Asia-Pacific Sustainability Action Awards-Sustainability Action Awards SDG15:Gold
Southern Region Branch Office, Highway Bureau, MOTC
Purple Butterfly (Euploea spp.) Highway – Valleys, Mango Trees, Colorful Butterflies.
Provincial Highway 27, known as the Purple Crow Butterfly Highway, demonstrates how transportation infrastructure can balance mobility, safety, ecology, and community values. To protect Purple Crow Butterfly migration, a 30 km/h speed-control zone, warning signs, rumble strips, vegetated hedgerows, earthen berms, and raised retaining walls were introduced to reduce road mortality. Native nectar and larval food plants, together with rewilded roadside spaces, form a continuous ecological corridor. The project adopted a “roads adapting to trees” approach, adjusting alignments and adding green buffers to preserve the historic mango tree avenue. To enhance resilience against extreme rainfall and landslides, sediment-collection facilities and rockfall buffer zones were constructed, while excavated and landslide materials were reused in protection works and site filling, reducing waste and emissions. Environmental education, tree planting, and community participation strengthen local stewardship. By integrating engineering, ecology, culture, and circular resource use, the project provides a replicable model for sustainable and climate-resilient road development across the Asia-Pacific.