Bos & Lommer is a district in the west of Amsterdam. The spatial plan for Bos & Lommer was based on the General Extension Plan (Algemeen Uitbreidingsplan /AUP), which was designed by Van Eesteren in 1935. In the 1960s this plan was seriously impaired by the E10 motorway, which cut the area in two, leaving it without a heart – until 2004, when it was reunited by a complex of buildings constructed on viaducts. The new centre, consisting of the district office, 96 apartments, a few dozen businesses and shops, a two-storey parking lot with capacity for more than 500 cars, and a market place, was completed in the same year. Less than two years later, in July 2006, this whole multifunctional complex had to be urgently cleared, because its safety could not be guaranteed. Serious cracks had appeared in the parking deck – so serious that it caved in under the weight of a beer lorry. Further investigations exposed even more design and construction errors.

The residents had to wait until Christmas 2006 before they could return to their homes. In the meantime, some additional and costly operations had to be carried out. The shops and businesses re-opened in January 2007.

On 20 July 2006, Amsterdam's mayor, Job Cohen, set up an Investigatory Commission consisting of former housing minister Margreeth de Boer (Chair), Lex Michiels (Professor of Public Law, Tilburg University) and the author. This Commission published its final report on 15 January 2007.

The remit of the Bos & Lommer Commission was to establish the course of the decision-making on the complex since 1990, to ascertain how the responsibilities were allocated and to identify the causes of the errors. The emphasis had to rest on the ‘safety’ aspects and on ways of preventing similar situations in the future.

The investigations revealed that the planning and realisation of the Bos & Lommer complex were anything but exceptional. What happened there could have happened anywhere in the Netherlands and elsewhere. So, some important lessons can be learned from this case. This paper traces the causes of this new planning disaster and try to specify guidelines for designing and building complex projects, based on an operational risk analysis, introducing more quality management in the contributions of each participant and strengthening the system responsibilities for the whole project. There is certainly scope for a better integration of design and building construction, to improve the construction safety of complex building projects.