Will the Mercedes-Benz B-Class F-Cell and Smart Electric Drive lead the way in future green technologies, or will they be guilty of under-performing and over-promising? The public will be the jury as Mercedes puts them both on trial.
Smart Electric Drive
The Smart Electric Drive (ED) is to hit UK streets in a real-world trial by everyday drivers.
The car goes on sale in 2012, but from April, 100 drivers in London, the South East and West Midlands will be leasing the latest Fortwo ED as part of a fact-finding test programme.
Tested in the real world
Customers chosen to be part of the real-world research programme will have an EDF charging pack installed in their garage, which can fully re-charge the car in eight hours.
When connected to the plug socket, the Smart ED's cabin can also be warmed ahead of the journey, which will avoid using the heater while on the move and help preserve the car's range. Drivers can also connect to the car over the internet to find out the car's level of charge.
Smart ED details
Unlike the previous Smart, the new ED has lithium-ion batteries (supplied by Tesla) for an increased range of 84 miles.
That's more than enough to cover the majority of journeys that most drivers undertake day-to-day, while providing a little extra on top to allay the dreaded range anxiety.
Top speed is 60mph, and while there's no 0-60mph time, Smart says 0-38mph takes 6.5 seconds.
Smart has talked about a monthly leasing cost of around 700 (628) for the car in Europe, but with a cash incentive from the Technology Strategy Board, the hope is to bring that below the 375 monthly figure paid by those who leased the previous version.
Smart ED drive
Performance around town is good as might be expected but it's not as nippy as the Mini. However, peak torque is available from virtually zero revs, allowing drivers to dart away from a standstill at an alarming rate.
The Smart doesn't struggle to gather speed once it's going, even up a steep hill, and has an automatic-like 'kickdown' of extra power when you stamp on the throttle. It's fine for short hops on slightly faster roads between towns, but it would be out of its depth on more major arteries.
The car has a regenerative braking system, which automatically slows the car as you lift off the throttle. In some electric vehicles, such as the Mini E, this can feel really abrupt; in others such as the Vauxhall Ampera, it's almost undetectable. The Smart ED is somewhere in the middle. The power created is used to top-up the batteries.
The Smart ED is better to drive than the petrol and diesel version of the Fortwo, and there are no gears to worry about, just forward and back.
While the ED might be heavier than its petrol and diesel siblings, its centre of gravity is lower, so it certainly doesn't feel out of shape darting along tight and twisty city centre streets.