Toyota Prius vs Jeep Patriot: the great MPG test by Claire Edwards and Jay Nagley

Introduction

Eager owners sometimes present a Toyota Prius as David Attenborough on wheels - decent, environmentally aware and beyond criticism. And yet there are nagging doubts that the Toyota is not nearly as irreproachable as Britain's national treasure. You don't have to look very hard on the web to find American buyers questioning the official fuel consumption figures, while some Europeans question whether a simple diesel engine would not be equally economical.

So, we decided to conduct the ultimate test, pitting the Prius (easily the world's biggest-selling hybrid with just over 1 million sold to date) against the devil's own tool; an SUV. Our choice of SUV was simple. Jeep was recognised in 2007 for having the most improved fuel consumption across its model range, and has won a Green Award for the Patriot. The Patriot Diesel is one of the most economical 4x4's available on the market today (thanks to its VW engine) and boasts lower CO2 emissions than, say, a Renault Scenic 1.6.

The rules would be simple; both drivers were to drive the way they normally would, but in order to ensure that driving styles didn't interfere with the results, they would swap half way and all speed limits would be adhered to.

The test

Despite being very different animals, the Patriot and the Prius are both acknowledged as family cars, so our route would take us on a typical family day out to the south coast. Starting from Tower Bridge in the centre of London, we set off at 10am to avoid the rush hour traffic heading out towards Brighton and our first waypoint.

The first impressions of the Patriot were not great - the first few seconds were spent scanning the truly nasty plastics of the interior. Once we had got used to the dashboard, we could not help noticing that it did not actually contain very much - even though we had the range-topping Limited model, there was no sat nav and only a basic radio and CD/MP3 player. However, once on the move, things rapidly improved, as it proved remarkably easy to pilot the Patriot around the city. Despite its size, it didn't feel awkward, and was comfortable inside.

The interior of the Prius was less offensive to the eye and came with more kit than the Patriot. The sat nav was easy to program, so it was decided that the Prius would lead the way. However, it took time to get used to the odd automatic gear lever, which sits on the dash next to the steering wheel. When we first tried to pull off at a set of lights the electronic parking brake wouldn't release and the gearbox refused to select 'drive'. It took quite a bit of persuasion before the electronic systems agreed to let us go on our way.

As we approached the motorway the two on-board computers were reading very different figures. The Prius was showing around 58mpg, whilst the Patriot showed just below 40mpg. The Prius is almost silent whilst driving in the city, but on the motorway you could hear the engine working quite hard - it is only a 1.5 litre unit and the batteries are no help at cruising speed. Nonetheless, by the time we reached the Brighton seafront the trip computer was claiming over 62mpg. In contrast, the Patriot's 2.4-litre diesel engine feels effortless at cruising speeds and the uncouth growl you get from it around town almost disappears. It also feels more spacious than the Prius, which would be a little cramped with the whole family aboard.

After stopping at Brighton, the rest of the journey took us along the coastal route for a few miles before we stopped again to swap drivers and headed back towards London. The entire route took us over 160 miles covering coastal, motorway and city roads.

The result

Had we relied on the onboard computers, the Prius would have won by a landslide, as by the end of the trip they read 57mpg and 42mpg for the Prius and Jeep respectively.

However, to get the real figure, we calculated consumption based on how much fuel each car had used over the 160 miles. The result was astonishing: both cars had used nearly identical amounts of fuel. The Jeep had averaged 38.9 mpg - only 3.1 mpg less than its computer had recorded. However, the computer of the Prius appeared to be telling whoppers: it actually achieved just 39.9 mpg - a massive 17.1 mpg less than it had claimed.

Whereas, the first impressions of the Patriot had been overwhelmingly negative - it's an SUV with interior plastics apparently supplied by a Chinese Christmas cracker factory - it converted us by the end of the day. It had been a better experience for both driver (more pleasant to drive) and passenger (more space). Our test also raises the question over the economy of hybrids overall - a subject to which we will be returning. Certainly it might feel like you're contributing to a greener world, but most manufacturers are constantly improving their diesel cars to make them greener and more efficient. It seems that if economy is what you're after from a family car, there are better, and - let's face it - more stylish, options than a Prius.