Overview: I-95 is the main freeway, which enters in the lower left corner and exits to the northeast. The highway leaving the northwest corner is Florida's Turnpike (also FL 91, which I don't think is marked). Another freeway enters in the center of the west edge; this is FL 826, also known as the Palmetto Expressway. A number of surface streets also add to the confusion present in the interchange. They are: FL 9, which enters from the southwest with a spread median, and leaves multiplexed with I-95; US 441, which enters just west of and parallel to I-95 (NW 7th Avenue) and leaves northwardly in the NE corner of the photo (NW 2nd Avenue); and FL 826, which enters on the Palmetto Expressway and leaves on NW 167th Street (North Miami Beach Boulevard), running due east out of the interchange. Don't forget the HOV lanes on I-95: one lane in each direction rises from the median of I-95, soaring 95 feet above the entire interchange and landing again in the median on the other side. (It's I-95, it's 95 feet high, and it opened in '95. Coincidence?)
|Interchange Description:After thinking this one over for a long time, I've decided that the best way to show the structure of this interchange is to look at it without the connections to Florida's Turnpike and the Palmetto Expressway. We'll add those in later.|
That said, the junction between US 441, FL 9, FL 826 to the east, and I-95 is rather complex on its own. It's basically a junction of two parallel highways, where I-95 runs inside the spread median of US 441. This results in only right exits and entrances for the main highway traffic, while traffic on US 441 enters and exits from either side. Throwing FL 9 and FL 826 into the mix adds a little more to the mess. The result is the diagram to the left. (Thanks to Jason Learned, who provided the original drawing of the whole interchange which I then proceeded to butcher to obtain this one.)
I-95 has two exits northbound: the first is a ramp for FL 826 East; and the second joins the left side of US 441 NB. I-95 SB has only one ramp: in enters US 441 SB, from which drivers can access FL 826 EB or FL 9 WB. Connections between I-95 to the south, FL 9 to the west and US 441 to the south were all deemed unnecessary. Although it appears that WB traffic on FL 826 can't reach I-95 NB, this is actually not the case: a surface street, serving as a sort of frontage road on the eastern side of this interchange, is used for this connection. (This is visible more clearly in the aerial photo.)
|Now, let's add the rest of the ramps in. All of the ramps to Florida's Turnpike include a cloverleaf loop off-ramp to add access to FL 826 WB. One ramp enters as a left exit from I-95 NB, joining a loop ramp from FL 9 and US 441 NB before entering the turnpike. The remainder of the traffic comes from a left exit from FL 826 WB and a right exit from I-95 SB (this ramp runs directly under the HOV flyover, making it difficult to discern on the photo.) In addition, an onramp in the parclo-esque interchange brings in traffic from FL 826 EB and US 441 SB.|
Traffic entering the interchange on the turnpike first comes to a fairly major split immediately. The left fork leads to FL 826 eastbound, while the right leads to FL 826 WB, I-95 SB, and a ramp to US 441 NB or SB. Incidentally, the only way to get from the Turnpike to US 441 NB is to exit at the US 441 SB ramp and make your way back through the entire interchange on US 441 - I'm not even sure if this is marked or not. There is no access from the Turnpike to FL 9 WB, which surprises me - I can't see any obvious local connection on maps of the area.
To decipher all of this verbiage, a diagram appears to the left from Jason Learned.
History:As much as this seems a conglomeration that tacked together over a period of 30 to 40 years, it's actually been pretty much the same since it was built in 1964. The only change has been the elimination of a loop ramp from the Turnpike SB to FL 826 EB - instead of this ramp running alongside its WB-NB counterpart as it does now, it actually branched off of the ramp to I-95 SB where the Park and Ride lot is now, and followed US 441 NB to the split for FL 826 East. Probably at this time, another ramp was removed; it was a slip ramp from the Turnpike southbound, just before the aforementioned loop, leading to FL 9 west. The elimination of these two ramps reduced weaving, both on the Turnpike and on US 441 northbound. The HOV flyovers were added in 1995 as well. (Again - I-95, 95 feet tall, built in '95...?)
Comments: Well, I must admit it's pretty hard to build an 8-way interchange with almost no missing connections. That said, the design here is remarkable. The only missing connection that isn't a "U-turn movement" (SB-NB, NB-SB) is the connection from the Turnpike to FL 9 WB. It's an expensive interchange, but it really had to be - it's hard to cheaply build a junction for five highways and make it something better than a giant traffic circle. The one thing here that surprises me is the at-grade intersection on FL 826 at its parclo-esque interchange with Florida's Turnpike; I would have to assume that the two connections that cross each other here are fairly minor.