The study team collected data for a two-week period from September 20 until October 1, 2004. From the past volume data, the northbound and southbound afternoon peak hours showed the most similar demand levels, so the study team focused data collection efforts on each afternoon period. While this approach was not exactly the same as a true 'before and after' study, it would have provided a reasonable comparison of a traditional merge setup with a dynamic merge setup. Since construction was occurring in both directions and demand levels were similar in both directions, the study team planned to use the southbound approach to the merge area as the "without ITS" condition and the northbound approach as the "with ITS" condition. The system deployment schedule mirrored the construction schedule, leaving little opportunity for establishment of baseline conditions (the "without ITS" scenario). Potentially reduce delay resulting from aggressive passing at the merge area.Smooth traffic flow through the merge area.Reduce aggressive driving at the merge point where two lanes were reduced to one in each direction.The main objectives of the system deployment were to: Each sensor had a five-minute minimum activation period. The occupancy thresholds for sensors 1, 2, 3, and 4 were 5 percent, 7 percent, 9 percent, and 11 percent, respectively. For example, when sensor #1 detected the threshold occupancy, sensor #1 sent a message to sensor #2 alerting it to activate the flashing lights. The closed loop system operated based on traffic occupancy. MDOT procured the system using a subcontract with the vendor through the prime construction contract. MDOT equipped each trailer with a Remote Traffic Microwave Sensor (RTMS) unit with the exception of the trailer furthest from the work zone. The trailer closest to the merge was always flashing. MDOT installed five trailers 1500 feet apart prior to the merge point, each equipped with lighted "Left Lane Do Not Pass When Flashing" signs. MDOT designed the DLM System to require traffic to merge early to smooth traffic flow and reduce aggressive driving at the merge point. The construction area covered approximately 11 miles, immediately north of the beginning of the lane closure merge point shown in the figure.įigure 4. The system deployment area is shown in Figure 4. The study team collected data during a two-week period in September 2004 to evaluate the benefits of the system. MDOT had used this type of system on multiple occasions in the past to mitigate impacts caused by work zone capacity reductions. The system did not cover the southbound direction. MDOT deployed a Dynamic Lane Merge (DLM) System in the northbound direction of US-131. In the summer of 2004, the Michigan Department of Transportation (MDOT) deployed ITS technology in a work zone on US-131 in Kalamazoo. Table of Contents US-131 in Kalamazoo, Michigan
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