Lowering the speed limit at night on Switzerland’s busiest motorway would be disproportionate. This among others is the conclusion reached by the Federal Administrative Court in two rulings.
With an average traffic volume of around 150,000 motor vehicles per day and peaks of over 10,000 per hour, the section of motorway between Zürich-Nord and Brüttisellen is the busiest carriageway in Switzerland. On this section, the maximum speed limit is 100 km/h. During an inspection of this section, the Federal Roads Office (FEDRO) found that existing noise protection measures were partly inadequate and that the drainage concept was in need of upgrading. It also identified traffic-related weak points responsible for repeated congestion and accidents.
Since 2018, traffic optimization, repair and maintenance work has been carried out. A second phase would involve the construction of two new drainage facilities and the implementation of noise abatement measures. A permanent repurposing of the hard shoulder on certain sections of the stretch is envisaged to reduce traffic congestion in both directions and improve the flow of traffic. For this purpose, FEDRO submitted the project "N01/42, 46 AP Verzw. Zürich Nord - Verzw. Zürich Ost - Verzw. Brüttisellen" to the Federal Department of the Environment, Transport, Energy and Communications (DETEC). During the publication term of the draft plans, the City of Zurich inter alia filed an appeal with the FAC.
Disproportionate reduction in speed limit
The FAC has now reached the conclusion that one of the measures contemplated for the motorway sections, namely the indefinite repurposing of the hard shoulder, is justified. On the other hand, the Court rejects the demand for a permanent reduction in the speed limit from 100 km/h to 80 km/h during the night (from 10 pm to 6 am) for noise abatement reasons. After weighing up the interests (noise-related consequences, traffic interests) and with due consideration of the criteria laid down by the Federal Supreme Court as well as of two expert opinions, the Court holds that reducing the speed limit was not proportionate. Among other things, an existing system already adapts the maximum speed to the ongoing traffic situation, both during the daytime and in the noisiest nighttime hours between 5 and 6 am.
Moreover, with regard to the noise abatement measures, the Court instructed FEDRO to obligate building owners to install soundproof windows in the buildings which are unlikely to be able to comply with noise emission limits. FEDRO must bear the corresponding costs of soundproofing the windows.
These judgments may be appealed to the Federal Supreme Court.