Environmental Capacity Urban Roads in Brussels

Development of a practical guide and an evaluation instrument for the environmental capacity of the urban roads in the metropolitan district of Brussels

The current hierarchy of roads within the metropolitan district of Brussels, as incorporated in the Iris Transport Plan, was mainly developed based on current and  expected traffic load, and according to their role in the overall mobility structure. But traffic intensity and the surrounding area have hardly been synchronized. For example, the GewOP classifies both the Louizalaan and the part of the E411 coming from Namen as metropolitan roads, though they actually have little in common on their typology and surroundings.

The aim is to achieve a balance between traffic function and urban function while respecting the acknowledged environmental criteria. In this regard, the concept of the road's 'environmental capacity' appears appropriate. Within this approach, the physical or technical capacity of the road (i.e. the traffic volume that can be handled by a certain profile) is complemented by an 'admissible traffic load' (the technical capacity is compared to the maximum hindrance the direct surroundings of a road can support while maintaining urban functions and quality of life).

In this project TML, in association with Ecorem, developed a method to analyse and evaluate the environmental capacity of roads. The task related to the combination of criteria and reference standards by profile type concerning, for example, noise emissions, air quality, security, and fragmentation. During the project, an analysis tool was developed, which - on the basis of these characteristics - will calculate one environmental score for the road under consideration.


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funded by

Leefmilieu Brussel (previously BIM)


Kristof Carlier




Kristof Carlier

+32 16 31.77.36
reference: 10.68