A study conducted by Cambridge Systematics for the American Highway Users Alliance identifies the most serious traffic bottlenecks across the country.

The top 10 offenders:
1. Los Angeles: San Diego Freeway at I-10
2. Houston: U.S. 59 at I-610 loop
3. Seattle: I-5 at I-90
4. Boston: Central Artery
5. Washington, DC: Beltway at I-270
6. Washington, DC: "Mixing Bowl"
7. Los Angeles: Ventura Freeway at I-405
8. Los Angeles: Newport Freeway at State Rt. 22
9. Los Angeles: Santa Monica Freeway at I-5
10. Albuquerque: "Big I"
Altogether, the study identified 167 bottlenecks. Fixing these bottlenecks would prevent nearly 290,000 crashes, nearly halve the pollution, and reduce delays by an average of 19 minutes per trip over the next 20 years, the study says.
"Freeing these bottlenecks is a critical starting point for curing the gridlock on our roadways," said William Fay, president and CEO of the American Highway Users Alliance.
The study recommends "a balanced, comprehensive approach to traffic congestion that uses all the tools at our disposal," including mass transit, intelligent traffic management systems, reversible commuter lanes and movable barriers in addition to more road capacity.
To see the study, "Unclogging America's Arteries," in its entirety, visit http://www.highways.org.