Joseph Stromberg explains the phantom traffic jam—that scourge of highway travel when everyone on the highway slows down for no apparent reason and then quickly accelerates to previous speeds.
Stromberg focuses on the work of Benjamin Seibold, a mathematician at Temple University, and colleagues, who have developed a concept called the "jamiton" to explain the phenomenon.
Here's how Stromberg describes a jamiton:
If there are enough cars on a highway, any minor disruptions to the flow of traffic can cause a self-reinforcing chain reaction: one car brakes slightly, and the ones behind it brake just a bit more to avoid hitting it, with the braking eventually amplifying until it produces a wave of stopped or slowed traffic.
The idea of jamitons raises additional questions about how much responsibility individual driving behavior impacts traffic flow. Stromberg also discusses a few of the options for preventing jamitons (spoiler: self-driving cars are one them).
FULL STORY: Why do traffic jams sometimes form for no reason?

Trump Administration Could Effectively End Housing Voucher Program
Federal officials are eyeing major cuts to the Section 8 program that helps millions of low-income households pay rent.

Planetizen Federal Action Tracker
A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

The 120 Year Old Tiny Home Villages That Sheltered San Francisco’s Earthquake Refugees
More than a century ago, San Francisco mobilized to house thousands of residents displaced by the 1906 earthquake. Could their strategy offer a model for the present?

HSR Reaches Key Settlement in Northern California City
The state’s high-speed rail authority reached an agreement with Millbrae, a key city on the train’s proposed route to San Francisco.

Washington State Legislature Passes Parking Reform Bill
A bill that would limit parking requirements for new developments is headed to the governor’s desk.

Missouri Law Would Ban Protections for Housing Voucher Users
A state law seeks to overturn source-of-income discrimination bans passed by several Missouri cities.
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