In 2008 the Dutch national government, the Zuid-Holland provincial executive and the Haaglanden district council started work on an exploratory study entitled ‘MIRT Verkenning Haaglanden’, designed to chart the access problems the region is likely to face in the longer term, how access to the region round The Hague can be improved and which issues should be given greatest priority in the years ahead. In particular, the study considers improvements to the A4 motorway around The Hague and access roads to the inner city and along Rijswijk and Leidschendam-Voorburg. The environmental aspects of the two alternatives ultimately chosen have been assessed in a Strategic Impact Assessment entitled ‘A4 Passage en Poorten & Inprikkers’, drawn up by CE Delft and Oranjewoud.
All the alternatives have a local environmental impact, mainly in the form of an increase in noise nuisance, impacts on biodiversity (due among other things to an increase in nitrogen deposition), (potential) damage to landscape values and (potential) impacts on archeological heritage. The overall review of the various environmental themes and aspects indicates that both alternatives score slightly worse than the baseline alternative.
With respect to noise, in particular, there will be a substantial additional impact. However, mitigating steps can be taken to address these impacts and these should be elaborated in the next planning phase.