Since the inception of the United States Interstate System in 1956, it has created more traffic congestion than any of the designers imagined. It costs tens of billions of dollars to keep existing interstates and bridges maintained. 

United States traffic officials warm the 47,182-mile system has areas of high stress. Here is a list of the 10 busiest U.S. interstates, according to the Federal Highway Administration‘s statistics.  

1.) I-405 

Interstate 405, or more commonly known as “the 405” is a major interstate highway that runs from northern California to southern California. To paint the picture for how busy it is, in 2011 national news stations called it “Carmageddon.”

It is estimated that 374,000 vehicles drive through per day.

2.) I-5

Interstate 5 originates at the world’s busiest border crossing, at San Ysidro on the Mexican border, and ends 1,381 miles away at the Canadian border, making it the only U.S. interstate to reach both countries. The segment of I-5 in Mission Viejo, roughly midway between L.A. and San Diego, is the second-busiest stretch of interstate in the U.S., with 334,000 vehicles per day.

 The California Department of Transportation is either performing or planning improvements at several points along I-5, which should help if they all come to pass. Traffic is much lighter after I-5 leaves Southern California on its way up the Pacific Coast, but Seattle adds more than a quarter-million vehicles into the I-5 mix each day and Portland about half that figure.

3.) I-90

If you were to ask a random Chicago citizen when the best time to avoid traffic on I-90 was, the answer might be “around 3 a.m.” I-90 passes through several other major cities on its coast-to-coast route, including Boston, Buffalo, Cleveland, and Seattle because it runs coast-to-coast. 

None of the segments are like Chicago-level traffic. On average, there are 329,542 vehicles pass this busy section each day. 

4.) I-95

There are stretches of the interstate that carry more traffic than the busiest parts of I-95, no interstate is as consistently busy from one end to the other like I-95.  I-95 runs from the Canadian border south to Miami, covering 1,917 miles and crossing through 15 states — the most of any interstate highway. According to the Federal Highway Administration, 1,040 of those miles are in urban areas, and more than 60 percent of those segments are classified as “under heavy congestion.”

328,000 vehicles travel on I-95 in Miami per day, and 325,495 vehicles travel on I-95 in New York/Newark per day. 

5.) I-45

I-45 in Houston carries more than 310,000 vehicles a day. Perhaps surprisingly, the Dallas/Fort Worth metroplex, which has extremely heavy traffic during rush hours and even off-peak hours, has only one section of the interstate on the FHWA’s list of the top 40 most-traveled urban highways. 

6.) I-605

The Los Angeles/Long Beach/Santa Ana is the most congested area on I-605 with 300,000 vehicles traveling through each day. This area has a lot of different commuters going in all different areas. This area is one of the many reasons why Los Angeles has the largest amount of traffic than in any U.S. city. 

7.) I-210

I-210 is also in the Los Angeles/Long Beach/Santa Ana, and 298,000 vehicles travel through this area each day. The Los Angeles/Long Beach/Santa Ana is home to 13 million residents. Usually, all roads are congested within this area, especially at rush hour. 

8.) I-110

I-110, better known as the Harbor Freeway, is the only 32 miles in length. The road carries some 328,000 vehicles per day in the Los Angeles/Long Beach/Santa Ana area.

Eight of the top 15 most-traveled urban highways in the United States are in the Los Angeles Metro Area. Everyone has undoubtedly heard that heavy traffic is a part of life in the Los Angeles area. On average, drivers spend 104 hours per year stuck in traffic around the city. 

9.) I-15

I-15 runs more than 1,470 miles from San Diego to the Canadian border. It covers some of the most rugged and scenic views in the United States, but it also runs through many heavily congested areas. San Diego is the most congested area on I-15 with 295,000 vehicles per day. 

It also runs through Las Vegas (263,000 vehicles per day) and Salt Lake City (245,000 per day). 

10.) I-80

I-80 is the second-longest interstate in the United States and is exactly 2,900 miles in length. It stretches from just outside New York, New York to downtown San Francisco, California. The highway travels through metropolitan cities (Chicago and Cleveland) to rural areas in the Great Plains and the Rocky Mountains. 

The busiest stretch of I-80 is known as the Eastshore Freeway in San Francisco. The area carries almost 300,000 vehicles per day. 

Have you traveled on one of these busy interstates? Let us know about your experience in the comments below.