Pa gynlluniau sydd gan Lywodraeth Cymru i adolygu'r terfyn cyflymder newidiol ar yr M4 o gwmpas Casnewydd?
The variable speed limit around Newport was removed and replaced with a fixed 50mph speed limit between M4 Junction 24 to Junction 28 in March 2021. This was one of the South East Wales Transport Commission’s recommendations in its interim findings report.
Traffic flow data produced by the commission showed late lane changes and variable traffic speeds often led to a breakdown of flow, especially on the approaches to the Brynglas Tunnels. Whilst the variable speed limit was effective at regularising speeds during the inter-peak period, it had a limited impact on improving traffic flow during peak periods.
As traffic flows have now returned to levels similar to or slightly higher to those recorded prior to the pandemic, we will be undertaking an effectiveness review of the interim measures.
However, it is acknowledged any changes to a fixed speed limit along with the other interim measures are not sufficient to tackle the wider issues along the M4 corridor around Newport and this is reflected in the Commission’s final recommendations report.