Five Mile Lane

  • Trunking of the A48 is not part of the LDP
  • Safety improvements for Five-Mile Lane are included in the LDP - However, it's difficult ot argue against these safety improvements due to serious and fatal accidents.  It's inevitable that a safer Five-Mile Lane will attract more traffic, and that some of that traffic will then use the A48 through St Nicholas.
  • When the safety work is complete, trunking of the route to the airport via St Nicholas may be considered again.

Improvements to Five-Mile Lane included in the LDP Deposit.  This has raised concerns that the Welsh Government will direct traffic for the Cardiff Airport and St Athan through St Nicholas.

The LDP Infrastructure Plan states:
Five Mile Lane (A4266) Improvements 
2.2.61  The  A4266  (Five  Mile  Lane)  connects  Barry  at  the  Waycock  Cross  roundabout  with the Sycamore Cross junction on the A48, and comprises an essential part of the highway network leading to the Enterprise Zone. It provides an important north-south corridor within the Vale of Glamorgan however there are road safety issues due to the road alignment. The proposed Five Mile Lane Highway Improvements stem from the Welsh Government’s proposals to trunk the route to Cardiff Airport via Culverhouse Cross – Sycamore Cross – Five Mile Lane – Airport.  
2.2.62  The Council has previously received a Principal Road Grant from the Welsh Government to advance the Five Mile Lane Highway Improvement Scheme, and to date this work has involved the  signalisation  of Sycamore  Cross  junction,  as  well  as  initial  design  and  feasibility  work together with various environmental assessments. Additional funding is required to complete the  development  and implementation  of  this  scheme,  with  the  Welsh  Government  having announced their commitment to the scheme. Future proposals will need to be the subject of formal  Environmental  Impact  Assessment  and,  if approved,  would  improve  highway  safety, help reduce congestion and enhance access to Cardiff Airport and St Athan.  

In 2006, a Public Inquiry was held when the Welsh Government decided to Trunk the A48 and Five-Mile Lane to provide a new route from the M4 and Cardiff to Cardiff Airport.

The recommendation of the public inquiry was to not trunk the A48 and Five-Mile Lane

The reasons can be summed up as:
  • Poor traffic modelling - the Welsh Governments numbers were wrong or missing
  • No risk assessment - Five-Mile Lane has a poor safety record compared to the existing route
  • The Welsh Government had not given enough priority to funding the necessary improvements

Below is a summary of the report of the Public Inquiry into the Trunking of the A48.

"I consider that none of the four advantages of the proposed Trunking route identified by AG [Welsh Government] have  been  convincingly  proven.  However,  I  accept  that  there  would  be  an  overall environmental impact advantage arising from the proposed Trunking. As discussed above I see the disadvantages of the proposed Trunking as the likely increased risk of accidents as a result of additional traffic on Five Mile Lane and the uncertainty of duration of that increased risk. As a consequence, it may well be that negative perceptions that currently exist regarding CIA are not changed but that they become even more negative. Accordingly, I conclude that the advantages of the proposed Trunking do not outweigh the disadvantages and therefore this condition has not been met."

"Five  Mile  Lane  needs  improving  to  enhance  road  safety,  support  development  in  the south  of  the  Vale of  Glamorgan  and  cater  for  projected  Airport  growth.    However,  the Minister acknowledges that the timing of improvements was a pivotal issue in the Report.

The Assembly Government will now work with the Vale of Glamorgan Council to deliver the improvements using Principal Road Grant funding.  In this way Cardiff International Airport will get improved access in the shortest time possible."

In his report on trunking of the A48, the Inspector named six conditions relevant to the expediency criteria identified above, of which 4 failed to comply:

Condition 1: There is a need for the proposed Trunking and that the proposed Trunking would meet that need.

"In my view, the need for the proposed Trunking has little to do with improving journey times or journey reliability to and from CIA as the direction of travel of airport travellers is mostly in the opposite direction to peak commuter flows [8.9]. Neither would the proposed Trunking resolve the congestion issues at Culverhouse Cross as this is not its purpose. The real need  is  to  overcome  the  perceptions  about  the  location  of  CIA  and  the  type  of  services operated by CIA. As these perceptions have not been quantified, in my opinion, the need has not  been  demonstrated.  Even  if  the  perceptions  and  hence  the  need  had  been demonstrated, no evidence has been presented that the negative perceptions about CIA would be reversed as a result of the proposed. It could be that perceptions would become even more negative than they are at present. I conclude therefore that this condition has not been met."


Condition 2: The proposed Trunking is appropriate and safe. 
  • No risk assessment of the highway had been undertaken by the Welsh Government.
  • No details are available of future safety improvements of Five-Mile Lane.
  • Widening and straightening of Five-Mile Lane would take several years.
  • Due the "very poor" safety record of Five-Mile Lane, the public enquiry was unable to conclude that sending additional traffic along Five-Mile Lane would be safe. 
  • The WG accepted that Five-Mile Lane that “represents a hazard to all types of traffic”.
  • In the inspectors opinion, "the standard of Five Mile Lane as it presently exists, falls far short of any reasonable person’s expectation of what should be provided by a “trunk road” and the WG accepted this.
  • "Unsatisfactory to create a trunk road that would be unsuitable for use by HGVs for a number of years".
  • The inspector found that the traffic modelling was inadequate, omitting the signalised junction of the A48 with Dyffryn Lane and providing inaccurate journey times.

Condition 3: Resources  would  be  available  within  a  reasonable  timescale  to  implement  the  proposed Trunking.
  • Medium term improvements could be subject to delay, due to further studies and acceptance of the study recommendations, and the CIA access project, at the time, not being a high priority.
  • Longer term improvements also depended  on  the  outcome  of  further  studies  and  the acceptance by AG of any resulting recommendations.
  • " Because of the Five Mile Lane safety issues this is a real concern."

Condition 4: The advantages of the proposed Trunking would outweigh any disadvantages.

The Welsh Government gave four advantages of Trunking the A48 and Five-Mile Lane. Trunking would: 

  • take traffic away from the existing route where it can only travel at relatively low speeds, because of numerous traffic signals and roundabouts; 
  • have greater capacity to absorb increased traffic volumes compared with the existing route; 
  • have greater potential for upgrading and incorporation into a long term solution; and 
  • provide more reliable journey times to CIA than does the existing route.

The public inquiry found:

  • No evidence to support the WG claim that "numerous roundabouts" (five roundabouts on the A4050) on the existing route delayed traffic
  • No compelling case for change of route on basis of time - delays would still occur at Culverhouse Cross
  • Spare capacity on A48 and Five-Mile Lane given no weight due to poor modelling - modelled journey times made no sense, with peak time travel shorter than absolute minimum travel time.
  • Journey reliability on Five-Mile Lane is poor due to farm vehicles


  • There was no evidence to support the case that the proposed trunking would lend itself better to future incorporation into a long term solution than would the existing route
  • The way in which the A48 could be improved in the vicinity of St. Nicholas has not been explained 
  • No evidence has been submitted to demonstrate the unsuitability of the existing route for incorporation into a long term solution.
  • Existing route 2.1 miles shorter and has a better safety record.
  • "No meaningful assessment has been undertaken of journey time reliability"
  • “Escape route” problems on Five Mile Lane compared with the existing route
  • "Five Mile Lane is a dangerous road that may not be improved for six to seven years. Repeated road closures could give the proposed Trunking route to CIA a reputation for being unreliable."

The Inspector found that the Welsh Government's proposal Complied in answering:

Condition 5: The impact of the proposed Trunking on the local environment would be acceptable.

"I accept that the proposed Trunking would have no significant environmental impact.  On balance fewer  people in St. Nicholas and Tre-hill would be affected by a small  negative impact than would a greater number of people in North Barry who would be affected by a small positive impact. I conclude that this condition has been met."

No conclusion - lack of evidence

Condition 6: The proposed Trunking would represent the best available option and best value for money.

The Welsh Government "presented only the proposed Trunking option to the inquiry; the only alternative is the Do Nothing scenario.  The proposed Trunking results in an NPV of -£37.907M and  an economic disbenefit of £46.49M over the 60 year assessment period.  From the evidence presented by AG [Welsh Government], it is not possible for me to reach a conclusion on this condition."


The Inspector concludes: "Overall therefore, I conclude that the proposed Trunking is not expedient."

Ian Perry,
9 Nov 2013, 18:13
Ian Perry,
9 Nov 2013, 18:12