S S now becoming quite common even on Landrover, there are many sensors on the engine to detect whether it should shut down or not ! for instance if its been stonking along a motorway and you suddenly stop in a traffic jam the system wont allow the SS to come into effect untill its started cooling down and battery voltage is monitered as well.SS can also be overidden by the driver.

Time will tell and will be very interested to see what heppens to some of these cars at 4-5 years old ! There are a few out there as i came across a diesel lupo from Germany must of been in 2006 ish that had SS, was well weird to drive at the time.

It's a bit of a gimmick. The NEDC has quite a few stationary components to the cycle so it helps bump the official figures up. In practice it's a lot of mechanical faffing for a very small gain. If you're stuck in a traffic jam, you know where the ignition key is....

If facing downhill in a jam, I often turn the engine off-and switch the ignition back to 'on', so the brake lights work. When I need to restart, just drop into 2nd and tickle the engine with the clutch-warm engine starts easily and avoids unnecessary wear to the starter motor. As usual a mechanical gimmick to carry out an operation a dilligent driver can do perfectly well themselves. Bit like automatic transmissions.

It is a complete gimmic, I have it on my A4. I always push the disable button when I set off because I cannot see the logic behind stopping the engine because I have been at the lights for 60 seconds. To answer some of your questions, these cars have a huge battery compared to a standard car, but there are various criteria when the system won't allow the engine to be stopped, eg , engine still cold, engine very hot, high power drain causing battery state to be sensed as dropping. For instance I was using an Audi A1 recently, and it stopped stopping as I was driving through town, because I had lights, wipers and demister all on.

On the plus side though, it does help the car to have low emissions on paper so less road TAX.

I think stop start will stop me considering any car with it. I can't see how switching the engine on and off do a car anything but harm, seems just a gimmick to me.

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They make a big difference to CO2 figures... it's not just about fuel.

I travel back and forth a lot to the UK, so I get to hire lots of cars, and have some experience of most of the different mainstream stop-start systems.

Firstly, it takes about a day to get used to the system working... in fact going back to a non stop-start car takes more getting used to!

In general they are all intelligent enough to cope with real-world driving, so they don't just keep tabs on aircon load, and keep the PAS running, etc - but also monitor the important things like brake servo vacuum, so you don't find yourself stranded at the top of a steep hill without powered brakes!

The VAG system that I've used in Audi A3s and A4s along with the VW Passat Greenline is the most intuitive I've used, and becomes second nature in no time. The engine stops in a logical way, without any fuss, it's a consistent experience, and can work out from gear position, clutch, brakes and general timing the occasions when you don't want it to kick in such as parking up.

The other extreme are systems like the Hyundai / Kia... the system is eager to kick in when you are still doing about 3mph, the engine then dies with a chug which makes you think you've stalled it (not intuitive), and takes a fraction of a second longer than the VAG system to restart (the VAG cars seem to be running before you've 50% dipped the clutch vs already selecting a gear with the others).

Of course, yes, these are all hire cars with <10k on the clock. How well they work with a duff battery, low compression and stagnant oil in 8-10 years time after 5 owners may be entirely different. But the theory is good! ;)