RACC believes that limiting speed does not reduce pollution
As we announced here, the new speed limits around the city of Barcelona (Catalonia, Spain) to reduce pollution are coming into effect very soon. The new limits will be instated before the end of fall and they require that in a radius of approximately 10 miles around the city, the maximum speed limit will be 80 km/h (50 mph). We already knew the reaction from the Car Dealers Association (Faconauto) was that these speed limits were not logical. Today we get the reaction from the RACC (Reial Automòbil Club de Catalunya).
RACC has published big advertisements on the local and regional press calling the measure "absurd" and they offer an alternative (variable speed limits according to traffic and weather conditions), justifying this suggestion with their own data. RACC considers the reports that the Catalan Ministry of Environment used to justify the speed limit were wrong.
According to RACC, its German equivalent ADAC made a report a few years ago stating that reducing speed actually reduced pollution levels by 24 percent but increased NOx pollutants by 26 percent, because cars would have to use lower gears with higher rpm. Moreover, this report was made with a balance of 50 percent gasoline and 50 percent diesel cars and the Ministry didn't take in consideration is that the actual percentage of diesel vehicles on the road is far more than 50 percent, increasing the effects of NOx pollution.
RACC says the Ministry's calculations didn't take into consideration that 40 percent of cars usually don't reach high speeds, because they're in traffic jams and constant starts/stops in congested traffic actually raises emissions by 60 percent.
[Source: RACC (link points to a .doc file in Spanish]
Reader Comments (Page 1 of 1)
rgseidl 4:33PM (10/17/2007)
There's an EU directive that compels cities to take action to clean up PM10 immissions if they exceed a threshold level on more than 35 days in a given calendar year. The highest administative court in Germany recently decided that the absence of a regional or national plan of action is no excuse for failing to act.
Short of shutting down main traffic arteries - which carries a high economic and political cost - there is unfortunately little cities can actually do in the short term. A general speed limit may not be particularly effective but it covers city hall's legal rear end.
Medium-term, the best bet is to eliminate high polluters (i.e. pre-Euro 3 diesels) from the vehicle fleet. Germany has developed a system of colored stickers that identify the emissions level at which the vehicle model was certified. Installing a qualifying retrofit particulate trap lets owners move their vehicles up one category.
The idea is to let cities ban only the worst polluting vehicles from city centers on problem days, mostly in winter. This would, however, sharply reduce their residual value. Since most of the affected cars are owned by low earners and seniors, mayors are loath to introduce the system until and unless they absolutely have to. No other European country has yet adopted the German approach, not least because of the additional red tape involved.
Note, however, that diesel engines are far from the only source of PM10. Tires and brake linings from all types of vehicles, industry, home heating appliances and agriculture contribute most of the emissions except in the immediate vicinity of major arteries. Unfortunately, city halls can do even less about them than they can about legacy diesels or congestion in general.
London and Oslo levy access tolls, which have eased the problem. However, London mayor "Red" Ken Livingstone now wants to modify this by raising the fee to GBP 25 per *day* for the least fuel-efficient cars and completely exempt to most fuel-efficient ones - a category that includes many small diesels. Three guesses what this will do to congestion and aggregate PM10 immissions.
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