HILO – The Hawaii Department of Transportation (HDOT) is providing additional details on the installation of traffic signals at the intersection of Volcano Road (Route 11) and Kipimana Street following observations conducted since their activation in late October.

The traffic signals were installed at this intersection to improve safety and accessibility for all roadway users. Crash information from 2019 and 2020 showed at least four serious collisions at this intersection where a traffic signal may have provided effective mitigation.

The Volcano/Kipimana traffic signals were designed as a “continuous green-T intersection” to allow northbound traffic on Volcano Road to flow continuously while controlling southbound traffic and traffic heading into and out of Shipman Industrial Park. This design reduces the potential for angle crashes (where one vehicle hits another at an angle) and makes traffic conditions at the intersection more predictable for cyclists and pedestrians that may be using the mixed-use shoulder.

HDOT and the Hawaii County Department of Public Works has adjusted timing of the signals since the installation. Adjustments made included:

• Dynamic maximum green time for Keaau-bound traffic on Volcano Road in the afternoon peak between 2 and 6 p.m. The signal facing southbound Volcano Road traffic is programmed to provide 130 seconds of green time for Keaau-bound drivers during the afternoon peak and to increase green time in 10 second increments if the max green time for this direction of traffic is hit more than twice. The maximum green time for Keaau-bound traffic will be 150 seconds.
• Decrease in green time for the Kipimana Street signal to 15 seconds. Prior to the adjustment, the green time for this movement was 35 seconds.

Additional observations from the first week in November show an average delay of 5-and-a-half minutes for Keaau-bound traffic on this stretch of Volcano Road. Delays on Oct. 26 and Nov. 6 were significantly increased due to rear end vehicle crashes on the route.

HDOT will continue to observe the intersection and adjust to support safety for all users of the highway.

Previous HDOT news releases on the Volcano Road/Kipimana Street traffic signals: