The View From Wisconsin

In celebration of the Interstate Highway System's 50th anniversary, the following is a list of the 50 oddest, strangest, most interesting and most frustrating things about the Interstates in the United States.

It is by no means a comprehensive list of every oddity about the system, but it does provide some of the most notable ones. The following is part one of five parts.

Many thanks to The Interstate Guide and Kurumi's 3dI Website for much of the information on these Interstates.

1. Interstate 97, Maryland. Interstate highways are divided into three general groups: "mainline" Interstate highways, consisting of one or two-digit designations running either north-south (odd numbers) or east-west (even numbers); "bypass" Interstates that circle around a city or a region, with three-digit designations beginning with an even number; and "spur" Interstates that travel from another interstate into a city or downtown area. The longest Interstate is I-90, traveling from Seattle, WA to Boston, MA over 13 states for a total distance of 3,020.54 miles. On the other end of the spectrum is Interstate 97, the shortest mainline Interstate. I-97 travels from I-695 south of Baltimore, past the east side of the Baltimore-Washington International Airport, to US 50/131 just east of Annapolis, for a total of 17.62 miles.
2. Interstate 90, Chicago, IL. The Chicago Skyway is a 7.8 mile toll bridge connecting downtown Chicago with East Chicago, IN. For the longest time, since the "bridge" was opened in 1958, it was considered to be part of I-90 – the longest Interstate highway in the United States. In 1999, however, the city of Chicago discovered in looking through its old records that it was never technically approved as an Interstate highway. Because of this, the city began placing "TO I-90" on all of the reassurance markers on the city-maintained Skyway. However, in 2005 the Federal Highway Administration (FHWA) refuted the mistake, saying that the Skyway has always been part of the Interstate system. The Skyway was "privatized" in 2004, as an international company based in Australia signed a 99-year lease to operate and maintain the toll bridge for the city, under the name Skyway Concession Company, LLC.
3. Interstate 4, Florida. The Interstate Highway System is formally known as the Dwight D. Eisenhower National System of Interstate and Defense Highways. Too many people forget that defense was the reason why the Interstate system was built in the first place; Eisenhower's 1919 convoy of troops and tanks across the US was a primary reason that the government started the program after World War II. It is because of this secondary purpose that not all Interstate highways cross state lines. There are 17 Interstate highways in the continental 48 states that are found in only one state. Interstate 4 is the furthest south of all of them, crossing the middle of the state of Florida from Tampa, through Orlando to Daytona Beach. It is also one of only three single-digit Interstates in the United States; the other two are Interstate 5, which travels from the Mexican border south of San Diego all the way to the Canadian border north of Bellingham, WA, and Interstate 8, which also travels from San Diego east to Casa Grande, AZ and I-10.
4. Interstate 78, New Jersey. The eastern end of I-78 connects Newark International Airport with Manhattan, crossing Newark Bay into Jersey City. However, when the Turnpike Extension ends, I-78 runs across surface streets for several city blocks to the entrance of the Holland Tunnel. I-78's eastern terminus is in the Tribeca District of Manhattan. This is one of a handful of instances of an Interstate having a section of "at-grade" intersections – though it is reasonable to consider that I-78 actually ends at its intersection with NJ 139. Originally, I-78 was intended to cross lower Manhattan into Brooklyn, then up to Queens and into the Bronx where it would end at the I-95/295 interchange. The section crossing lower Manhattan was never built; the section on the other side of the island is now I-278.
5. Interstate 878, Queens NY. As a rule, Interstate highway "spurs" are not very long stretches of freeway. Their intent is to take drivers on a brief stretch of freeway into the downtown portion of a city. Some are so short that they aren't even worth signing as an Interstate – thus creating what is known as a "hidden" Interstate route. An example of this is a section of the Nassau Expressway in New York that connects the Van Wyck Expressway (I-678) and the JFK Expressway (the eastern part of the "loop" around JFK International Airport) is just under three-fourths of a mile. The section is designated as Interstate 878, but is not signed as such over the short route (the rest of the Nassau is signed NY 878). There are a myriad of reasons for the designation; the most logical is that the stretch connects the two parts of the freeway into JFK. There are other "hidden" Interstates, mostly because the stretch of freeway already carries one or more highway designations – such as I-595, which is signed as US 50/301 between I-95/495 outside of Washington, DC to the southern end of I-97 in Annapolis, MD. I-595 is considered to be the longest "hidden" Interstate in the US.
6. Interstate 476, Pennsylvania. Some three-digit interstates are longer than some two-digit "mainline" interstates. One example is I-476, which runs from Chester, PA west of Philadelphia and northwards to I-276 where it becomes the northeast Extension of the PA Turnpike. This section of the Turnpike extends northward to a terminus at Clarks Summit and I-81, just north of Scranton, PA – for a total length of 129.61 miles, the longest three-digit Interstate in the US. I-476 is slightly misnumbered, as it is mostly a north-south route. The original portion of the freeway, from the PA Turnpike down to the Schuylkill Expressway, wasn't finished until the 1990's. The southern portion of the Interstate was finally completed to I-95 in Woodlyn, PA by the Boeing plant along the Delaware River in 1993. Three years later, the Pennsylvania legislature passed a measure to resign the northern extension of the Turnpike as I-476.
7. Interstate 375, Detroit, MI. As pointed out previously, Interstate spurs are generally short freeways that route traffic into a central section of a city or other metropolitan area. Sometimes, the spur is simply a continuation of an existing freeway to a downtown location, after intersecting with another freeway. An example of this would be I-375 in Detroit. I-75, better known as the Chrysler Freeway, swings west once it reaches downtown Detroit, becoming the Fisher Freeway. The Chrysler Freeway doesn't end at that point, though; it continues on to Jefferson Avenue, along Chrysler Drive, ending near the Renaissance Center and the Ambassador Bridge to Windsor, ONT. This short section, signed as I-375, is only 1.06 miles in length – the shortest signed Interstate in the US.
8. Interstate 12, Louisiana. This Interstate is one of the 17 "Intrastate" highways in the US. It is essentially a long 85-mile bypass of I-10, running along the northern edge of Lake Ponchatrain in the Gulf Coast region of Louisiana between Baton Rouge and Slidell, LA. Because a large portion of the twin spans of I-10 across Lake Ponchatrain were damaged in Hurricane Katrina, I-10 was temporarily routed along I-12 until October of 2005, when a two-lane section of the bridge was reopened to traffic.
9. Interstates 35W and 35E, Dallas/Fort Worth. In 1980, the American Association of State Highway and Transportation Officials (AASHTO) declared that Interstate highways should no longer carry a letter designation, and urged state Department of Transportation officials to change existing letter designations to numbers. In the Dallas/Fort Worth Metroplex area, neither city wanted to change the name of their freeway to a three-digit "bypass". So, the two lettered freeways from Hillsboro to Denton, Texas, remain as one of only two left in the US. I-35E is the longer of the two freeways, at 96.76 miles due to its winding route around Waxahachie before entering Dallas.
10. Interstate 16, Georgia. Interstate 16 in Georgia connects Macon, in the middle of the state, to the Atlantic coast city of Savannah. The eastern terminus of the 166.81 mile Interstate is approximately three miles due south of the Georgia/South Carolina border along the Savannah River – making it one of the 17 single-state Interstates. Its western end is at I-75 on the north side of downtown Macon. Like most highways in Georgia, I-16 runs concurrently with GA 404 for its entire length, though the latter is unsigned. The freeway is also named the Jim L. Gillis Highway for its entire length.