Down the Tube: Part II

Several friends have asked what is so fascinating about non-motorized access to the Posey Tube. I'm not sure how to answer other than to say that it's hard to find a more poignant illustration of the imbalance between motor vehicle facilities provided by the State and those provided to non-motorized transport (i.e. walking or bicycling). The single, narrow sidewalk called the Posey Tube Trail is meant to be shared by two-way pedestrian and bicycle traffic. It is so inadequate it seems medieval, especially when you consider that bicyclists traveling in opposite directions have to lift and then dangle one bike over the railing so the other can pass. The only reason that this arrangement is allowed to continue seems to be that the conditions inside the tunnel limit the number of people willing to use the trail. And those users are not influential or well-heeled. But this was all hearsay. I had to transit the Posey Tube myself to see the conditions firsthand (video at the end).

The first thing that strikes you is the narrow space between the steel pipe railing and the tiled wall. It would be uncomfortable for two average-sized people to walk side-by-side. Adding to the challenge for cyclists is a seam right in the middle of much of concrete pavement, an indentation that tends to cause your front tire to stray in ways you'd rather it didn't. The sidewalk seems to get slightly wider in the center of the tunnel, only to become narrower at the ends. I didn't take measurements. I didn't have time.

I transited from Oakland to Alameda on a Tuesday around 12:30pm, on my way to work at the Oakland Airport. The vehicle traffic was light and the air was not as profoundly polluted as when I first peered into the portal a few weeks ago. I measured the sound level with an iPhone decibel meter app at 85 to 105db. Not pretty, but not much louder than inside a BART train (sorry BART - your cars are very noisy). There's a headwind the entire way because 1) the vehicle traffic is headed toward Oakland and 2) the giant ventilation fans on the Oakland side draw fresh air in from the Alameda side.

The first 20 yards of the sidewalk are especially difficult given the 3 inches of clearance on each end of my handlebars. Now you know why all the young hipsters ride fixed-gear bikes with incredibly sawed-off, narrow handlebars: They make it easier to transit the Posey Tube, of course! I had recently installed new handlebars on my Prole and it's a good thing I had trimmed 25mm off each end.

Others have written about how filthy the tunnel walls can be when coated with soot from diesel exhaust and what one writer described as "human disappointments." Lucky for me, the walls of the Posey Tube seemed to had been recently pressure washed. I slid against the wall a few times and I was wearing a light colored shirt and came away without any visible dirt or stain.

I didn't encounter an opposite-direction cyclist during my trip. My commuter bike is heavy and lifting it over the railing was something I'd rather avoid. I did encounter two pedestrians: One, a smartly dressed young professional, the other a man who seemed to have all his earthly possessions stacked onto a dolly. Good thing he had not yet begun to transit the tube with his dolly - that would have been a real challenge.

When I reached the Alameda side, I carried my bike up the stairs rather than continuing on the narrow path. Once past the man and his stuff and being careful to not step in some human excrement, I looked back as I rode away and marveled at the primitive, dangerous, and inadequate facilities the Posey Tube Trail provides and the message it sends to those of us who choose not to drive motor vehicles.

My thanks to Hamish for the lending me his GoPro Hero3 for this project.

SoCal Exploring and Intermodal Transport

With a busy schedule, it's unusual for self-employed entrepreneurs (like me) to do something different. Uncertain of how much work may be available in the future, we live work in the moment. And sometimes we work too much. But last Tuesday provided the rare opportunity to explore a bit of Orange County, CA in an active yet leisurely fashion. An instrument student had a work meeting near the Fullerton Airport that would start early on Tuesday. He proposed an instructional flight on Monday afternoon, an overnight stay, and a return on Tuesday afternoon. The gears started turning in my brain and soon there was a plan: Load my BikeFriday Tikit into the back of the DA40 and use it to explore Fullerton and environs. I've done this type of intermodal transportation before and have found a folding bike a great way to travel, transforming a potentially boring trip into exercise and adventure.

Tikit (just) fits without disassembly.

With full fuel, BikeFriday Tikit, and our minimal bags, we were below maximum gross takeoff weight and right in the middle of the center-of-gravity range. The southbound flight was smooth and uneventful, culminating in a practice RNAV approach into Fullerton. Between the evening haze, the glare from the setting sun, and my vague familiarity with Fullerton (I've visited handful of times) it was a good choice: We visually acquired the airport about 2 miles out.

Approaching the LA Basin

The folks at General Aviation Co. had a rental car for my instrument student. I had my trusty BikeFriday Tikit. As we headed our separate ways in the evening twilight, I turned airplane mode off on my iPhone noticed it was searching for a cellphone network. I had reviewed the 3 mile route to my hotel in nearby Buena Park when I made the reservation, but hadn't paid close attention. Being unable to navigate with the iPhone, I did what any good pilot would do: I reverted to pilotage, of course.

I knew the general direction. Head west on Commonwealth, then a left turn, followed by a right turn, another left, cross I-5, right turn on Orangethorpe Avenue, and a few blocks down on the right. An interesting feeling, being forced to revert to basics. At the hotel, my phone was still "Searching ..." I connected to the hotel's WiFi and used Skype to call home. Skype calls appear as a "private caller" which, heretofore unknown to me, are blocked by our telco. So I sent an iMessage. A bit later, my wife launched Skype on her Mac and we were in business.

Waking up to overcast skies, mild temperatures, and light winds, I saddled up and headed back to the General Aviation Co. to drop off non-essential items. I yearned for a light breakfast and good espresso. My iPhone was still "Searching ..." so I was reduced to pilotage and intuition. Cycling eastward on Commonwealth Avenue, I got my first taste of the roadway facilities provided to cyclists in Fullerton. Every community integrates bicycles in a unique way, but the first thing I noticed was the local cyclists ride on the sidewalk. I'm not a fan of cycling on sidewalks because 1) sidewalks are for pedestrians, 2) many municipalities have ordinances against bike riding on sidewalks, 3) sidewalks have numerous, often blind intersections with streets and parking lots, and 4) it takes longer to get where you're going. So I rode on the right side of the rightmost lane. The road surfaces ranged from smooth and clean to seriously mangled and potholed. There are some nice bike routes in Fullerton, but finding them requires local knowledge, a functioning iPhone, or both.

In the business district at Harbor and Commonwealth, I located the Rialto Cafe  where I didn't find espresso, but did discover better-than-Starbucks coffee, nice oatmeal, and sidewalk seating in the shade. Try as I might, I couldn't locate any bike racks so I locked the Tikit to a bench on the sidewalk. I was too slow to snap a photo, but an elderly Asian woman appeared amused by the Tikit and inspected it very thoroughly. When one is behind the Orange Curtain (as some refer to Orange County, CA) it seems the accepted conveyance is a super-sized, gasoline-powered vehicle. Ah, America!

Freaking out the locals ...

Next on the agenda was to continue eastward to the Cal State Fullerton campus and the Fullerton Arboretum. But first, I found myself diverting westward again. I spotted a residential street flanked with blooming jacaranda. I was first attracted by the purple blossoms, then noticed an entire block of beautiful craftsman bungalow-style houses.

Continuing on Harbor, then on Brea Boulevard, I discovered ... bike lanes! Not only that, but a very nicely maintained, tree-lined walking path. And this: A baseball field with a deactivated oil rig, neatly fenced in, situated in the field's parking lot. Holy hydraulic fracturing, local residents!

Without a map or a functioning iPhone, I made a wrong turn and got lost. So did the uncharacteristic thing for a male of the human species - I asked for directions to the Fullerton Arboretum. I found the arboretum, took a few photos, but truth be told, it wasn't my cup of tea. Besides, I had consumed considerable calories with the unnecessary detour and was in need of espresso and something sweet. Following my nose, I made my way through the Cal State Fullerton campus and retraced my steps. That's when I stumbled upon McClain's Coffeehouse.

The sun being out in full force made McClain's all the more appealing with it's chill, slightly dark atmosphere. The espresso was tasty and the pumpkin pastry had just the right mixture of sweetness and calorie density. And thanks to the wifi, I was able to receive an iMessage about our proposed ETD. Time to hightail it back to Fullerton Municipal. Refueling completed, preflight completed, Tikit and luggage loaded, and a right downwind departure toward El Monte. With luck, we'd make it back to the Bay Area before sunset.

Avoiding Pain-in-the-Neck and TTCBCOAB #37

Each of us accumulates wisdom, important information about the world and ourselves that can only be realized over time. One thing I've learned the hard way is I don't recover from strains, sprains and pulled muscles as quickly as when I was in my 20s, 30s, or even 40s. I like to think I'm more careful now. Try as we might, some things remain beyond our control.

About six weeks ago I had to make a panic stop when a driver ran a stop sign, made a sharp right turn, and cut right in front of me and my bike. I ride defensively, but this driver took me by surprise because she was looking me in the eye as she performed this maneuver. When a driver makes eye contact it is usually a good indication that a driver has their head is in the game. On this occasion a desperate braking maneuver was required.

Sliding off the saddle and throwing my weight over the back wheel, I braked heavily and just missed becoming an insult to this driver's rear, left fender. It was over in a flash and a collision was avoided, but i felt something in give between my shoulder blades around thoracic vertebrae T3 and T4. The discomfort grew during the remaining 11 mile ride home, so I did my usual approach: arnica oil applied to the area and rest. After two days, it got better ... mostly. Several weeks later, it was still bothering me and I began to look for other solutions and explanations.

I use the MapMyRide app on the iPhone to track my mileage and reviewing the statistics for the last 12 months, it showed that I'd gradually increased my mileage. And there was an interesting coincidence between the back strain incident and a spike in my daily mileage. Only a few days before the above-mentioned incident, I'd completed a ride significantly above my usual mileage. A physical therapist friend frequently reminds me that ramping up too quickly is a good way to injure an aging body. She's right, of course, but there seem to be other factors at work, too.

Experimenting with different riding positions, I discovered that angling my elbows closer to my torso helped ease the mid-back discomfort. This required placing my hands on the ends of my mostly straight handlebars: Not a longterm solution. Different handlebars seemed to be indicated, so I did some research.

I briefly considered drop bars, but that would require significant re-rigging of the Rohloff shifter - a costly and time-consuming endeavor. Then I found the Salsa Bend 2 mountain handlebars. These come in two versions: The 23 degree bend model seemed to provide the hand position I was seeking.

Salsa Bend 2

The new bar length was roughly equivalent to the old bars, but I wanted a closer hand position and some trimming was in order. 25 millimeters off each end (about an inch) seemed right.

Measure twice ...

Cut once (well, twice actually ...)

A bit of smoothing ...

Old versus new (hard to capture in a photo)

Finished product

My initial impression is that the new bars are helping, though it will likely take a while for things to heal completely. The joys of aging!

In other news, here are more TTCBCOAB (things that can be carried on a bike): Three bags of groceries. Several apples, peaches, nectarines, some pasta, tortillas, various greens, pasta sauce, cucumbers, etc.

Three bags full. A mere 35 pounds!

Collective Nouns

During a quiet moment with our two basenji, I found myself considering one of the more fascinating parts of the English language: The tradition of "terms of venery" (sometimes called "nouns of assembly"). Collective nouns for specific animals were developed by hunters. They originated in France and migrated to England, where their use flourished in the Late Middle Ages. The Book of St. Albans contains over 150 collective nouns for describing groups of animals. Some common examples: a pride of lions, a gaggle of geese. More evocative examples include a murder of crowns, a boil of hawks, a skein of geese. Which got me to thinking about what one might call a collection of basenji.

"Pack" seems good for large dogs, especially German sheppards, Irish wolfhounds and the like. But Pack doesn't seem to fit basenji. Maybe it's because of their size or maybe it's because they don't really seem to be dogs at all. Instead of Canis lupus familiaris some say Canis basenji is more apropos. Many popular ideas about the basenji's unique features are true, but some are not so accurate. You may have heard that basenji don't bark, but the breed standard more accurately describes "seldom barking." Our male will often let out a single bark and he becomes very vocal when he's happy or excited, yodeling and howling. On the other hand, our female is generally quiet except when she's angry at which point she will readily make all sorts of growling, hideous, awful sounds. Why basenji do not exhibit common barking behavior is a bit of a mystery and a subject of much speculation.

Another mystery is that most female basenji go into estrus only once a year, usually in the late summer or autumn. Many theories have been offered as to why this is. Some say it is an adaptation to seasonal weather patterns in central Africa (where the breed originated) that aren't conducive to the survival of young offspring. Whatever the reason, basenji tend to have birthdays in October, November or December.

The 1950's B movie, Goodbye My Lady, was partly responsible for popularizing, and in some case exaggerating, basenji traits. Basenji do indeed groom themselves, but not quite as much as cats do. Like cats, they generally don't like water or getting wet, but there are exceptions: Our female will gladly enter the chilly waters of San Francisco Bay in motivated pursuit of another dog or a flock of birds. In contrast, our male will hop over water puddles to avoid getting his paws damp. And he will give incredulous looks when the front door is opened for a morning walk and rain is falling. 

When basenji get together with other basenji, it's clear they have a strong recognition of their own breed. And you can expect fireworks as they establish the pack dynamic. A wise basenji owner once told me when basenji are "working things out" that all is well as long a they are making a lot of noise. If the vocalizations stop and the tussling continues, it means the posturing has ended and they have gotten serious.

One of the most ancient breeds, basenji were unknown to westerners until the 1800s. The first Basenji to come to the US reportedly did so in the early 1900s as a stowaway on a ship carrying coffee. The breed wasn't formally introduced until the 1930s. At early dog shows where basenji were first shown, it was said that someone was bound to be bitten: A handler, a judge, or another dog. Much has been done to calm their primitive temperament, but this leads to one of the more problematic aspects to basenji ownership: Off leash, most basenji have a strong prey instinct and little or no traffic smarts. If they see a cat or squirrel, they will chase it down, they'll likely never hear your voice calling, and never see the car that hits them. Basenji are often referred to as sight hounds, but that seems controversial since they have both keen sight and sense of smell. Owning a basenji requires good situational awareness and respect.

Various studies have attempted to measure dog intelligence, often boiling down to how obedient a dog breed tends to be. Basenji can obey, but they seem to do so when they choose to. Basenji are self-directed and they seem to see humans as their peers. That's not exactly right, but it's the closest I can come to describing the relationship. You cannot force a basenji to do anything and if you try, you're in for trouble. Instead, you find ways to get them to cooperate. Does this make basenji less or more intelligent than other dogs? Hard to say, but it helps to have a good sense of humor because a basenji will outwit you at least once a day.

You'll often see basenji in pairs for the simple reason that it's easier to have two rather than one. Mostly. Like humans, dogs need companionship. Without a partner, basenji get bored and a bored basenji is dangerous: When frustrated, their problem-solving abilities (read destroy and escape) is legendary. Which brings us back to collective nouns. What to call a group of two or more basenji? What collective noun captures the complexity of this unique breed?

I'd have to say "tangle." A Tangle of Basenji.

TTCBCOAB #36 - Six Cubic Feet of Soil and a Gasoline-free Day!

Having committed to at least two gasoline-free days each week (Sunday and Monday, our days off) my wife and I went for a nice ride for breakfast at Venus. Cycling downtown Berkeley is so much easier and stress-free than driving, especially when it comes to finding parking. We just locked our bikes together, right in front and took a window-side table so we could keep an eye on things. I'm always in a better mood when I cycle because I can see and hear things (most of them good) that I'd otherwise miss in a car.

After breakfast, we swung by the North Branch of the library and then Five Star Video to return two DVDs. And then it was on to some gardening. Oh, that's right: We need to buy some soil to top off one of the vegetable beds. No worries, American Soil has good vegetable soil by the bag, but today was a "no gasoline" day. Well, time to test out the load carrying abilities of the Blue Ox (aka our Yuba Mundo cargo bike).

After deciding on a route involving the fewest hills, I made my way in leisurely fashion. It was a beautiful day with mostly clear skies and light westerly winds. Upon arriving at American Soil, the sales person estimated the weight of each 2 cubic foot bag to be 70 to 80 pounds. After paying, I headed to Area A to pick up my three bags of soil. Worst case scenario, this would total about 240 pounds. Even though the Yuba Mundo has a placard on the frame stating that the maximum load is 440 pounds (not including the rider), this would be the most weight I had ever attempted to carry on the Blue Ox.

Initially there were no employees to be found. They must have been helping other customers, so I located the pallet containing the bags of soil I'd purchased. Loading the Blue Ox turned into quite a balancing routine. I struggled and somehow managed to get one bag secured on the right side without the bike tipping to the right. The second bag was wrestled into the left pannier, which should have balanced things, but with the bike on its center stand it still had a mind of its own, tending to tip one way or the other. The third and last bag went on top of the wooden deck I created a while back. I thought that would have stabilized things, but it didn't. I was trying to figure out how I would get the two load binding straps around the bag on the top while holding the bike steady when an employee showed up and gave me a hand.

With the bags loaded, everything cinched in place, and my receipt verified I began the trip home. Whoah! The bike was a more unstable than I had anticipated. The third bag on the top of the rear rack put the center of gravity higher than optimal. Things were made worse by the lack of weight on the front rack: I just had my lock, cable and a water bottle in the front basket, so the steering was a bit squirrelly. And even though the other two bags were cinched low into the panniers, there was a tendency for the bike to start swinging and swaying like a pendulum. Oh well, too late to do much about it now.

Shifting my weight forward, I focused on pointing the Blue Ox straight and making every move as gently as possible. I tested the braking before I got onto the open road. The caliper brakes worked, but squeaked and complained mightily. It was clear I'd have to plan all my stops well in advance. Even hitting a bump or pothole started a  spooky sequence of shifting moments that were ... interesting. Not wanting to ponder a gasoline-powered solution, I leaned forward, pedaled with purpose and thought happy thoughts.

The reaction of drivers I encountered on the way home was, surprisingly, one of deference. They must have seen the bike was heavily loaded and a bit hard to control. Everyone I encountered was civil and several drivers waved me ahead so I could avoid stopping. The few turns I had to negotiate were done slowly and with great care. The few times I had to start from a dead stop proved a challenge until the wheels got spinning fast enough to add stability.

Arriving at home, I unloaded before taking a picture since the Blue Ox wanted tip off the center stand with the slightest provocation. That's my story and I'm sticking to it! Here are some the results of our labors, done the old-fashioned way, sans gasoline!

Potatoes go here ...

Tomatoes and marigolds ...

CO2: Making a Difference

 “There’s no stopping CO2 from reaching 400 ppm. That’s now a done deal. But what happens from here on still matters to climate, and it’s still under our control. It mainly comes down to how much we continue to rely on fossil fuels for energy.” 

Ralph Keeling, a geochemist at Scripps

The recent announcement that the world's atmosphere has exceeded an average of 400 parts per million of CO2 has me, for one, wondering if and how humankind can stop or slow this process. Some obvious changes include growing local-based economies that rely less on fossil fuel for the transport of goods and services. Another obvious avenue is supporting the development of alternative energy sources. Yet many of us feel helpless in the face of what's happening.

Well here's something you can do: Consider funding Steve Halverson's Kickstarter project Windenhol (a combination of the Hungarian word "mindenhol," meaning "everywhere," with the English word "wind"). You can help Steve build a prototype by pledging as little as $1.

Prototype of a small wind generator.

Trying to Remain Neutral

We live in a culture of denial, something you already realized, but you persuaded yourself to forget. Okay, this is going to be a bit uncomfortable, but you can handle it once you wake up and realize what's happening. Our predominant myths? We are all in competition with one another. Only the strong survive. Not everyone can have the good life, so it's every person for themselves. 

We live in a culture of denial where people can say anything. And we want to believe them because believing will keep us from realizing the seriousness of our situation. We can have it all. Drive as big a vehicle as you want. Drive as much as you want and don't give it a second thought. Sure gas is expensive, but just drive a hybrid and forget about it.

We live in a culture of denial where deception is so widespread that there are now professionals who specialize in lying. They lie to themselves, they lie to their families and their friends. And before we know it, we're lying, too. About all sorts of things. Some are small lies, fibs, makey-ups. Others are real whoppers, lies that could kill an elephant or any of a host of other endangered species, lies that can and will kill ourselves and our world.

We live in a culture of denial, and then someone like Bill McKibben comes along and makes the seriousness of our situation crystal clear, he does it in a very simple way. Do the Math. You just need to remember one number: 350. That's 350 parts per million of carbon dioxide in the our atmosphere, the target amount that will keep the earth livable for you and me and everyone else. Unfortunately, we're already over that amount and there's enough fossil fuel available and ready to be burned that ... well it's not going to be pretty.

We live in a culture of denial and it's time to wake up. We can't have it all and in fact, we need to cut back, consume less. It doesn't have to be painful or austere if we untangle the new myths and remember the old ones. We only have one earth. We are all interconnected. We have the power and the ability to stop the damage we're doing. We are all in this togther. All we have to do is wake up and take action. Here are two simple things you can do.

Reduce your carbon footprint by driving less.

Designate one or two gasoline-free days each week where you walk, cycle, or take public transportation.

Readers of this blog know I'm big into bicycle commuting and there's an event coming up called Bike the Math. You can read about it here. If you live nearby and you wake up in time, I'll see you there.

Down the Tube: Part 1

The other day I needed to bicycle to a part of Alameda that I never visit, so I did the natural thing and used an on-line map to investigate. The route looked predictable until I got to step 24: "Turn left on Posey Tube Trail - Take the stairs." That's when it dawned on me that while I knew one could theoretically walk or cycle on the sidewalk through the Posey Tube, I'd never actually tried to do so. In fact, I'd never personally met anyone who had attempted this passage.

Posey Tube Portal

Each day, about 50,000 drivers in the San Francisco Bay Area use the Webster and Posey Tubes, tunnels that allow vehicles to pass under the estuary separating Alameda and Oakland, California. Only a few dozen intrepid pedestrians and bicyclists brave the Posey Tube on any given day, at least according to a City of Alameda Estuary Crossing Study from 2009. Seems to me there are four basic reasons for the imbalance between motorized and non-motorized use: Only the Posey Tube is accessible for pedestrians and bicyclists, that access is a single four-foot wide sidewalk, the air quality inside the tube is awful, and the noise is deafening. In short, when non-motorized commuters succeed in finding their way to the Posey Tube, they may wish they hadn't.

The Posey tube (named after George Posey, Chief Engineer and County Supervisor) was the first tube constructed at a cost of about $4.5 million.  Completed in 1928, it replaced the problematic Webster Street swing bridge that hampered ship access to the inner bay. The old swing bridge was disabled at least once when it was struck by a ship and the bridge was scrapped after the Posey Tube opened. The Posey Tube originally featured one lane leading to Alameda and the other leading to Oakland. When the Webster Tube was completed some 35 years later in 1963, it became a oneway route to Alameda and the Posey Tube became a oneway route to Oakland. Both tubes were constructed by sinking pre-cast concrete sections and then connecting them once they were underwater.

I have no real need to use the Posey Tube as part of my regular bicycle commute, but nevertheless there's an odd attraction to trying my hand at it, at least once. Maybe it's the fact that part of the futuristic getaway chase scene in George Lucas' directorial debut, THX 1138, was filmed in the Posey Tube. Or maybe it's the deco-inspired structure that houses the fans that remove (most of) the vehicle exhaust from the Posey Tube. Or maybe it's that so few people attempt to travel through the Posy Tube in anything but a motor vehicle. Whatever the reason, I hereby vow to traverse the Posey Tube. At least once.

Rather than just showing up on my bike and taking the plunge, I wanted to conduct some reconnaissance and clear up some confusion about these structures. Why can non-motorized users only access the Posey Tube and not the Webster Tube? Why is only one sidewalk open to pedestrians and cyclists?

Finding the pedestrian/bicycle access to the Posey Tube involves navigating a maze of oneway and dead end streets in the Forth Street neighborhood, almost beneath interstate 880. It's fairly easy if you use an on-line map. Once you get to 4th Street, locate the intersection with Harrison Street and you'll be at the foot of the Posey Tube's deco-inspired ventilation structure.

A quick drive in my car provided more answers. The Posey Tube was constructed with sidewalks on both sides, but only the right (southeast) side is open to pedestrian and bike traffic. The lefthand (northwest) sidewalk has emergency call boxes and what appears to be a fire sprinkler system. The pipe and sprinkler heads anchored to the sidewalk surface would certainly present a hazard to any bike or pedestrian who might try to use that sidewalk, but the point is moot: Access to that sidewalk is blocked by a locked gate on the Oakland side.

Wrong side. No Entry. Or Exit for that matter.

The newer Webster Tube was constructed with only one sidewalk on the right (or northwest) side. Emergency call boxes are stationed along this walk, every few hundred yards, leading one to conclude the Webster Tube's only sidewalk is intended for emergency use by a driver of a disabled vehicle or fire crews.

Make your way to the southeast side of the Posey ventilation structure and you'll encounter a weight-lifting gym, occasional piles of rubbish and, quite possibly, the strong smell of urine. Eventually you'll find a stairway that leads down to the Posey Tube Trail. If the stairway is blocked by a locked gate, you're on the wrong side.

Southeast entry. All hope abandon ye who enter here...

Walk down the stairs of the southeast side (carrying your bike, if necessary) and you will have entered the Oakland pedestrian portal to the Posey Tube.

What comes down, must go up ...

During the short period I stood photographing at the portal (at 3:30pm on a Monday), three cyclists came through to the Oakland side. Since the path is too narrow for bikes to pass in opposite directions, the common procedure is for one cyclist to pick up their bike and dangle it over the railing to allow the other cyclist to pass. I will probably try to transit the Posey Tube during non-peak hours for both motorized and non-motorized vehicles. And I'll probably take my BikeFriday since it is lightweight and has fairly narrow handlebars. I intend to video my transiting the Posey Tube, so stay tuned.