The speed limit has been cut to 25km/h on the road bisecting Victoria Square while the Adelaide City Council checks the safety of the newly paved surface.

The Victoria Square concern follows the reduction of the speed limit to 10km/h on a similarly paved section of Hindley Street west, near the University of South Australia.

The tests on the recently completed Hindley Street upgrade showed it was too slippery in the wet for vehicles, resulting in the limit being reduced to a snail’s pace.

This morning, the Adelaide City Council revealed that it had similar concerns about the paved section of road between the two halves of Victoria Square.

That section has been reduced to 25km/h while the council evaluates the results of slip tests.

The projects had different designers but the same construction contractor – Fulton Hogan. Taylor Cullity Lethlean designed the Victoria Square upgrade.

The past president of the Adelaide West End Association, Andrew Wallace, told InDaily he was concerned that the wrong pavers had been used on the Hindley Street project, which is a joint council/UniSA effort funded by the state and federal governments.

He said he doubted that the designers of the award-winning project, Hassell, would have specified the incorrect pavers.

“Maybe that isn’t the right paver that’s sitting down there,” he said.

In November last year, the association reported to its members that part of the upgrade had been pushed back due to a delay in the supply of pavers.

Fulton Hogan would not respond to InDaily’s queries, referring questions to the Adelaide City Council.

Hassell also referred questions to the council and the university.

InDaily understands the university and the council will work with both Hassell and Fulton Hogan to determine whether the problem was in the specification of the pavers, the installation, with a third-party supplier of the pavers, or an unexpectedly poor slip performance despite the use of correctly specified and laid pavers.

Responding to an Advertiser report about Hindley Street today, the council’s manager of city infrastructure and public works, Neil Brown, told ABC radio that slip tests had been conducted on the Victoria Square road paving and the speed limit had been reduced as a precaution while the results were assessed.

He said the council was “working through a process with the contractor to ensure it’s a safe and secure environment for road users”.

Later, the council released a statement saying it had “proactively undertaken skid resistance testing of the stone pavers used through the centre of Victoria Square/Tarntanyangga”.

“The test results, based on an agreed DPTI testing procedure for urban roads, show that the skid resistance is lower than bitumen surfaced streets,” the statement said.

“As a precautionary measure, the speed limit will be temporarily reduced to 25km/h for the time being for the safety of all road users while the project team ascertain the level of risk in this important city space.

“The decrease in speed provides the maximum opportunity for the public, including pedestrians, cyclists and drivers to be aware of their surroundings and alert to the presence of others.”

The council was seeking independent expert advice on the test results and the use of stone pavers on urban roadways.

“A risk assessment will be performed and consideration will be given to any subsequent treatments that could be deployed to improve the performance of the roadway and mitigate safety concerns.”

The council said both the Victoria Square and Hindley Street upgrades “have taken an innovative approach to design and the materials used that challenges traditional streetscape design”.

Options for fixing the Hindley Street surface, which was part of a $4 million upgrade, include roughing the surface.

City councillor David Plumridge told InDaily he was “concerned and disappointed, but I’m sure it can be deal with fairly easily”.

He said the speed limit reduction was reasonable – and suggested it could remain.

“It’s a short distance,” he said. “It’s where people are crossing the road freely and (they) shouldn’t be worried about being run down by a speeding car.

“Pedestrians and other traffic – cyclists and cars and so on – can mingle in a shared space and 10 kilometres is recognised as a reasonable speed to have. It may seem a bit slow for cars, but it’s just the only way to allow safety for pedestrians.”

– additional reporting by Bension Siebert