By ANNA USHER

The biggest shake-up to the Warringah Freeway in a generation kicks in from 6am Saturday 2 May, and Monday morning’s peak hour will be the real test.

Five permanent changes will impact every commuter route from Mosman, Neutral Bay, Cremorne, Cammeray and Kirribilli into the CBD.

Drivers who have not done their homework risk finding themselves in the wrong lane, on the wrong ramp, or hunting for a slip lane that no longer exists.

Here is what is changing, and what to do.

1. The Sydney Harbour Bridge slip lane is gone

The slip lane just south of the Ridge Street shared user bridge is being permanently removed. Drivers must now choose between the Bridge or the Tunnel about 1 kilometre earlier (at the West St bridge).

What to do: get into the correct lanes by the West Street bridge in Cammeray. Outer lanes for the Sydney Harbour Bridge, inner lanes for the Sydney Harbour Tunnel. Final chance to switch is 350 metres south of the Miller Street bridge.

Morning peak silver lining: the reversible (tidal flow) lane stays open Monday to Friday from 5.30am to 9.30am and still gives access to Lane 4 of the Sydney Harbour Bridge from the inner lanes.

Stuck in the Tunnel by mistake? After the Domain Tunnel, take the City / Woolloomooloo exit and loop back.

2. Falcon Street / Military Road: two ramps, two purposes

This is the change Mosman, Neutral Bay and Cremorne drivers will notice most.

The new eastern on-ramp becomes a dedicated 24-hour bus lane. No cars. General traffic must use the western on-ramp for the Bridge or Tunnel.

Access to the Cahill Expressway and the Alfred Street off-ramp from this interchange is gone.

Heading to the Cahill Expressway? Use the Miller Street or Mount Street on-ramps instead.

Heading to North Sydney or Kirribilli? Travel via Miller Street and the Pacific Highway.

3. Ernest Street on-ramp is now Tunnel-only

The Ernest Street on-ramp in Cammeray becomes a dedicated entry point for the Sydney Harbour Tunnel. There is no longer any way to reach the Bridge from this ramp.

Bridge-bound drivers: travel along Ernest Street to Miller Street, turn north, then turn right onto the Miller Street southbound on-ramp. The middle lane of the Falcon Street on-ramp also gets you to the Bridge.

4. The new dedicated southbound bus lane opens

A dedicated southbound bus lane runs from south of the Miller Street overpass all the way to the CBD and the Sydney Harbour Bridge. A new bus on-ramp at Mount Street feeds directly into it.

According to Transport for NSW, the new corridor will make the bus run to the city safer, faster and more reliable in peak hour.

5. Truckies and overheight vehicles

Vehicles over 4.4 metres high are banned from the Sydney Harbour Tunnel.

Significant penalties apply for breaches, including suspension of licence and registration, and demerit points, according to Transport for NSW.

What to do: keep left at the West Street bridge. Use the Falcon Street or Miller Street on-ramps. Do not use the Ernest Street on-ramp.

Before Monday

Watch the official Transport for NSW driver-view animations linked through this story. If you can, do a practice run over the weekend. Information line: 1800 931 189.

The full gallery is on the Transport for NSW project portal here.

The $2 billion-plus Warringah Freeway Upgrade began in March 2022 and is due for completion in late 2026.

Mosman Collective will be on the road Monday morning tracking how the changes bed in. Spot chaos? Send your photos and tip-offs to [email protected]