While sales continue to grow, electric cars still represent a tiny fraction of the vehicles on the world's roads.

Perhaps that explains the proclivity of electric-car advocates to assemble them into ever-larger groups: It's a case of strength in numbers.

Last week, 507 electric cars gathered in Stuttgart, Germany--enough to break the Guinness World Record for the largest electric-vehicle parade in history.

The rally was organized by the World Advanced Vehicle Expedition (WAVE)--an electric-car advocacy group started by solar-energy promoter Louis Palmer, who made round-the-world trips in a solar-powered car in 2007 and 2008.

WAVE electric-car parade in Stuttgart, Germany.

WAVE electric-car parade in Stuttgart, Germany.

A WAVE press release said observers from the Guinness Book of World Records were on hand to witness the gathering of electric cars, although the organization is still awaiting official certification of the record.

Participants ranged from a Volkswagen Beetle and vintage 1963 Land Rover, both converted to electric power, as well as at least one Tesla Model and a Smart ForTwo Electric Drive from the Car2Go car-sharing service.

According to Transport Evolved, Guinness rules required all vehicles participating in the rally to be powered solely by electricity. Hence, plug-in hybrids and extended-range electric cars like the Chevrolet Volt and BMW i3 REx were not included.

The WAVE rally surpasses the 431-car record set in April by the National Advanced Transportation Center--a Canadian electric-car advocacy group.

The fleet of plug-in cars--assembled in a long parking lot on the Île Sainte-Hélène along the Saint Laurence River, in Montréal--included both battery-electric vehicles and plug-in hybrids.


Follow GreenCarReports on Facebook, Twitter, and Google+.