Interstate H1 in Hawaii


Begin California
End Honolulu
Length 27 mi
Length 44 km
  • 1 Kalaeloa Boulevard2 Kilo Drive
  • 3 Kualakai Parkway
  • 5 Kunia Road
  • 7 Paiwa Street
  • 8A Kamehameha Highway
  • 8B
  • 10 Moanalua Road
  • 13
  • 15 Nimitz Highway
  • 16 Honolulu International Airport
  • 18 Nimitz Highway
  • 19
  • 20 Kalihi Street
  • 21 Pali Highway
  • 22 Ward Avenue
  • 23 Punahou Street
  • 24 University Avenue
  • 25 Kapiolani Boulevard
  • 25B 6th Avenue
  • 26A Blood Head Avenue
  • 26B Waialae Avenue
  • 27 Kalanianaole Highway

The Interstate H-1 is an Interstate Highway in the U.S. state of Hawaii. The freeway is the main east-west highway on the island of Oahu and runs for 44 kilometers from Kapolei to the capital Honolulu. The highway is also known as the Lunalilo Freeway. It is the busiest highway in the state.

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Travel directions

The interchange with the Nimitz Highway in western Honolulu.

The highway begins just west of Makakilo City and then runs 2×3 lanes to the northeast. It passes through an urbanized part of Hawaii, there is a large industrial area and an airport along the highway, as well as suburbs of Honolulu. From Village Park, the highway has 2×4 lanes. In Pearl City, at Pearl Harbor, the H-2 begins to Wahiawa in the north. From here, the highway has 2×5 lanes. One passes through several Honolulu suburbs leading into the mountains. At Aiea there are 2×6 lanes. The highway splits here into the H-2 along the airport and the bypass that forms the H-201. Both highways meet again later. The H-3. also starts here, the highway to Kaneohe. The H-1 has 2×4 lanes here because the H-201 blocks part of the traffic. Right off the highway is Honolulu International Airport. After this, the H-201 merges again but narrows to 2×3 lanes, the largest bottleneck in the state. One then passes through the large city of Honolulu where the H-1 is the only fast east-west connection, to the north are steep mountains, to the south the Pacific Ocean. The highway continues to the eastern half of Honolulu, after which a State Route continues to the eastern suburbs.

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The H-1 is the first highway in Hawaii and opened in 1953 at the height of Downtown Honolulu. In June 1965, a 2-mile section opened between 1st Avenue and Koko Head Avenue. The highway through Honolulu was completed in 1969. The westernmost 5 miles opened in 1967, followed by the section up to Halawa in 1971. H-1 was completed in 1986, opening the section along Honolulu International Airport. In the 1970s, the H-201 formed the through route between both segments of the H-1.

It is also the westernmost and southernmost highway in the United States. At first it was not an Interstate Highway because Hawaii only later became a state of the US. The H1 has been an Interstate Highway since 1960. The section through Honolulu was very outdated with too many turns running too tight. There are often long queues here. To mitigate the problem, the highway between H-201 and Ward Avenue near downtown was widened from 2×3 to 2×4 lanes in 2013-2014.

Zipper Lane

De zipper lane.

The highway has had a Zipper Lane between Exit 7 and Exit 18A (Waipahu – Nimitz Highway) since May 1986. This is an alternating strip that is used in the rush hour by moving the barrier with a ‘ zipper barrier ‘. The reversible lane is only for HOV 3+ users. This system costs $3 million a year to operate. The major disadvantage is that 2 lanes have to be closed in the opposite direction to create 1 extra lane in the rush hour, which actually reduces the total capacity.

In 2014, an additional weaving strip was constructed on the Pearl City Viaduct, from Pearl City to the H-2. The bridge deck of the Pearl City Viaduct was also renovated. A rush- hour lane was also constructed in 2016 from the H-3 to Pearl City, so that 6 westbound lanes are available during rush hour.

Traffic intensities

Interstate H1 door Honolulu.

The H1 is one of the most congested highways in the United States. It should be noted that Oahu has almost no backcountry and the peak-to-valley ratio is more skewed than elsewhere. The intensities mentioned are after the connection.

Exit Location 2012
Exit 2 Kilo Drive 86.000
Exit 10 Moanalua Road 235.000
Exit 18 Nimitz Highway 60.000
Exit 19 H-201 159.000
Exit 20 Kalihi Street 173.000
Exit 23 Punahou Street 133.000
Exit 24 University Avenue 106.000


Interstate H1 is very prone to traffic jams, traffic is high all day long. One problem is that almost all traffic on Oahu uses the H1 at some point. In particular, the section along the center of Honolulu has insufficient capacity.

Interstate H1 in Hawaii