With the testing restrictions getting tighter and tighter, every lap counted at Jerez this week - but with rain disrupting two and a half of the four days, the teams' efforts to fine-tune their 2010 cars were often frustrated.
As if the conditions weren't making things hard enough to judge, there was the added complication of fuel loads, with teams running with anything from a few cups' full in qualifying trim to a fully laden tank ready to get them through a 300km race.
Even the drivers aren't sure exactly where they stand at the moment, but at the halfway point of winter testing 2010, itv.com/f1 evaluates the week's events team by team, and brings you the full list of best times and top mileages from Jerez.


McLaren
Driver schedule: Weds/Thurs - Button, Fri/Sat - Hamilton
Best time: Hamilton, 1m19.583s, Sat
Day by day results (Weds to Sat): 6th, 3rd, 9th, 1st
Total laps: 332
McLaren caused a few ripples of concern among its fans by sporting outlandish aero flow measuring devices early in the test - raising fears of perplexing aero problems like last year - and when Lewis Hamilton gave an apparently terse press briefing on Friday.
But the truth was that the team ended the week in great shape: the unusual measuring appendages having just been part of the team's desire to maximise what it could learn on-track, and Hamilton's frustration being with the weather rather than the car, which he is revelling in at present.
Sure enough, after some promising long runs, Lewis took on a fresh set of tyres in the final ten minutes yesterday and blasted out a string of laps could enough to comfortably top the combined testing times.
Jenson Button made strides too, declaring himself significantly more comfortable in the new car after his two days.


Mercedes GP
Driver schedule: Weds/Fri - Rosberg, Thurs/Sat - Schumacher
Best time: Schumacher, 1m20.613s, Sat
Day by day results: 1st, 6th, 7th, 5th
Total laps: 317
With a few changes to the car and set-up since Valenca, Mercedes seemed to be in better shape at Jerez, lapping close behind the absolute pacesetters while not letting off too many fireworks.
By coincidence, Michael Schumacher ended up with the lion's share of dry running, Nico Rosberg's two days both turning wet within an hour.
But despite this, the younger German took bragging rights by setting the fastest time of the day just before Wednesday's cloudbursts, and reported that he felt much more at home in the Mercedes at Jerez following cockpit adjustments.


Red Bull
Driver schedule: Weds/Thurs - Webber, Fri/Sat - Vettel
Best time: Vettel, 1m21.203s, Sat
Day by day results: 9th, 9th, 5th, 6th
Total laps: 297
An inconclusive first week for the car many expected to be the title favourite this year.
The rain got in the way of Red Bull's efforts to put miles on the RB6, as did an oil leak on Wednesday and a fuel pump failure on Saturday, both of which stranded the car in the garage for a while.
The drivers were both adamant that the car is an excellent baseline, though, and expect it to show its true pace once its achieves a few more laps in the dry.


Ferrari
Driver schedule: Weds/Thurs - Alonso, Fri/Sat - Massa
Best time: Alonso, 1m21.424s, Thurs
Day by day results: 4th, 7th, 4th, 7th
Total laps: 449
After dominating at Valencia, this appeared from the outside to be a quieter week for Ferrari - but it ended the Jerez test still at the forefront of the pack.
Ferrari chose to work on reliability and heavy fuel loads for most of the week, and that programme went extremely well, as Fernando Alonso and Felipe Massa racked up an enormous 449 laps between them.
Only tiny glitches were experienced, and while neither driver went for any headline-grabbing lap times, their speed on fuel tanks was ominous for their rivals, with Alonso's 50-lap stint on Thursday both extremely rapid and unnervingly consistent.

Williams
Driver schedule: Weds/Thurs - Hulkenberg, Fri/Sat - Barrichello
Best time: Barrichello, 1m20.341s, Sat

Day by day results: 3rd, 4th, 8th, 3rd
Total laps: 395 Williams didn't really show what it could do at Valencia, with the returning Cosworth choosing to run its engines on conservative settings for its first test back in Formula 1.
But at Jerez Williams was able to step up a gear and get among the front-runners more often.
That was despite suffering more gremlins than most, with a hydraulic leak and then later a driveline problem delaying Nico Hulkenberg on Thursday, and Rubens Barrichello forced to abandon his last run of the week due to a gearbox glitch.


Renault
Driver schedule: Weds/Fri - Petrov, Thurs/Sat - Kubica
Best time: Kubica, 1m20.358s, Sat
Day by day results: 8th, 8th, 6th, 4th
Total laps: 283
Encouraging noises from one side of the Renault garage, with Robert Kubica much happier with the car this week and convinced it was getting quicker and quicker each day.
Eager to make the most of Kubica's experience and feedback, the team shuffled its schedule to ensure the Pole had maximum dry mileage.
But that meant his rookie team-mate Vitaly Petrov made little progress this week, with the team unwilling to give the inexperienced Russian too many laps in the tricky conditions on Wednesday - although he handled Friday's rain well.


Force India
Driver schedule: Weds/Thurs - Liuzzi, Fri/Sat - Sutil
Best time: Sutil, 1m20.180s, Sat
Day by day results: 7th, 5th, 3rd, 2nd
Total laps: 282
It was easy to forget that this week marked the Force India VJM03's debut, for the team was rapid from the outset, and immediately up with the cars that had already notched up three days of running at Valencia.
Both Tonio Liuzzi and in particular Adrian Sutil were absolutely buzzing about the car afterwards too, raising hopes of a great start to the season.
The team still feels there is more speed to come from the car, and there were one or two mechanical issues to deal with as well, but overall it was a great start to Force India's build-up.


Toro Rosso
Driver schedule: Weds/Thurs - Buemi, Fri/Sat - Alguersuari
Best time: Alguersuari, 1m19.919s, Fri
Day by day results: 2nd, 2nd, 1st, 10th
Total laps: 369
Plenty of optimism at Toro Rosso, with the car's Red Bull lineage (still being inspired by last year's ultra-successful RB5 despite the customer car relationship now being banned) helping it to hit the ground running.
Jaime Alguersuari's super-fast Friday time owed something to the young Spaniard being one of the few to bang in a flat-out run in the brief period between the rain hit, but was still good enough to stand as the week's benchmark until the last ten minutes of Saturday - suggesting the new STR has plenty of pace.
The fact that Alguersuari plunged to the foot of the times when doing race work yesterday however hinted that it might have been running lighter than others earlier in the week.


Virgin
Driver schedule: Weds/Thurs - Glock, Fri/Sat - di Grassi
Best time: Di Grassi, 1m22.912s, Sat
Day by day results: 10th, 10th, 10th, 9th
Total laps: 87
A fraught start for Virgin, which was waiting for last minute parts to arrive for most of Wednesday, had to cut short its running when the front wing came off the VR-01 on Thursday, then sat out the majority of Friday while waiting for the rapidly-redesigned wing mounting to arrive.
But finally on day four Lucas di Grassi was able to reel off a longer string of laps, and although he was 3s off the pace, that was more than respectable for what was effectively the first proper day of running for this brand new team's car.
The Virgin crew put in a huge effort during the tribulations, which bodes well for the season, but the issues did underline the scale of the task facing the start-up teams.


Sauber
Driver schedule: Weds/Thurs - Kobayashi, Fri/Sat - de la Rosa
Best time: Kobayashi, 1m19.950s, Thurs
Day by day results: 5th, 1st, 2nd, 8th
Total laps: 321
The surprise package of winter testing so far remained among the leaders at Jerez - although Kamui Kobayashi's super-fast Thursday time was achieved with relatively little petrol in the tank.
Nevertheless, when Kobayashi was asked by journalists if he could win this year, he hinted that it would be his inexperience - not any lack of pace in the car - that precluded this...
Sauber wasn't totally happy with the amount of running that it managed this week and rued the incessant rain, but remains in good shape heading towards the season opener, even if it is unlikely to be as close to the front as its testing positions have so far suggested.


Combined testing times from Jerez
1 HAMILTON McLaren 1m19.583s (181)
2 ALGUERSUARI Toro Rosso 1m19.919s (174)
3 KOBAYASHI Sauber 1m19.950s (158)
4 BUEMI Toro Rosso 1m20.026s (195)
5 SUTIL Force India 1m20.180s (131)
6 BARRICHELLO Williams 1m20.341s (210)
7 KUBICA Renault 1m20.358s (188)
8 SCHUMACHER Mercedes 1m20.613s (207)
9 BUTTON McLaren 1m20.618s (151)
10 HULKENBERG Williams 1m20.629s (185)
11 DE LA ROSA Sauber 1m20.736s (163)
12 LIUZZI Force India 1m20.754s (151)
13 ROSBERG Mercedes 1m20.927s (110)
14 VETTEL Red Bull 1m21.203s (148)
15 ALONSO Ferrari 1m21.424s (217)
16 MASSA Ferrari 1m21.485s (232)
17 PETROV Renault 1m22.000s (95)
18 WEBBER Red Bull 1m22.043s (149)
19 DI GRASSI Virgin 1m22.912s (71)
20 GLOCK Virgin 1m29.964s (16)

* laps completed in brackets


TOTAL MILEAGE COMPLETED

1 Ferrari 1,236 miles
2 Williams 1,087 miles
3 Toro Rosso 1,016 miles
4 McLaren 914 miles
5 Sauber 883 miles
6 Mercedes 872 miles
7 Red Bull 817 miles
8 Renault 779 miles
9 Force India 776 miles
10 Virgin 239 miles



source[www.itv-f1.com]