More than 24,000 runners are expected to participate in the Great Aloha Run, which kicks off 7 a.m. Monday on Presidents Day, meaning numerous road closures will be in effect as early as 3:30 a.m.

The 8.15-mile, mostly flat course starts on Nimitz Highway fronting Aloha Tower in downtown Honolulu, then winds its way along the historic harbor, down Nimitz and Kamehameha Highway, and on to the Aloha Stadium.

Race organizers say Ewa-bound traffic to downtown will be diverted onto South Street, and motorists then can use South Beretania and Punchbowl streets to get onto the freeway. Also, it’s best to avoid using the Middle Street and Dillingham Boulevard intersection, as delays on these streets may result from the closure of the Middle Street interchange.

Road closures are scheduled for the following times:

>> From 4 to 8 a.m.: All downtown roads will be closed from Beretania Street to Ala Moana Boulevard/Nimitz Highway and from Nuuanu Avenue to Punchbowl Street.

>> From 4 to 8 a.m.: Ala Moana Boulevard/Nimitz (both directions) will be closed from South to River street intersections.

>> From 4 a.m. until after the race passes: Nimitz Highway (westbound) will be closed from River Street to the H-1 freeway/viaduct, and Nimitz Highway (eastbound) will be closed from Sand Island Access Road to River Street. Access to Sand Island will be via H-1 eastbound or Nimitz eastbound only.

>> From 4:15 a.m. until after race passes: Nimitz (under viaduct) will be closed from Kakoi Street to Valkenburgh, and Dillingham Boulevard will be closed at Middle Street (for westbound traffic under viaduct). Also, the H-1 freeway will be closed at Kamehameha Highway (exit under H-1 freeway).

>> From 3:45 a.m. until after race passes: Kamehameha Highway will be closed between Valkenburgh (westbound) and Aloha Stadium. Center Drive at Kamehameha Highway (both directions) also will be closed.

>> From 3:30 a.m. until after race passes: Radford Drive between Kamehameha and Bougainville Drive.

>> From 3:45 a.m. until after race passes: Kamehameha between Center Drive and Essex/Salt Lake Boulevard.

>> From 6:45 a.m. until after race passes: Salt Lake Boulevard will be closed between Kahuapaani and Kalaloa streets, and also between Kalaloa (both directions) and Kamehameha Highway.

On Monday, Joint Base Pearl Harbor-Hickam will make the following modifications during the run:

>> Borchers Gate will be closed from 4 a.m. to 1 p.m.; Luapele Gate (via Salt Lake Boulevard) will open in its place.

>> Makalapa Gate will be closed starting at 9 p.m. today and reopen at 5 a.m. Tuesday.

>> Center Drive and Radford Drive will not be accessible via Kamehameha.

>> Kuntz Gate access via Elliott Street will be modified outbound to allow eastbound traffic on Nimitz.

>> Catlin Drive, Camp Catlin Drive, Peltier Avenue and Puuloa Road will not be accessible from Nimitz.