Interesting stuff. A quick Google pulls up conflicting advice on coasting. However some of the more thoughtful opinions seem to be saying it depends on the engine management system. So if Volvo are advocating it then I guess they've set up the V40 to deal with coasting in a fuel efficient manner.London_2012 said:
The 15 seconds threshold is one of those bits of information that's interesting to know, but you can't do whole lot about it, unless you want to hold up the traffic for a few extra seconds