VANCOUVER -- Drivers who usually take the George Massey Tunnel are being warned of two upcoming closures.

The tunnel on Highway 99 will be closed in both directions for two nights later this month, allowing the its fire suppression system and overhead lane control signals to be tested.

B.C.'s transportation ministry said in a news release Monday those closures will happen between 10 p.m. and 4 a.m. on May 28 and May 29.

Detours are available via Highway 91 and the Alex Fraser Bridge. Northbound traffic should detour by taking Exit 16. Southbound traffic should detour via Exit 37.

"Signage will be set up in advance of these exits to advise drivers of the tunnel closure," the transportation ministry says.

"All emergency vehicles will be accommodated through the George Massey Tunnel during this work."