The bridge sits just east of Tokyo’s city center, the original was built way back in 1603. This one was built in 1911, as a replacement to the others which had been destroyed through various wars.

The zero milestone was conceived of in the 1700s when Japan was building a vast road network. It really came into play in 1868 when Tokyo became the national capital and the nation’s roads converged here. During the American occupation, a route numbering scheme was enacted and the zero milestone became the begin and end point for many of the most important national routes. The milestone used to be in the center of the pavement, but was moved in 1973 to a point just off the bridge.

Many national routes end and begin here, but the only three that are signed are 1, 4, and 15. Route 1 runs southwestward from Tokyo and connects it with Osaka and Yokohama. Before the expressways were built, it was the most important road in Japan. Route 1 also follows the Tokaido for most of its length, Japan’s most important medieval road.
The first Rt. 1 shield is at the southern foot of the bridge.

Another view from the opposite corner. Rt. 4 begins on the opposite end of the bridge and connects the capital to the northern half of the country.

The Nihonbashi and zero milestone are marked on just about every map of Tokyo, and many maps of the country showing mileages also list it. It’s important from a historical standpoint, and from a practical one. When you’re looking at mileage to the world’s largest city, knowing where exactly in the city the mileage is measured to can prove very helpful, as it’s about 200 kilometers from one end of Tokyo to the other. It’s marked on this expressway map by a cross surrounded by a circle.

“Being such an important historical and practical spot, it is a shame that the Nihonbashi has to endure being under such an ugly freeway” – that’s a paraphrase of the position of the national road authority. Plans are underway to both widen and relocate the city’s central loop away from the river. It will cost billions, but the city will get a new outdoor spot and the sun will again shine on one of Japan’s most interesting roadgeek spots. This rendering has the freeway built through adjacent skyscrapers.

The bridges are part of the B (B for Bayshore) route that runs along the north and west side of the bay. Coming onto the bridge from the south, traffic is routed through a “helix” interchange. The interchange connects 2 freeways coming in while at the same time routing traffic upwards to about 400 feet, the height required to get on the bridge. I have no idea what that sign means.

The Yokohama Bay bridge is about 500 feet long, and is a monster – it’s high enough to accomodate the cargo ships spewing Toyotas and Samsung TVs and Anime DVDs to the world.

The next bridge along the B-route, Tsurumi Tsubama, looms next at the crest of the Bay Bridge.

In between the two bridges, on a manmade island in the bay, there is a rest area (with a McDonalds!) in the midst of yet another helix interchange. This interchange spirals traffic in a “spring” 5 levels high with ramps eminating out to three directions (to the B-route and the K5 freeway) plus a ramp to ground level to access the rest area. The helix interchange opened, partially, in 1990 and rises to the height of about a 14 story building.

If you’re at all unfamiliar with the bridges, just check out the map at the rest area:

The Tsurumi Tsubasa Bridge opened in 1994 and it’s the longest single plane cable stayed bridge in the world (until San Francisco’s new bay bridge East Span opens, I think). It gives view of the impressive 20km long Kawasaki/Yokohama skyline to the west, and of the open bay and container ships to the east. This bridge is the first example of this particular style of tower design on cable stayed bridges. The bridge towers and landscape in the area were designed by Motomi Kawakami, who is more famous for designing furniture. That’s right, the Tsurumi Tsubama Bridge towers were thought up by a furniture guy. Think of ottomans next time you’re on the Charles River Bridge in Boston.

The Aqua-Line is a bridge-tunnel complex that spans Tokyo Bay. It’s a very important part of the regional road network because it connects the country’s major international airport at Narita in Chiba Prefecture (east) with the city’s second and third largest urban areas (Yokohama and Osaka) to the west – bypassing Tokyo and it’s traffic completely. It’s also part of the larger Tokyo freeway network in that it is part of the third beltway project, which is currently under construction.
In the center of the span sits the Umi-Hotaru (Ocean-Firefly) – an artificial island with a viewing platform and visitor’s area.

The design of Umi-Hotaru is meant to invoke a ship sailing towards the city. It looks a bit like a ferry, coming from the east (bridge) portion of the span.

LED signs warn of high winds upon entrance of exit of the tunnel when needed. The bridge portion of the span is 4 km long, while the tunnel section is 9.6 km long, making it one of the world’s longest road tunnels – and the longest road tunnel on earth that runs under a body of water. Large numbers on each side of the tunnel tell the driver how much longer it is to the end (8km……..7km……….etc)

The western entrance to the span consists of a large four-level stack, in which the lowest level is partially buried underground. The entire interchange sits on a manmade island just off the coast of the city of Kawasaki. The aqua line is prominently signed all around the Kawasaki/Yokohama area. Traffic LED signs warn of backups on the road. Occassionally an accident on the aqua line (Japanese drivers speed like mad) will back up traffic for up to 8 hours.

The western entrance to the tunnel, upon leaving the stack. LED signs warn of high winds when exiting. The venting system of the tunnel consists of two large chimney structures. The landside chimney features a pyramid structure sitting above the tunnel entrance.

Upon exiting the tunnel, drivers are immediately faced with the decision to exit at Umi-Hotaru or to continue to Chiba Prefecture. Let’s exit. The manmade island features a sweeping flyover.

Upon entering Umi-Hotaru, drivers are routed into the central parking structure. The rest area has restaurants and shops, and normally remains pretty crowded even in really windy weather. The entire span opened in December of 1997 after construction delays, and it could use a paint job.

Looking east from the rest area, the network of ramps serving Umi-Hotaru are obvious, as is the short 4km bridge to the mainland.

Looking eastward towards Chiba on the bridge portion of the route.

The Aqua Line is a toll facility, and indeed is one of the most expensive toll facilities in the world. When constructed, the road cost 4,000 yen to traverse – which translates to about $40 US dollars. No one used it. In 2000 the toll was reduced to 3,000 yen to increase traffic, but that did not work much either. The Aqua Line continues to be a money pit year after year. Drivers exiting the aqua to the east can continue into Chiba on the Tateyama Expressway, or meader to the Ocean going straight ahead. Its not signed anywhere, but the span sends National Route 409 over the bay, and is signed as Shuto Expressway K3 on the western side.

Now for two views (click for larger)

Looking southwest from Umi-Hotaru, Yokohama’s skyline is visible. The cable stayed bay bridges are prominent features, and most prominent is Mount Fuji – which is obscured by clouds (as usual) on the left side of this photo.

The skyline of Tokyo is extremely visible looking west and north from Umi-Hotaru. The full skyline of the city takes of 40% of the entire horizon, and is unfathomable to look at.

I could not figure out what this sign was for at first – until my friend translated it for me. It means, be quiet! The Japanese politeness culture extends even on to the untamed road network. Don’t play loud music, or honk, or have a loud muffler because people in the very closeby apartments might be asleep.

Rest areas all over Japan display large expressway maps with traffic information on them. Tokyo is the largest city in the world, and there really are not that many freeways to go around. Couple the bad traffic with the cultural propensity for punctuality and you have people who are very much into knowing traffic conditions at all times. If you can’t make it to a rest area, or get the map on your phone, there are these:

LED traffic display signs. Maps of the upcoming junctions and route choices are shown along with an LED display of traffic conditions. This one is currently all black on a Saturday morning – but will light up yellow and red as traffic builds. Drivers can then make better decisions about which direction to go. How about some of these on Washington’s Beltway, or the 405???

Most of the expressways in the city are two lanes, and wind through skyscrapers and apartments. Each route has a name, and that is used more often than the number. The kanji above the 9 in this route marker translates to “Deep River Line”. Line, as in a train line, but that term translates over to roads here as well. Route 9 is so named because it was built right over the Sumida River, because there was no where else to build it. We’ll revisit this road from beneath in a future post. The LED sign in the background warms of a traffic jam ahead.

Now for one of the complicated overhead signs. Shuto Expressways’ overhead signs all have the same characteristics, pretty much, although the newest ones are backlit. Route designations take center stage, if the route is a loop – as in the case of C2 (the second beltway) you’ll get an arrow indicating the direction of travel, in this case it is counter-clockwise. Control point route markers are placed beneath the main shield to indicate that these other freeways can be reached by taking this one. Control points are marked in Kanji (large) and Romanji (smaller) – secondary control points are placed at each end. Sometimes, the important junctions like this one are given a name. Travel times to other destinations are listed in the LED displays up top. This sign assembly is near the port southeast of the city, where the Bayshore Line meets the second Beltway. There is a lot of truck traffic on the B route, as it connects all of the port areas.

This view is on the C1, or the innermost beltway. This is the most interesting road in Tokyo, in my opinion. It runs through tunnels near the Imperial Palace, between Shinjuku’s skyscrapers, and connects most of the spoke freeways. This view is looking northward on the eastern side of the inner city. The road has two decks, and winds a great deal.

This view is looking towards the C1 junction from Route 6, coming in from the east. Travel choices for the C1 indicate that you can choose between clockwise or counter-clockwise travel around the inner city. Most signs in the densest part of the city omit exit numbers, and because Japan does not use many street names, they usually omit those, too.

This is a view of Yokohama’s K3 expressway. Most of this route is elevated as well, and runs south of downtown. Yokohama is Japan’s second largest city, and has its share of really neat road-related things. The leftmost sign points towards the Yokohama Bay Bridge, and the rightmost points towards the Aqua-line – both of which will show up in later posts.

Finally, the Rainbow Bridge. You will not find any “no photography” signs on this one, this is not New York! The Rainbow Bridge was built in the early 90s and is a beloved local landmark. It links the mainland part of the city with the manmade island city of Odaiba, and the B Expressway. If you’ve ever seen Kill Bill Volume 1, this is the bridge that O-Ren Ishii crosses on her way to the House of Blue Leaves – for the final showdown.

Guide signs on national expressways are green, and usually contain tons of text. This sign is on the Tateyama Expressway south of Chiba. Route numbers are shown, as are the romanji equivalents of the names of control points.

Expressways in Japan are managed by one of 3 private companies. In the Tokyo area, they are called locally “Shuto Expressways” and are managed by the Metropolitan Expressway Corp. This sign shows a typical expressway entrance, backlit with an LED display of traffic conditions. The C1 road is Tokyo’s innermost beltway (there are 5 beltways in various stages of completion). The arrows in the route shield indicate traffic entering here can go in either clockwise or counter-clockwise directions.

This is a Blue overhead sign (BOS from now on). There are national routes, and prefecture (state) routes in Japan. All of them are signed with these BOS’s, which contain a graphical display of the intersection. Any BOS put up before 1990 is in Kanji only, any signs after that have at least some romanji on them.

A typical BOS, with Romanji and Kanji showing control points. This sign located in Tokyo’s Roppongi neighborhood shows both the national route shield and two secondary route shields (the hexagons) – along with a graphical representation of this 5 point intersection. The street name, if there is one, is shown with arrows at each end.

Another BOS near Yokohama. Sometimes, the second intersection is shown after the most immediate (in this case Rt. 141 comes right after Rt. 16). Toll roads and expressways are shown in green boxes.

In addition to BOS, routes can be signed in three other ways. In metropolitan areas, like Osaka, Nagoya, or this one in Tokyo – routes are placed on street signs. National routes with a red background, and secondary routes with a brown one. There are tons of secondary routes (think Virginia) and almost every major street is numbered in some way. This is in response to the American occupation after WW2. Japan does not traditionally use street names except on major roads. The Americans instituted a numbering scheme, which was largely discarded except for the route numbers which still remain. The Japanese addressing system is both interesting, complicated, and nearly impossible for foreigners. They still dont use street names, normally.

This is a standalone national route sign. The top characters say “National Route” – this one is located in Kamakura Prefecture. Most reassurance shields are located at intersections, and are almost always angled towards the road.

This is a secondary route standalone sign, located at Enoshima Island. The top characters say “state route” and the bottom ones have the name of the Prefecture – a lot like a state name interstate shield here in the US.

So that is a primer on the guide signs in Japan, in the following week I’ll post about Tokyo’s Freeways, The Aqua Line, Yokohama’s Bridges, the Nihonbashi, and Tokyo’s Freeway plan. No, no asia.aaroads.com, I have my hands full with Europe (and it will be updated very soon, I promise)!