Flowers have been left at the crash scene

The victims were named locally as driver Natalie Malpas, 20, her brother Marc, 16, and friends, brothers Aaron and Gavin Matthews, aged 16 and 19.

They died when their yellow Renault Megane hit a wall near Ammanford in Carmarthenshire on Wednesday night.

A police investigation is continuing into the cause of the accident.

People living in houses near the crash scene said they had been campaigning for years for additional traffic calming measures.

Marc Malpas and Aaron Matthews were killed in the crash

David Harries, owner of the property hit by the car, said he had intended to send a letter to both the council and the police calling for action along the straight stretch of road.

"My first reaction after the accident was one of utter disbelief," Mr Harries said on Thursday.

He added: "It is ironic that I was going to send off that letter today. It was only typed up yesterday."

Mr Harries said there had been two accidents on the stretch of road in the last month and residents had written to police before.

Dyfed-Powys Police added that, as well as a coroner's inquest, there will be a multi-agency inquiry into the need for further traffic calming at the site.

Police said they were looking at "all possible causes" for the crash on a straight section of the Pontamman Road.

Initial reports suggest the car veered across the road and mounted the kerb on the opposite side of the carriageway about 50 yards before the smash, before heading towards the wall of a bungalow.

Eyewitness reports say the car flipped over onto its roof and debris was scattered in neighbouring gardens.

It is thought the car crashed after mounting a kerb

All four victims, who had been playing pool at a local pub before the accident, were pronounced dead at the scene by paramedics.

Marc's 15-year-old girlfriend Rachel Meed said she had seen him just minutes before the crash.

The Malpas family are originally from Kent and had only recently moved to the area, while the Matthews brothers were originally from the Bridgend area.

The driver, Natalie Malpas, was the mother of an 18-month-old boy.

Insp Tom Edwards said that it was at the very early stages of investigation but they were "looking at all possible causes" and that speeding could not be ruled in or out.

"I can't confirm that speed was in any way a contributory factor in connection with this particular incident," he said.

He confirmed there had been four accidents that resulted in injuries on that stretch of road in the last five years.