So says long-time Thirroul resident Alyn Vincent, who expects the closures to funnel even more traffic through the Thirroul area and "already congested" road.

"The bottleneck that already exists in Thirroul during the school peak time hour and the business peak hour is going to be exacerbated," Mr Vincent said.

"Getting in and out of the side streets is going to be more than problematic."

Roads and Maritime Services is looking to carry out work to reduce the risk of land slips along Lawrence Hargrave Drive at Stanwell Park.

The work would see the full closure of Lawrence Hargrave Drive in both directions for 1.3-kilometres between Otford Road near Bald Hill and Chellow Dene Avenue.

The work will be carried out in two stages, with two four-week closures.

The first four-week closure is proposed during February-March 2020 and the second during May-June 2020.

Detours will be via Bulli Pass and the M1 Princes Motorway, which means anyone living south of the road closure and wanting to go to Sydney will need to travel down Lawrence Hargrave Drive and use Bulli Pass.

"The RMS says that local residents will be allowed access but they do not define local," Mr Vincent said.

"Are school buses going to be allowed to go up and down Bald Hill?

"And what about fire brigades, ambulances and police cars who need to make a quick transit to hangliders, paragliders or motorcyclists who may be involved in a serious accident from Bald Hill.

"Do they have free access? Too many questions remain unanswered."

The one-time pharmacist at Thirroul added businesses north of Coledale will also be affected by the closure.

He said the major traffic flow on weekends was either south on LHD and north up Bulli Pass or vice versa.

"To expect traffic to travel down Bulli Pass and drive north to Stanwell Park then reverse direction is not on," Mr Vincent said.

"I'd imagine the owners of Scarborough Pub would be far from happy because their weekend trade is just totally dependent on north south traffic.

"The motorcycle traffic to Bald Hill on weekends via National Park and LHD is a major part of the business for the café and ice cream van at Bald Hill. It is hoped the RMS will compensate these businesses but historically that has not been the case."

Read more; Lawrence Hargrave Drive to close for eight weeks next year

Mr Vincent said while the RMS were asking for community input, they seemed to be fairly well set on a 24/7 closure of Bald Hill.

The same situation occurred when Bulli Pass closed.

"Then, in quick succession, there were major accidents on Mount Ousley which necessitated immediate opening of Bulli Pass. Despite the RMS saying this was not possible, they managed to achieve the re-opening of the Pass within hours," Mr Vincent said.

Earlier this month a Roads and Maritime Services spokeswoman told the Mercury a full closure was the only option due to the narrow and winding nature of the road.

People can give feedback online at rms.work/lhd-closure.

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