The View From Wisconsin

This is the last in the series... and these are (at least in my opinion) the 10 strangest things about the Interstate Highway System in the United States. Feel free to dispute.
41. Interstate 73, North Carolina. I-73 is currently a single-state Interstate, but it is not planned to remain that way. The existing stretch, extending south along the US 220 freeway from Greensboro to Ulah, NC, is planned to extend south to Charleston, SC and as far north as Sault Ste. Marie, MI. So far, however, most of I-73 is signed as "FUTURE 73" on non-Interstate sections of highway in central North Carolina. I-73 is co-signed with I-74 along its current route; I-74 is another violation of AASHTO guidelines, in that its designation should not be allowed as US 74 runs along the southern edge of the state. In fact, where I-73 and I-74 are currently planned to separate near East Rockingham, I-74 and US 74 would run concurrently on the same stretch of freeway towards Wilmington, NC. There is some debate as to whether I-73 is actually the shortest mainline Interstate in the US, as it is listed at only 12 miles on its own (separate from I-74).
42. Interstate 87, New York. I-87 is a single-state interstate, but it actually does touch a border – the Canadian border between New York and Quebec north of Champlain, NY. The Interstate travels south alongside the Vermont border to Albany as the Adirondack Northway, where it intersects I-90 and the New York State Thruway. I-87 takes over the Thruway's southern leg down past west Point and the US Military Academy. It continues south, missing the New Jersey state line at Suffern, NY by little more than 500 yards at its junction with I-287. I-87 and I-287 duplex all the way to the Hudson River, crossing over the Tappan Zee Bridge and then heading south into the Bronx. In New York City, the freeway is known as the Major Deegan Expressway, from its border with Yonkers to its southern terminus at the Bruckner Expressway and I-278, just north of Randalls Island and the Triborough Bridge. In 1967, Parade magazine declared the Adirondack Northway (or simply "The Northway") to be America's Most Scenic Highway.
43. Interstate 96, Michigan. I-96 was originally a bypass of US 16, heading from Muskegon to Detroit as a single-state Interstate. Its western terminus is US 31, northeast of Muskegon; it traverses the lower peninsula of Michigan, through Grand Rapids and Lansing. In Lansing, it runs for seven miles concurrently with I-69 – the only instance in the US where two Interstates with "reflective" numbers run concurrent with each other. I-96 heads east from the south side of Lansing, past the GM Proving Grounds in Milford to Farmington Hills. It then joins with I-275 south to Livonia, where it heads back east into Detroit on what is now known as the Rosa Parks Memorial Freeway. I-96 ends at the Fisher Freeway, about a mile west of the site of Tiger Stadium in downtown Detroit and two miles northeast of the Ambassador Bridge into Canada.
44. Interstate 465/865, Indianapolis, IN. The "Indianapolis Loop" around the capital city of Indiana has many odd features as it circles around Marion County. First of all, the I-465 freeway crosses, intersects or runs concurrent with four separate freeways (five if you count the I-865 spur to the northwest of Indy). It also runs concurrently with five US highways (and crosses a sixth to the west). A seven-mile section of I-465 from the East Street exit to the interchange with I-74 east near the Marion County Fairgrounds is actually a co-signed route of seven different Interstate, state and US highways: I-74, I-465, US 31, US 36, US 40, US 52 and IN 37. Indiana route 37, which runs concurrent with I-69 from northeast Indianapolis, is slated to be the eventual route of I-69 as it is completed on its proposed routing to Texas. I-465's "branch" highway, I-865 in northwest Indianapolis, allows traffic headed south on I-65 to take the northern leg of the bypass, since the intersection of I-65 and I-465 on the west side of Indy does not allow for a northbound exit on the western leg of the loop. The entire length of the bypass, numbered from its southern interchange with I-65 to the west around the "loop", is about 54 miles – meaning drivers would only need to circle the loop approximately nine and a quarter times to equal the length of the Indianapolis 500. If you did so from the southern I-65/I-465 interchange headed west around Indy, you would hit mile number 500 at the southern edge of Speedway, Indiana.
45. The "Interstates" of Hawaii. The state of Hawaii has three "Interstates" on the island of Oahu; all three connect Pearl Harbor with the other military installations around Honolulu. These Interstates are designated H1, H2 and H3, roughly in that order from the west to the east side of the island. H1 runs along the southern shore of Oahu, from Kapolei, around Pearl Harbor to just past Diamond Head State Monument. H2 extends north from H1 and Pearl Harbor to Wahiawa and the Schofield Barracks Military Reservation. H3 runs from northwest Honolulu at Aliamanu Military Reservation to the Hawaii Marine Corps Base on Kaneohe Bay. A "spur" highway, H-101, has also been designated in recent years. Contrary to popular belief, there has never been any idea of building a Trans-Pacific Freeway from Oahu to the mainland of north America. All three of Hawaii's Interstates have an "Ø" marker at their termini, instead of signposts indicating their end.
46. The "Interstates" of Alaska. Alaska has four highways that are designated as Interstates, though only two sections of them (A1 and A3) have been upgraded to freeway status – and both of those are around the Anchorage area: the New Seward Highway, heading south out of the city to the Kenai Peninsula, and the Glenn Highway, which is 5th Avenue in downtown Anchorage. None of the Alaskan "Interstates" are signed as such. Though the capital city of Juneau does have a state highway running through it (AK 7), it is not considered to be an Interstate highway, making it one of only a handful of state capitals not served by an Interstate. By the way: the Alaska Highway is designated as Interstate A2 between Fairbanks and the state border with Canada and the Yukon Territory – but is not Interstate grade. The closest Interstate to the Alaska Highway is Interstate 5 in Bellingham, WA; the distance between the end at Dawson Creek and I-5's terminus at the Canadian border is approximately 1,180 kilometers (733 miles).
47. The "Interstates" of Puerto Rico. Puerto Rico's Interstates are also unsigned; however, unlike Alaska, the island has many freeways (called "autopistas"), many of them tolled. Puerto Rico's Interstates are designated in the same way as Federal highways, and are maintained as "state" highways. The island's "Interstates" are PRI 1, running from San Juan to Caguas, down to the southern coast and then over to Ponce (numbered mostly as PR 1); PRI 2, running from San Juan along the northern and western coast to Mayaguez, then south and east to Ponce (numbered as PR 2); and PRI 3, running along the eastern coast from San Juan to Fajardo and Roosevelt Roads Naval Station, then south and west to meet up with PRI 1 near Salinas (numbered PR 3).
48. Interstate 676, Philadelphia, PA. The Vine Street Expressway was built in downtown Philadelphia more or less as a "parkway" to connect the Schuylkill Expressway (so named for the river it follows) to the Benjamin Franklin Bridge. Only one problem: at the foot of the Bridge are Franklin Square and the northern end of Independence Mall. Freeway planners knew better than to try to bulldoze American history – the site is supposedly where Franklin flew a kite in his experiments with electricity – so the Interstate designation for the Expressway "ends" at North 6th Street. A spur continues to the north over to the Vietnam Veterans Memorial Expressway (I-95); an entrance to the Franklin Bridge is located near the southern end of Franklin Square. I-676 continues on the other side of the Franklin Bridge in New Jersey, connecting downtown Philadelphia to I-76 on the opposite side of the Walt Whitman Bridge. The two blocks are a rare occurrence on an Interstate: at-grade intersections with surface streets between two sections of a freeway. The westbound section of I-676 has an Interstate-grade exit to I-95, but drivers continuing on I-676 have stoplights at North 7th and 8th Streets. Another slight oddity: the section of I-676 in Pennsylvania is signed east-west, but the section in New Jersey is signed north-south.
49. Interstate 99, central Pennsylvania. This is the freeway that drives "road geeks" crazy. This Interstate is a bypass of US 220 through central Pennsylvania, extending from Bedford north to Bald Eagle, PA. The primary reason for vexation is the old adage: location, location, and location. The route designation does not follow the AASHTO rules for placement of an Interstate; the "proper" location would be along the Atlantic coastline. The credit for the rule breaking comes from Rep. "Bud" Shuster (R-PA), in whose district I-99 runs. Shuster had the I-99 designation written into an appropriations bill, the National Highway Designation Act of 1995, to supersede AASHTO rules. It is currently the second shortest mainline Interstate in the US at just under 70 miles. It is scheduled to eventually extend northward to State College, PA (home of Penn State University) and Interstate 80 at Bellefonte. Eventually, it is scheduled to connect I-80 via Williamsport to I-86 in Corning, NY, bypassing US 15, with a possible extension via I-380 to Rochester. That day is a long way off, however; there are environmental concerns with the section between Bald Eagle and State College. In excavations for the route of the freeway near Skytop Mountain, the rocks were found to contain large amounts of pyrite – a substance that, when exposed to oxygen and water, turns into sulfuric acid. The state has been attempting to get rid of the acidic waste for several months, and construction on the segment between Bald Eagle and State College has been hampered by the environmental issue. Highway observers argue that because of its distance and planned location, a spur designation (such as I-576) would have sufficed. The problem, though, is that I-99 does not have a direct interchange with I-76 or I-70, since the latter two are routed on the Pennsylvania Turnpike. To reach the turnpike, drivers have to exit onto Business US 220 north of Bedford to reach the exit. The freeway extends for a mile and a half beyond the Turnpike to US 30, signed only as US 220.

And the oddest of the oddities:

50. Interstate 70, Breezewood, PA. This is the result of what happens when Federal regulations brush up against the desires of a state government. The Pennsylvania Turnpike is one of the oldest limited-access tolled freeways in the US, pre-dating the Interstate system by nearly two decades. In 1940, an exit was created at a small town named Breezewood where US 30 (then known as the Lincoln Highway) met up with the Turnpike. Because the exit was the first major stop as the Turnpike crossed the Allegheny Mountains, it turned into a tourist trap of sorts, with all sorts of hotels, motels, gas stations and truck stops. When the Interstate Highway Act was signed into law in the 1950's, it was planned that a section of I-70 would meet up with the Turnpike – which was to be designated I-76 – at Breezewood. However, the act specified that Interstates could only be designated on existing toll roads if certain requirements were met: either the money that went into building the roads would be completely repaid by the tolls (and then the toll road would be disbanded), or the state authorities would provide access to an alternate, non-tolled route on a Federally-sanctioned highway – like US 30. The Turnpike Authority didn't want to build a new interchange at Breezewood, since it would require constructing a new on-ramp and a new toll plaza (tolls were taken as vehicles enter the turnpike). Because of this, I-70 was routed to "end" at US 30, about one-quarter of a mile west of the entrance to the Turnpike – and the western leg of I-70. The ramp at the end of the eastern leg of I-70 leads to a stretch of highway that has 37 restaurants, gas stations, truck stops and motels – all on that quarter-mile strip between the two exits on US 30. The "gap" remains because the owners of the various businesses have allies in the Pennsylvania state government to prevent any changes to the "interchange."