For a year, the speed was lowered by 20 km/h on the busy ring road around Rennes …
Motorists will be able to adjust their speed on Friday night. At midnight, motorists can again travel at 90 km/h on the Rennes ring road. For the past year, the prefecture and the city of Rennes had taken the decision to lower the maximum speed on the bypass to just 70 km/h. The stated objective was to reduce congestion, improve traffic flow and improve air quality.
Tout le monde se réjouît que les portions à 70 de la rocade de Rennes reviennent à 90. Mais celles à 110 qui restent à 90 aucune réaction
— Alexis Karamazov (@AlexLeuf) 28 September 2016
— Dinde (@Ama_Jnn) 27 September 2016
No Less pollution at 70 km/h
But after a year of testing, the results were not very convincing. “70 km/h was considered the optimum speed for causing less congestion. This is true in open country. This is not the case on a ring road. People have underutilized the middle lane and the left lane, “explains Frédéric Lechelon, director of DirOuest.
Lowering the speed from 110 to 90km/h on the East and North of the ring road, however has seen spectacular results from the standpoint of pollution. According to the statements of Airbreizh , nitrogen dioxide emissions dropped by 30 to 40% year on year. On the portions 70, however, the effect is neutral or even negative. “The trucks pollute more above 80 km/h. At 70, the effect is much less, “explains Frédéric Lechelon.