Audi claims to have beaten its premium rivals to offer a stop-and-start system on a car with an automatic gearbox.
Audi's start-stop fuel-saving system had only been available on manual transmission cars with four-cylinder engines up to now, but customers can now order versions of the A3 1.4 TFSI and 1.6 TDI using start-stop with Audi's S-tronic dual clutch semi-automatic gearbox.
It means the 105bhp 1.6 TDI version of the A3 S-tronic with start-stop emits CO2 at just 109g/km, while the 125bhp 1.4 TFSI petrol model with the same technology has CO2 emissions of 124g/km.
The stop-start system cuts engine power when the car comes to rest at traffic lights or in queueing traffic. When used with S-tronic, the engine remains switched off as long as the driver's foot remains on the brake pedal.
It's activated regardless of whether the engine is in gear or in neutral, and releasing the brake pedal prompts the engine to restart in two tenths of a second.
The technology also uses a recuperation system to harness energy generated during braking which also improved fuel consumption and helps reduce emissions.
The 1.4 TFSI model will sprint from 0-62mph in 9.3 seconds, while the 1.6 TDI version will cover the same benchmark in 11.7 seconds. Fuel consumption is 53.3mpg and 67.3mpg respectively.
Both versions are available to order now with deliveries beginning in December 2009, and prices start at £18,300 on the road.
Despite claiming a first to market with such a system on a premium car, Lexus launched a version of stop-and-start on its petrol-electric hybrid RX400h in 2005, which also has an automatic transmission.