How far have roadside curb inlets evolved towards sustainable urban drainage?

Stormwater management has become a critical issue, particularly with the ongoing urbanization and the impacts of climate change. Roadside curb inlets are key components of grey infrastructure that convey stormwater to various drainage systems. Curb inlets for conventional drainage systems are typically long, whereas they are usually shorter for directing stormwater to sustainable green stormwater infrastructures (GSIs), such as a roadside bioretention cell. As shorter curb inlets drain stormwater to GSIs, they have noteworthy advantages over conventional inlets such as environmental sustainability, urban flood resilience, pollution control, improved public health, and mitigating urban heat stress. This perspective aims to present a global outlook on the implementation of sustainable GSI curb inlets while also exploring the transition from conventional to sustainable systems. While some countries such as the USA, Canada, and China have adopted sustainable drainage practices including curb inlets, most regions, such as South Asia, Central America, and Africa are still far from embracing these practices. For the wider implementation of sustainable curb inlets with GSIs, recommendations include framing policies at the ministry level, raising awareness through research institutes, and educating the public on the benefits of sustainable drainage. For efficient design, it’s crucial to understand curb inlet hydraulics, consider various design parameters, monitor for clogging and sediment buildup, and account for climate change impacts.