Motorists are advised of single-lane closures throughout the week except Thursday (a holiday) along H-1 and H-2 freeways to allow the state Department of Transportation to improve guardrails and shoulders.

Specifically:

• The right lane and shoulder lane of H-1 east-bound between the Lumiaina Street Overpass in Waipahu to the Kaimakani Street Overpass in 'Aiea from 8:30 a.m. to 3:45 p.m. will be closed intermittently.

• The left and right shoulder lanes of H-2 north-bound off-ramp (Exit 8B) from 8:30 a.m. to 3:45 p.m. will close in an alternating fashion.

• The right and shoulder lanes of H-1 east-bound between the Salt Lake Boulevard and the Hickam AFB/Nimitz Highway off-ramp (Exit 15) from 8:30 a.m. to 3:45 p.m. will be closed. There will also be alternating shoulder lane closures on the off-ramp at this time.

• The right and shoulder lanes of H-1 westbound between the Hickam Air Force Base/Kamehameha Highway onramp and the 'Aiea/Pearlridge off-ramp (Exit 13A) from 9:30 a.m. to 2:15 p.m. will be closed intermittently.

Electronic message boards will be placed at various points around the construction areas. Motorists are advised to use caution while driving through the work areas and to allow for extra travel time. Roadwork is weather-permitting.