FL MORRIS / FMORRIS@STARBULLETIN.COM
Traffic was heavy yesterday on the Lunalilo Freeway westbound.
UH study halves
traffic timeThe report offers changes to
cut the H-1 morning traffic jams
by 53 percent westbound and
46 percent eastbound
Closing the Piikoi Street H-1 freeway onramp and creating a new onramp off Punahou Street near Kapiolani Medical Center are among the recommendations in a new study that could cut traffic delays through urban Honolulu in half.
The five-year long study, by University of Hawaii civil engineering professor Panos Prevedouros, used computer simulations to figure out how to reduce congestion on the H-1 from Koko Head Avenue to Middle Street.
His recommendations range from widening the viaduct over University Avenue to relatively inexpensive fixes like re-striping and narrowing existing lanes and freeway shoulders to create additional traffic lanes between the Likelike and Pali highways.
Prevedouros admits some of his recommendations may be controversial.
However, his study was not designed to look at the financial and political costs of the projects, just at whether they would improve travel times.
"The study was primarily to show us if we did this what would happen," said Ron Tsuzuki, program manager of the state Department of Transportation's Highways Planning Branch. "How can we best utilize our existing freeway and make it more efficient? ... How can we make the freeway flow better?"
Tsuzuki emphasized that the DOT is still evaluating Prevedouros' study and may not agree to implement all of his recommendations.
Prevedouros said closing and consolidating onramps and offramps will have an affect on neighborhoods around the freeway."All our recommendations were made in mind that we provide a reasonably convenient alternative," Prevedouros said.
"It's very simple to say, 'I'm going to improve the freeway by closing ramps,' but that's myopic because you simply divert people to city streets," he said.
To conduct the study, Prevedouros did extensive measurements of traffic on and off the freeway and created a computer model of the H-1. He then created changes to the freeway on the computer, and the computer calculated how it would affect traffic.
The $188,000 study took longer than expected, in part because Prevedouros had to conduct new measurements after the H-3 freeway opened in 1997. He also had to set up and evaluate data from a demonstration peak morning closure of the Lunalilo Street freeway onramp in 1997.
In the westbound direction, the worst backups were at the onramps at Old Waialae Avenue, Alexander Street and Lunalilo Street in the morning and at the Alexander Street, Lunalilo Street, School Street and Vineyard Boulevard onramps in the afternoon.
Prevedouros estimates his recommendations would reduce traffic delays by 53 percent in the morning and 39 percent in the afternoon.
He found that the worst backups on the eastbound H-1 through town were at the merge of the H-1 and Moanalua freeways, the Kalihi Street underpass and onramp, the Liliha Street onramp and on the viaduct from the Ward Avenue onramp.
His computer study calculated that implementing his recommendations would reduce the morning traffic delay by 46 percent and the afternoon delay by 59 percent.
Tsuzuki said he was especially interested in Prevedouros' recommendations to narrow the freeway lanes and shoulders to fit under existing freeway overpasses. It wouldn't cost that much to make the changes.
However, the state would have to get an exemption from the federal government to make the freeway lanes narrower than the standard 12 feet and reduce the freeway shoulders.
Prevedouros said that adding a lane from Likelike Highway to the Vineyard offramp would have a significant effect on one of the worst backups on the freeway, where the H-1 and Moanalua freeways merge from five lanes into three lanes.
He would also like to see the Vineyard offramp enlarged to two lanes, which would also relieve traffic downstream because more people would use the Vineyard offramp.
Tsuzuki said the H-1 through town was built with too many onramps and offramps and would not be built the same way if it was constructed today.
One of the purposes of the study was to see how the onramps could be consolidated and changed.
Prevedouros suggests that the Bingham Street offramp be moved closer to Isenberg Street and that the traffic could connect from there to University Avenue near Varsity Circle.
He also believes that the University interchange could be improved by expanding the University Avenue viaduct to add a lane in each direction.
"It's going to create controversy, and, of course, during construction you're going to have delays," Prevedouros said.
Tsuzuki said the DOT is not sure yet what it wants to do with the University interchange, but "we do agree we've got to modify that interchange."
State Department of Transportation Director Rod Haraga said he is looking at Prevedouros' study and other studies done over the years to come up with a comprehensive plan to improve traffic flow on H-1 through the heart of Honolulu.
Haraga said he is working with the city on the plan because improvements on the freeway are likely to have an impact on city streets, and changes in city streets will have an impact on freeway traffic.
Prevedouros agrees that a master plan for H-1 is necessary because changes to one section of the freeway affect what happens on the next section.
For example, he said, closing the Piikoi Street onramp on the eastbound H-1 freeway would necessitate the creation of the Punahou Street onramp. If you build a Punahou Street onramp, the Bingham Street offramp needs to be moved. Moving the Bingham Street offramp closer to University Avenue would allow the closure of the University Avenue offramp. Closing the University Avenue offramp would create room to improve the University Avenue onramp.
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Study recommendations
University interchange: Add an additional lane from the Old Waialae Avenue onramp to University Avenue onramp, and extend the northbound University Avenue onramp by widening the viaduct above University Avenue. The viaduct would connect the two existing University Avenue onramps and give motorists a longer acceleration lane.
for westbound H-1 freewayAlexander Street onramp: Install a traffic light meter at the onramp similar to those on freeways in Los Angeles which would regulate how often cars can enter the freeway between the hours of 3 p.m. to 7 p.m.
Lunalilo Street onramp/ Vineyard Boulevard offramp: Cone off the Lunalilo Street onramp so that cars won't be able to get on the freeway between 6 and 9 a.m. Divert the traffic to Vineyard Boulevard to get on the freeway from Punchbowl Street. Prohibit left turns from eastbound Vineyard Boulevard to Punchbowl Street, providing two turning lanes for the intersection of Vineyard Boulevard and Pali Highway and prohibiting left-hand turns at the Vineyard Boulevard intersection with Liliha Street.
Likelike Highway offramp/ onramp: Narrow existing lanes and shoulder, and create an additional lane from the Likelike Highway offramp to the Likelike Highway onramp, creating four continuous westbound lanes from the Vineyard Boulevard onramp through the Kalihi Interchange.
H-1 eastbound
Likelike Highway offramp to Vineyard Boulevard offramp: Narrow existing lanes and shoulder to create an additional lane beginning at the Likelike Highway offramp. Create a two-lane Vineyard Boulevard offramp.
recommendationsLiliha Street onramp to Pali Highway offramp: Narrow existing lanes and shoulders to create an additional lane beginning as far upstream of the Liliha Street onramp as possible and ending at existing Pali Highway offramp.
Vineyard Boulevard onramp to Punahou Street offramp: Close Piikoi Street onramp, and extend existing Vineyard Boulevard onramp auxiliary lane from Ward Avenue onramp to Punahou Street offramp. Add a freeway onramp at Punahou Street. In the short term, close Ward Avenue and Piikoi Street onramps between 7 and 8 a.m., and meter Vineyard Boulevard onramp to reduce traffic on the freeway during peak morning rush hour.
Bingham Street offramp: Relocate Bingham Street offramp nearer to Isenberg Street. Create an extension from Isenberg Street to meet University Avenue near Varsity Place.
University Interchange: Close University Avenue offramp, and extend University Avenue onramp by widening the viaduct over University Avenue to create a longer acceleration lane.
