A grieving mother has accused Prince Charles’s designer town Poundbury of putting aesthetics over safety after its refusal to install its first yellow lines at the spot where her son was killed in a motorcycle accident.

Poundbury is the Dorset town owned by the Duchy of Cornwall and built in line with Charles’s vision of a sustainable and architecturally pleasing community.

Tina Cooper has campaigned for the road safety markings to be installed after her 25-year-old son, Richard Hallett, died in September 2018 in a low-speed collision with a van.

The duchy had initially agreed to install yellow lines at the spot, in light of the “strength of feeling” expressed by grieving relatives. In an updated statement on Thursday, however, a proposal was submitted to install two traffic bollards at the spot to deter parking.

Cooper said: “It is ridiculous. Parked cars on the junction where Richard crashed made sightlines hard and they know that full well.

“The truth is Prince Charles doesn’t want road furniture because he doesn’t want Poundbury to look like other towns with road signs at junctions. The duchy feel if they agree to doing this at one junction they’ll have to do it at all the danger spots in Poundbury.”

She added: “It’s them putting the prettiness of the town above saving lives”. Cooper also claimed parts of the town were a “death trap”.

A duchy spokesperson said: “Having investigated the matter further with the highways department of Dorset council, it became clear the key reasons for this tragic accident were not related to the highway design and there would be no real benefit of installing double yellow lines. We have therefore taken the decision not to go ahead.”

Dorset’s assistant coroner, Brendan Allen, expressed concerns after the inquest into Hallett’s death. It heard there were no road markings in the Poundbury estate to indicate which vehicle had the right of way when reaching a junction, and parking was permitted in the area of the collision so reducing the sightline of the van driver. He recommended the Duchy of Cornwall take urgent action to prevent future deaths.

Clarence House said Prince Charles had no part in the decision not to install yellow lines, which was made by the duchy at local level in consultation with Dorset council’s highways department.

The duchy said that Poundbury is a walkable community that constrains car speeds through road designs that achieve all national highway safety standards. It added that all areas of the town have been designed with traffic calming in mind. This was the first fatality since the town began, and there have been only a few minor accidents in the past five years.

Poundbury’s roads are mostly controlled by the duchy as landowner, though some have been adopted by the council.

Oliver Letwin, the MP for West Dorset, said: “I have talked to Tina and I think there is a problem with road safety in Poundbury, as is demonstrated with the tragic accident involving her son.

“I agree with her view that the roads in Poundbury which have not been adopted by the council need to be, and I’ve asked the council to look again at that to speed the process up so that we can make these roads as safe as possible. They need to be adopted quickly and properly regulated.”

Earlier this year the sight-loss charity RNIB described the shared-space scheme in a square in Poundbury that had no traffic lights, kerbs, road markings or crossing points as “an accident waiting to happen”.