This week brings us to Chicago:

This is the northern terminus of the Stevenson Expressway, I-55, at US 41 (Lake Shore Drive) a bit south of downtown Chicago.

Most of the ends of interstates I???ve encountered in the US tend to be rather anticlimactic.  However, at least I-55???s north end benefits from the distinction of ending on the shore of Lake Michigan, at a road that is remarkable in its own right (Lake Shore Drive).

Oh, and that would be Chicago???s McCormick Center at the left-hand side of the image, in case you were wondering.

This wee brings us to Thailand

(View in Google Maps)

This is the new (opened in 2006) Dipangkorn Rasmijoti Bridge, a.k.a the Mega Bridge.  It carries the Industrial Ring Road across the Chao Phraya River, and connects Bangkok with the Samut Prakan Province.

Last week, we visited the host city of this year???s Summer Olympics.  So, this week, we???ll visit the host for the 2012 Games ??? London.

This would be the iconic Tower Bridge, carrying the A100 across the Thames River immediately southeast of the Tower of London.    It???s a drawbridge, and was opened in 1894.

Traffic using the bridge is also limited to a 20 mph speed limit, and an 18 ton weight limit, with both restrictions strictly enforced via sensors and cameras with license-plate recognition technology.  Orwell would be proud, I???m sure.

It’s Beijing’s week to get a highway feature highlighted.?? So, in honor of the Summer Olympics….

(View in Google Maps)

The Fourth Ring Road is a frequently congested loop about 8 kilometers outside the core of the city of Beijing.?? This particular location is where the expressway passes just south of the new National Stadium, the “birds nest” that will be the venue for the opening and closing ceremonies of the 2008 Summer Games.

This week brings us to the outskirts of Paris, where we see what happens when the French need to build an interchange between two partially underground autoroutes:

This is the interchange between the Autoroute 14 (running northwest-southeast in the map above) and the Autoroute 86, the Paris Super-P??riph??rique (second beltway, running southwest-northeast in the map above).

The interchange is unusual in that both autoroutes are partially underground at this point — the A14 in the Tunnel de la D??fense, which travels under the La D??fense skyscraper district northwest of the City of Paris proper, and the A86 which heads underground to avoid additional disruption to the commune of Nanterre.

This week brings us to Germany, home of the Autobahns.   In the industrial Rhine-Ruhr megalopolis, we can find the answer to the question — how exactly do you design an interchange between two freeways meeting at a shallow angle, with a river and a railroad complicating matters:

This is the Kreuz Kaiserberg, the interchange between the A3 and the A40.

The A3 is the primary north-south freeway through the Rhine-Ruhr metropolis, while the A40 (the Ruhrschnellweg, locally also known as a parking lot) exists theoretically to carry traffic east-west through the region.  In the picture above, you can also see the Ruhr River angling from the north to the east edge of the map, as well as several tracks of the Deutsche Bundesbahn.

I’ve come to the conclusion that America doesn’t have enough roundabouts or traffic circles.  They’re beautiful structures and, the way we drive in the States, they provide a practical field test of Darwin’s theories.

Consider, for example, this highway feature in Tehran:

(View in Google Maps)

This is the Hagh-Shenaas Square, a roundabout-based interchange for the recently constructed Navab Highway in Tehran.

It’s a beautiful structure.  Robert Moses would be pleased.

While poking around aerial imagery of Karachi, I found this beautiful structure:

This is the Jinnah Bridge, a.k.a. the Native Jetty Bridge, located on the harbor in Karachi.   It’s a roundabout, with a flyover bypass, all positioned over a couple of rail lines.

This week brings us to Dhaka, Bangladesh

One of the few prominent highway features in Dhaka is the Babu Bazar Bridge, which spans the Buriganga River.  It’s one of two bridges spanning the river — rather remarkable considering the metropolitan area is home to roughly seven million people.