Keaukaha Speed Study

Why Keaukaha

As the Hawaiʻi Island nēnē population has grown, birds are returning to coastal areas they had not used in decades. The stretch of Kalanianaʻole Street between Liliʻuokalani Park and Kings Landing now hosts 23 banded individuals plus goslings that we have identified. Coastal restoration work by ʻĀina Hoʻōla Initiative, Kamehameha Kumuola, and Hui Hoʻoleimaluō pulled native habitat back to the shoreline. The birds followed. That habitat sits directly across a residential road.

Vehicle collisions are a documented mortality source for nēnē. The longest dataset, from Hawaiʻi Volcanoes National Park, recorded 92 vehicle deaths between 1977 and 2014, with mortality concentrated on three road segments and peaking in November and December during the breeding season (Lepczyk et al. 2019). Segment-level mitigation works in the places that have tried it. That is what we proposed for Keaukaha.

County response

In June 2023, Jordan Lerma presented the Hawaiʻi Island nēnē update and the Keaukaha data to the Hawaiʻi County Policy Committee on Infrastructure and Assets. The committee and Public Works ran with it:

• The County adopted a resolution dropping the speed limit on the affected stretch to 25 mph.
• Hawaiʻi County Public Works produced a site plan covering:
• Six speed tables
• Two raised crosswalks

How we collected the data

In May the team built, tested, and deployed radar speed loggers along Kalanianaʻole Street. The point was to take the conversation out of the realm of impressions:

• Capture actual vehicle speeds rather than estimates
• Measure compliance on the segment where nēnē strikes were happening
• Pair traffic data with field observations of how nēnē were using the road
• Hand the County something concrete to work with

From the field

Press coverage