A 60mph speed limit is planned for the M3 motorway, following the intriduction of the same smart motorway strategy for the M1. These new limits are the result of government plans to combat emissions and congestion.
This three-mile smart motorway and its 60mph restriction will run between J3 at Lightwater and J4 near Farnborough between 7am and 7pm.
The 60mph limit covers part of a 13.4-mile stretch between J2 and J4a where additional lanes will be opened in both directions to improve capacity - at a cost of £174million.
The Highways Agency (HA) hopes this new motorway can ease congestion flowing in and out of London. Traffic currently enters the capital on a 45mph average in the mornings and exits at a 56mph average in the evenings.
According to the HA, the motorway expansion would cut journey times by four minutes in the morning and one minute in the evening, but the 60mph limit is needed to ensure air pollution does not breach legal limits following the planned expansion of the route.
The HA also stressed that these restrictions may be lifted within four years as emission reducing technology in cars improve.
Robert Goodwill, the Roads Minister, said: “The M3 is heavily congested and the introduction of this smart motorway will help improve journey times by smoothing traffic flow.”
Another 60mph restriction on the M1 between South Yorkshire and the East Midlands was announced last month, affecting junction 28 at Mansfield and junction 35a at Sheffield and Rotherham.
Four other major roads covering 38 miles of the UK’s 4,300-mile strategic road network may soon get the same restrictions.
Edmund King, president of the AA, said: "The AA believes that the extra capacity is required and that ironically 60mph speeds at peak times would actually speed up journeys.
“However a majority of drivers question whether reducing motorway speeds will make any difference to air pollution as 69 per cent see lorries as the main culprit.”
David Bizley, technical director of the RAC, said: “Coming hot on the heels of the M1 announcement, the M3 plan 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.”