Facts
On January 25, 1977, at 7:16 PM, [B.] drove his car at 92 km/h on a section of highway where the speed limit is 60 km/h, at the exit of the highway in Geneva, at the height of Vengeron. The speed was measured with a radar device placed about 200 m after signal no. 216 limiting the speed to 60 km/h. This signal was double (one on the left and one on the right of the road) and placed at a location where the road first makes a slight turn, then becomes more pronounced, shortly before joining the "Suisse" road.
The signal limiting the speed to 60 km/h is preceded by three or four signal no. 216, also fixed on the right and left of the road, but limiting the speed to 80 km/h; these signals are about 200 m apart, the first being preceded, about 200 m away, by a signal limiting the speed to 100 km/h. The first signal no. 216 fixed on the Suisse road, after the junction of the two lanes, again authorizes a speed of 80 km/h.
About 80 m before the location of the radar device, a sign marking the highway exit and a signal indicating the entrance to a priority road are placed. The streetlights planted at equidistant from the 80 km/h and 60 km/h signals do not directly illuminate them. It is also highly likely that the 60 km/h signal in question was covered with a layer of black dust, but this coating did not excessively obscure the visibility of the signs.
The Police Court of the Canton of Geneva convicted [B.] for an infringement of the RTC, namely for not respecting the 60 km/h speed limit, to a fine of 280 CHF. The Court of Justice of the Canton of Geneva confirmed this judgment while reducing the fine to 120 CHF.
Considerations
The Federal Tribunal partially upheld B.'s appeal. The cantonal court made an error in considering that the 60 km/h speed limit signal was sufficiently visible, whereas the factual findings do not allow determining whether this signal was readable from a distance of at least 100 m, as required by Art. 73 para. 5 OSR for signals intended for high-speed traffic.
The Federal Tribunal therefore…