The latest notice confirms that the Bang Khu, Samkong, Darasamut and Chalong underpasses will be closed nightly from 8pm to 6am through to June 30.
The closures are required to allow contractors to continue upgrading infrastructure as part of the Smart City Underpass Monitoring and Control Centre project.
According to the Phuket Highways Office, the works include the removal of ageing lighting systems and the installation of new electrical systems equipped with remote power outage notification technology.
Crews are also installing automatic licence plate recognition cameras and upgrading traffic signs to internet-connected variable message systems capable of displaying adaptive traffic information.
The project is intended to improve traffic management, safety and monitoring capabilities at key transport routes across Phuket.
The latest announcement marks an extension of ongoing upgrade works that have been taking place at several underpasses on the island in recent months.
Previous phases of the project included upgrades at the Phuket Airport Underpass, while work has continued at the Bang Khu, Samkong and Darasamut underpasses. The Chalong Underpass has now been added to the list of locations affected by overnight closures.
Motorists are advised to avoid the affected underpasses during closure hours and use alternative routes where possible.
The Phuket Highways Office apologised for any inconvenience caused by the works and said the temporary closures are necessary to ensure the safe installation of the new systems.
The project is being supervised by Senior Civil Engineer Sanakorn Thabthimthongsuk.
Members of the public can report damaged road surfaces, potholes, faulty street lighting, malfunctioning traffic signals, damaged traffic signs and other highway-related issues to the Phuket Highway District Office by calling 076-212179 during office hours.
Reports can also be made through the Department of Highways’ 24-hour hotline on 1586.