Mark Webber was satisfied with a 'pretty straightforward' Friday for Red Bull

Mark Webber was satisfied with a 'pretty straightforward' Friday as Red Bull topped both practice sessions despite some reliability concerns ahead of the United States GP.

Indeed, with this being the first race at the Austin venue, grip is at a premium and only one racing line will rubber in over the weekend. "The best way I can describe it is like when you are driving in the snow in the slow lane and you are in the tracks of a lorry in front," said Sky Sports F1's Anthony Davidson. "And you daringly try to pass him in the middle lane, but it is too risky, too snowy and that is what it is going to be like for the drivers out there. It is pretty much going to be down to single file and it will be only the brave that risk going down the inside."