Left-turn slip lanes are being removed from some of Adelaide's busiest intersections following a number of pedestrian deaths over the past five years.

Key points: Four pedestrians have been killed in the past five years at left-turn slip lanes

Four pedestrians have been killed in the past five years at left-turn slip lanes A number of the lanes in SA are being removed to improve safety

A number of the lanes in SA are being removed to improve safety There are at least 750 left-turn slip lanes throughout the state

The lanes allow drivers to bypass traffic by turning left at red lights — as long as they give way to pedestrians and oncoming vehicles.

The Department of Planning, Transport and Infrastructure (DPTI) confirmed four pedestrians had been killed at left-turn slip lanes over the past five years.

It said 20 other pedestrians had also been injured, one seriously.

'Safety is first and foremost in our minds'

DPTI today confirmed left-turn slip lanes had been removed and replaced with signalised left turn lanes around East Terrace at Botanic Road, Rundle Road, Grenfell Street and Bartels Road in Adelaide's CBD.

It has also modified the slip lane to a higher angle at the intersection of Henley Beach Road and Tapleys Hill Road, west of Adelaide.

Three slip lanes were also removed at Carlisle Street in Ethelton and a separate left-turn lane has been created at the intersection of Greenhill Road and Portrush Road, and Greenhill Road and Fullarton Road, in Adelaide's east.

DPTI said Adelaide City Council had also improved safety at slip lanes in the CBD at the intersections of North Terrace and Frome Road, South Terrace and Sir Lewis Cohen Avenue, and West Terrace and North Terrace and in Hindmarsh Square.

A diagram which shows an example of the correct way to enter a left-turn slip lane in SA. ( mylicence.sa.gov.au )

Transport Minister Stephan Knoll said the change was all about eliminating risks for pedestrians.

"First and foremost, our road network needs to try and keep everybody alive; whether that be cars, pedestrians or cyclists — or now even e-scooters," he told the ABC.

"We need to make sure that safety is first and foremost in our minds."

He said following the spate of deaths, a decision was made to change the way slip lanes were designed as part of road upgrades.

"This means having a much shorter slip lane at 45-degree angles to the right angle traffic," he said.

"This means that pedestrians can stay alive. We've seen too many deaths of pedestrians at these slip lanes."

The department said while exact numbers were not available, there were at least 750 slip lanes throughout South Australia.

RAA road safety manager Charles Mountain welcomed the move and said motorists were often more focused on other cars, ignoring pedestrians.

"If you watch people using slip lanes, they tend to focus towards the right so they're looking at the oncoming traffic," he said.

"So, if there's a pedestrian approaching on their left, sometimes motorists simply will not see them."

'Where there's confusion, there's potential for harm'

Harold Scruby from the Pedestrian Council of Australia said it was time pedestrians were put first in terms of road safety.

"Number one: a pedestrian can cross any road, anywhere, any time with safety, providing it's not within 20 metres of a pedestrian crossing," he told ABC Radio Adelaide's Drive program.

"Secondly, and this is the second-most misunderstood rule in the road rules: if a motorist is turning left or right at an intersection, the motorist must give way to the pedestrian.

Mr Knoll said the change was all about pedestrian safety. ( ABC Radio Sydney: Amanda Hoh )

"That doesn't mean it has to be a pedestrian crossing, it means just left or right and that includes these so-called slip lanes."

He said the danger posed for pedestrians at these crossings could be traumatic.

"One of the worst things that's happened over the years is that authorities have put in what we call a green on green," he said.

"That means that they let the lights turn green for the motorist and for the pedestrian at the same time and it's resulted in a lot of trauma.

"Where there's confusion, there's potential for harm.