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12 The researchers performed phone surveys to obtain information on current practices and lessons learned related to the selection of TTC methods for planned maintenance activities, specifically focusing on VSDWZs. A structured questionnaire, which can be found in Appendix A, was used for the survey. Responses were obtained from 41 states. Appendix B shows which states responded, along with the job title(s) of the responding individual(s). At the beginning of the survey, the interviewer reviewed the mobile and short duration definitions from the national MUTCD. The term âvery short durationâ was also explained, based on the synthesis scope-of-work definition. The respondents were told that the objective of the survey was to gather information about VSDWZs or alternative TTC methods that might be used to perform quick maintenance work. The goal of the survey was to collect information about â¢ Types of work activities that state maintenance crews perform. â¢ How maintenance crews set up TTC for those activities. â¢ Factors considered in that decision-making process. â¢ Agency policies and support documents. â¢ Innovations to reduce exposure and/or enhance visibility. â¢ Worker training. â¢ Lessons learned. Maintenance Activities All 41 states surveyed are responsible for maintenance work on their freeways, multilane highways, and two-lane roads. Wisconsin is the only state that does not perform the actual maintenance work with state crews. Instead, maintenance on Wisconsin roads is performed under annual routine maintenance agreement contracts with county public works departments. In Florida, a significant portion (but not all) of roadway maintenance work is contracted out as well. Based on research experience with TTC for mobile and short duration maintenance opera- tions, the study team developed and used a list of maintenance activities that could be performed with some form of abbreviated TTC. These maintenance activities were considered candidates for VSDWZs. All respondents were asked if their maintenance crews perform these activities. The responses are shown in Table 2. With these activities in mind, the respondents were asked to identify any TTC strategies they use that are different from those found in the national MUTCD. Many respondents indicated that they have applications and/or supplements similar to the national MUTCD; C H A P T E R 3 State DOT Practices and Experiences
State DOT Practices and Experiences 13 however, most were found to have little or no difference. Only a few states actually use the term âvery short durationâ in their policies, while others have some type of guidance or decision- making tool that includes several factors that could be considered when adjusting the TTC for maintenance work. Very Short Duration Work Zone Policies All respondents were asked if they have any of the following: â¢ TTC strategies for performing VSD work (i.e., standards or typical applications other than those shown in the MUTCD). â¢ Written or unwritten policies, practices, or standards that address VSDWZs. Fourteen states responded that they have information related to VSDWZs. Only three states (Mississippi, Texas, and Washington) reported having a policy that specifically addresses VSDWZs. These states define very short duration and provide support for using VSDWZs to perform maintenance work. The Idaho Transportation Department (ITD) is developing a policy, but it has not yet been published. The ITD policy is based heavily on the Texas and Washington policies. Mississippi In its Traffic Control for Maintenance Operations manual, the Mississippi Department of Transportation (MDOT 2018) defines very short duration as follows: Very short duration operations may take only a few seconds or minutes to perform. These actions may include debris retrieval, taking a survey shot, a quick inspection of roadway infrastructure or crossing or walking along the roadway. Quick repairs intended as a partial or temporary response to damage or failure may be included in this type of activity only when the action does not require repeated access to a live traffic lane. In most cases, the minimum required equipment and devices would be a strategically placed vehicle with warning lights flashing or engaged and high-visibility safety apparel. Additional work zone safety measures can be applied to raise the level of safety without adding to worker exposure time. A spotter â a second worker whose sole responsibility is to keep an eye on traffic from a safe location â is a good example of this type of safety measure. Remember: Short and Very Short Duration work is not a âshort cut.â Live traffic areas in high speed and high volume locations may not be good candidates for Short Duration or Very Short Duration work zones. The MDOT (2018) manual also has two typical applications for VSDWZs, shown in Figure 5 and Figure 6. For the multilane application (Figure 5), the work vehicle is parked on the shoulder Maintenance Activity Percentage of States That Perform This Activity (%) Debris removal 98 Mowing/brush cutting 95 Pothole patching 95 Sign installation 95 Sign maintenance 93 Short line striping 87 Crack sealing 83 Lighting maintenance (relamping) 80 Guardrail work 78 Signal work 76 Traffic counter installation 72 Pavement marking retroreflectivity testing 63 Pavement testing (core sampling and deflectometer) 62 Table 2. Maintenance activities performed by state forces.
14 Very Short Duration Work Zone Safety for Maintenance and Other Activities and no shadow vehicles are used. A spotter monitors traffic approaching the work area. This application is limited to roadways with speeds of 40 mph or less. For the intersection application (Figure 6), the work vehicle is parked on the shoulder and a spotter monitors traffic. Texas TxDOT issued a memo on very short duration operations (VSDOs) to its district engineers. The memo defines a VSDO as âan unplanned or urgent activity, to be executed in 15 minutes Typical Very Short Duration Work Operation (Multi-Lane Application, low speed, 40 mph or lower) Figure 5. MDOT TA for multilane VSDWZ (MDOT 2018).
State DOT Practices and Experiences 15 or less by a crew of at least one worker and one truck, in which the hazard of not executing the work as a VSDO is greater than executing it.â The memo includes a decision process (flowchart), potential maintenance activities where the strategy may be useful, and a list of risk factors that could be considered. The decision process, based largely on research performed by Wang et al., is shown in Figure 7. Washington State In the Washington State Department of Transportation (WSDOT 2018) Work Zone Traffic Control Guidelines for Maintenance Operations, very short duration is defined as âwork that will only take a few seconds or minutes to perform.â Typical maintenance activities associated with Typical Very Short Duration Work Operation (Intersection Application) Figure 6. MDOT TA for intersection VSDWZ (MDOT 2018).
16 Very Short Duration Work Zone Safety for Maintenance and Other Activities Figure 7. TxDOT decision process for VSDO (Chacon 2017).
State DOT Practices and Experiences 17 this work duration include removing lost cargo or debris, installing or removing traffic control devices, taking a survey shot, providing motorist assistance, and performing quick maintenance or repairs intended as a partial or temporary response to an issue. The policy recognizes that sometimes it may be necessary for workers to walk on a roadway shoulder, cross traffic lanes, or momentarily step into a lane to access work locations or to perform work. The guidelines provide qualitative measures for determining the work zone condition, primarily based on traffic volume and speeds. The guidelines also include typical applications for VSDWZs, which are listed below: â¢ TCP 25 Typical Very Short Duration Work Operation (Outside Traveled Way). â¢ TCP 26 Typical Very Short Duration Work Operation (Multi-Lane Application, Low Speed, 40 mph or Lower). â¢ TCP 27 Typical Very Short Duration In-Lane Work (Multi-Lane Freeway and Highway Application, High Speed, 45 mph or Higher). â¢ TCP 28 Typical Very Short Duration Lane Closure (Two-Lane Highway). â¢ TCP 29 Typical Very Short Duration Work Operation (Intersection Application). More details about this policy are given in the case example chapter of this report. Temporary Traffic Control Decision-Making Support The survey showed that several states have some type of guidance, support, or decision- making tool that includes several factors that could be considered when adjusting the TTC for maintenance work. Although the specific term âvery short durationâ may not appear anywhere in these documents, they provide information to support TTC decision making for maintenance operations that may take only a few minutes to complete. This decision-making support can include one or more of the following: â¢ A list of factors that could be considered when selecting TTC strategies (eight agencies). â¢ Written policies on the use of spotters or lookouts for maintenance work (ten agencies). â¢ Written exceptions to lane closure standards based on conditions (four agencies). â¢ Decision-making tools for proper selection of TTC (four agencies). Factors to Consider in TTC Strategy Selection Eight state agencies (California, Kansas, Kentucky, Maine, Minnesota, Texas, Washington, and Wyoming) have developed a list of items that could be considered when making TTC strategy decisions (California Department of Transportation [Caltrans] 2014; Chacon 2017; Kansas Department of Transportation [KDOT] 2015; Kentucky Transportation Cabinet [KTC] 2008; Maine DOT 2013; Minnesota Department of Transportation [MnDOT] 2015; WSDOT 2018; WyDOT 2011). A summary of those factors is provided in Table 3. Written Policies on the Use of Spotters/Lookouts The role of a spotter is to continuously watch approaching traffic and warn workers of errant vehicles. Using a spotter can be a helpful strategy during VSD work activities and is often used in lieu of TTC devices when traffic volumes are low. Ten state agencies (California, Colorado, Illinois, Maine, Minnesota, Mississippi, New York, Oregon, Virginia, and Washing- ton) encourage the use of a spotter for mobile/short duration maintenance operations when certain conditions exist (Caltrans 2014; Colorado Department of Transportation [CDOT] 2013; Illinois Department of Transportation [IDOT] 2016; Maine DOT 2013; MDOT 2018; MnDOT 2018; New York State Department of Transportation [NYSDOT] 2018; Oregon
18 Very Short Duration Work Zone Safety for Maintenance and Other Activities DOT 2011; Virginia Department of Transportation [VDOT] 2015; WSDOT 2018). These conditions include â¢ When workers are on foot on or near the traveled way. â¢ When workers are without positive protection. â¢ When the posted speed limit is 55 mph or more. â¢ When two or more workers are working near each other. â¢ When traffic volumes are low. Exceptions to Lane Closure Standards Four state agencies (California, Florida, Maine, and Minnesota) allow fewer TTC devices to be used by making exceptions to their lane closure policies. Caltrans (2014) uses a statewide Maintenance Manual to provide information on the methods and procedures to be used for maintenance activities. Chapter 8 of the manual addresses the protection of workers. Section 8.25 describes standard exceptions to lane closure procedures, as follows: Short-Duration operations may be conducted on the traveled way without using a lane closure or signs. Pothole patching and debris retrieval, are examples of brief operations. Prior to using this method, a California Highway Patrol (CHP) traffic break should be considered. In order to conduct short term operations on the traveled way without using a lane closure or signs, all of the following conditions must exist: (1) The traffic volume must be light. This means the worker can walk from the shoulder to the site on the traveled way, do the job, and walk back to the shoulder without interfering with traffic. (2) Sight distance shall be at least 500 feet in each direction. Where 500 feet of sight distance is not available at the work site, one or more lookouts should be posted to extend visual coverage if necessary. (3) Vehicles must be parked completely off the traveled way. Factors to Consider Percentage of Responses Traffic speed 88 Traffic volume 75 Sight distance 63 Location of work 63 Weather 50 Roadway type 50 Duration of work 50 Availability of refuge or escape route 38 Roadway geometry 25 Use of law enforcement 25 Work type 25 Use of flaggers 25 Time of day 25 Intersections/interchanges nearby 25 Distance between stops 25 Sign priorities/requirements 25 Speed of work convoy 13 Shoulders less than 10 ft wide 13 Surface condition 13 Changing traffic conditions 13 Severity of risk 13 Traffic mix (vehicle types) 13 Channelizing devices required 13 Other roadway users (bikes and peds) 13 Table 3. Factors to consider in TTC selection.
State DOT Practices and Experiences 19 If all three of these conditions exist, the supervisor may instruct workers to perform the work on a specified section of highway without a lane closure. All of the following work methods shall be used: (a) When the crew consists of at least two (2) workers, one (1) of the workers shall act as a lookout. The lookoutâs exclusive duty will be to continually watch for approaching traffic and to warn the worker whenever trouble is suspected. (b) The lookout shall not carry a flag or paddle and shall do nothing to control or influence traffic. All workers shall be off the traveled way when traffic passes. (c) Only one (1) production worker shall be on the traveled way, unless more are needed to reduce the exposure time. (d) Workers shall face approaching traffic whenever possible. (e) Workers shall have a planned escape route. (f ) A flashing arrow sign in the caution mode or a flashing amber light shall be operating. (g) W20-1 âROAD WORK AHEADâ signs are not required, since passing traffic is not to be affected. FDOT (2015) allows for signs, channelizing devices, arrow boards, and buffer space to be eliminated when certain field conditions are met. Details are provided in the case example chapter of this report. Maine DOT (2013) developed a short duration work zone procedure that allows for simplified TTC procedures when the work duration is 30 minutes or less. The guidance, which is covered in the case examples of this report, does not include details on the specific TTC to use; instead, it allows for judgment in the field after variables in the policy are considered. MnDOT has made a considerable effort to reach out to local agencies with more simplified TTC strategies. In a recent update of the MnDOT Temporary Traffic Control Field Manual, specific TAs or layouts are identified for low-volume roads; two-lane, two-way roads; two-way roads with continuous left-turn lanes; multilane undivided roads; multilane divided roads; and miscellaneous conditions (MnDOT 2018). When performing mobile or short duration work, more than 28 different layouts may be used. Selection is based primarily on roadway type, traffic volume, and work location. In many cases, notes on the layouts allow for fewer TTC devices and shadow vehicles based on the posted speed limit and how quickly the operation moves down the roadway. The new layouts are discussed in greater detail in the case example chapter of this report. Decision-Making Tools Several agencies have added decision-making tools to their standards, guidance, and/or TAs to help personnel select a proper TTC strategy. In some cases, states have developed TAs for use with specific work operations. TTC Selection by Work Activity Four states (Illinois, Iowa, Minnesota, and South Carolina) have included a table or listing of various work activities (or work activity codes) that note which of their TAs are appropriate for performing those activities. An example from the IDOT (2016) Traffic Control Field Manual for Employees is shown in Table 4. For each work activity code and roadway type, there are a number of work zone cases from which to choose. Each case has condition descriptors (i.e., daytime/nighttime, work duration, traffic volume, etc.) to further assist with selection. The Iowa Department of Transportation (IADOT) also has a similar selection guide. The MnDOT Temporary Traffic Control Field Manual includes layout selection tables for performing work on low-volume roads. Table 5 shows which layout(s) could be used for a few specific maintenance activities. The manual also has a similar table for rural locations. The South Carolina Department of Transportation (SCDOT) includes detailed work activity codes in its Work Zone Traffic Control Procedures and Guidelines for SCDOT Maintenance Activities (SCDOT 2017). For each work activity, there is a series of TAs that can be selected based on roadway type, location of work, traffic speed, and traffic volume.
Table 4. IDOT index guide for work zone case number selection (IDOT 2016). Table 5. MnDOT layout selection matrix for urban areas (MnDOT 2018).
State DOT Practices and Experiences 21 TAs for Specific VSD Operations Two states (North Carolina and Massachusetts) have developed TAs for specific work activities. The North Carolina Department of Transportation (NCDOT) has a Maintenance/Utility Traffic Control Guidelines document that provides TAs for specific work activities, such as mowing, spraying, placing pavement markings, shoulder sweeping, litter pickup, plant bed fumigating, permanent pothole patching, sign support work, shoulder and ditch construction, signal loop installation and repair, and signal maintenance and repair. Users can select from 38 different TAs depending on the roadway type, location of work, traffic speed, and traffic volume. Figure 8 shows the TA for litter pickup (NCDOT 2014). Figure 8. NCDOT TA for litter pickup on a multilane road (NCDOT 2014).
22 Very Short Duration Work Zone Safety for Maintenance and Other Activities In response to an incident, the Massachusetts Department of Transportation (MassDOT) developed a TA showing the procedure for moving mowers across a multilane road, shown in Figure 9. Several other states have developed typical applications for various work activities such as herbicide application (or vegetation spraying), striping, and raised pavement marker (RPM) installation. However, these are essentially mobile operations in which the TTC is similar to all other mobile operations. Guidance for Specific VSD Operations Two states have developed safety guidance for personnel to follow when performing certain activities, such as relamping, litter/debris pickup, and pothole patching. Caltrans (2014) provides instruction for pavement marking and relamping operations in Section 8.25 (B) as follows: (B) Pavement Marking and Relamping Operations A supervisor may allow pavement marking and relamping operations on the traveled way without a lane closure. The posted speed limit must be Note â The Police Detail is Optional based on the operating conditions for that roadway under the direction of the Engineer or Field Supervisor Figure 9. MassDOT TA for moving mowers across traffic lanes (MassDOT 2018).
State DOT Practices and Experiences 23 less than 55 miles per hour and the work must take less than 20 minutes to complete. It is recom- mended that the supervisor also use devices such as signs, FAS [Flashing Arrow Sign], barrier/shadow vehicles, MAZEEP [Maintenance Zone Enhanced Enforcement Program] and lookouts to increase worker protection. In addition, Section 8.32 addresses picking up litter and debris, as follows: Normally, the safest way to pick up litter is to work individually and always face approaching traffic. Trucks should be parked away from the work area unless needed to provide protection from traffic. The workers may be dropped off and picked up later. The practice of employees walking beside a truck loading litter with a pitchfork or other hand tool should be avoided. In narrow medians, protective vehicles may be necessary at both ends of the work area. When retrieving debris from a freeway lane, workers shall wait for a break in traffic. A break in traffic is defined as all lanes clear of traffic long enough for the employee to walk out, retrieve the debris, and walk back to the shoulder (refer to Section 8.25 in this chapter). If no traffic breaks occur, contact the CHP [California Highway Patrol] to provide one. Workers shall not try to flag traffic, use hand signals, or otherwise attempt to create a traffic break. When debris is retrieved from the traveled way, workers shall follow these guidelines: (A) Workers shall remain in the vehicle until the traffic break approaches. (B) An escape route shall be planned before leaving the vehicle. The vehicle shall not be parked where it will block the workersâ escape route. (C) When workers are on foot, their vehicle shall be kept between themselves and approaching traffic. Workers shall walk beyond the outer edge of the shoulder, staying as far from moving traffic as possible. (D) Workers shall always face approaching traffic. The above procedures, except the traffic break, should be followed when removing debris from shoulders. However, a CHP traffic break should be considered when working in areas with limited or no escape routes. The Ohio Department of Transportation (ODOT) uses the term âvery short durationâ in its Traffic Engineering Manual section on TTC for pothole patching (ODOT 2018): On non-interstate multi-lane roads where there are very low volumes, providing sufficient gaps to perform very short duration work, the use of high-intensity rotating, flashing, oscillating or strobe lights only may suffice. The work vehicle would be positioned on the shoulder. This method of TTC is only intended for use on very low-volume multi-lane highways (e.g., rural US 30, Appalachian highways, etc.) where the pothole patching work duration is very short and the roadway geometry and terrain do not necessitate additional measures (shadow vehicle, TMA, LEO, etc.). Similar language is included in the ODOT document for two-lane roads, and the policy only applies to pothole patching operations. TTC Selection Flowchart The Louisiana Department of Transportation and Development (LADOTD) has developed a decision-making flowchart that can be used for proper selection of TTC. The flowchart, shown in Figure 10, is independent of the work activity being performed and prescribes the absolute minimum standard for TTC (LADOTD 1979). TxDOT also has a flowchart, which was shown in Figure 7 and discussed earlier in this report (Chacon 2017). TTC Selection Hazards Survey respondents were also asked to identify the conditions that present the most difficulty when agency staff are trying to select the most appropriate TTC setup for VSD work activities. The results are shown in Table 6. Impaired or inattentive drivers were the most frequently reported hazard associated with mobile, short duration, and VSD operations, with 39% of states indicating this problem. Some
Figure 10. LADOTD decision guide for maintenance traffic control (LADOTD 1979).
State DOT Practices and Experiences 25 states reported that they would never allow workers to be on the roadway with fewer than three advance warning signs. Others reported an increase in TMA strikes by motorists, despite the availability of adequate sight distance on flat terrain in many cases. Other driver behaviors (disobedience, impatience, and speeding) were also mentioned. High traffic volumes were also a hazard, reported by 17% of states. Managing traffic often created limited work windows, which subsequently limited productivity of the work crew. Inadequate sight distance was also noted to be a hazard, particularly in states with mountainous or rolling terrain. Many states noted worker decision-making hazards, which include their inability to properly assess risk (15%) as well as estimate the duration of the work (10%). These responses demonstrate the need to address relative risk and include work duration in TTC decision-making processes. New Technologies Survey respondents were asked to identify any new technologies used to (a) reduce worker exposure, or (b) enhance visibility of workers or the work operation itself during VSD work activities. Reducing Worker Exposure Several states have experimented with various products that allow work to be performed by a single worker who can remain in the work vehicle or off the roadway. These work activities include debris removal, pothole patching, and bridge inspection. Working with the Advanced Highway Maintenance & Construction Technology (AHMCT) Research Center, Caltrans funded development of an automated road debris vacuum (ARDVAC; Hargadon et al. 2006). The ARDVAC, shown in Figure 11, consists of a large truck with an extendable-arm vacuum that picks up smaller pieces of debris. In addition to reducing worker Hazard Group Responses Percentage of Responders Who Identified This Hazard Driver behavior Impaired/inattentive drivers 39 Disobedient/impatient drivers 12 Speeding 12 Driver behavior around ramps 5 Unfamiliar drivers (e.g., tourists) 2 Roadway characteristics Inadequate sight distance 15 Interstate roadways 5 Substandard geometrics (including lack of adequate shoulder) 7 Traffic characteristics High traffic volumes (including limited work windows) 17 High posted speed limit 2 Queue end management 2 Workers Inability to properly assess risk 15 Inability to properly estimate work duration 10 Inadequate staffing/manpower 2 Inadequate safety training 2 Location of work Working in center lane of multilane roadway 5 Table 6. Hazards associated with mobile and short duration work activities.
26 Very Short Duration Work Zone Safety for Maintenance and Other Activities exposure, the ARDVAC was estimated to save $122 per mile when compared with manual pickup methods. In addition, Caltrans has experimented with another litter bag/debris collection vehicle, shown in Figure 12. It has a contractible basket to scoop debris and can handle larger debris items such as tires, mufflers, litterbags, and more. Several other states have experimented with automated debris removal, including Colorado, Idaho, Minnesota, Missouri, Ohio, and Utah. One device, referred to as the Gator Getter, shown in Figure 13, can be used to sweep roadway trash and debris (Avelar et al. 2017). This device is driven at near-highway speeds along the roadway. It scoops up large truck tire treads and automatically contains them on the vehicle until reaching the disposal site. When laying on the roadway, these tire treads bear a small resemblance to alligators, thus the name of the product (Strong and Valdes-Vasques 2014). Another device that is commercially available, shown in Figure 14, is called a road rake. It sweeps debris into a position where the debris can be picked up by a conveyor belt, and then it is stored in the hopper. Figure 11. Caltrans automated road debris vacuum (AHMCT 2013). Figure 12. Caltrans litter bag/Debris collection vehicle (Strong and Valdes-Vasques 2014).
State DOT Practices and Experiences 27 Two states have developed their own debris removal equipment. Missouri DOT (MoDOT) employees created Julieâs Automated Waste-Removal System (JAWS) in memory of a MoDOT worker who was struck and killed while retrieving debris on a roadway in 2004. JAWS, shown in Figure 15, can be operated by one worker, who uses hand controls and a camera display to pick up roadway debris. Although it has been used primarily in the Kansas City District, MoDOT intends to implement 27 more of these throughout the state in the coming years (MoDOT 2018). MnDOT also developed a truck-mounted plow device that can move debris to the side of the road, where it can be picked up later by workers (see Figure 16). The center of the plow is hinged so the plow can move debris to the right or left side. Figure 17 shows a pothole spray-patcher used by Caltrans to dispense and compact asphalt into potholes. The driver/operator controls these functions from inside the cab (AHMCT 2014). North Carolina and New York reported using similar devices (e.g., âpothole killerâ). MnDOT is using UAVs to remotely capture high-resolution imagery during bridge inspections. This equipment, shown in Figure 18, allows this maintenance task to be performed without a lane closure. This technology could be applied to other inspection activities as well. Figure 13. Gator Getter (Strong and Valdes-Vasques 2014). Figure 14. Barber road rake (Barber 2016).
28 Very Short Duration Work Zone Safety for Maintenance and Other Activities Figure 15. MoDOT JAWS (Photo courtesy of MoDOT). Figure 16. MnDOT debris plow (Photo courtesy of MnDOT). Figure 17. Caltrans pothole patcher (AHMCT 2014).
State DOT Practices and Experiences 29 Increasing Visibility of Workers/Work Operation Five state agencies (Caltrans, Georgia DOT, MassDOT, NCDOT, and Utah DOT) reported the use of law enforcement vehicles with flashing lights to perform quick maintenance activities. Some transportation agencies have on-call contracts or interagency agreements with law enforcement agencies that can provide support for maintenance TTC. Some conditions under which the use of law enforcement may be suggested include â¢ During night maintenance activities that do not create an obvious work zone, such as replacing RPMs or night sweeping operations. â¢ For anticipated traffic queues that cannot be avoided. â¢ At locations where traffic has been flowing at high-speed, free-flow conditions for a significant period of time prior to the work zone. â¢ On routes with high volumes of truck traffic and/or steep downgrades. â¢ During flagging operations. â¢ During TTC setup and removal. Other visibility enhancement includes use of supplemental lighting on worker vests and/or hardhats, as well as upgrades to vehicle lighting to include high-intensity lights. However, these enhancements are not limited to VSDWZs, but instead are used during maintenance work of all durations. Worker Incidents in VSDWZs Survey respondents were asked if their agency had ever experienced a crash or near miss involving a worker during a VSDWZ operation. Eight states reported significant events. Caltrans had two separate worker fatalities involving debris removal and pothole patching being performed in gore areas. In both cases, the workers were struck by errant vehicles. This led to policy changes regarding the use of shadow vehicles and spotters or lookouts, which are included in Chapter 8 of the Maintenance Manual (Caltrans 2014). In Illinois, an engineer was working alone to mark a left-turn lane at an intersection and was struck when he inadvertently stepped into the path of a vehicle in the intersection. This event led to the requirement for DOT staff to work in pairs so that one person could act as a spotter. Several other state agencies experienced worker fatalities when work vehicles were struck by passing motorists. In Kansas, a worker was straightening a box culvert marker in an area with Figure 18. MnDOT bridge inspection UAV (Zink and Lovelace 2015).
30 Very Short Duration Work Zone Safety for Maintenance and Other Activities rolling terrain and limited sight distance. There was no shoulder and the parked work vehicle was encroaching into the lane when it was struck by a passing motorist. A similar event occurred in Maryland during sign maintenance work, even though the work vehicle was parked on the shoulder and not encroaching into the lane. In this case, the worker was pinned between the work vehicle and a section of guardrail. Massachusetts reported two fatal events during debris removal activities. In the first case, the worker was on foot when his work vehicle was struck, pinning him between the work vehicle and a section of guardrail. In the second case, a worker was waving to warn an approaching motorist to slow down. The motorist apparently misunderstood those instruc- tions, stopped in the lane, and was struck from behind by a tractor trailer. This also led to policy changes for MassDOT. In Nevada, a worker fatality occurred during a pothole-patching operation. The worker was walking on the shoulder, returning to the work vehicle, and was struck by the mirror of a passing tractor trailer. As a result, the DOT changed the conspicuity markings on work vehicles and expanded the state âmove overâ law to include maintenance vehicles. In North Carolina, a worker was picking up litter on a shoulder when an errant vehicle struck the worker, pinning him against his work vehicle. Although the worker survived, he lost use of both legs after the event. Virginia also reported several events during patching and litter pickup activities. Although specific details about those events were not available, they did result in VDOT adding spotter language to the Work Area Protection Manual (VDOT 2015). In several of these events, the work vehicle was (a) parked close to where the accident ultimately occurred, (b) struck by an errant motorist, and (c) interacted with the worker to cause serious bodily harm or fatality. In addition, litter pickup and debris removal appeared to be represented more than other types of VSDWZ activities in these crash events. For these types of work, the location of the work vehicle and the worker are usually near the location of the litter and debris, there is little or no buffer space, no shadow vehicle is used, and the worker may be performing the task alone (paying little or no attention to passing traffic). Potential countermeasures for these events may include improved planning by the worker to identify the best location for the work vehicle (e.g., parking a greater distance upstream) so that it serves as a shadow vehicle with sufficient roll-ahead (buffer) space, addition of a second work vehicle that serves as a shadow vehicle, and/or use of a spotter to monitor traffic and provide warning(s) to the worker if an errant vehicle appears to pose a threat. Addressing VSDWZs in Worker Training Programs When asked if VSDWZs are addressed in worker training programs, WSDOT was the only state that responded positively. The WSDOT traffic control training course for maintenance workers uses the Work Zone Traffic Control Guidelines for Maintenance Operations manual (WSDOT 2018) as the course book. This training is performed in-house. The remaining states do not address VSDWZs in their worker training programs. Summary The survey showed that only three states have a formal VSDWZ policy in place. Although most agencies do not use the term âvery short duration work zoneâ in their official documents, they do recognize the need to perform very short duration work activities as part of their main- tenance programs. Eight agencies simply provide a list of factors to consider and allow the workers to make their own decisions about how to best perform the work activity. Ten agencies encourage the use of a spotter or lookout when performing quick maintenance activities. A few
State DOT Practices and Experiences 31 states use guidance language to allow exceptions to their lane closure policy. Some states provide decision-making support by way of â¢ Tables for TTC selection by work activity (four states). â¢ TAs for specific VSD activities (two states). â¢ Guidance for specific VSD activities (three states). â¢ A flowchart for TTC selection (two states). The most commonly cited conditions that are considered hazards to proper TTC selection include â¢ Impaired/inattentive drivers. â¢ High traffic volumes. â¢ Inadequate sight distance. â¢ Worker inability to properly assess risk. â¢ Disobedient/impatient drivers. â¢ Speeding. â¢ Worker inability to properly estimate work duration. Given the amount of time and effort required to set up a full lane closure, a complete array of TTC devices is difficult to justify from a worker safety risk perspective. To balance the use of TTC strategies using fewer devices, some agencies may use innovative equipment to reduce worker exposure or enhance the visibility of the workers or the work operation itself. New technologies that agencies are using to reduce worker exposure during quick maintenance operations include â¢ Automated debris removal (vacuums, scoops, rakes, and plows). â¢ Pothole spray-patching trucks. â¢ UAVs for inspection jobs. In addition to the widespread use of high-intensity lighting packages on work vehicles, some states use law enforcement to increase the visibility of workers or the work operation itself when performing VSD activities. Eight agencies have experienced crashes or near misses during VSDWZ operations. Many of those agencies have changed their approach to VSD activities in an attempt to prevent those events from reoccurring. However, only one state provides workers with formal training on VSDWZs.