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From page 3... ... Executive Summary Traffic congestion continues to grow significantly in the United States and throughout the world. Agencies tasked with managing traffic control systems are continually challenged with moving traffic in congested conditions and situations where the traffic demand exceeds the capacity of the system. Read the entire page →
From page 4... ... • Interim Report • Preparation of Practitioner Guidance • Application of Guidance and Strategies on Test Scenarios Summary of Task 1: Literature Review Development of strategies to handle oversaturated conditions is not a new concept; however literature that could directly be used for the purpose of this project was very limited. The research team found a variety of work in both diagnosis and strategy development. Read the entire page →
From page 5... ... (intermittent, persistent, pervasive) , causation (demand, incidents, timings) Read the entire page →
From page 6... ... Minimizing delay is not appropriate when the situation is oversaturated since it is no longer possible to avoid phase failures. Thus, maximizing the number of vehicles actually served by the intersection, with respect to the vehicles presented to the intersection (the load) Read the entire page →
From page 7... ... Figure 1. Research methodology for development and evaluation of mitigation strategies In Task 3, we also qualitatively described a wide variety of potential mitigation strategies and allocated them against to the taxonomy developed in Task 2. Read the entire page →
From page 8... ... • Re-allocate split time to the oversaturated phase. • Decrease the cycle time when more than one phase is oversaturated. Read the entire page →
From page 9... ... At the network level, most expert practitioners reported metering as the predominant approach for alleviating gridlock conditions in critical areas. Identifying metering locations was suggested to be done on a case-by-case basis. Read the entire page →
From page 10... ... resolution, starting with problem characterization as illustrated in Figure 2. The goal of the initial steps of this approach is to answer several basic questions: • How many intersections and travel directions are affected? Read the entire page →
From page 11... ... Summary of Test Applications In Task 7, we applied methodologies developed in this project to six test networks. Two of the tests were used in the development and testing of the methodology for developing mitigation strategies and testing those strategies using a multi-objective Pareto analysis. Read the entire page →
From page 12... ... Table 1: Summary of attributes of test cases Test Case Config Number of Ints Spacing (ft) speed (mph) Read the entire page →
From page 13... ... Test Cases for the Multi-Objective Pareto Analysis Two scenarios were used to develop and test the strategy development methodology. The first test case applied a single mitigation timing plan to the entire oversaturated scenario. Read the entire page →
From page 14... ... reductions were typically at the locations where SOSI was non-zero (portions of the green time were wasted because no vehicles could move) Read the entire page →
From page 15... ... mitigation strategies were formulated and tested on this scenario. The mitigations included combinations of cycle time adjustment, green time re-allocation, negative and simultaneous offsets, dynamic lane allocation, and double cycling. Read the entire page →
From page 16... ... Directions for Future Research It is often said that good research generates more questions than provides answers. This project generated a number of significant directions for further research. Read the entire page →
From page 17... ... The FBP could be extended to a rolling-horizon formulation to take another step in that direction. Much additional research would be necessary to extend the basic heuristic of the FBP to consider phase sequencing, cycle time, protected/permitted lefts, and so on. Read the entire page →

From page 3...

... Executive Summary Traffic congestion continues to grow significantly in the United States and throughout the world. Agencies tasked with managing traffic control systems are continually challenged with moving traffic in congested conditions and situations where the traffic demand exceeds the capacity of the system.