Sheikh Zayed Tunnel will close until Saturday for maintenance work, Abu Dhabi Police said.
Traffic will be diverted to the Sea Palace Tunnel while roadworks are under way.
The closure will begin on Wednesday and continue until Saturday, closing from 12am to 5.30am every day except Friday when the tunnel will remain closed until 11.30am.
Police advised motorists to use alternative routes during those times.
تنبيه
— شرطة أبوظبي (@ADPoliceHQ) January 9, 2018
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In June last year, Abu Dhabi Municipality began work on Dh109 million worth of improvements to the Sheikh Zayed Tunnel to meet the needs of road users.
Three northbound lanes in the tunnel and two heading south were closed for maintenance and were scheduled to reopen on Wednesday.
The work includes building a 400-metre slipway between Sheikh Zayed Road and the tunnel between Al Falah Street and Hazza bin Zayed Street junction by adding two tunnel-bound lanes each in the directions exiting Abu Dhabi and the city entrance.
The project is now expected to be completed by August 2019.
The Sheikh Zayed Tunnel, originally known as the Salam Street Tunnel, runs from the Hazza bin Zayed Street at the Sea Palace junction and forks out to Reem Island and farther ahead again to the Corniche and Mina Street.
The project, which started in 2007 in an effort to ease traffic on what was then Salam Street (now Sheikh Zayed bin Sultan Street), was completed in December 2012.
The covered section of the tunnel runs for 2.4 kilometres, while the open section covers 1.8km.
