Yesterday was a lazy late June day in Washington, D.C, about 90 degrees and only moderately humid. For Washington in late June, that made it a perfect day for a bridge trek.
Key Bridge crosses the Potomac River and connects Arlington, Virginia, with Georgetown in Washington, D.C. It was named after Francis Scott Key, who lived in Georgetown for a time and wrote what would become the lyrics to the Star Spangled Banner after watching (while held on a British ship) the British naval bombardment of Fort McHenry in Baltimore Harbor during the War of 1812--yes in the morning, looking at the fort, he did see that the "star-spangled banner yet wave." The Potomac River bridge bearing his name was completed in 1923, making it the oldest of a series of bridges that cross the Potomac in the Washington, D.C. area. It's a short bridge, about one-third of a mile long, with 5 lanes of traffic in all. It has sidewalks on both sides for pedestrians and bikers, with barricades to separate the sidewalk users from cars, and neck-high metal railings to separate the sidewalk users from the river below. The bridge is very popular with both pedestrians (especially joggers) and bikers. We walked on the south side of the bridge, nearest to the major parts of Washington. We started from the Virginia side, walked across to Georgetown, then recrossed.
For full disclosure, I've walked this bridge before. It's a quite manageable walk. The bridge is much lower and with much more modest views than the George Washington and Brooklyn Bridges in NYC, our recent bridge treks. But in Washington, where nothing other than the Washington Monument gets very high off the ground, you still can get a great view of the area off of the Key Bridge. We could easily see (though difficult to see in the photo below) the Washington Monument, the Kennedy Center for the Performing Arts, and the Watergate Hotel (scene of the burglary in 1972 that started the whole Watergate Affair, of course, that brought down President Nixon). In the other direction is a nice view of the spires of Georgetown University. 
I don't know exactly how high the bridge is above the river; I'm guessing 80 feet or so. Aren't there maps that boaters must have in order to know the clearance for various structures, depending on the tides and river flow? Well, I'm not a boater, and if the internet doesn't provide reliable estimates, I can estimate the height myself. 
So, walking Key Bridge is a great way to get a different perspective on Washington. And it provides a great way to get up close to the edge of a bridge. Those neck-high metal railings are solid and there is no way to fall over them, although they do shake a bit when you actually hold onto them (what a complainer). Overall scariness rating is a 10, with a 3.5 for height, 1.5 for length, and 5 for width (yes, fractions are allowed).
Key Bridge, Washington, DC (south walkway)
George Washington Bridge, lower deck
The George Washington Bridge is one of the busiest suspension bridges in the world, connecting Fort Lee, New Jersey with Upper Manhattan in New York City. The bridge is about a mile long and has 2 decks, an upper one completed in 1931 and a lower one added in 1962. Once a year they close the lower deck for a few hours early on a Sunday morning for a walk/run/bike across, starting from the NJ side, as part of a fundraising effort for the American Cancer Society. A perfect opportunity to support the effort and, yes, try out a bridge walk.
I, my wife, and reportedly another 700 or so people participated yesterday in the walk part. We may not have looked, in general, in as good physical condition as the bikers and runners (who started and finished earlier), but we were a quite determined group nonetheless. We walked right by the toll booths and onto the road for cars that went down through a short tunnel that exited right onto the lower level of the bridge. The top level was just above us, enclosing the lower level a lot and making it less bridge-like. I could hear the cars rolling over on the top level, just above us. In fact, when I stopped, I could feel the bridge moving some as it seemed to adjust to bumps from the cars overhead. A little disconcerting, and definite incentive to keep moving.
Walking on the lower deck roadway of the George Washington Bridge, with 3 lanes for traffic in our direction, meant you didn't have to get all that close to the edge. That was fortunate because the barriers on the side were rather low and somewhat open, and we were quite high off the ground from the get go. The roadway height above the water is officially listed at 212 feet, but that's from the upper level. So, subtracting, say, 20 feet for being on the lower level, puts the height at maybe 190 feet or so, and no time for acclimating whatsoever. The views were actually quite spectacular, with a sweeping view of downtown NYC. The views were obstructed somewhat by the upper deck, but were so spectacular nonetheless that I don't think I've held my wife's hand for so long since maybe our 5th year of marriage. (Unlike the Brooklyn Bridge walk, some of my fellow walkers might have guessed the reason this time, like the family that, from my perspective, went around me to ask my wife to take their picture). The spectacular views did not include the beautiful, signature bridge towers. I could see them from land.
So we pushed on. The course didn't actually allow participants to enter New York City and exit the bridge, but rather the course went to one end and then just reversed, retracing the steps on the same part of the bridge. This was an untimed, non-competitive race (though we did get numbered bibs), and so we were allowed to just go halfway over the bridge and turn right around in order to keep the distance manageable. Thus, we made it to the goal of halfway over the bridge, at just about the sign announcing the New York line, and turned around. It now officially counts as a full bridge walk if you do the same half of the bridge twice in the same walk. 
For scariness rating (height/length/width, like the old volume formula), I have to give the lower level Geo Washington an 8 for height, 5 for length, and 5 for width (nearness to solid side supports), for a total score of 18.
It's time for some shorter bridge treks, closer to home, to focus on some less high Washington DC bridges and actually get up to the edge.
Brooklyn Bridge
Under the theory that if you can walk panic-free over a bridge, then you can drive over it comfortably as well, I have started a progressive program of walking over scary bridges. The more people I speak with about my big discomfort about driving over major bridges, the more I find others who are also uncomfortable, but, unlike me, most of them will at least do it. (Of course, maybe they're just trying to make me feel better and say they're uncomfortable.) Anyway, it's time to put my walking theory to the test. Although I've done some preliminaries on Washington, DC bridges, where I live, there's nothing like New York City for lots of high, long bridge choices, and the first step in the program is a trek to the Brooklyn Bridge.
Last Sunday, May 23, was a cloudy day, but at 70 degrees pretty much perfect for a good bridge walk. With me were family who live right on the Manhattan side of the bridge, perfect guides, and my wife. The Brooklyn Bridge, if you haven't seen it, is a beautiful structure built in the 1870s and early 1880s, with the towers (for the suspension cables) built of stone. The bridge, of course, goes between Manhattan and Brooklyn. Solid as a rock. John and Washington Roebling knew what they were doing when they designed and built that bridge. But it is rather high. Fortunately the pedestrian path goes above the road, right in the center of the bridge, so while walking over it I was far from the bridge edge; no way a rogue gust of wind could do any damage, except maybe to my hat. And I guess if you fell, it would be 15 feet or so into traffic, and there were lots of cabs down there who could pick you up. And there were lots of people, lots and lots of people to keep you company. And benches to rest on. That bridge was built for walking. (Well, it actually was built before automobiles, so maybe it was built for horses, too.)
Back to the bridge walk. The bridge was about a mile long including all the approaches, and walking over it was moderately anxiety inducing, at least at first. You have to climb upgrade somewhat, and that doesn't help. And it does get pretty high up, I'll say again. But with my cool, young niece there to point out the sights and provide real perspective, and my wife to hold hands with at one point (an affectionate couple, everybody figures), and other family encouragement, it was quite manageable. A challenge, but not overwhelming so, thus a perfect start to the bridge walking experience.
The scariness of bridges can be rated, I believe, by three factors: height, length, and width (think of the mathematical formula for volume). With each of the factors getting a score of up to 10 (with higher numbers being worse), I give the Brooklyn Bridge a scary score of 13: 6 for height (135 feet in the air according to wiki), 5 for length, and 2 for width (nearness to edge, openness of bridge, solidity of side supports). No intangibles to add to or subtract from that score. 13 out of 30 leaves lots of room for bigger challenges.
Next stop may be the George Washington Bridge in a couple of weeks. We'll see.