How did Philadelphia get a lock on 76?

Does anyone know the process by which Philadelphia got a lock on the designation “76” for Interstate Highway System routes leading to it?

The Pennsylvania Turnpike is I-76 East from the Ohio border to its Valley Forge Interchange with the Schuylkill Expressway. From there, the *Schuylkill * becomes I-76, still designated an east-west route even though now running directly south its whole length, the last 20 miles to Philadelphia. (The remainder of the PA Turnpike to the New Jersey border becomes I-276.)

In the center of Philadelphia, entering I-676 East, the Vine St. Expressway, from its interchange with I-76, brings you directly to an exit for Independence National Historical Park.

I know (or suspect) this is the reason PA got I-76. But what was the process? Did laws have to be changed? Was there any certain individual spearheading a drive for the I-76 designation?

By the way, I-476 leads to I-76 as well. All 76’s lead to Philadelphia.

Wikipedia has a useful summary of the history of I-76 which includes the following statement at the end of the article:

Here is the source for Wikipedia’s assertion if you want to dig deeper. The key quotation from that article reads:

FWIW, the interstate highway numbering system is pretty simple. N/S routes have odd two integer designators, and E/W are even. The numbers increase as you move either north or east. An even number prefix, as in 276 means the route goes around a metro area, and an odd number prefix is a feeder into a metro area.

The whole deal dates back to the Eisenhower administration, and I’m not aware of any smoke-filled-room type deals involving number lobbyists. :wink:

It doesn’t answer explicitly but here is a detailed history of I-76.

Apparently the original designation was to be I-80 (and some maps showed that in the early '60s) but in 1964 a single designation was given for the stretch connecting Philadelphia and Pittsburgh. It comments on the appropriateness of “76” but does not mention any particular fooforah about getting it. Absence of evidence is not evidence of absence and all of that but with the detail on that page, if there had been some big campaign I suspect it would be there.

Anyway that provides a longer history. This page at the US Department of Transportation is directly on point and finds no strong evidence that the selection of I-76 as the new number in 1964 was strongly connected to 1776 or the bicentennial.

As for all of the other x76’s that is just a convention of the interstate system. Short spurs of interstate off a main route always (almost) have a three letter designation where the last two letters are the main route. So in the San Francisco Bay Area the main interstate is I-80 and we also have I-280, I-580, I-680, I-880, and I-980. In the LA area all the interstates seem to end in x05 or x10 because of I-5 and I-10 running through there.

Also, Philadelphia does not have a monopoly. The I-76 through Pennsylvania isn’t the only one. There is also an I-76 that runs from Denver to the northeast corner of Colorado where it connects to I-80.

And there’s I-380 and I-780, too- 780 is a short run up near Vallejo, and 380 connects 101 and 280. At least, that’s what’s in my head.

Philadelphia is the largest city that I-76 (either one of them) runs through, so it does in fact have most of the x76 routes; however, there’s an I-376 in the Pittsburgh area as well.

It’s not at all obvious to a sufficient amount of people that there are prominent signs east of Flint, Michigan, indicating that the I-69 NORTH becomes the I-69 EAST (it ends shortly later at the US border with Canada). I wonder how prevalent these meaningless exceptions are?

Yeah, they slipped my mind. The Bay Area has several very short interstates.

I-380 is 3.3 miles long. I-780 is 6.5 long. I-238 (connecting 580 and 880 around Hayward and a complete naming exception) is 2.2 miles long.

That page mentions that an exception name was needed for I-238 because all other x80 numbers were taken. So I looked and I-180 was an interim number for the Richmond-San Rafael stretch of what is now I-580 (and there is an SR-180 in Fresno which is apparently too close).

I-480 was never officially used but was reserved for a proposed expansion of the Embarcadero Freeway from the Bay Bridge to the Golden Gate Bridge. Apparently that was on the tables for about 30 years but the removal of the Embarcadero Freeway after the quake finally killed it off for good.

Interesting history. That has nothing to do with the question.

Edit: I’m an idiot. For some reason I forgot all about I-380 route to the airport and thought you meant where 101 and 280 meet down south. Was very very confused for a second.

My OP is answered to my complete satisfaction – something I’ve wondered about for years – and within half an hour of my posting it. Thanks, Jurph and obfusciatrist especially, and I’m grateful to the others who helped also.

I never suspected the ironic twist that I-76 *would have run all the way * to Independence Hall National Historical Park if not for the last minute switch of the I-676 and I-76 designations. The Vine St. Expressway, today’s I-676, was originally slated to be I-76. I-76 would then have run: along the PA Turnpike, then down the Schuylkill Expressway, then onto the Vine St. Expressway and across the Ben Franklin Bridge – the exit for Indepence Hall National Historical Park coming just before the Bridge. That was felt to be too confusing for motorists, though, and hard to sign at the Vine St. / Schuylkill Expressway Interchange. So I-76 remained on the Schuylkill, and the Vine St. Expressway became I-676.

I now see that even though the renumbering took place in the period leading up to the Bicentennial of 1976, there is apparently no connection to the Spirit of '76, just a happy coincidence. It does increase anticipation as you enter Philadelphia as a tourist, from whichever direction. You cannot escape the number 76, or the name Benjamin Franklin.

The Odd = N/S, Even = E/W system has always allowed for variations along the overall length of the highway. Whether a road is numered odd or even is affected by the relative direction between each terminus. For example, in the old system of “US” designated state highways, US-24 is even as it runs from Michigan to Colorado. However, its entire length in Michigan, running from Pontiac to the Ohio border just outside Toledo is a North/South road and it does not turn West until it gets to Maumee, OH. Similarly, US-10 used to run from Detroit to Seattle (until much of it was replaced by I-94 ibeginning in North Dakota), but it runs more North than West as it makes its way from Detroit to the ferry at Ludington.

I always thought calling the Schuylkill Expressway ‘east/west’ was a fiction simply to get I-76 down into Philadelphia, for reasons of their own. But, the Schuylkill can be thought of as east/west, as Tom points out above, as part of the larger and legitimately east/west I-76.

It’s confusing, though, to hear a traffic report, “the Schuylkill eastbound is backed up.” An extra mental step is necessary to figure out which direction is backed up. Many times the traffic reporter will say something like, “coming into” or “leaving the city the Schuylkill is backed up,” which doesn’t require that extra step.

The Schuylkill most definitely does not run directly south it’s whole length. It’s southeast from the Turnpike to Fairmount Park, kind of sou’ southwest for a few miles through the Park, southwest again till it meets the Vine St. Expressway, then meanders it’s way south and east (with some occasional westing) to the Walt Whitman where it enters New Jersey and ceases to exist.

Thank you for pointing that out. It is true, but like saying the Schuylkill River flows east/west. The common denominator in all the directions you give is “south.”

I would like to amend my hasty Reply to ‘muldoonthief,’ in Post 14 immediately above. The Schuylkill Expressway indeed runs southeast and not “directly south its whole length,” as I said in the OP. It always seems to me to run directlly south, but does not, in fact. Thanks for your correction, muldoonthief.

If you really want to suggest Pennsylvania transit route skullduggery, take a look at the whole 51.2 mile length of I-99, aka Bud Shuster Highway. Yes, that is a whole 2-digit major interstate designation for 51.2 miles of road that are contained entirely within the state of Pennsylvania.

Never let anyone tell you Bud Shuster didn’t deliver anything to Altoona…

I’ve learned that calling the Schuylkill an Expressway in any direction is fiction.

I find it amusing that I-76 run from Philadelphia to the middle of nowhere outside of Lodi and Chippewa Lake, Ohio in Medina County. It literally goes nowhere. I suppose you could say it goes to US 224 (thechnically, for a stretch it is both 224 and 76), which it does. But US 224 ends halfway between Lodi and Esseburg. It turns into US 42, which eventually meanders into Mansfield Ohio, but no one in their right mind is goint to go that way unless they are in for a nice (looong) country drive. A better way is I-71.

And while we are on the subject, at one point I-76 and I-77 are running straight east and west, and are the same road. At the western edge of this, 77 goes north (running north south as it should) and 76 goes south (running north south) for a few miles. The north/south, east/west are always a bit fuzzy when you get to the actual highway laying out part.