Metadata: Traffic jam severity

Flemish Traffic Centre (via dataroom Department of Mobility and Public Works)

Traffic jam severity: indicates the average scale (on an average working day) of the traffic jams on a certain collection (group) of road segments.

• The traffic jam severity is equal to the product of the length and duration of the traffic jam, cumulated over the different phases of the traffic jam (cf. the length of the traffic jam evolves over time).
• Traffic jam severity is expressed in kilometre-hours (km x hours).
• Adding up the traffic jam severity across all the traffic jams on a specific group of road segments, such as an area, establishes the total traffic jam severity for this area.
• The traffic jam severity indicator only takes into account the duration and length of the traffic jams, not the speed of the vehicles in the traffic jams, nor the number of vehicles involved.

The figures reported here concern a 12 monthly moving average. This is the daily average for the month in question and the 11 previous months. Only working days are counted (Monday to Friday, excluding public holidays).

Kilometre-hours: unit of measure used for the traffic jam severity indicator. 100 kilometre-hours is the equivalent of a 100-kilometre traffic jam for 1 hour or a 200-kilometre traffic jam for half an hour.

The data is based on:

• Traffic counting loops, traffic counting cameras, automatic incident detection cameras, floating car data and additional reports (from police, road users, etc.).

• Traffic jam notifications communicated as traffic information by the control room of the Flemish Traffic Centre: in turn, these notifications are generated on the basis of a mix of automatic and manual sources (detection loops, camera images, road police, road users, etc.).

The figures are available for the whole Flemish Region, for the impact areas around the major cities or by road. In all cases, they pertain only to traffic jams on motorways.

The figures reported here relate to the region and the approach roads to Antwerp, Brussels and Ghent and to the other motorways in Flanders.

Due to a new calculation method, these figures differ from those set out in the 'Traffic indicators for the Main Road Network in Flanders’ reports (editions 2010 through 2014). From the 2015 edition, the new method has also been used in these reports.

The figures reported here (based on the new calculation method) are available from April 2012 onwards.

The figures for the 2007 to 2014 period (using the old calculation method) (in Dutch) are still available on Datavindplaats.

Flemish Traffic Centre: Traffic indicators(opens in new window)

Traffic jam severity