Flagman Remote Flagger. Wisconsin DOT. June 2004. See Appendix 4. NYSDOT, Highway Design Manual. June 24, 2005. http://www.dot.state.ny.us/cmb/ consult/hdmfiles/hdm.html. Information on Current Knowledge Regarding Agencies or Organizations That Are Implementing This Strategy Texas DOT has used portable signals on several projects. Use of the signals is evaluated by Daniels et al. (2000). Washington DOT has identified Unilight traffic signals as a top-rated ITS application to avoid stationing flaggers close to traffic (http://www.betterroads.com/articles/brjun00c.htm). V-66