Although measuring and archiving freeway traffic performance using commonly available loop detector data has become a norm for many transportation agencies, similar approaches for urban arterials do not exist. In practice, operational data from traffic signal systems are neither stored nor analyzed, which prevents proactive management of arterial streets. The development of the SMART-Signal (Systematic Monitoring of Arterial Road Traffic Signals) system fills in this gap. The SMART-Signal system simultaneously collects event-based high-resolution traffic data from multiple intersections and generates real-time arterial performance measures including intersection queue length and arterial travel time. The development of the system has laid the groundwork for better traffic models and control strategies and opens up entirely new opportunities for managing traffic on congested roads.
    Traffic Behavioral Study on the Effects of the I-35W Bridge Collapse
The I-35W Mississippi River bridge (officially known as Bridge 9340) was an eight-lane, steel truss arch bridge that carried Interstate 35W across the Saint Anthony Falls of the Mississippi River in Minneapolis, Minnesota, United States. During the evening rush hour on August 1, 2007, it suddenly collapsed, killing 13 people and injuring 145. Immediately after the collapse, help came from mutual aid in the seven-county Minneapolis-Saint Paul metropolitan area and emergency response personnel, charities, and volunteers. Within a few days of the collapse, the Minnesota Department of Transportation (Mn/DOT) planned a replacement bridge, the 10-lane I-35W Saint Anthony Falls Bridge. Construction was completed rapidly, and it opened on September 18, 2008. Although the capacity of the new bridge is larger, the daily traffic volume drops, comparing to the old bridge. What's going on?