Paul in Canterbury: Am I the only person to think it's already been decided there will be three car teams next year? Would explain Alonso's cryptic messages - Hamilton/Rosberg/Alonso at Mercedes anyone?!

Mercedes' Nico Rosberg: "Problem with the gearbox on the downshift."

Lotus F1 on Twitter: Rumours that Pastor had a spin are completely unfounded and totally untrue...well... Maybe there's some truth to it.

Only the Mercedes have managed to get into the 1m39s. Here's how they stand with just over 30 minutes remaining.

1) Ham 2) Ros 3) Alo 4) Ric 5) Mas 6) Rai 7) Kvy 8) Mag 9) But 10) Hul 11) Bot 12) Gro 13) Ver 14) Per 15) Mal 16) Sut 17) Gut 18) Vet

Image source, Getty Images

Fernando Alonso goes third quickest on his soft tyre run with a 1:40.189, 1.1 seconds off the pace. Daniel Ricciardo is one tenth further adrift in fourth.

Andrew Benson
Chief F1 writer

"At the end the session, as was the case after first practice, the teams will trial a new system aimed at removing the possibility of a repeat of Jules Bianchi's awful accident in Japan. The 'virtual safety car' is an extension of the system used when a safety car is deployed but has not yet found the leader. All drivers will have a 'delta' time displayed on their dashboard - which will be about 35% of a dry lap time - and they have to stay 'positive' to it, i.e. slower. The results will be analysed afterwards before governing body the FIA and the teams decide how to proceed with it."

Image source, Getty Images

And it doesn't look like that is about to change in Austin...

Pastor Maldonado spins, not for the first time today, down at Turn 19. The Venezuelan lost the rear of the car mid-corner. Meanwhile, Romain Grosjean reports that he lost Kers at the end of the last lap. Problem after problem after problem.

Second time around, Lewis Hamilton manages to get something more from those soft tyres to go quickest by 0.003 seconds. His team-mate Nico Rosberg, meanwhile, chose to pit. As it has been all season, it's just so close between the pair.

Image source, Getty Images

Lewis Hamilton is just 0.009 seconds up on team-mate Nico Rosberg on his soft tyre run after two sectors, but he loses time in the final sector and slots into second, 0.053 seconds off the pace.

Nico Rosberg bolts on the soft tyres and heads out for his qualifying-simulation run. It's a stunner, the German clocking a 1:39.088 to improve on his previous best by nine tenths of a second.

Sebastian Vettel makes an appearance at last. The four-time world champion's first effort is nothing to shout about, though, as he slots into 18th - and last - with a 1:44.588.

Image source, Getty Images

Kimi Raikkonen and Fernando Alonso got a taste of the future when they got behind the wheel of two concept cars, created by students who had to make the most of aerodynamics and materials so as to reduce the impact on the environment, ahead of this weekend. They probably had a lot more fun driving those than this year's Ferrari which has been very, very disappointing.

Image source, Getty Images

McLaren are continuing their upward curve of form with another strong performance so far this weekend in Austin. Kevin Magnussen is third quickest, one second adrift of Hamilton, with Jenson Button a few thousandths back in fourth.

Jayne:, external Austin track looks so wide, double decker bus races wide not F1!!

Nico Rosberg wrestles P1 off his Mercedes team-mate Lewis Hamilton, his lap of 1:40.078 is 0.537 seconds quicker.

Image source, Mercedes/Twitter

Mercedes on Twitter: Lewis Hamilton comes over all psychedelic - it's a slick look too

Here's how they stand with 68 minutes remaining:

1) Ros 2) Ham 3) Mag 4) Alo 5) Ver 6) But 7) Ric 8) Kvy 9) Mas 10) Gut 11) Hul 12) Bot 13) Per 14) Sut 15) Rai 16) Gro 17) Mal 18) Vet

Everyone has been out and set a time apart from Sebastian Vettel, who is going nowhere fast. The four-time world champion is pacing around the garage, arms folded, while his team change the gearbox on his Red Bull.

Image source, Lotus/Twitter

Lotus F1 on Twitter: Well it was only a matter of time until Romain came back in, he wants to say hi to Matt LeBlanc too!

The Friends star is watching this session from the Lotus garage.