(15 May 2018, 6:55 pm)Andreos1 wrote I meant to reply to this when you posted.
The original hybrids on the 21 (now on the 1) are like this.
From a passenger perspective, I didnt enjoy riding them at all.

The replacements seem slightly different. 
On my first ride, the engine didnt cut out at all.
On a subsequent one, the engine cut out on occassions.
Keeping an eagle eye and ear out since, I'm wondering if there is some sort of 'over-ride' function.
The ride is a lot more pleasant when it doesn't cut out.

One way to 'over-ride' it, is to keep your foot on the pedal when you come to a stop.

I still don't see the real need for stop start, it just seems to make things even more inconvenient IMO, was on one of Darlington's StreetLite's the other week which has this technology, we got to the Pease Way Doctors Surgery stop on the 5/5A route and the bus cut out at the stop and the passenger who was alighting asked for the bus to be lowered, the driver ended up folding the ramp out instead for some reason but some comments were made about the technology.