A Conservative MS says the Welsh Government has failed to commit to a review into safety on the A48.
Andrew RT Davies called for ministers to take action after three men died in a two-vehicle collision near Bonvilston on 1st April.
But responding to a letter from the South Wales Central MS, transport secretary Ken Skates made no mention of a review.
He said: "As the local highway authority, the Vale of Glamorgan Council is responsible for the A48 at this location, and we will work with the council towards an aim for zero road deaths on the road network."
Mr Davies wrote to Mr Skates: "It is truly devastating to acknowledge that this is the fifth fatality on this stretch of road in two years and I believe we must recognise that there is an issue and take measures to prevent further tragedies taking place."
"As such, I believe it is vital for the Welsh Government to urgently assess the safety of the A48."
"I am therefore writing to you in your capacity as Cabinet Secretary for Transport to urge you to commission an urgent engineering review of this stretch of road to fully assess the risks and identify what measures can be taken to avoid more lives being lost."
Mr Skates - who is also the minister for North Wales - replied: "My thoughts are with the family and friends of those who sadly lost their lives in the collision that took place near Bonvilston on Tuesday 1 April."
The letter went onto add there had been fewer collisions on 20mph and 30mph roads in Wales this Spring compared with last year - the lowest Spring figure recorded outside the Covid pandemic.
Mr Skates added: "The Welsh Government provides annual road safety grant funding to local authorities to assist them in making safety improvements on the road network and also provides funding for road safety training and education."
"This year we provided the Vale of Glamorgan with £177,479 to improve Port Road and Porthkerry Road, Rhoose."
Reacting to the response, Mr Davies said it was "not on" to fob "local people off with some generic statistics".
He added: "The A48 forms part of the trunk road network, so Labour Senedd ministers have a responsibility to ensure it's safe."
"It's unacceptable that they've refused to review the stretch in question – a blanket approach does not work when it comes to road safety, the specific conditions of the road must be assessed."
An inquest heard Scott Jeffrey (34) from Bridgend, Lawrence Howells (51) and Barrie Jones (48) from Porthcawl died from multiple injuries when a Ford Puma car hit a Scania tipper lorry near Bonvilston on 1st April.
A South Wales Police investigation into the collision is continuing and the inquest is due to resume at a later date.

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