- 3 updates
The RAC has said there would "negative impact on business efficiency and individual mobility" if a lower speed limit of 60mph was introduced more widely.
The Highways Agency proposed a 60mph speed limit on a 32-mile stretch of the M1 as part of an attempt to ease congestion.
The proposed reduction is part of the "smart motorway" scheme, which would involve the hard shoulder being used as an extra lane.
But the added volume of traffic would risk violating EU restrictions on air pollution.
Lowering limits would reduce amounts of pollution emitted by vehicles at high speed and reduce polluting traffic jams, the Highways Agency believes.
Motoring campaigners have warned that speed limits on motorways across the country could be lowered after the Highways Agency proposed a 60mph zone on a section of the M1.
The plan would come into effect between junction 28 of the M1 at Mansfield and junction 35a for Sheffield and Rotherham between 7am and 7pm, seven days a week.
The Highways Agency said the reduced speed limit would be used to help reduce carbon emissions along the route.
But RAC technical director David Bizley said the trial "could pave the way for similar restrictions on other sections of motorway".