Facts and figures. The dull but impressive conversation-killers that completely define this latest Toyota Prius are nevertheless very appealing to your inner nerd. The most important two you need to know are that it will now manage 72.4mpg and splutter out a mere 89g/km of CO2. Or 70.6mpg and 92g/km in top-spec T Spirit models on account of the bigger, 17-inch wheels. Even more impressively, the former figures stay exactly the same on the urban cycle thanks to the electric hybrid system.
This all-new Prius is more about evolution than revolution, so anyone expecting the sort of giant leap there was between the first and second generation will be disappointed. Everything is generally better, but it uses largely the same kinds of tech to achieve those marketing-friendly figures. So there's still the basic architecture of a petrol engine, an electric motor and a battery, albeit tarted up in an eco-fashion with optional items such as remote-start air-conditioning (so you can pre-cool the car on the key fob three minutes before you get into it) combined with solar panels in the roof to keep the ventilation going when you park it up.
But don't think evolution is Toyota code for window dressing. If there's a part that could be improved, it has been. The battery voltage has been increased to 650V from 500V, because higher voltage equals fewer amps, which means less heat loss through the cables. The battery has been reduced in size, 90 per cent of the hybrid system is new, there's even a valve in the exhaust which channels heat more directly back into the engine coolant to make everything reach optimum operating temperature faster.
More obvious news is that the Prius now has a new 1.8-litre engine, which has boosted outright power to 134bhp. Not a figure that will make you catch your breath, but the extra oomph makes motorway cruising much more relaxing because the engine isn't buzzing quite so extravagantly. It also means that fuel economy should be significantly better on longer, higher-speed journeys.
Or so goes the theory anyway. We weren't being careful with the throttle, admittedly, but we only averaged 53.6mpg. Which is pretty similar to the current crop of economically minded conventional diesels. And this extra power begs a question - if the Prius is all about fuel economy, why bother tweaking the power levels at all? Compared to the last car, power is up by 24 per cent, but fuel economy is only improved by 10 per cent and emissions by 14 per cent. The latter two figures are heading in the right direction, but it makes you wonder how much better they might have been if Toyota hadn't chased the bhp.
There are now three driving modes, Eco, Power and electric-only EV, and it's seriously easy to chop between the three - there's a set of buttons just by the fly-by-wire CVT gearstick. ‘Power' does just that, and makes the throttle less restrictive so it's much easier to overtake. It's no diesel for in-gear punch, but the Prius does at least do overtaking now without feeling like you're trying to make it explode. As with the last Prius, the electric motor lends a torque-laden hand with accelerative duties and then when you brake, reverses itself, acts as a generator and charges the battery.
The ‘Eco' mode makes it feel like you've got a tennis ball lodged under the accelerator, but it does encourage you to be more gentle. Possibly too gentle. The electric-only operation is far too short-lived when you drive off at traffic lights in either ‘EV' or ‘Eco', so do anything but breathe on the accelerator and the Prius beeps to tell you you're accelerating too hard and reverts back to petrol and electric combination.
Other disappointments with the Prius include road noise, which is far too intrusive, and wind noise, although it's not quite as bad. Oh, and the steering still feels dead, but that's probably not a particular Prius priority. At least the ride is comfortable enough, whether you're on the 17-inch wheels or the 15s.
Weirdly, if you opt for the former, you can't have the solar roof. Weight and centre of gravity issues apparently. Mind you, it's a mighty expensive option at £1,450 so will probably be limited to the eco-warriors in Hollywood where they also have the sunshine necessary to power it. What we will get is a head-up display as standard and a generally much smarter interior - the cabin is still seriously practical and the central dash looks good. There's also the usual smattering of clever and slightly patronising screens telling you how well, and economically, you're driving.
But none of the above really matters. Eco warriors with knowledge medals pinned to their hair shirts had started to worry about the whole life costs of the previous Prius, how much damage was being done to the environment in the making and shipping. Toyota is now careful to stress how much of the Prius can be recycled, including 95 per cent of the battery, how it's using far cleaner energy sources at the factory in Japan and that it now uses quite a few plant-based plastics in the car. There are still worries about where the nickel in the battery comes from, but steel/iron has to be dug out of the ground as well, so ‘normal' cars are not all that different.
So new Prius is good then. It almost makes you feel like you might be helping the environment a little bit just by driving it. The last one had started to lose that feel-good sheen, but with this version the polish returns. Not totally guilt-free motoring, but closer than ever before.