While the United States may have the largest road network in the world, the title of the busiest freeway on the continent belongs to their neighbors up north in Canada with its Ontario Highway 401.

Known as King’s Highway 401, the freeway also goes by its official name of the Macdonald–Cartier Freeway. A 400-Series Highway in the Canadian province of Ontario, the 401 stretches from Windsor to the Quebec border. The segment of Highway 401 passing through Toronto is not only the busiest highway in North America but also one of the widest and busiest in the world.

So, what makes this freeway so busy? According to a report from the Federal Highway Administration, the annual average daily traffic (AADT) count between Weston Road and Highway 400 in Toronto was estimated at 431,900. On some days, the number exceeds 500,000 vehicles.

Those stats make the 401 the the busiest roadway in North America, surpassing those in the U.S., including the Santa Monica Freeway in Los Angeles, Interstate 10 (I-10) in Houston, and I-75 in Atlanta.

Have you driven on Ontario Highway 401? What was your experience like? Be sure to let us know in the comments below.

Image: Danielle Scott, PLTam

Airports Council International and British Airports Authority (BAA) release data each year on every airport’s traffic numbers. The busiest airports are measured by the total number of passengers, with one passenger being someone who arrives in, departs from, or transfers through the airport on a given day.

There’s no doubt that some airports are better than others when it comes to lines, traffic, parking, and crowds to deal with. Which ones should you try to avoid when booking that next flight?

Based on the annual figures, here’s the list of the top 10 busiest airports in the United States of America.

10. Phoenix Sky Harbor International Airport

25,882,875 passengers

Phoenix Sky Harbor International Airport (IATA: PHX, ICAO: KPHX, FAA LID: PHX) is located in Phoenix, Maricopa County, Arizona and is the largest and busiest airport in the state of Arizona, followed by Tucson International Airport.

9. San Francisco International Airport

26,077,386 passengers

San Francisco International Airport (IATA: SFO, ICAO: KSFO, FAA LID: SFO) is a major international airport located 13 miles south of downtown San Francisco, California, United States, adjacent to the cities of Millbrae and San Bruno in unincorporated San Mateo County. It is often referred to as SFO. The airport has flights to destinations throughout North America and is a major gateway to Europe, Asia, and Australasia.

8. McCarran International Airport

26,265,203 passengers

McCarran International Airport (IATA: LAS, ICAO: KLAS, FAA LID: LAS) is the principal commercial airport serving Las Vegas and Clark County, Nevada, United States. The airport is located five miles south of the central business district of Las Vegas, in the unincorporated area of Paradise in Clark County. It covers an area of 2,800 acres and has four runways.

7. George Bush Intercontinental Airport

27,272,169 passengers

George Bush Intercontinental Airport, (IATA: IAH, ICAO: KIAH, FAA LID: IAH) is a Class B international airport in the city of Houston, Texas, United States, serving the Greater Houston area. Located 20 miles north of Downtown Houston between Interstate 45 and U.S. Highway 59, Bush Intercontinental is Texas’s second-largest air facility—after Dallas/Fort Worth International Airport—covering an area of 10,000 acres.

6. John F. Kennedy International Airport

31,104,761 passengers

John F. Kennedy International Airport (IATA: JFK, ICAO: KJFK, FAA LID: JFK) is an international airport located in Queens County, on Long Island, in southeastern New York City. The airport is approximately 12 miles from Lower Manhattan. It is the busiest international air passenger gateway to the United States. It is also the leading freight gateway to the country by value of shipments. In 2009, the airport handled 45,915,069 passengers, making it the 12th busiest airport in the world by this measure.

5. Denver International Airport

35,150,666 passengers

Denver International Airport (IATA: DEN, ICAO: KDEN, FAA LID: DEN), often called DIA, is an airport in Denver, Colorado. By land size, at 53 square miles, it is the largest international airport in the United States, and the third largest international airport in the world after King Fahd International Airport and Montreal-Mirabel International Airport. Runway 16R/34L is the longest public use runway in the United States.

4. Dallas/Fort Worth International Airport

38,016,962 passengers

Dallas/Fort Worth International Airport (IATA: DFW, ICAO: KDFW, FAA LID: DFW) is located between the cities of Dallas and Fort Worth, Texas, and (at least as of 2007) is the busiest airport in the U.S. state of Texas. It generally serves the larger Dallas–Fort Worth metropolitan area, with carriers providing regional, national and international flights.

3. Los Angeles International Airport

39,502,735 passengers

Los Angeles International Airport (IATA: LAX, ICAO: KLAX, FAA LID: LAX) is the primary airport serving Los Angeles, California, the second-most populated metropolitan area of the United States. It is most often referred to by its IATA airport code LAX, with the letters pronounced individually (el-a-ex). LAX is located in southwestern Los Angeles in the neighborhood of Westchester, 16 miles from the downtown core.

2. O’Hare International Airport

44,576,625 passengers

Chicago O’Hare International Airport (IATA: ORD, ICAO: KORD, FAA LID: ORD), also known as O’Hare Airport, O’Hare Field, or simply O’Hare, is a major airport located in the northwestern-most corner of Chicago, Illinois, United States, 17 miles northwest of the Chicago Loop. It serves as the primary and largest hub for United Airlines. Following United’s merger with Continental Airlines, O’Hare will become the second largest hub for United after Houston’s George Bush Intercontinental Airport. O’Hare is also a hub for American Airlines.

1. Hartsfield–Jackson Atlanta International Airport

59,790,608 passengers

Hartsfield–Jackson Atlanta International Airport (IATA: ATL, ICAO: KATL, FAA LID: ATL), known locally as Atlanta Airport, Hartsfield Airport, and Hartsfield–Jackson, is located seven miles south of the central business district of Atlanta, Georgia, United States. The airport is the primary hub of AirTran Airways, Delta Air Lines, and Delta Connection partner Atlantic Southeast Airlines; the Delta hub is the world’s largest airline hub.

Did your favorite airport make the list? What do you think are the some of busiest airports? Be sure to let us know in the comments below.

Data: ACI, BAA, Wikipedia

Image: lunchtimemama, gTarded, Mastery of Maps, Storm Crypt