M25 junction 10 to junction 16 smart motorway
We’re working up smart motorway design options for this busy stretch of the M25.
Project information
In 2014 the government announced the preferred solution for this stretch of the M25 was to upgrade it to a smart motorway. This means the existing hard shoulder would be converted into a traffic lane so there would be five lanes between junctions 15 and 16 and four lanes elsewhere and there’d be emergency access areas instead of the hard shoulder.
This section of the M25 has the highest traffic flows of any motorway in England. More than 200,000 vehicles use this stretch every day. Where the M25 connects with the M4 and the M40 between junction 15 and 16 is particularly busy as is junction 14 which connects directly with Heathrow Airport.
By converting this stretch to a smart motorway the flow of traffic can be better controlled and there will be less congestion and fewer delays. Upgrading the stretch will also create more capacity.
Documents
Related Road projects

Traffic information
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