The rollout of smart motorways could eventually see the speed limit increased to 80mph, according to Transport Secretary Patrick McLoughlin.Speaking to The Times, he said: "We will look at [80mph limits] in a couple of a years' time when there's more smart motorways."Once we get smart motorways up and running and we get the free-flow through, and we get better running on motorways, I think that it is something that's there."Smart motorways convert the hard shoulder to a running lane to boost capacity and smooth traffic, operating either permanently or during busy periods.