Urban mobility performance indicators, third quarter 2020

Released: 2021-01-18

Transport Canada's travel time index (TTI)—which reflects 21 key trade corridors in Vancouver, Calgary, Toronto, Montréal and Halifax—is now available on the Transportation Data and Information Hub. The TTI will be updated on a quarterly basis.

Urban mobility refers to a person's ability to move around the city in which they live and work. Congestion on city roads reduces mobility, which is not only an individual inconvenience but also has an economic impact. While the amount of additional time spent in traffic, excess fuel consumed and other costs of congestion may be large in Canada, the full impact is not known. Using key indicators to evaluate congestion, its cost and its impact on the economy is the first step to understanding the magnitude of the problem.

To that end, Transport Canada is now using a key mobility indicator—the TTI—to track the performance of a series of key urban trade corridors across Canada. Put simply, the TTI is the ratio of actual travel time to the ideal or "free-flow" travel time or, equivalently, the ratio of free-flow speed to actual speed. The TTI is recommended by the Transportation Association of Canada and used by the United States Federal Highway Administration.

The TTI is available in three formats—maps, tables and charts—each with its own advantages and limitations. The data used to calculate the indices are supplied by HERE Technologies, a company that collects detailed speed data from Canada's entire road network. The data remain anonymous, as vehicle speeds are combined into link and time bins and available within days of collection.

Key urban trade corridors

Transport Canada and provincial ministries of transport have defined a series of key urban trade corridors in Canada's largest urban areas. The focus is on travel time during the weekday morning peak (6:00 to 9:59 a.m.) and afternoon peak (3:00 to 6:59 p.m.) Note that holidays were not removed from the analysis. The TTI is displayed on maps, in tables and graphically.

Link versus corridor travel times

A corridor consists of a series of links that vary in length, from approximately 20 metres to 2 kilometres. A link refers to a specific section of road, such as the length of a city block between two intersections or the stretch of highway between two on- and off-ramps. The TTI can be presented at the link level with a separate value assigned to each link for a given month. This format makes it easy to visualize bottlenecks on a corridor and how the index varies for the corridor during a given month. However, link values are more difficult to compare from one month to another.

The TTI can also be presented at the corridor level in the form of tables and graphs, but only for a single value per peak period in each direction. To compute a corridor index, the TTI link values along a corridor are aggregated in a way that accounts for traffic volume, for example, a longer and more heavily travelled link contributes more weight to the index. Therefore, a single TTI value is calculated for weekday morning and weekday afternoon peak periods per direction on each corridor. While this corridor level allows for easy month-to-month comparisons, the single value for each peak period will mask traffic details along the corridor, such as the locations of bottlenecks. In some cases, the aggregated value is close to 1.00, as the effect of high values is simply offset by low values.

Products

The product Urban Mobility: Performance Indicators, Transport Canada is now available.

Contact information

For more information, contact us (toll-free 1-800-263-1136; 514-283-8300; STATCAN.infostats-infostats.STATCAN@canada.ca) or Media Relations (613-951-4636; STATCAN.mediahotline-ligneinfomedias.STATCAN@canada.ca).

To enquire about the concepts, methods or data quality of this release, contact Transport Canada's Media Relations (613-993-0055; media@tc.gc.ca).