What's this about?
An NBER study on urban congestion pricing and the response times of emergency medical services.
Why is this a good natural experiment?
Because congestion pricing is a sharp, dated policy change applied to a defined geography, and ambulance response times are measured continuously and precisely for entirely unrelated reasons. You get a clean before-and-after with a control area, on an outcome nobody was optimising for and where the stakes are unambiguous — minutes of ambulance delay convert to survival rates in a well-studied way. That is a much stronger design than most transport-policy research can manage.
Why is it worth noticing?
HN 57 points, 112 comments — twice as many comments as points
- Emergency response time is the rare outcome measure both sides of the congestion-pricing argument accept as important.
- High comment ratio because congestion pricing is a reliably contentious topic on HN.
- A useful reminder that policy effects show up in places nobody designed the policy to affect.