Skip to Content
Streetsblog New York City home
Streetsblog New York City home
Log In
Japan

Traffic Jam on a Petri Dish

10:46 AM EDT on March 11, 2008

This one comes to Streetsblog via the Sightline Institute's Daily Score, a blog covering environmental issues in the Pacific Northwest.

Why do traffic jams materialize for no apparent reason? In an effort to answer that question, here's a surprisingly simple experiment cooked up in Japan by the University of Nagoya's "Mathematical Society of Traffic Flow:" 

If you are the kind of transportation geek who finds this sort of thing fascinating then you'll also really love this web-based traffic simulator out of Germany. But "prepare to lose your afternoon," says Sightline's Brad Plumer:

A few years back I wasted hour after hour playingwith the java settings, and watching "traffic" jams materialize andmelt -- just like in real life.  My favorite quirk:  for onelane-narrowing scenario, I could make traffic flow along beautifully at40 miles per hour, but seize up like glue at either 20 mph or 60 mph. Another fave (and very relevant to congestion pricing debates) wasletting traffic flow along smoothly at, say 1,400 "cars" per hour, andthen increasing traffic volumes to 1,500 -- and watching the trafficjam crystallize within moments.

Stay in touch

Sign up for our free newsletter

More from Streetsblog New York City

Can We Just Keep Cars Off the Queensbridge Baby Greenway?

Why do we allow car drivers to park on greenways, in parks and on tree beds?

March 29, 2024

Maximum Rage: Delivery Workers Protest Low Wages, App ‘Lockouts’

Couriers with bikes and signs urge the city to step in as Uber Eats, GrubHub and DoorDash withhold work, they say.

March 28, 2024

The Toll of History: MTA Board Approves $15 Congestion Pricing Fee

New York City's congestion pricing tolls are one historic step closer to reality after Wednesday's 11-1 MTA board vote. Next step: all those pesky lawsuits.

March 28, 2024

Company That Fought McGuinness Safety Project Wants to Seize Bklyn Street for Private Backlot

Broadway Stages to Greenpoint residents: "Street safety for me, not for thee."

March 28, 2024
See all posts