Vancouver, Calgary or Toronto - big cities are marked by traffic congestion, roadway accidents and daily conflicts between motorists and pedestrians.

Lina Kattan wants to change that. She is working on ways to improve the flow of vehicles and people, and make urban roads safer.

"I'm looking at the way artificial intelligence can be used to develop modern controls and techniques - 'smart' traffic systems that work in real time to enhance mobility," says Kattan, the Urban Alliance professor in transportation systems optimization at the University of Calgary.

Kattan is an expert in systems that integrate, for example: The way traffic lights, cars and public transit interact; how traffic flows around construction sites or during special events; and traffic-smoothing techniques such as pedestrian scramble operations (PSO).

Lina Kattan

A PSO is a traffic light configuration that stops all vehicle traffic with a red light to allow pedestrians to cross the intersection at the same time in all directions - diagonally as well as laterally.

This "pedestrian-only" signal is used in several cities in the U.S., as well as in Japan, Taiwan, Norway, Israel, Australia and New Zealand. The goal is to promote walking in downtown and encourage motorists to park and walk to destinations.

Kattan is working on two key projects.

The first uses a computer simulation model to evaluate the potential use of adaptive ramp meters, a traffic light that controls vehicles at the entrance ramp to a freeway. She is also working on "responsive traffic signal systems," which can detect, in real time, the actual vehicle demand at an intersection and adjust the signal timing accordingly.

The benefits of these projects for businesses across Canada are obvious: Cost-efficient delivery of grocery supplies, retail goods and other products and services.

"The goal is to help us find even better ways to keep (motorists) on the move, by improving traffic flow and safety," says Troy McLeod, manager of traffic engineering for the City of Calgary.

Enhancing the mobility for both people and the movement of goods has a positive impact for all road users, McLeod adds. "Transportation projects that reduce delay can have time savings for commercial vehicles as well as other traffic," he says. "Even minor enhancements that produce a five- to 10-percent reduction in delays can save thousands of vehicle operation-hours, and reduce emissions and wasted fuel consumption."

The City of Calgary tested Western Canada's first PSO at a busy downtown intersection that at peak times handles 1,800 vehicles and 2,800 pedestrians per hour. Toronto introduced its first experimental PSO last August at Yonge and Dundas, an intersection used by at least 100,000 people a day.

The City of Vancouver is monitoring the PSO experiments in Toronto and Calgary before deciding whether to install similar systems - which Vancouver city engineers estimate would cost about $50,000 to $100,000 per location.

Kattan, along with Richard Tay, Alberta Motor Association chair and professor in road safety at the University of Calgary, and civil engineering graduate student Shanti Acharjee evaluated Calgary's first pedestrian scramble.

The PSO significantly reduced the number of pedestrian-vehicle conflicts - a pedestrian or vehicle taking sudden evasive action to avoid a collision - at an intersection where there had been six collisions from 2004 to 2006. However, the number of pedestrian violations - people entering the intersection against the "don't walk" signal - also increased.

Kattan notes that 30 percent of pedestrians who crossed on the "don't walk" signal were able to cross completely before the traffic light turned red.

And 13 percent of the total pedestrian violations occurred on "safe side" crossings, or concurrent to the vehicle movement.

In a survey done by the U of C researchers last May and June of pedestrians using the PSO intersection, 79 percent were in favour of implementing the system in Calgary.

"People like it," says Kattan, who believes that when it comes to optimizing traffic flow, "we don't have to focus anymore on just vehicles."

Kattan became interested in how people move about when she saw how mobility patterns changed after the end of the 15-year civil war in Lebanon. The war had divided her native city into segregated East and West Beirut.

"I find this work very interesting because it doesn't involve only engineering. It's also social and psychological," Kattan says. "You have to study people's behaviours at the same time ... it's very human."

Her study of adaptive ramp meters - lights designed to smooth traffic flow, reduce bottlenecks and reduce accidents caused by unsafe mergers - has shown they can have a "huge" impact on traffic, she adds.

Toronto already uses ramp meters on the Queen Elizabeth Way during morning and afternoon rush hours.

Kattan's two-year study, a collaboration with the City of Calgary and Alberta Transportation, will assess the potential for an intelligent ramp metering system on Calgary's Deerfoot Trail freeway in a variety of conditions, including heavy traffic volume, construction, adverse weather, and changing patterns of origin-destination trips.

Responsive traffic signal systems may also prove to be a valuable solution to traffic congestion. Many traffic lights are now "actuated" - a roadside detector in the light standard cycles the signal whenever it detects a vehicle.

The signal stays on for as long as vehicles are detected up to a certain count, based on historical data on vehicle volumes at certain times for any given intersection.

Such systems are unable to respond to fluctuating traffic flow, such as many more vehicles than usual approaching the intersection from one direction due to construction, a special event, a collision or adverse weather conditions.

In the laboratory, Kattan and her team are using an advanced traffic micro-simulator software package, coupled with real-time traffic data from the City of Calgary, to simulate traffic flow on a busy city street.

The team will develop a responsive traffic signal system and will evaluate the likely improvements from using the system on a congested road network.

"When you have less congestion, it means you have less travel time through traffic," she notes. "This means you are using less fuel and producing lower emissions."

(Mark Lowey is communications director at the Institute for Sustainable Energy, Environment and Economy - www.iseee.ca.)