Compounding the massive carbon footprint left by all these old-skool engines is the rotten traffic. City streets can be as wide as twelve lanes — though lanes are mere suggestions for the citizens of Buenos Aires. Cars cram the smaller side streets, with drivers idling at red lights and honking in frustration. Even ambulances have a hard time getting through.

I saw not one hybrid or electric car on the streets in the week I spent in the city, but I did see a sign of green hope, like the single plant Eve retrieves from a ruined Earth in Wall-E (why yes, it was the in-flight movie. Why do you ask?). Argentine petroleum company YPF has billboards along the city’s streets informing the diesel-choked drivers that clean diesel is on its way.

The web site (which is in Spanish) lists the advantages of what the company is calling D-Euro diesel: cleaner combustion, more miles per gallon, and fewer emissions. The fuel will have fewer than 50 ppm of sulfur, closer to the 15 ppm in the ultra-low-sulfur diesel used in the U.S. D-Euro diesel is classified as Bin 4 in Europe.

Photo of Bs. As. buses by blmurch.

• Roadsharing This site skews toward Europe, but what a way to get around the Continent. It’s way more reliable than sticking out a thumb and hoping for the best. Terms and conditions, as of this posting, are only in Italian.

• Zimride This ride, carpool, and cabshare finder is also available as a Facebook app, a widget, and, as of September 2008, on your mobile phone. Free registration.

• Carticipate Get this rideshare app for your iPhone via iTunes. Free.

• PickUpPal An ticker at the bottom of the homepage tells you how many potential tons of CO2 have been kept out of the air thanks to the site’s bidding system for rides. Free registration.

• Ridester A clean, simple web interface for finding a commute buddy. Ticket Fee, Driver’s Fee, and Processing Fees.

• Divide The Ride Carpooling for families who have to deal with soccer, ballet, Little League, the school paper, etc. The same people have launched CarLine Manager for after-school pickup, too. Free.

Many communities also have local rideshare boards online (like San Fransisco’s rideshare.511.org), so search for sites in your city for a local commuting option to save gas and seriously cut down on traffic and emissions.