This paper presents the analysis results of driver responses during a yellow phase, based on field observations of 1,123 drivers collected with a specially designed system from six signalized intersections of high crash frequency in Maryland. By classifying drivers into aggressive, conservative, and normal groups based on their responses (i.e., stop or pass) and the distances to the stop line when the signal turns yellow, the statistical tests with the ordered probit model clearly indicate some critical variables and their impacts on a driver’s decision at intersections. Such variables include average traffic flow speeds, traffic volume rate, the green split, the number of through and crossing lanes in the target approach, signal coordination, the difference between a vehicle’s approaching speed and the average traffic flow speeds, a driver’s gender and age, talking over a cell phone or not, a vehicle’s type and model, and so on. The research findings for this study offer the basis for responsible agencie...

This paper presents a new lane-based signal merge (LBSM) control system for freeway work zone operations. The proposed system applies the signal control concept to regulate the vehicles passing the work zone area at a lane-by-lane basis and offers an effective way to maximize the operational efficiency as well as safety. Introduction of the preliminary configuration and principal components associated with the proposed LBSM control contribute the core of this study. To evaluate the effectiveness of the proposed system, this study has also conducted extensive simulation experiments, based on a freeway simulator calibrated with real-world work zone data. The experimental results show that under heavily congested traffic conditions the LBSM can outperform all existing control strategies with respect to the work zone throughput, the average vehicle delay, the average stop delay, and the average number of stops. This study has also investigated critical traffic flow related factors that may impact on the perfo...

Despite the increasing use of continuous-flow intersections (CFIs) to contend with the congestion caused by heavy through and left-turn traffic flows, a reliable and convenient tool for the traffic community to identify potential deficiencies of a CFI’s design is not yet available. This is due to the unique geometric feature of CFI, which comprises one primary intersection and several crossover intersections. The interdependent relationship between traffic delays and queues at a CFI with five closely spaced intersections cannot be fully captured with the existing analysis models, which were developed primarily for conventional intersections. In response to such a need, this study presents a comprehensive analysis for the overall CFI delay, identifies the potential queue spillback locations, and develops a set of planning-stage models for the CFI design geometry. To facilitate the application of these proposed models, this paper also includes a case study of a CFI at the intersection of MD 4 and MD...

This paper presents a comprehensive model for ranking candidate location plans of multiple urban transit hubs, which can effectively capture various aspects of concerns in the transit hub location planning process, including the overall efficiency of the transit network, the transfer intensity, the proximity to major passenger generators/attractors, the effectiveness of hub service coverage, the compatibility with land use restrictions, and the adaptability to future developable transit concepts. Grounded on an analytical hierarchy process (AHP)-based framework integrated with fuzzy logic, the proposed model offers the strengths to effectively determine the weights for multiple evaluation criteria and to synthesize the final score of each candidate plan for comparison. Results from a case study in Suzhou Industrial Park, China, reveal that the proposed model offers some promising properties for transportation planners to use in planning of transit hub locations. Comparative studies with respect to differe...

Despite the fact that both traffic researchers and highway agencies have devoted considerable efforts over the past few decades to improving intersection safety, the development of effective strategies remains a challenging task. This research presents an integrated dilemma zone protection system (DZPS) for contending with the safety issues caused by the presence of a dilemma zone, a primary factor contributing to the rear-end collisions or side-angle crashes at intersections, especially at those experiencing high-speed traffic flows. The entire paper includes three parts: (1) development of an integrated system for protecting vehicles within the dilemma zone; (2) procedures to calibrate those key system parameters with field data at a candidate intersection; and (3) design of a per-deployment assessment process for evaluating such a design prior to its field deployment. The proposed DZPS, developed with a target intersection’s traffic characteristic data and geometric constraints, consists of thr...