Speed limit on city ring road returns to 90kph after year-long 70kph experiment

Year-long experiment on city ring road show no improvement in air quality or noise pollution at 70kph, officials say

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OFFICIALS in Rennes have agreed to set the speed limit on the city's ring road at a uniform 90kph, after a year-long €240,000 experiment in which long sections of the route were limited to 70kph.

The experiment saw speeds by 20kph along the entire route. Now, sections that had previously had limits set at 110kph will be brought into line with the majority of the ring road at a single limit of 90kph.

The prefect of Ille-et-Vilaine said there was little change in noise pollution and no improvement in traffic flow or journey times due to the cut in speed limit to 70kph, regional newspaper Ouest France reports.

Pollution tests on stretches of the road where the speed limit had been cut from 110kph to 90kph showed marked improvement in air quality, with nitrogen dioxide levels down as much as 40%. Similar tests in the experimental 70kph zone were less clear, but regional air quality monitor Air Breizh's figures show they tended towards a deterioration in air pollution.

Officials said that there were 33 accidents on the road in 70kph zones in 2015/16, compared to 28 a year previously when the speed limit on these sections was 90kph.

As well as the €240,000 cost of the year-long experiment, changing road signs along the route will cost the prefect €40,000.