My 20 Dream Interchanges
When I was a little boy growing up in Chicago, I used to draw maps of the city, with all of its expressways and major streets.  I gave some of my maps a little more detail, like interchanges and route numbers.  Later on, I got to draw maps of the 50 United States and Canada, too.  I even let my imagination run wild and drew a few nonexistant interchanges.  Most of these are showcased here.

After checking out the many different interchange designs at
Kurumi's website, as well as Brian Polidoro's showcase of unusual interchanges and Steve Alpert's creations, I decided to make 20 interchanges of my own.  Some are modifications of well-known interchanges, and most of them probably will never be built in real life.  So, without further ado, I present to you the following 20 interchanges:
Part 1:  TPUI, Three-street interchange, Four-street interchange, Two-street SPUI

TPUI (Triple-Point Urban Interchange):  This interchange has four ramps meeting at three different points.  All of the ramps are two-way, meaning that traffic can turn either left or right from one street to go onto the other.  At the end of the ramp, traffic from the left-most ramps will turn right, and traffic from the right-most ramps will turn left.  There are traffic signals at all three points, and they're synchonized to allow the same traffic action from opposing directions.

Three-street interchange:  One street crosses over (or under) a two-street intersection.  Ramps provide access between the three streets.  The ramps are two-way.

Four-street interchange:  Two intersections overlap each other.  Ramps provide access from one intersection to the other.  The ramps are two-way.

Two-street SPUI:  A variant of the classic one-street SPUI, all ramps and streets meet at one point.  Thusly, one set of traffic signals is required.  The signals are synchronized to handle the following movements through the intersection:  through traffic on one street, through traffic on the other street, left turns from the freeway ramps, and left turns onto the freeway ramps.

Part 2:  "H" Interchange, "H" Interchange 2, SPUPCLO, Frontage mixer

"H" Interchange:  This interchange is so called because it resembles the letter "H."  In the illustration, two "T" interchanges are used to connect the freeway to the surface street, hence the nickname.  This eliminates the need of traffic lights and left turns.

"H" Interchange 2:  Same as the above, except that it uses two trumpet interchanges.

SPUPCLO (Single-Point Urban Partial Cloverleaf):  Special thanks to Scott "Kurumi" Oglesby for dreaming this up.  The interchange works the same way as a regular SPUI, but it uses a folded-cloverleaf design.

Frontage mixer:  This cleverly-designed interchange allows access from the freeway to two frontage roads (or one-way streets, depending on the location).  That way, drivers won't have to hunt for the nearest exit to get gas or stop into a hotel.  Not only convenient, but a real time-saver.

Part 3: Two-freeway roundabout, "K" interchange, Cloverleaf crossover, Crossover stack

Two-freeway roundabout:  This utilizes four ramps and a roundabout, and thus eliminates the need to build flyover ramps (like a stack interchange).  Traffic on the roundabout moves in only one direction (in this case, to the right), and can access the freeway a lot easier than it would on a stack.

"K" interchange:  Three freeways meet in this interchange.  This interchange is so named because its configuration resembles the letter "K."

Cloverleaf crossover:  Two freeways cross over themselves, so that the travel lanes are reversed when they pass through the interchange.  Four cloverleaf ramps are placed in the middle of the interchange.  Cool, isn't it?

Crossover stack:  Only one freeway crosses over itself, and four stack ramps are placed in the middle of the interchange.

Part 4: Five-way interchanges

Five-way interchange 1:   Three freeways meet at this interchange.  One of these freeways branches off at the interchange, and ramps provide access to all three of the routes.

Five-way interchange 2:  A slightly different variant of the previous interchange.

Part 5: Six-way interchange, Eight-way interchange

Six-way interchange:  Three freeways meet at this interchange.  Ramps provide access to all three of the routes.

Eight-way interchange:  Four freeways meet at this interchange.  Ramps provide access to all four of the routes.

Part 6: Deluxe stack, Surface cloverleaf

Deluxe stack:  At first, this looks like a regular stack interchange, but take a closer look at it, and you will find a few more ramps that lead to and from surface streets.  These extra ramps set it apart from other stack interchanges, and thus earn it the "Deluxe" moniker.  Note the arrows that denote the correct traffic movement on the additional ramps.

Surface cloverleaf:  Note the traffic signals in the middle.  Left-turn movements are eliminated, and traffic that would normally make such movements must use the cloverleaf ramps here.  Regular right turns are made using the straight ramps.  As a result, all turns are disallowed at the intersection.

Part 7: Looped "T", Four-freeway roundabout

Looped "T":  Here's a "T" intersection with two cloverleaf loops.  As before, all left turns are eliminated, as traffic must use the loops for such movements.  There's no need to use additional ramps for right turns, as they can be made at the intersection itself.

Four-freeway roundabout:  This is a variant of the two-freeway roundabout, but four freeways pass through this interchange.  It's basically a simplified version of the eight-way interchange, and exiting traffic will utilize the turnabout to go onto another freeway.

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