The Highways Agency is already consulting, on a reduced speed limit on a 32-mile section of the M1.
It has now launched a consultation on a similar move on a 2.8-mile section of the M3 between junctions 3 and 4.
The Highways Agency says the new restriction would apply from 7am to 7pm, seven days a week.
It would be in place between Junction 3 at Lightwater and Junction 4 near Farnborough on what the agency describes as “this major motorway link between London and the Port of Southampton and the South West of England”.
The proposal has been prompted by concerns about higher levels of pollution at peak times following the conversion of the hard shoulder into a traffic-carrying lane – something which is happening at other parts of the motorway network as part of efforts to cut congestion.
The agency says that the extra lanes will cut journey times during peak times, so even with the lower speed limit, journeys will be quicker.
It said it also expects to be able to remove the 60mph limit by 2019, as cars become less polluting.
Motoring group the RAC warned it could pave the way for a reduction from the national standard 70mph to 60mph at other parts of the network where hard-shoulder running is to be allowed.
RAC technical director David Bizley said: “Given the landmark announcement in early January about a reduced speed limit of 60mph on a 32-mile stretch of the M1 in order to protect air quality in the area, this should really not come as a surprise.
“It does, however, come hot on the heels of the first announcement and invites the question as to whether any of the eight other planned all-lane running, smart motorway schemes which the government have heavily invested in will also need to have reduced speed limits put in place to protect air quality?
“News that the restriction should lead to higher average traffic speeds on this stretch is something of a consolation for commuters, but others who travel outside of peak times will no doubt wonder why they can’t drive at 70mph on a clear motorway.”
Motorists and other interested parties have until 11 April to comment on the M3 proposals.
The M1 consultation ends on 3 March.