The authors are gratefully acknowledge the cooperation of a major supermarket group and taxi company, advice from the Department Editor, Associate Editor, referees, Daron Acemoglu, David Autor, Emek Basker, Niloofar Abolfathi, Simone Santamaria, Kai-lung Hui, Pushan Dutt, other NUS colleagues, and superb assistance by Yige Duan, Chun-beng Leow, Valerie Chuang, Fiona Lee, and Enqi Teo. The research protocols were approved by the National University of Singapore, Institutional Review Board, S-17-252 and LS-17-090E. This project was funded by the Singapore Ministry of Education, grant MOE2016-SSRTG-059, SPIRE.