My jawed dropped when I saw the headlines yesterday that Vancouver has the second worst congestion in North America. TomTom, the GPS maker, released the North American Congestion Index which found that Metro Vancouver had an index of 30%. It didn’t seem to make sense to me so I looked into the number. The congestion number is based on the percentage difference between free-flow travel time and congested travel time. So if three cities have free-flow travel times of 35, 30, and 25 minutes and during peak periods travel time is 5 minutes longer in each city, the city with the shortest free-flow travel time will appear to have worse congestion using the TomTom Index. Another fatal flaw of this report is that it does not take transit, cycling, or walking into account which in Metro Vancouver plays a large role during peak commuting times.
Information from Statistics Canada points to the link between population and commute time. The not-so-surprising result is that the larger the population, the higher the commuting time.
|Average Commute Time vs Population (Source: Statistics Canada)|
When you plot the average commute time to the TomTom Index, there is a weaker correlation that becomes glaringly obvious with Metro Vancouver.
|Average Commute Time vs. TomTom Congestion Index (Source: Statistics Canada)|
The big difference between Metro Vancouver and every other major region in Canada is that we have fewer freeways which means that the average speed in Vancouver is slower. Many people confuse speed and mobility with travel time and accessibility. While Vancouver roads are the slowest of any major region in Canada, yet we have shorter commute times than Toronto or Montreal. Metro Vancouver is a more accessible region.
What I did find really interesting about the TomTom report is the other data it contained. There seems to be a link between the amount of freeways built and congested speed. It seems that the more freeways you build, the larger the difference between free-flow and congested speed. You could draw the conclusion that freeways actually make more congestion!
|Congested Speed vs Free-Flow Speed (Source: TomTom)|
The TomTom congestion index is useful for the region that builds more freeways as its population grows and doesn't rely on public transit, walking, or cycling, but in a region like Metro Vancouver (which bucked the freeway trend until recently) the index proves to be of little use.
PS: The average commute time in the freewayless City of Vancouver is 27 minutes, while outside of the City of Vancouver the average commute time is 31 minutes.
|The raw data. Click image to view.|