Investigation of the Effects of Limited

Ramp Closures along the H-1 Freeway

F I N A L R E P O R T

Principal Investigator:

Panos D. Prevedouros, Ph.D.

Associate Professor of Civil Engineering

Prepared In Cooperation With:

State of Hawaii, Department of Transportation, Highways Division

and U.S. Department of Transportation, Federal Highway Administration

Honolulu, Hawaii

May 31, 2003

EXECUTIVE SUMMARY

This is part of a three volume research report to address the feasibility and benefits of temporary ramp closure and other alternatives to reduce traffic bottlenecks on a seven mile segment of the H-1 Fwy. in Honolulu, Hawaii between Koko Head Ave. and Middle St. This first volume describes project scope, objectives, data, and methodology then provides west bound freeway analyses and recommendations. The second volume provides east bound freeway analyses and recommendation. The third volume presents findings from fall 1997 experimental morning “closure” of the west bound Lunalilo St. on-ramp (by diversion of traffic to west bound Vineyard Blvd.).

Most west bound data used for freeway simulation were collected in mid-October 1996. Speed data collected simultaneously with traffic counts on typical school days were used to fine-tune KRONOS freeway simulation models for both the existing morning and afternoon “base case”. Software parameters were incrementally adjusted until the duration of simulated congestion and simulated speed were approximately equal to that actually observed. Limited data were also collected in mid-February 1999 to evaluate how opening of the H-3 Fwy. (in December 1997) affected use of west bound ramps of the Kalihi Interchange. Data has not been collected to evaluate how widening of Punchbowl St. (fall 2001) has affected use of the west bound Punchbowl St. on ramp.

West bound freeway congestion in the study area is not quite as severe on weekday mornings as on weekday afternoons. Peak morning west bound H-1 Fwy. traffic queues typically extend about 3.7 miles from Koko Head Ave. to Ward Ave. Peak afternoon west bound H-1 Fwy. traffic queues typically extend about 4.5 miles from University Ave. to Kalihi St. The worst morning bottlenecks include heavily used on-ramps at Old Waialae Ave., Alexander St., and Lunalilo St. The worst afternoon bottlenecks include heavily used on-ramps at Alexander St., Lunalilo St., School St. and, to a lesser extent, Vineyard Blvd.

Base case simulations (reported in this volume) estimate that west bound H-1 Fwy. bottlenecks between Koko Head Ave. and Middle St. result in 1,879 vehicle-hours of traffic delay on a typical weekday morning and 2,895 vehicle-hours of traffic delay on a typical weekday afternoon. By comparison base case simulations (reported in volume two) estimate that east bound H-1 Fwy. bottlenecks between Middle St. and Koko Head Ave. result in 3,777 vehicle-hours of traffic delay on a typical weekday morning and 825 vehicle-hours of traffic delay on a typical weekday afternoon.

As summarized in the table at the end of this Executive Summary, 15 alternative west bound scenarios were simulated separately for both morning and afternoon conditions. Essential elements were the same as the base case to permit analysis of effects on freeway traffic flow (in terms of speed and delay). Based on benefits and relative feasibility, a combination of actions was selected which is estimated to result in 1002 vehicle-hours (53%) less morning traffic delay and 1,137 vehicle-hours (39%) less afternoon delay than the base case. These recommended actions are detailed in Chapter 5 and are summarized below:

1. Additional lane from Old Waialae Ave. on-ramp to the University Ave. off-ramp (auxiliary lane) plus consolidation of the University Ave. on-ramps. Primarily to improve safety, an auxiliary lane would be added to connect the Old Waialae Ave on-ramp and the University Ave. off-ramp and the northbound University Ave. on-ramp would be extended with a viaduct over University Ave. then merge onto the southbound University Ave. on-ramp.

Meter the Alexander St. on-ramp from 3 to 7 p.m. Most diverted traffic would use the Punahou St. on-ramp.
Divert traffic from the Lunalilo St. on-ramp to Vineyard Blvd from 6 to 9 a.m. Delays for diverted traffic could be significantly reduced by prohibiting left turns from eastbound Vineyard Blvd. to Punchbowl St., providing two turning lanes for all left-turn movements at the Vineyard Blvd. intersection with Pali Hwy., and prohibiting all left turns at the Vineyard Blvd. intersection with Liliha St.

4. Additional lane from Likelike Hwy. off-ramp to the Likelike Hwy. on-ramp. This would provide four continuous west bound lanes from the Vineyard Bvd. on-ramp through the Kalihi Interchange. The Likelike Hwy. on-ramp would merge into the new lane.