Written question asked by Ranil Jayawardena (Conservative) on Tuesday, 23 May 2023, in the House of Commons. It was due for an answer on Thursday, 25 May 2023. It was answered by Jesse Norman (Conservative) on Thursday, 1 June 2023 on behalf of the Department for Transport.

M4: Speed Limits

Question: To ask the Secretary of State for Transport, for what reason the speed limit on the M4 eastbound along the route of the now defunct M4 bus lane has been reduced to 60 miles per hour.

Answer: The 2002 Statutory Instrument set speed limits for sections of the M4 between J1 and 3 (various sections at 40mph, 50mph and 60mph). There is a recent SI that set the speed limit between J3 – J4 and this was to manage the air quality for this section so that it was compliant. The M4 between J3 -12 is a smart motorway and therefore the area between this stretch without a fixed speed limit is subject to a Variable Mandatory Speed Limit (VMSL).

Secondary information