You’ve all probably read or heard by now about the Bay Area freeway collapse–early Sunday morning, a gasoline tanker speeding through the MacArthur Maze in the East Bay flipped over and exploded into flames. The driver escaped with 2nd degree burns, but heat from the fireball melted steel girders and collapsed a double-decker section of freeway in Oakland near the base of the San Francisco-Oakland Bay Bridge.

I’m already getting a lot of questions from people around the US about how this is affecting us, so I decided to take the time to paint a picture of the situation for my colleagues around the world. The short answer is that everybody is fine so far, but it’s going to be a huge mess. The long answer is more difficult.

The MacArthur Maze is so called because it’s an immensely complicated system where three major freeways (80, 880, and 580) converge en route to the single Bay Bridge to San Francisco. All the exit and entrance ramps tangle in a spaghetti heap of concrete reminiscent of those Bugs Bunny cartoons from the 1950s that lampooned the Interstate highway system being built in LA at the time–remember the loop-de-loops, the swirls, and the ramps that led to oblivion? Even lifelong residents sometimes make a mistake and get lost in the Maze.

The section of freeway whose dramatic wreckage you see pictured here in the NYTimes is the segment shown in blue on this Google map. The larger context of the entire MacArthur Maze can be seen on my custom map here.

The upper deck is how traffic on I-80 from the bridge connects with I-580 heading east to Oakland, Hayward, Livermore, etc. The lower deck is how traffic from the east and north on I-80 (Sacramento and Berkeley) connect with I-880S to Oakland and San Jose. What this means is that for months, at least, there will be no direct connections between I-80W/I-880S and I-80E/I-580E. So, for example, my commute to the office would be delayed but possible, but on the way home I would have to detour south from the bridge onto W Grand Ave and take locals back to I-980E, completely bypassing the stretch of 580 between 80 and 980. (Zoom out four clicks on the first Google map to see this.) If nothing were amiss and I were the only one doing this, it would cost me 10-15 minutes, but with half the traffic coming off the bridge needing to do this, I can’t even begin to guess how many hours of backup we’ll see.

The governor has declared a state of emergency, which waives a lot of red tape so that reconstruction can be finished in months (we hope) instead of the ten years it took to rebuild a section of the Cypress freeway that collapsed in the Loma Prieta earthquake of 1989. (The rebuilt section is the stretch of 880 just south of the current wreckage.)

We’re lucky that this happened early on a Sunday morning, when no other drivers were around to be injured. We’re lucky that this happened in the spring, so that repairs will happen during the usually lighter traffic of summer. We’re lucky that it happened away from residential neighborhoods. We’re lucky that nobody has any excuse to leap to panicky conclusions about terrorism.

Authorities are encouraging everybody who can possibly telecommute or stay home to do so, and today mass transit is free. So far the morning traffic reports have been saying that the disaster has actually improved traffic on the Bay Bridge, which means that lots of people have heeded the warnings. We won’t see the real impact until this evening when the people who did drive in are trying to drive home, because it’s the outbound directions that are most affected. And this is just day one. In coming weeks, fewer people will heed the warnings, and traffic will probably get uglier and uglier.

I’m working from home today and plan to continue doing so as much as possible. Nobody can completely avoid driving in and out of the city, though, and when I do have to go in, I won’t have good mass transit options to most of my destinations. My office would be easy, except that I will have to compete with everybody else for parking at the train station, where lots are usually full by 7am. I’m giving serious thought to replacing the motorcycle I sold a few years ago–it’s probably the only option that would enable me to get around with only, say, half-hour delays.

Frankly, I’m a lot more worried about the social impact this could have than I am about traffic.

I’m a white-collar tech worker, and like many citizens around here I can telecommute and solve most of my other new transportation problems by throwing money at them. What about all the blue-collar and no-collar workers who commute through the Maze or on the newly-flooded, already inadequate mass-transit system? What are they supposed to do?

Another thing you have to realize is that most people who commute home on this section of freeway don’t know the first thing about finding their way around the local streets of Oakland. I’ve lived here for eight years, and even I get turned around sometimes, because in the 1950s the freeways were jammed through with little or no regard to the neighborhoods and the local arteries they disrupted. They got away with that because those neighborhoods were mostly poor, minority enclaves; wealthier Berkeley to the north could force the interstates to divert around the city along the coastline. In addition, local topography has forced neighborhoods to be built at funny angles to others. You can see all this on the satellite imagery of the google map. What it means in practical terms is that if you’re traveling to an East Bay neighborhood you don’t know well, you had better have maps and directions both to and from your destination.

Now, imagine all those commuters who don’t have the first clue about Oakland geography, trying to find their way on locals from Interstate 80 to Interstates 880, 580, or 980. Those locals are mostly two- and four-lane streets with stop lights every few blocks, and the lights are poorly timed if at all. If you get off these roads to try to detour around traffic jams, you will end up on streets that “don’t go through,” you will have no signage directing you back to the freeway, and you will eventually have to find your way back to the traffic jams you tried to escape.

Now realize that most of these commuters are white suburbanites in fancy cars, they’re driving through rough neighborhoods where some of the cars are clunkers up on blocks, they’re lost, and the people they see who are just trying to go about their normal modest lives don’t look like them, don’t dress like them, and certainly don’t throw money around like them. Do you suppose some of these people might decide they need to have a gun in their car to feel safe? It’s not too hard to imagine we could be one frustrated commuter away from a Rodney King situation. The record number of homicides in Oakland this year remove any doubt that the gangs proliferating in its worst neighborhoods already have guns. I hope those commuters decide to detour north and jam up Berkeley streets instead, because they won’t find those neighborhoods quite as unnerving. The maps seen on pages 10-13 of the 2006 Oakland Homicide Report by the Urban Strategies Council provide cold comfort about pretty much all the detour possibilities, though.

The San Francisco Bay Area has a reputation for being a liberal bastion, and I hope that the compassion, tolerance, and patient embrace of diversity we’re famous for is the face that we again show the nation in coming months. But I worry that we could see a far different face emerge out of the frustrations, fears, and the racism that lurks here as everywhere.

There is much reason for hope. We survived the collapse of the Cypress freeway and ten years of detours, and even the much-briefer period when the Bay Bridge was out of commission from a piece of the upper deck falling on the lower deck. The difference is that in 1989 the entire Bay Area was rocked by an astonishing force of nature that ripped across all strata of society, and as we saw again after Hurricane Katrina, humankind can display enormous strength and unity in the face of natural disaster. (I should mention that I didn’t move here until 1994.)

That’s not the situation we have today. This is just an immensely complicated mess created by a truck flipping over; an already-fragile transportation system crippled by a mundane human accident. The LA riots of 1992 were caused by an already-fragile equilibrium of racial and economic tensions turning disastrously to violence when one more incident of police brutality was caught on videotape. I hope I’m being alarmist rather than prescient in seeing this connection.

May we rise to the challenge and handle this mess with patience and grace.