Application of Diamond Interchange Control Strategies at Closely Spaced Intersections

• Published in: Transportation research record 2007-01, Vol.2035 (1), p.32-39
• Main Authors: Tian, Zong, Urbanik, Thomas, Gibby, Reed
• Format: Article
• Language: English
• ISSN: 0361-1981; 2169-4052
• DOI: 10.3141/2035-04

Signalized diamond interchanges are one of the most common interchange types in U.S. urban areas. Special signal control strategies have been developed for diamond interchanges to address their unique traffic flow and geometric characteristics such as tight spacing and one-way cross streets. The application of diamond interchange signal control strategies on a site consisting of six closely spaced intersections in Reno, Nevada, is documented. These intersections represent or closely resemble a standard diamond interchange. Advance control strategies are derived on the basis of diamond interchange signal control schemes. Simulation results of the timing strategies indicate significant reductions in the number of stops; however, no significant change is found for overall travel time and delay for the study site. Because the proposed control strategies emphasize maximum progression between closely spaced paired signals, the external approaches normally experience increased delay and stops. The proposed control is considered more efficient than the existing control because of significant reduction in stops and much improved driving experience and drivers' expectations. Public reaction to the new timings has been positive. Similar applications could be easily adopted at other locations with similar site characteristics. The proposed control enhances the knowledge of traffic signal control and coordination for closely spaced intersections.