NRDC was the only international NGO invited to the Beijing Municipal Transport Commission's "Car-Free Day" event on September 22, 2015. The event promoted green transportation to the public, encouraging them to use public transport and to bike instead of relying on motor vehicles. The Sustainable Cities team handed out metro card holders designed by the NRDC to raise public enthusiasm for green transport. The "Car-Free Day" event was a perfect venue to further the goals of Sustainable Cities' Walkability Project, which advocates for the expansion of non-motorized transport in China's cities. Mr. Zhou Zhenyu, Director of the Beijing Municipal Transport Commission, encouraged the team to continue its walkability research.