Quantifying Dynamic Factors Contributing to Dilemma Zone at High-Speed Signalized Intersections

2011 ◽  
Vol 2259 (1) ◽  
pp. 202-212 ◽  
Author(s):  
Heng Wei ◽  
Zhixia Li ◽  
Ping Yi ◽  
Kevin R. Duemmel
Keyword(s):  
High Speed ◽  
Signalized Intersections ◽  
Dilemma Zone ◽  
Dynamic Factors

Performance of Advance Warning for End of Green System for High-Speed Signalized Intersections

2005 ◽  
Vol 1925 (1) ◽  
pp. 176-184 ◽  
Author(s):  
Srinivasa R. Sunkari ◽  
Carroll J. Messer ◽  
Hassan Charara
Keyword(s):  
High Speed ◽  
Red Light ◽  
Signalized Intersections ◽  
Traffic Signal ◽  
Traffic Operations ◽  
Dilemma Zone ◽  
Green Approach ◽  
High Speeds ◽  
Approach Speed ◽  
Green System

A major difficulty with traffic signal operation on high-speed approaches is the dilemma faced by approaching motorists when the downstream signal turns yellow. Should the motorists stop or proceed through the intersection? Crashes that may occur at these intersections result in excessive property damage and personal injury because of the high speeds involved. The Texas Transportation Institute has developed a new system named the Advance Warning for End of Green System (AWEGS) for application at high-speed signalized intersections. Typically, dilemma zone detection strategy is based on a certain approach speed (typically the 85th percentile). AWEGS provides protection for the majority of motorists who are not covered by the dilemma zone treatment. AWEGS provides advance warning to motorists by using signs mounted on the roadside. These signs (Be Prepared To Stop When Flashing) would flash a beacon about 5 to 6 s before the onset of the yellow signal for high-speed approaches. Similar systems have been implemented in Canada and in a few U.S. states that use the trailing-green approach, which results in loss of dilemma zone protection every cycle. AWEGS, however, is almost completely independent of the traffic signal controller, and hence the signal controller would continue to provide the dilemma zone protection for which it was designed. The system was implemented at two sites in Waco and Brenham, Texas. Results of AWEGS implementation illustrated an improvement in traffic operations. AWEGS consistently enhanced the dilemma zone protection at intersections and reduced red light running by about 40%.

Fuzzy sets to describe driver behavior in the dilemma zone of high-speed signalized intersections

2012 ◽  
Vol 15 (2) ◽  
pp. 132-143 ◽  
Author(s):  
David S. Hurwitz ◽  
Haizhong Wang ◽  
Michael A. Knodler ◽  
Daiheng Ni ◽  
Derek Moore
Keyword(s):  
Fuzzy Sets ◽  
High Speed ◽  
Driver Behavior ◽  
Signalized Intersections ◽  
Dilemma Zone

Improved Detection and Control System for Isolated High-Speed Signalized Intersections

2003 ◽  
Vol 1856 (1) ◽  
pp. 212-219 ◽  
Author(s):  
Karl Zimmerman ◽  
James A. Bonneson ◽  
Dan Middleton ◽  
Montasir M. Abbas
Keyword(s):  
High Speed ◽  
Control Algorithm ◽  
Signalized Intersections ◽  
Flow Rates ◽  
New Approach ◽  
Dilemma Zone ◽  
Allocation System ◽  
And Control ◽  
Intersection Control ◽  
New System

High-speed signalized intersections have both safety and efficiency problems. The safety problems traditionally have been overcome by using advance detectors. However, at relatively moderate flow rates, multiple advance detector systems tend to extend the green phase to its maximum allowable duration (i.e., max-out). At max-out, drivers on the intersection approach may be faced with the decision to proceed or stop. This creates the safety problem the system was intended to prevent. Also, extending phases to their maximums increases delays to other movements. A new approach to high-speed intersection control is outlined—a dynamic dilemma zone allocation system that uses measured vehicle speeds with a control algorithm to decide when to end the signal phases. The new system was evaluated by simulation and field installation. In both instances, the new system indicated it could improve safety and maintain efficient operations at high-speed intersections.

Determination and Utilization of Dilemma Zone Length and Location for Safety Assessment of Rural High-Speed Signalized Intersections

2020 ◽  
Vol 2674 (4) ◽  
pp. 272-280
Author(s):  
Min-Wook Kang ◽  
Moynur Rahman ◽  
Joyoung Lee
Keyword(s):  
High Speed ◽  
Red Light ◽  
Signalized Intersections ◽  
Percentage Error ◽  
Traffic Operations ◽  
Safety Level ◽  
Zone Length ◽  
Dilemma Zone ◽  
Intersection Safety ◽  
Traffic Conflicts

The objective of the present study is to see how the dilemma zone length and location are related to intersection safety at rural high-speed signalized intersections. For that, dilemma zones at 30 rural signalized intersection approaches where similar traffic operations and land-use conditions are present were identified, and traffic conflicts associated with the dilemma zones were investigated. Drivers’ stop or go behaviors as well as vehicle dynamics (e.g., vehicle speeds and locations) during the yellow and red clearance intervals were collected and analyzed to determine the dilemma zone length and location of each site. Red-light running violations and vehicles’ abrupt stops were also collected to investigate the relationship between such conflicts and dilemma zone length and location. As a result, two dilemma zone conflict models were developed. The analysis results show that the conflict models are accurate enough to predict the safety level of high-speed signalized intersections using the two dilemma zone variables. Results show that the chance of intersection angle conflicts increases if the dilemma zone is located farther from the intersection stop bar. Results also show that there would be a high chance of rear-end conflicts if the dilemma zone length is longer. The models were validated with additional datasets, and acceptable root means square error and mean absolute percentage error values were obtained as a result.

The Effect of Strain-Rate Upon the Tensile Deformation of Materials

1975 ◽  
Vol 97 (2) ◽  
pp. 151-155 ◽  
Author(s):  
R. G. Davies ◽  
C. L. Magee
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
High Speed ◽  
Tensile Deformation ◽  
Rate Sensitivity ◽  
Al Alloys ◽  
Reinforced Plastics ◽  
Strain Behavior ◽  
Static Testing ◽  
Dynamic Factors

The tensile strength of seventeen engineering materials including steels, Al alloys, and fiber-reinforced plastics, has been determined at strain-rates from 10−3 to 103 sec−1. Variable effects on the stress-strain behavior were found in the different materials with the Al alloys showing minimal strain-rate sensitivity and the plastics highest. All results exhibit a logarithmic dependence of flow stress on strain-rate and thus the dynamic factors (ratio of dynamic to low rate or quasi-static strengths) are as dependent upon changes in quasi-static testing speed (∼1 in./min (0.42 mm/s) as they are to changes at high speed (50,000 in./min or 50 mph (22.35 m/s). No significant influence of strain-rate on elongation or reduction in area has been found for any of the materials. Steels, which comprise the majority of the presently investigated materials, exhibit a higher rate sensitivity for yielding than for higher strain deformation. It is shown that the flow stress results for these steels leads to an internally consistent scheme when (1) strength level and (2) strengthening mechanisms are properly accounted for.

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