The ATTAP team is developing a Systemic safety project selection tool for MDOT SHA. The systemic approach to safety is a data-driven process that involves analytical techniques to identify sites for potential safety improvement and suggests projects for safety investment not typically identified through the traditional site analysis approach. It serves as an addition to the site-specific analysis.
İzmir Escort Bayan – Aliağa Escort Bayan – Balçova Escort Bayan – Bayındır Escort Bayan – Bayraklı Escort Bayan – Bergama Escort Bayan – Beydağ Escort Bayan – Bornova Escort Bayan – Buca Escort Bayan – Çeşme Escort Bayan – Çiğli Escort Bayan – Dikili Escort Bayan – Foça Escort Bayan – Gaziemir Escort Bayan – Güzelbahçe Escort Bayan – Karabağlar Escort Bayan – Karaburun Escort Bayan – Karşıyaka Escort Bayan – Kemalpaşa Escort Bayan – Kınık Escort Bayan – Kiraz Escort Bayan – Konak Escort Bayan – Menderes Escort Bayan – Menemen Escort Bayan – Narlıdere Escort Bayan – Ödemiş Escort Bayan – Seferihisar Escort Bayan – Selçuk Escort Bayan – Tire Escort Bayan – Torbalı Escort Bayan – Urla Escort Bayan
Authors: Yao Cheng, Gang-Len Chang, and Saed Rahwanji
Journal: Journal of Transportation Engineering, Part A: Systems
Abstract:
Diverging diamond interchanges (DDIs) are widely recognized to be capable of reducing conflict points, number of stops, and consequently average traffic delay. However, the design of their crossover spacing and signal offsets, which is critical to the capacity and efficient operations of DDIs, have not been addressed in most design guidelines. These two critical design components are actually interdependent in nature, because the estimated travel time between a DDI’s two subintersections for all movement paths is essential for the design of signal offsets. Also, the crossover spacing should be designed to accommodate queues comprised mostly of those vehicles not moving within the signal progression band, which is often designed with a given crossover spacing. Considering such an interdependent relation between signal offsets and the crossover spacing, this study presents a model that can concurrently optimize these two vital DDI design elements at the planning level. A case study at a DDI site with the proposed model has also been conducted to justify the necessity to perform the concurrent optimization under different operational conditions. The results of extensive numerical experiments confirm that the design with the optimized crossover spacing and offset can yield the shortest total delay and the least number of stops for vehicles over the entire network, especially under near-saturated conditions. The optimized crossover spacing can also prevent the formation of the queue spillover over the crossovers in a DDI.
Maryland Intersection and Interchange Design & Capacity Analysis Program (MIDCAP), developed by University of Maryland, College Park and MDOT SHA, is a tool to conduct a capacity/ queuing analysis for signalized intersections and interchanges, signal warrant and shoulder bypass analysis at the preliminary, planning, or design stage along with left turn phase selection and lighting recommendation. For questions or technical support, please contact us at midcap@umd.edu.
Download (MIDCAP_INTRO_website_05202020.pdf)
