A section of the M6 near Rugby is one of several motorways in the country to have its speed limit temporarily dropped to 60mph in a bid to tackle pollution.
Highways England (HE) has said it will introduce temporary lower limits on at least nine stretches of motorway as part of a wider monitoring programme that takes in 101 roads.
Among those roads affected will be the M6 from junction six to seven.
HE says that reducing the speed limit by 10mph lowers emissions by 17 per cent and can accelerate efforts to bring affected areas within legal limits by one to two years.
It argues that the trial zones cover a maximum of 4.5 miles, so will have a “negligible” impact on journey times.
HE says the measures are not permanent but will remain in place “until the results of the monitoring show that we can remove the restrictions and maintain clean air within the limit value”.
It hopes that a move to lower emissions vehicles will provide a longer-term solution but has not ruled out implementing lower limits in more locations if the trial proves successful.