Reversible Lane Control Systems

Calgary, AB

To avoid the need for costly or controversial road widening projects, the team of ISL and PBA Engineering were engaged by the City of Calgary in 2008 to plan, design, build and commission an automated control system for innovative lane reversals for Memorial Drive and the 5 Avenue Connector on Bow Trail. This was the first such system implemented in Calgary since the 1970s.

Automated Mechanisms

This project introduced new traffic control devices, including signals, traffic-control gates, dual-state sign boards, variable message prism signs and traffic-monitoring cameras. The reversible lane control systems are also the first to be integrated with the City’s Traffic Management Centre (TMC), providing a flexible system that safely and efficiently transitions the reversals from the central control centre using a fibre-optic network, central server and software integration.

Traffic Management Centre

The automated systems provide video monitoring and remote-contral capability to the TMC operators. Nine pan-tilt-zoom cameras (7 new, 2 existing) were installed for the projects, allowing operators to visually verify that lanes are clear prior to opening a lane to opposing traffic. All field devices are monitored and operated through 5 distributed controllers and two remote I/O cabinets. Communications are relayed using a fibre-optic-based Ethernet and a 802.11G wireless network.

Traffic Improvements

The project has significantly increased traffic capacity around Calgary’s downtown core by more effectively using existing road infrastructure. It has also reduced peak hour congestion, saving affected commuters up to 11 minutes of delay for each trip, or nearly 60,000 hours annually. A marked reduction in community shortcutting on parallel roads has improved quality of life for residents of established communities around the downtown core.

Project Completion

Completed in March 2010, the reversible lane control systems are now a permanent feature of Calgary’s weekday commute. This project won a 2011 Consulting Engineers of Alberta Award of Merit for Studies, Software and Special Services.

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