Why are many European carmakers now planning to build electric vehicles? Because many European cities are widely expected to ban high-emissions vehicles from their city cores over the next decade--perhaps even vehicles with any emissions at all.

Now, Paris may be the first city to experiment with such a policy. Next year, it will begin to test restrictions on vehicles that emit more than a certain amount of carbon dioxide (CO2) per kilometer--the measure of a car's contribution to greenhouse gases.

An official within the Parisian mayor's office, Denis Baupin, identified older diesel-engined cars and sport-utility vehicles as specific targets of the emissions limit.

"I'm sorry," Baupin said on RTL Radio, "but having a sport utility vehicle in a city makes no sense." He suggested that Parisian SUV owners replace their sport utilities with vehicles that are "compatible with city life."

Thus far, the specific details of the restrictions--including numeric limits, which types of engines and vehicles would be targeted, the locations and the timing of the bans--are still being debated, as are the penalties for flouting them.

2009 Hummer H2

2009 Hummer H2

Other French cities planning to test similar restrictions over the next two years include Lyon, Grenoble, and Aix-en-Provence.

London's congestion-charging scheme, which levies a fee of £10 (roughly $15.50) to enter a large area of the central city during weekday business hours, permits zero-emissions vehicles to enter free.

Residents and travelers have responded by buying thousands of electric cars, including the low-speed fiberglass G-Wiz--despite major safety concerns with the vehicle.

Electric cars such as the 2011 Nissan Leaf are expected to sell for the same reason. In fact, Nissan plans to build up to 50,000 Leafs a year at its plant in Sunderland, England, starting in early 2013.

[AP via Detroit Free Press]