article: Rivals were awestruck by the amount of mileage the team were able to manage with a brand new car. Mercedes were determined to turn so many laps that they had to start splitting each day between drivers Lewis Hamilton and Nico Rosberg to avoid over-exerting them. "Amazing," said Williams technical chief Pat Symonds. Another senior figure put it into context: "800km is an entire grand prix weekend in one day." Not everyone was charitable, though. "It looks like they're gearing up to take that car to Le Mans," said one rival. "It's admirable, but it's taking the Mickey a bit. You don't need to do that many miles." Perhaps not. But, at this stage of the preparations, as Hamilton put it: 'Mileage - that's the key. To try and get as much mileage as we can." The world champion added: "It's incredible. And I've never seen anything like it. Just the strength of this car, it just keeps going and going and going. "To think we won the two world championships and going into a third year you would think it is so easy to lose focus, but everyone has done an even better job with delivering the whole package." The Mercedes did not produce any stand-out lap times, but then that was not in the programme. Others were left to do that. Nevertheless, Hamilton's team-mate Nico Rosberg made it clear they were not lacking for performance. "I'm paying attention, of course," said Rosberg, who described the car as "quick". "We have strategists and they're doing calculations already, so more or less we already know where we are, with a band of errors. "Would you like to know? Sorry, I'm not going to say!" Red Bull team principal Christian Horner called Mercedes "stand-out favourites" on the first day of the test. Nothing that happened over the next three days made it feel like that analysis needed to be revised. Ferrari's Sebastian Vettel left the test with the fastest time - a one minute 22.801 seconds lap set on the second day on the new ultra-soft tyre. Indeed, Ferrari were fastest on three of the four days. Vettel's time was two seconds quicker than Mercedes' best, set by Rosberg on the medium tyre, which Pirelli estimates to be in the region of 1.8-2.3 seconds slower than the ultra-soft around Barcelona. In isolation, that makes it appear as if Ferrari were pretty even with Mercedes, even if other teams were not as impressed by Vettel's time as you might expect at face value. Now, let's state before we get too far into this that it is notoriously difficult to draw firm conclusions from pre-season testing times, especially the headline fastest laps. That's because there are so many variables - fuel load, usage of the DRS overtaking aid, circuit conditions, engine mode, different tyres. The list is endless. But ex-Jordan, Jaguar and Stewart technical director Gary Anderson used to say that you could get a reasonable idea by looking at the fastest times set by each car and factoring in the tyre used and the
summary: Formula 1 pre-season testing reached its halfway point in Barcelona on Thursday evening and one thing is abundantly clear - Mercedes are once again in formidable shape.