Ever since the TomTom Traffic Index started being released annually, it has generated headlines that Metro Vancouver has some of the worst congestion in North America.
Unfortunately, the TomTom Traffic Index has a flawed methodology which favours auto-oriented regions with large freeways over walkable, transit-friendly, and accessible regions. For more information about the why the methodology for the TomTom Traffic Index is problematic, please read a previous post I wrote on the topic.
Earlier this year, the CAA’s Congestion Index was released. This report was focused on freeway bottlenecks, and as I posted previously “there is an underlying assumption that if a bottleneck exists for single-occupancy vehicles, the solution is to expand capacity. Of course, we know that building more capacity simply leads to even worse congestion and/or a shift of the bottleneck to another area.”
Earlier this week, the INRIX Global Traffic Scorecard was released. It looks at congestion in regions through the world.
In the INRIX Global Traffic Scorecard, Metro Vancouver is the 157th most congested region, and the fifth most congested region in Canada. Montreal, Toronto, St John’s, and Ottawa all had worse ICI scores (an INRIX metric.) So why is the INRIX ranking so different than the TomTom ranking? It’s all about the methodology.
|Top 10 list of regions with highest ICI score in Canada. Select table to enlarge.|
The INRIX Global Traffic Scorecard has a more robust methodology than the TomTom index.
The INRIX methodology evaluates congestion based on time-of-day, and differentiates highways from local roads. As I posted about previously, this is important.
INRIX defines congestion as 65% of free-flow speed. Free-flow speed is basically driving the posted speed limit on roads with no traffic, at-grade intersections, crosswalks, or construction. Free-flow speed is not the most efficient speed for traffic flow. Traffic flows best at speeds between free-flow and congestion. Wikipedia has a good article on the fundamental diagram of traffic flow.
The INRIX methodology also includes median travel time in its Congestion Index (ICI.) As I posted about previously, Metro Vancouver has a lower median travel time than Montreal or Toronto.
|The time it takes to get to work and back. Source: Statistics Canada 89-622-XIE and 11-008-X.|
What this all amounts to is a better representation of actual congestion in a region.
Will building more freeways reduce congestion? If Toronto and Montreal are any indication, no. As stated by INRIX, “the fundamental cause [of congestion] is an imbalance between the demand for roads and the supply of road space. Managing demand for road space is critical. That includes smoothing demand through flexible working, avoiding peak hour trips through remote working and encouraging the efficient use of our roads through wider adoption of road user pricing.”