Not usually regarded for their outside the box thinking, transportation engineers have nevertheless come up with some radical ideas for improving the flow of traffic and reducing the potential for collisions at busy intersections.
"Geometry tells us that the traditional four-way intersection is inherently dangerous," writes Emily Badger. "When you plot all of the potential points of conflict on a diagram – and transportation engineers actually do this – it turns out that vehicles have 32 distinct opportunities to collide into one another at the nexus of two two-lane roadways."
"With that geometry in mind, it becomes clear what we need in the holy grail of intersection design: a scheme that would eliminate left-hand turns while still enabling drivers to move in all four directions."
"John Sangster, a doctoral candidate at Virginia Tech and an alternative intersection enthusiast, introduced us to several and pointed us to some spellbinding animations from the Applied Technology and Traffic Analysis Program at the University of Maryland (many thanks to researchers there for sharing these clips)."
With such exotic names as the Jughandle, the Superstreet, and the Diverging Diamond, and even wilder traffic patterns, "these designs are not an easy sell."
"In theory – i.e., in conflict-point diagrams – these intersections should be safer than more traditional ones," says Badger. "But there are two caveats to that promise: Sangster is really talking about safer intersections for cars. Pedestrians and bikers aren’t figured into any of these models, and Sangster has yet to encounter designs that do a good job of incorporating them (or transit). There also isn’t much hard data on the safety of these designs because so few of them have been built (and even accurately modeling them on a computer can be tricky and expensive)."
FULL STORY: Could These Crazy Intersections Make Us Safer?
Where 2024 Presidential Candidates Stand on 12 Issues Important to Urban Planners
Whether you’re yet undecided or have already cast your early vote, here is a roundup of the key positions of Vice President Kamala Harris and former President Donald Trump on important urban planning policies.
Commentary: New Bill Holds Key to Solving US Housing Crisis. We Just Have to Pass It.
Two bills currently moving through Congress could make mass production of prefabricated, affordable housing possible on a large scale.
Amtrak Expanding Service in California’s Central Valley
Amtrak is planning a major expansion to the passenger rail lines connecting the Central Valley and the Bay Area.
Denver Slaughterhouse Measure Reveals Impacts of Meat Industry
Voters did not approve a measure that would have closed a slaughterhouse that is key to the nation’s lamb production.
Chicago Transit Increasing Rail Service to Pre-Pandemic Levels
The Chicago Transit Authority is close to returning both rail and bus service to pre-pandemic schedules, with some adjustments for new travel demand.
Baltimore Traffic Suffering From Absence of Key Bridge
The loss of a key route to the Port of Baltimore is causing major delays and long detours on alternate routes.
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.
University of Southern California
City of Meridian
University of Calgary
HUDs Office of Policy Development and Research
HUDs Office of Policy Development and Research
HUDs Office of Policy Development and Research
Detroit Regional Partnership
San Joaquin LAFCo
City of South Portland