A report from Cerema, a public establishment placed under the supervision of the Minister for the Ecological and Inclusive Transition, finds that cars pollute more at 30 than 50 km / h. This does not prevent the French agglomerations, aware of this phenomenon, from generalizing the “30 zones”. This measure, they explain, is part of a broader policy of improving safety, combating noise pollution and reducing the place of cars in the city.
” Shows [de gaz à effet de serre] are important at very low speed. “ This observation from the Center for Studies and Expertise on Risks, the Environment, Mobility and Planning (Cerema), a public establishment placed under the joint supervision of the Minister for the Ecological and Inclusive Transition, and the Minister of Cohesion of the territories, highlights a problem that the generalization of zones at 30 km / h, in the city center, is likely to encounter. If a car pollutes more at 30 than 50 km / h, do these measures generalized by Lille, Grenoble, Strasbourg, Paris, Montpellier and other large cities in France make sense?
Comment ?
The Cerema study, published on August 17, 2021, questions the effects of speed limits on automobile pollution. The finding is clear: the least polluting speed is 70 km / h. But the curve seems to stabilize, in minimum values, on the line of 150 grams per kilometer, between 50 and 90 km / h.
In town, in “zones 30”, cars would therefore pollute 15% more. “Road traffic congestion situations are very penalistic from the point of view of air quality”, concludes the study of Cerema.
However, transport is presented as “An essential health challenge”, through Paris Climate Agency. According to this association, which supports the Paris Climate Energy Plan, “Each year in Paris there are around 2,500 deaths linked to atmospheric pollution, largely generated by road traffic”.
Contacted by phone, Fatoumata Koné, president of the Paris Climate Agency, tells us that the 30 km / h limitation measure must “Streamline traffic and reduce atmospheric pollution”, explaining that with “Less jolts caused in particular by acceleration and braking, vehicles pollute less”. She adds that, “Anyway, the average speed is already 11.6 km / h in Paris”.
The elected Europe Ecology The Greens of the 19e arrondissement of Paris also recalls that the main objectives of this measure, which was “Already in place on 60% of Parisian roads”, are to improve the safety of Parisians and reduce noise pollution.
➡ Road emissions of atmospheric pollutants: Curves and influencing factors
➡A note from #Cerema on the causes of emissions by type of vehicle, with a forward-looking vision for 2050#pollution#mobilityhttps://t.co/oTNDOps5Qf pic.twitter.com/qhtzzF1MF1— Cerema (@CeremaCom) August 18, 2021
A matter of security
“At 50 km / h, we travel 27.5 meters to stop. At 30 km / h, we travel 13.5 meters to stop, ie a distance that is half shorter ”, poses the Road Safety Association, in a communicated, adding that the difference is not less “Whether to stop to leave a pedestrian”.
Going from 50 to 30 km / h would reduce “82% risk of injuring a pedestrian in the event of a collision”, according to the Road Safety Association. In his “Speed and mortality” sheet, the Service for studies on transport, roads and their improvements (Sétra), which depends on the Ministry of Transport, notes that“At 30 km / h, the most frequent injuries are light contusions with a probability of 15% of being killed ”, when, at 50 km / h “Disability and fatalities are common, with a 60% probability of being killed”.
An evaluation of the device in Grenoble, carried out by Cerema, notes, in this regard, that between 2016 and 2019, the decrease in average speed “Was accompanied by a declining accident rate, both in number and in severity”, notes Flavien Lopez, author of the report, for the Sunday Newspaper.
Reduce the space of the car
This is why Fatoumata Koné argues that the passage to 30 km / h must “Improve the comfort and safety of Parisians”. “We want to allow those who dared not ride a bicycle because they did not feel safe to be able to ride”, she adds. Same story in Strasbourg, where these measures are incentives.
“The change to 30 km / h is part of a series of measures aimed at reducing the place of private cars and promoting other modes of travel”, explains Sophie Dupressoir, municipal councilor responsible for the Cycling and Merchant City, before adding that “Zone 30 makes it possible to reduce the size of the roadway, to leave more spaces for cyclists and pedestrians and, thereby, increase the competitive advantage of these modes of travel” greener.
Reduce noise pollution
Then a car makes less noise at 30 than 50 km / h. the Ademe guide for the development of environmental noise prevention plans notes a reduction in noise of the order of 3 decibels.
However, car traffic is the main source of noise pollution in large cities. And noise has harmful consequences on health, as demonstrated by a medical journal study European Heart Journal, in 2015: hypertension, cerebrovascular accidents, etc.
The reduction in noise, during the confinement of March 2020, was also widely noticed and well received. Sign that the quality of life was at least better at this level. According to Cantonal energy and environment services, in Switzerland, the noise would even be “One of the factors that most reduces the quality of life”.
In line with the City of Paris, which wishes “Allow Parisians to sleep better” by reducing road traffic noise as Fatoumata Koné explained to us, in Switzerland the public service notes that each year, “900 years of life are lost because of the noise suffered during the night” and he recalls that from 50 km / h “Tires make more noise than engines”.
Towards clean vehicles
Quieter, less polluting, electric, hybrid and hydrogen vehicles seem to be the solution to preserve air quality while ensuring the safety of city dwellers. “Several studies have indeed found that cars pollute more up to 30 km / h, because current engines are adapted to run between 50 and 70 km per hour”, specifies Fatoumata Koné.
In addition to speed limits and pedestrianization of lanes, Cerema notes that the “Composition of the vehicle fleet” a, in fine, also its importance in “Reduction in emissions of atmospheric pollutants and greenhouse gases”. The report states that it remains “However important to analyze the complete life cycle in terms of greenhouse gas emissions, in particular the life cycle of batteries for electricity”.
For all these reasons, Paris, Strasbourg and other large agglomerations are planning the final exit of thermal vehicles. In the capital, diesel vehicles (2,024) and petrol vehicles (2,030) will be the first to be affected.
–
