Satnav that allows green driving

IT MAY drive you round the bend, but this hi-tech nagging device could save you petrol and the planet

Meet the satnav that nags you to conserve fuel. Dubbed the Econav, this new gadget will not only guide you from Land's End to John O'Groats but will also tick you off when you abuse the accelerator and brake pedal. It'll sigh — well, flash a visual and audio warning — when you need to shift gear.

If you believe its makers Vexia, it could also cut your car's CO2 emissions by 30 per cent. That sounds over-hyped to me, considering most research suggests that eco driving techniques — such as driving smoothly, keeping windows shut and avoiding unnecessary luggage — save more like five to 17 per cent on fuel. Still, Vexia's UK country manager Chris Hobbs tells me "our independent tests with the Spanish government's department for transport measured tailpipe emissions, and those tests suggested 30 per cent savings using the Econav."

The technology behind this satnav is certainly clever. As well as using satellites to monitor your driving style, it also has a database of around 8,000 recent UK cars, so it knows — for example — exactly when the most efficient time is to switch from third to fourth gear on a 2008 Ford Focus.

You can even set the Econav to one of three levels of sensitivity, depending on how much fuel you want to save (and how much hectoring you can stand). Though all this real-time advice is great, one omission I'd like to see on future models is a journey's end summary of how many miles per gallon you achieved. But maybe that's just my inner runner and love of beating PBs.

The recommended gear is shown top right, with an acceleration monitor centre.

Ultimately you won't need a sat-nav to coerce you, as your next car is increasingly likely to partake in eco-nagging.

Observer