Alternative Technologies for Mitigating the Risk of Injuries and Deaths in Work Zones: Conduct of Research (2022) / Chapter Skim
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131 APPENDIX E: Work Zone Intrusion Technology Case Studies 1.
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132 1. AFAD Technology Description and Functions Automated flaggers, commonly referred to as AFADs, are portable equipment stations used as a TTC device to control access to a roadway work zone.
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133 The manufacturer's instructions for placing and setting up the AF-100 system near the work zone include the following steps: • Place sign unit at desired location. • Set up proper cones and signs per work zone regulations.
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134 • Immediately replace the unit or system with the same type of AFAD model. • Revert to flagging using a human flagger.
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135 Technology Adoption The decision to adopt one or more AFADs for use in work zone flagging operations should include consideration of factors related to the technology and expect use cases. Caltrans staff interviewed preferred AFAD units that are light weight so that they can be easily transported and oriented, and have a sturdy gate arm that can withstand the repetitive up and down movement and operate in heavy winds.
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136 specifications and estimate (PS&E) packages.
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137 paddle was used. This feeling was eliminated with the use of the red-yellow style lens with gate arm.
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138 • Limiting length of lane closures to avoid blocking driveways may reduce delays and thus decrease the potential for drivers to get impatient and try to go around the flagger. To provide further improvement, uniformed officers may be present to guide the traffic flow.
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139 systems is expected to increase safety for the motorists and decrease the number of intrusions that lead to worker injuries and fatalities. The downside of this form of setup that it may prove to be costly and the locations of the work zone intrusion alert devices should be monitored continuously.
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140 2. MOBILE BARRIER Technology Description and Functions A mobile barrier is a mobile traffic barrier system used to provide positive protection between passing vehicles and the work area.
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141 In order to provide protection to work zones, additional barriers are provided between the fastflowing traffic and the work crew. Positive barriers such as a mobile barrier can provide this additional guard.
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142 • The traffic face of the MBT-1® maybe flush with the edge of the adjacent travel lane. • The MBT-1® proceeds or is relocated downstream within the designated work area, channelizing devices shall be placed at the required spacing from the end of the tape in advance of the designated work area along the appropriate longitudinal line to the MBT1®.
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143 Table E2.2. Anticipated ODOT work activities for mobile barrier implementation Work Operation Type of Work Surface • Minor/Major Surface Repair • Deep Base Repair • Concrete Repair • Crack Sealing Drainage • Minor Culvert and Inlet Cleaning • Minor Culvert and Inlet Repair Traffic Services • Pavement Legend Marking • Major/Minor Sign Installation Maintenance • Traffic Signal Maintenance • Illumination Maintenance • Flasher/Beacon Maintenance • Guardrail/Barrier Maintenance/Repair/Clean • Attenuator Maintenance Structures • Bridge Maintenance • Bridge Repair • Structure Painting ODOT and MnDOT employees indicated that, since a mobile barrier is a trailer, the DOT needs to provide a semi-truck cab to transport the mobile barrier to the work area.
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144 • Where deflection can be accommodated – steel barrier deflects over 5 feet if anchored at the ends only, and minimal deflection can be achieved for at least one type of system where the steel barrier is anchored approximately every 33 feet. Generally, deflection may occur in the range of 6 to 8 feet when impacted by a full-size pickup truck.
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145 Pre-planning and Implementation Plan Several planning issues have been identified by those DOT personnel who have used a mobile barrier. Based on input from the MnDOT employees interviewed, the following factors and recommendations should be taken into consideration when deciding when and where to utilize the mobile barrier: • The overhanging beam in the mobile barrier may require the workers to close two lanes instead of one lane if the lanes are narrow.
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146 Figure E2.1. State DOTs that responded to survey (Gambatese and Tymvios, 2013)
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147 • The MBT-1® is seen as a guard barrier between the work zone area and flowing traffic which provides a higher level of comfort for the workers, but sometimes it is perceived as a false sense of security. This comfort and protection eliminate the need for a worker to act as a spotter for possible hazards that they might be exposed to from the passing vehicles.
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148 Barriers to Use and Limitations to Effectiveness For the MBT-1®, space is needed to switch out the axle connections and reconfigure the barrier to the other side. For planning such an operation, according to MnDOT personnel interviewed, the crew can use the mobile barrier on one side of the work zone and finish that part of work first.
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149 3. ATMA Technology Description and Functions TMA, also referred to as an impact attenuator and crash attenuator, is a device mounted to a truck that is designed to reduce the damage resulting from an errant motor vehicle collision into the truck.
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150 to traffic controls and associated guidance by absorbing the impact of collisions (Blackman et al., 2020)
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151 Figure E3.1. TMPs 1–3 and camera placement (drive on left)
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152 in overall site lengths of between 950 m and 1,100 m (0.59–0.68 mi) from tail vehicle 3 (where present in TMP2)
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153 all of these factors, and can be used on roads to reduce the number of fatalities (Hallowell et al., 2010)
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154 E-Stop, or emergency stop, is a button that the lead vehicle driver can press when an obstacle is encountered that could not be crossed over or during emergency events When the E-Stop button is pressed, the system simultaneously sends a signal to the following ATMA vehicle to stop. The A-Stop feature is for "automated stop" where the vehicle system detects obstacles in the vehicle's path and, when the sensors pick up an obstacle that is very large in which the lead vehicle cannot pass over or by, the lead vehicle communicates with the trailing ATMA vehicle to stop.
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155 Table E3.2. ATMA tests conducted and results (Kohls, 2020)
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156 fixed with upcoming system updates. The cost-benefit trade off can be seen as a concern, but the features and application can be justified for the cost.
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158 QWS contain sensors, a portable variable message sign (PVMS) board, a communication system and operating system.
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159 Figure E4.2. Location of SWZ devices (Waldman, 2020b)
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160 Figure E4.3. Queue warning system layout on I-25 (Waldman, 2020b)
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161 Along with a discussion of integration and testing aspects of the SWZ, the introduction of the SWZ operation plan is seen at the Final Office Review meeting. This collaboration enables the designers, construction members, DOT agencies, and other stakeholders to discuss the roles and responsibilities for the construction phase.
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162 The Bluetooth travel sensor time data was compared with the CDOT COGNOS database and included Device 025N174, Device 025N175, and Device 025N177, which were located at Tomah Road intersection, 1.8 mile north of Tomah Road and 3.8 miles south of Plum Creek Parkway. One of the specifications included was not to repeat static messages, such as "Caution," on the DMS.
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163 The effectiveness of the QWS was evaluated using two MOEs. Both MOEs consist of 1-month period with the QWS and 1-month period with the system.
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164 It was observed on a project in Tuscaloosa, AL that the work crew liked the DMS system. The public was aware of the upcoming road conditions and helped to avoid high-speed crashes and prevent traffic congestion.
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165 Figure E4.5. Road pathway before (left)
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166 5. IAS Technology Description and Functions IASs with or without networked sensors typically use various types of sensors attached to channelizing devices that can detect intrusions into a work zone.
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167 Intrusion Alert System Type of Sensor Technology Used Audio Alert Visual Alert Vibrational Alert Traffic Guard WAS Microwave and pneumatic tube-based Present Present Present SonoBlaster Kinematic energy Present Not present Not present Intellicone Radio wave signal Present Present Not present AWARE* Radar Present Present Present *
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168 one speaker in the corner. The warning sound is 110 decibels at 0 feet and gradually decreases to around 85 dB at 50 feet.
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169 the downsides of having a large number of false positives. The use of a SonoBlaster, Intellicone, and WAS, when placed strategically between AFAD systems, is expected to increase safety for motorists as articulated by Caltrans professionals interviewed.
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170 Table E5.2. Intellicone components and features Component Description Features*
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171 AWARE The AWARE system is a radar-based system that can identify a potential work zone intrusion from several vehicles while also warning the errant driver and personnel who may be in danger. The system is comprised of a sensor that includes electronically-scanned radar, high-precision differential GPS, accelerometers, gyroscopes, and magnetometers for position and orientation sensing.
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172 6. WEARABLE LIGHTS Technology Description and Functions Wearable lights are worn by individual workers to enhance their visibility to oncoming drivers during nighttime work.
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173 Table E6.1. Halo Light™ SL Specifications (https://illumagear.com/wp-content/uploads/2020/05/Specifications-Sheet.pdf)
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174 Another scenario where the Halo Light™ was used for the communication of worker presence to road users is during a natural disaster such as a storm, and during heavy rainfall where the workers had to clean up the debris off the road. Apart from the above application, the Halo Light™ has been used in various conditions and operations.
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175 as input where the lighting system should be mobile in nature. In the case of Halo Lights™, it is mobile and lightweight in nature as well.
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