Imagine the scene; you are happily driving along with The Wurzels hit song Twice Daily, banned by the BBC for referring to shotgun weddings at full blast when, as you turn the corner, there is a red light and a queue of traffic as long as you've ever seen.

Your co-passenger, in this case one Simon Wood from Mercedes Benz, leans across and turns off the music just as you are about to discover what Twice Daily means.

"Once you come to a standstill, Mr Swallow," he says, "slip the transmission into neutral, lift your left foot off the clutch, and the engine will cut out. You needn't apply the hand brake but it's probably wise that you do. Then, to reignite the engine, re-engage the clutch and the engine will start. If the vehicle rolls forward, or backwards, the engine will start as you need the driveline to assist the servo for any potential braking procedure that might be required as you roll, perhaps unwittingly, towards another object. And that, Mr Swallow, is how Eco Start works."

While I have paraphrased Mr Wood somewhat, Eco Start's benefits have already been seen. A Sprinter van roadtest for Motor Transport saw Eco Start activated four times, saving more than eight minutes of idle time on the test route. That equates to eight minutes of diesel consumption not used during a 67 minutes section of the test route. At £545 is should pay for itself sooner if you work urban routes, and perhaps a little longer if you travel on the motorway networks.
Turning off the engine during unforeseen delays is good practice but with traffic lights playing a bigger part in the UK road network, idle time is only likely to increase, as will your fuel bill.