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?

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

San Francisco's School District Spent $105M To Build Affordable Housing for Teachers — And That's Just the Beginning
SFUSD joins a growing list of school districts using their land holdings to address housing affordability challenges faced by their own employees.

The Tiny, Adorable $7,000 Car Turning Japan Onto EVs
The single seat Mibot charges from a regular plug as quickly as an iPad, and is about half the price of an average EV.

Even Edmonton Wants Single Staircase Buildings
Canada's second most affordable major city joins those angling to nix the requirement for two staircases in multi-family buildings.

Duffy Threatens to Cut DOT Funds to “Sanctuary Cities”
“Follow the law or forfeit the funding” says US Secretary of Transportation.

Trump Approves Futuristic Automated Texas-Mexico Cargo Corridor
The project could remove tens of thousands of commercial trucks from roadways.
Urban Design for Planners 1: Software Tools
This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.
Planning for Universal Design
Learn the tools for implementing Universal Design in planning regulations.
Smith Gee Studio
City of Charlotte
City of Camden Redevelopment Agency
City of Astoria
Transportation Research & Education Center (TREC) at Portland State University
City of Camden Redevelopment Agency
Municipality of Princeton (NJ)