Honolulu congestion ranks among the highest in the nation, with a travel time index higher than many metropolitan areas much larger. According to the Texas Transportation Institute, the Honolulu region's travel time index of 1.24 is the highest among medium-size cities it tracks from year to year and ranks 28th highest out of 90 overall.
Practical solutions exist to reducing congestion, however, and they are detailed in an excellent study by University of Hawai'i traffic engineer Panos Prevedouros. In a report titled "Transportation Alternatives Analysis for Mitigating Traffic Congestion" released in June 2008, Dr. Prevedouros provides a detailed analysis of core infrastructure projects that would dramatically improve travel times and create free-flow travel across the city, including:
- A 2-3 lane, reversible, High Occupancy Toll (HOT) lane that would reduce congestion (not slow the rate of increse) by 35 percent;
- A 2-lane reversible toll tunnel under Pearl Harbor that would cut travel time from Westeran Oahu (Ewa) to downtown from 65 minutes to 11 minutes;
- The toll tunnel would also reduce traffic on the main highway (H1), reducing commute times from 65 to 40 minutes;
- Four underpasses (queue jumpers) at critical intersections that would improve flow equivalent to a proposed 20 mile heavy rail system (at a small fraction of the cost).
Additional information on congestion mitigation can be found at Honolulutraffic.com.