FOI release

Speed Limits Due To Air Quality

Case reference EIR2024/00183

Received 1 June 2024

Published 6 September 2024

Request

I was again restricted to 60mph westbound on the M4 on Saturday 4 May 2024 @10:30 With the political statement “Speed Limit for air quality” I expect speed restrictions for safety reasons not arbitrary political dogma. I do not want the response you gave last year when you miscalculated the delay your signage caused. By not answering a question I asked but answering a question you chose to give a misleading shorter period of delay. I am not interested even if you get the calculation correct, this delay when multiplied by every journey on this Motorway is exacerbating the cost of living crisis. As I stated previously stated there is no incentive to go Electric as your “smart” signage is dumb with no differentiation for polluting vehicle. The effect of arbitrary restriction is against my human rights. I wish to challenge your right to impose it. Under the freedom of information I would like you to confirm to me: Who approved this restriction, was it: An apparatchik in the highways Agency based on their own personal politics? A direction by a political organisation and if so who: the local council or the mayor of London or Department for transport? Please state the scientific level of air quality at which this restriction is applied? How many days in 2024 this restriction was actioned?

Response

I can confirm that we hold the information you have requested.

Who approved the 60mph speed limit trials including the M4 Jn3-4?

The Department for Transport approved the speed limit trials.

The scientific level of air quality requiring the 60mph speed limit for air quality

The annual mean nitrogen dioxide (NO2) limit value of 40μg/m³, as set out in Schedule 2 of the Air Quality Standard Regulations (2010).

How many days in 2024 this restriction was actioned?

The limit value is calculated as the average of all hours in a year (8760 or 8784 for leap years), therefore the 60mph speed limit for air quality is displayed at all times.

The only times the message for air quality is not displayed is where there is a need to display an alternative message and / or lower speed limit. For example in the case of congestion or a lane closure.

Documents

There are no documents for this release.

This is National Highways' response to a freedom of information (FOI) or environmental information regulations (EIR) request.

You can browse our other responses or make a new FOI request.