We happened to be in London earlier this week, where it's hard to avoid the sight of the ubiquitous "London Taxi," a distinctive vehicle purpose-built to meet a specific set of regulations involving tiny turning circles, top-hat headroom, and other arcana.

That hasn't stopped a consortium of British companies from developing a radically new way to meet the specs and transport Londoners and their visitors around the capital. Their project, the E-Vito electric taxi, was announced last February and is now ready for road tests.

Mercedes-Benz E-Vito taxi, adapted to electric drive by consortium of British companies

Mercedes-Benz E-Vito taxi, adapted to electric drive by consortium of British companies

Carriage requirements

The all-electric taxi project was partly funded by the government's Advantage Niche Vehicle Research & Development Programme, and has been deemed to meet all the requirements of the charmingly named London Carriage Office.

And, yes, those requirements do in some cases date back to the days of carriages, though the spare-bale-of-hay requirement was finally dropped after World War II.

Off-the-shelf van body

While less distinctive, the E-Vito has the advantage of using large numbers of off-the-shelf components including, most significantly, a Mercedes-Benz Vito European delivery van body and large portions of its suspension and running gear.

Extensively tested for durability, the slab-sided van--as modified to meet the taxi code--seats up to six passengers, and the sliding side doors require minimal opening radius at tight kerbs (or, if you like, curbs) and in dense traffic.

Electric conversion

Together, the four companies--Zytek, Valence Technology, Penso, and Mercedes-Benz UK--have converted the Vito to electricity by switching it from rear- to front-wheel-drive.

Removing the driveshaft makes it possible to mount a 35-kilowatt-hour lithium-ion battery pack from Valence under the floor, giving it a stated range of up to 75 miles on a six-hour charge at the U.K. standard of 240 Volts. And it lowers the center of gravity for better ride.

The group then mounts a 70-kilowatt Zytek electric motor under the bonnet (hood) using standard engine mounting points, with just three new connections to be made: coolant, high-voltage electronics, and low-voltage power.

And the E-Vito retains the van's standard electronics and safety systems, including its anti-lock braking system (ABS), electronic stability program (ESP), and even its onboard diagnostics (OBD).

Mercedes-Benz Vito taxi from Eco City Vehicles PLC, from Flickr user Ross Campbell

Mercedes-Benz Vito taxi from Eco City Vehicles PLC, from Flickr user Ross Campbell

25-foot turning radius

Crucially for such a large vehicle, the engineers managed to meet the requirement for a 25-foot turning radius by making the rear wheels steer as well, giving the E-Vito the ability to make U-turns in surprisingly narrow streets--of which London has a great many.

The E-Vito builds on work done to modify the Vito into a taxi by Eco City Vehicles PLC, which turns Vitos into black cabs by modifying the rear axle using technology licensed from One80 Ltd.

Emissions-free Olympics taxis

Eco City says that since the Vito cab was launched in June 2008, it has won almost one-third of the orders for new London taxis from the traditional alternative, the TX series of cabs offered by London Taxi Inc. Last December, it said it had sold a total of 500 Vito taxis.

With London Mayor Boris Johnson pledging emissions-free transportation of various sorts for the London Olympics two years hence, the E-Vito's timing is likely to be good. Whether 65 miles will prove to be sufficient range for a taxi in London is a different story altogether.

[EVworld, Green Car Congress; Vito photo from Flickr user Ross Campbell]