I can see this is going to be hell on batteries and starters.
I drove a diesel Focus in belgium with start-stop. I suppose it would be OK if you sit at stoplights a lot. Stopping at a stop sign for a few seconds and having the engine quit is an annoyance. But I quickly learned to just keep the clutch down.
Here in Boston, we aggressive drivers will never put up with this. Even if all cars come standard with thsi feature, we will figure out how to override it. Even if we don't override, we will simply start going before the light turns green. We do that now anyway.
Back in college I drove a 1966 Envoy Epic, the North American version of a Vauxhall, and used stop/start technology whenever the clutch cable broke (which was often). Learned how to shift a manual transmission without releasing the clutch by matching engine revs, killed the ignition at traffic lights and stop signs, restarted in 1st gear with the starter. Eventually I would get around to replacing the broken clutch cable...
In Australia, my wife got a new Subaru Forester recently, with stop start technology. It works fine, and to my mind is quite non-invasive. There is a slight delay as you take your foot off the brake, but it is less than a second. When we were evaluating cars we rejected one with Volkswagen's Dual Clutch Transmission, which had horrible "pedal delays".
With the Subaru's S/S, you can control if the engine will stop by how hard you brake. Brake gently, and it doesn't stop. That means in congested traffic, where you move a few centimetres at a time, the engine doesn't stop all the time. When stopped at a red light, the engine will re-start if the ECU decides power is needed for the A/C.
The car also has continuously variable auto transmission, so it can always use the optimum gear ratio for the conditions.
As an aside, Subaru also has adaptive cruise control, that maintains a constant distance from the car in front. We didn't buy that option, but it was fun to play with on the test drive. It will also warn you if you drift across the white lane dividing line.
BTW: On my regular commute I turn off the engine in my older car at traffic lights where I know there will be a long wait.
"Since it is winter, I don't know about air conditioning, but the heater worked fine while the engine was off. If the red light was sufficiently long-- say a minute or more-- the engine would restart even with the brake pedal depressed, and then run for a short period of time, perhaps 2 or 3 seconds."
Right. That's the way one would expect it to work, and it's also a mode of operation that is unliklely to save a lot of gasoline. Similarly, on a congested freeway, where you move and stop incessantly, but you don't stop for a long time.
Time will tell how well the engineers design the start-stop logic to work. That will determine whether batteries AND engines AND catalytic converters last an acceptable amount of time. It shouldn't be surprising if car companies go through growing pains, with such innovations.
Continuing my chain of thought... there may already be ECU's that implement variable fuel injection in today's automobiles, thus saving fuel when the car is idling at traffic lights or in stop-n-go traffic.
I think instead of completely stopping the motor/engine in fossil-fuel based vehicles, the automobile industry perhaps could draw parallels from electronics industry to use a quiescant mode of operation. The traffice lights in many metropolitan areas are long enough to implement this to realize fuel savings, not to mention reduction in atmospheric and noise pollution. There could be more fuel efficiencies to gain in idle-mode operation of the engines...
>>I would love if this automatic start-stop mechanism can be fitted to the old
>> cars ( with good starter motors!) as they are not as fuel efficient as today's cars .
I would think that your engine has to be designed for stop/start. Shutting off and restarting engines can be hard on the engine if it is not designed to take it. You always hear that electronics or mechanical devices break when you start them, and rarely after they start operation.
I've just returned from Japan, where I drove a Nissan mini-van with stop-start. The lag on re-start was less than a second. Since it is winter, I don't know about air conditioning, but the heater worked fine while the engine was off. If the red light was sufficiently long-- say a minute or more-- the engine would restart even with the brake pedal depressed, and then run for a short period of time, perhaps 2 or 3 seconds. I guess this would circulate coolant, keeping the heater core warm.
I looked under the hood, and the battery, alternator and starter are all larger than normal. I'd say the battery was at least 50% larger than typical for an inline 4 cylinder.
I very quickly became accustomed to it, and I don't think the short lag is a problem.