Check out my new working paper on using supply shocks to quantify traffic congestion externalities! You can find it at papers.ssrn.com/sol3/papers.cf… or on my website. Here follows a thread: (1/13) Motivation: Traffic congestion is one of the most challenging issues of urban agglomeration and bears substantial costs. Congestion costs are often higher than their socially optimal levels because of a missing market problem: roads are generally not priced (2/13)