As the name suggests, it’s not a traditional satnav service. Instead, it’s a monitoring and diagnostic tool for your car, tracking your journey and serving up a wealth of details for inquisitive drivers.

The main screen — with a sleek, gunmetal grey UI — shows your average speed, distance travelled and total time for your current journey, and below these vital statistics sit bars that illustrate your accelleration, braking and variation to your average speed in real time. At the bottom of the screen is a graph that illustrates your speed, average speed and, if you choose, your current and average fuel economy.

More detailed fuel consumption figures are kept in a separate screen, and Mechanic’s profile screen allows for personalisation: detail the engine size, weight and type of vehicle and the results will be more accurate. And, if you’ve got a fleet of vehicles, it’s possible to add more profiles and select which car you’re using before you set off.

There’s one tab, though, that’s off-limits to all but the most devoted petrolheads. It’s used in conjunction with Garmin’s ecoRoute HD — a tiny dongle that plugs into your car’s engine computer and sends signals back to your phone using Bluetooth.

Originally designed for Garmin’s nuvi satnavs, it’ll add a host of features and make the app’s readings much more accurate, with real-time diagnostics, temperature information and engine performance data all available. There’s a couple of stumbling blocks, though: not all cars are compatible, and it’ll set you back £99 inc VAT.

Aside from this, there’s plenty to like about Garmin Mechanic. Its personalised car profiles enable a fine range of features, from fuel tracking to speed and distance monitoring, and it’s free in the Android Market.

Want more great Android apps? Check out our previous Android Apps of the Week or read our 36 Best Android Apps feature

There have been several blogs from various members of the PC Pro team about the joys of sat-nav recently. First I gushed about the ease with which I drove 1,400 miles in a couple of days, and barely got the map out once. Then Darien got all excited about the beat-the-ETA game everyone inevitably ends up playing to liven up long journeys.

But this… well. This is just brilliant.

According to CNN, General Motors is developing a windshield that “combines lasers, infrared sensors and a camera to take what’s happening on the road and enhance it” for ageing drivers.

So in the fog they’ll see a laser-projected blue line marking the outside edge of the road they’re on, and it’ll even enhance and outline objects like animals, pedestrians or trees to reduce the possibility of accidents in poor visibility conditions. And if they’re speeding, a pink outline will highlight speed limit signs to attract their attention.

But let’s be honest here, it’s not just old people who’ll love this. I’ve already had the odd scary moment where I’ve drifted off into a trance and found myself actually driving based on the curves on my sat-nav rather than watching the road. If that route can instead – by some sort of hook-up with a sat-nav – be beamed on my windshield, I’ll never have to look at a map again. It’ll be like those bits in Terminator and Robocop where you see through their computer eyes and everything’s pointed out for you. Idiot-proof navigating.

And just think of the benefits: that’ll leave me totally free to concentrate on beating that all-important ETA.