One freeway tunnel closed every night all January, speed limits and delays all month

Speed limits and delays will hit the freeway tunnels for weeks as urgent repairs and upgrades take place. Here’s how long traffic will be slowed.

Freeway delays and speed restrictions through the tunnels will remain in place 24/7 for most of January – longer, if the weather is bad.

The Heysen Tunnels are undergoing a major refit and safety upgrade to fix some elements at the end of their service life, with work focusing on the Adelaide-bound tunnel in January.

The downtrack tunnel will be closed every night until at least January 25, with all traffic heading through the uptrack tunnel.

During the day both tunnels are open, with one lane shut in the downtrack tunnel and speed restrictions in place.

The Heysen Tunnels on the South-Eastern Freeway will be partly closed and speed limits in place during January as safety upgrades. Picture: Facebook

Work, which the Transport Department said was on schedule, will revert to nights in February.

The upgrades include improved traffic management and will allow emergency services to better respond to incidents within the tunnels.

The $150m works are jointly funded by the federal and state governments. Speed cameras inside the tunnels are not included in the refit.

Tunnel works include lighting systems upgrades, new automated fire sprinklers, upgraded jet fans for ventilation and repairs to tunnel lining.

Giant fans – 23 in total – are being installed as part of an upgrade to the fire suppression system in the Heysen Tunnels. Picture: Dan Cregan / Facebook

Giant fans – 23 in total – are being installed as part of an upgrade to the fire suppression system in the Heysen Tunnels. Picture: Dan Cregan / Facebook

CCTV cameras will be replaced, the emergency communication system upgraded and thermal incident detection systems and new digital signage installed.

A key part of the upgrades is to improve how crashes as managed with an extension of the Intelligent Transport Systems (ITS).

This will include installing “formalised temporary crossover points” in the median strip to allow vehicles to shift quickly to the other tunnel in the event of a crash or breakdown to keep traffic moving.

Work is continuing 24/7 until January 25, when traffic volumes are historically lower on the freeway, the department said, weather permitting.

During January, the downtrack tunnel will be closed from 7pm to 6am every night, with traffic heading in both directions through the uptrack tunnel and speed limited to 40km/h.

Both tunnels will open during the day from 6am to 7pm in January, with the left lane in the Adelaide-bound tunnel closed to all traffic, with two lanes open and speed limits cut to 60km/h.

The tunnels will be open normally during the day from February, the department said, with the majority of work returning to Sundays to Thursdays between 7pm and 6am.

It said work should finish in the second half of 2024, weather permitting.

Works will stop and posted speed limits reinstated for both tunnels in the event of a bushfire.