There are three different stickers: a green one certifying that the vehicle is environmentally acceptable; a yellow one for less acceptable vehicles and a red one for those that are still less acceptable. Yellow and red stickers will eventually be phased out, after which all vehicles permitted in the environmental zones will need a green sticker. The stickers are hard to counterfeit and would be destroyed in any effort to remove them from the windshield.

Gasoline- and diesel-powered vehicles without catalytic converters will be unable to get any kind of a sticker and will not be permitted in the environmental zones. All gasoline-powered cars with catalytic converters will get a green sticker. So will the best of the diesel-powered vehicles. Diesels, however, present a greater pollution hazard, and many will only get yellow or red stickers.

Signs that tell you you’re entering an environmental zone will picture the stickers that are allowed beyond the sign. If you have a red or yellow sticker and that sticker is not pictured on the sign you must turn around. Cars found in an environmental zone without an appropriate sticker are subject to a €40 fine. The fact that your car is eligible for a sticker is no excuse.

The first environmental zones were established on January 1, 2008 in Berlin, Cologne and Hannover. Others have since been established in Düsseldorf, Stuttgart and a group of smaller communities in the Stuttgart area. Many other cities are scheduled to come on board in 2008 and early 2009.

Foreign plated cars, and those of the US forces in Europe, are also required to have the stickers. They can be had, for €5, at vehicle registration offices and vehicle inspection stations (TÜVs) on presentation of your car’s registration, which usually has data on its pollution level. Authorized garages also supply them, but possibly will charge more than €5. It’s also possible to order one online.

Among other places, you can order the sticker online from the cities that have environmental zones. Your car doesn’t have to be registered in the city to which you apply, and a sticker, once obtained, is good for all of the environmental zones nationwide. Even a foreigner can get a sticker online, and it is advisable to seek it at least three weeks before a planned visit to Germany.

You don’t necessarily have to have a sticker to drive your car in Germany, as long as you stick to the highways and the more rural areas. Just don’t try to enter an environmental zone. The zones were established after it was determined that many German cities don’t meet the air purity standards set by the European Union in 1999.

Here is a partial list of some of the cites that have already initiated the zones:

Berlin, Hannover, Köln, Dortmund (Brackeler Straße), Ilsfeld, Leonberg, Ludwigsburg, Mannheim, Reutlingen, Schwäbisch-Gmünd, Stuttgart, Tübingen, Pleidelsheim, Bochum, Bottrop, Dortmund, Duisburg, Essen, Frankfurt am Main, Gelsenkirchen, Mülheim an der Ruhr, München, Oberhausen, Recklinghausen, Augsburg, Bremen, Herrenberg, Karlsruhe, Nürnberg, Pforzheim, Ulm, Dresden, Freiburg (Breisgau), Heidelberg, Mühlacker, Dresden, Wuppertal

Here is a partial list of some of the cites that plan zones in 2010:

Bonn, Freiburg (Breisgau), Heidelberg, Münster, Pfinztal, Osnabrück

The following cities plan zones but have not yet set a fixed date:

Braunschweig, Darmstadt, Dresden, Gera, Jena, Kassel, Magdeburg, Regensburg, Nürnberg, Ruhrgebiet-Großumweltzone

Also, expect the following cities to have zones sometime in the future:

Arnsbach, Arzberg, Aschersleben, Bayreuth, Bernau, Brandenburg an der Havel, Burgdorf, Burghausen, Castrop-Rauxel, Chemnitz, Cottbus, Eberswalde, Erfurt, Erwitte, Frankfurt an der Oder, Görlitz, Halle (Saale), Hambach, Hamburg, Ingolstadt, Itzehoe, Kassel, Krefeld, Lahn-Dill, Landshut, Lindau, Ludwigshafen, Lutherstadt Wittenberg, Mainz, Mühlheim an der Ruhr, Nauen, Neuruppin, Neuwied, Neuss, Passau, Potsdam, Rhein-Main, Schwandorf, Speyer, Trier, Warstein, Weiden, Weimar, Worms, Wuppertal, Würzburg.

You’ll find a continually updated list of cities with current and planned environmental zones at www.umwelt-plakette.de/int_england.php

Those with foreign plated cars who may be driving to Germany may also order the sticker from this site. The information is in English.

A good site in English with an extensive FAQ section on the Environmental Zones can be found at www.tuev-nord.de.