Williams technical director Pat Symonds suspects Formula One's new-look cars are on course for a lap time improvement of four seconds per lap at high-downforce circuits next year.

F1's new regulations will see wider cars with wider wings and wider tyres in 2017, with the aim of increasing cornering speeds and lowering lap times. The hope is that the faster cars will create more excitement for fans, with FIA simulations earlier this year indicating a four- to five-second reduction in lap time.

Although Symonds may be inclined to play down the lap time improvement so as not to give Williams' 2017 development level away, he expects the final result will be in the lower range of the FIA estimate at high-downforce circuits such as Barcelona, and much less at low-downforce tracks like Monza.

"The performance is getting more like the mid-2000 cars but not really there," he said. "You remember the target was five seconds a lap quicker, well I'm not sure we will achieve that.

"We've got this big unknown of the tyres, of course, we really don't know where we are there. But making some sensible assumptions with the tyres I think we're going to see more like the four-second mark.

"A place like Barcelona where this type of car will be quite performant, I think it will be a bit more than that but some places like Monza for example, where actually you'll be taking a lot of downforce off because you've inherently got a bit more drag from the wider tyres, I don't think we'll see much difference in lap time at a track like that. Or nowhere near that amount."

Asked if drivers could struggle with the extra physical demands of driving the 2017 cars, Symonds said he is not expecting any more of a challenge than drivers had in the mid-2000s.

"They've driven cars like this before, it's like what we had in in 2004/5, around then. To give you an example of a sort of typical 200km/h corner, it's probably going to go up by 30 or 35 km/h, which adds a G to it. Yeah, it's going to be a bit more physical but it's not mindblowing I don't think."