Interstate 5 or I5 is an Interstate Highway that runs parallel to the Pacific Ocean and extends all the way from Mexico to Canada. In the Portland-Metro area it’s home to some of the worst traffic snarls and the subject of much debate from commuters, environmentalists and everyone in between.

I myself, am a commuter, meaning that I live in Vancouver, Washington but I work in Portland, Oregon. Unlike some of my commuter brethren, I don’t hold a grudge against people that are anti-commuting; I see their point as equally as I see my own. I firmly believe that a solution won’t present itself until both sides drop the tribal/faction mentality, stop stereotyping and start work collaboratively towards a vibrant and workable metropolitan area.

Until that time, I5 is what it is – a traffic quagmire. Having resigned myself to this realization, I started trying to understand why I5 traffic is this way. Like any good geek, I started this process by collecting data. In a forthcoming article, I’ll describe in detail how I’m collecting the data, but for now I’ll just give a summary. Every 15 minutes, between the hours of 5 AM and 9 PM, an automated script will fetch a speed map of the Portland-Metro area from WSDOT (Washington State Department of Transportation).

Although I’m still early in the process of collecting the data, I found something interesting on July 21st. Although I have no hard data to support this (I wasn’t there and I only have the empirical evidence of the speed maps), I’m fairly certain that an I5 bridge lift occurred in the late morning.

Before we get to the data, I should note, I’m not a traffic engineer, I don’t hold a degree in Civil Engineering, I don’t work for a government agency and the images below are copyrighted by WSDOT. I’m just a web developer with a thirst for knowledge and an intense curiosity for how and why traffic systems work and don’t work.

Let’s look at the data, shall we?

Our story begins at 12:30 PM, traffic on both sides of the Columbia River seems to be flowing normally as evidenced by this traffic shot:

Fifteen minutes later, I5 is at a complete standstill heading southbound from Washington as well as heading northbound from Oregon. Conversely, traffic directly after the I5 bridge – in both directions – is free flowing. This is usually indicative of a bridge lift that allows marine traffic to pass.

Our next shot, 15 minutes later, seems to indicate that the bridge has been lowered. We can deduce this because of movement on I5 south from Vancouver; it is “Wide Open” just before the bridge and “Heavy” just north of that. On I5 north, there is a different story, traffic is actually getting worse as is evidenced by the “Stop and Go” section extending further into north Portland.

At 1:15 PM, on I5 south in Vancouver, we see the “Wide Open” status just before the bridge change to “Moderate” with everything else being “Wide Open”. On I5 north in Portland, we see traffic migrate from “Stop and Go” to “Heavy”; which seems to be a natural progression. You can also see a small band of “Moderate” traffic begin just south of the “Heavy” traffic. This may or may not be unrelated to the bridge lift since it’s separated by a patch of “Wide Open”, free flowing cars.

One hour after we observed the bridge lift, I5 south in Vancouver is free flowing; there are no more slow downs. However, I5 north in Portland still seems to be having issues. Right before the bridge, it’s migrated from “Heavy” to “Stop and Go” and it’s still experiencing “Heavy” traffic just south of the bridge.

At 1:45 PM, heading north on I5 in Portland, the band of “Heavy” transitions back to “Stop and Go” just like it was at 1:00 PM. I5 south in Vancouver remains unchanged.

At 2:00 PM, I5 south from Vancouver is still free flowing, but I5 north continues to experience issues. Right before the bridge, a small band of “Heavy” traffic materializes but the band of “Stop and Go” traffic just after that remains unchanged.

At 2:15 PM, I5 north is beginning to see some small measure of relief as the band of “Stop and Go” traffic transitions, once again, back into “Heavy” traffic. However, all is not well. Just before the bridge, things seems to be getting jammed up again as traffic transitions, once again, from “Heavy” to “Stop and Go”.

At 2:30, all bets are off on I5 north in Portland. The slowdown at 2:15 PM right before the bridge sends a traffic shockwave down I5 south, transitioning the “Heavy” traffic back into “Stop and Go” traffic. If that wasn’t enough, even further south, we now see a new patch of “Heavy” traffic. This new patch is the start of Rush Time traffic (Rush Hour is a misnomer as periods of heavy traffic on I5 north can go on for five to six hours). Because this is now Rush Time traffic, we can stop our sampling and take a look at the results.

So it easier to visualize, I’ve created a time lapse image of the event from 12:30 PM to 2:30 PM.

Ending Observations

It is common knowledge that in the morning commuters will jam I5 south as they head into Portland and beyond. In the afternoon, the inverse is also true, commuters jam I5 north bound as they leave their jobs and head home. This is not a disputed fact. However, it’s interesting that the data shows that I5 north can become quite a mess even when the bulk of commuters are still at their jobs (assuming that the earliest commuters start at around 6:30 AM and leave at 2:30 PM). This is something that’s rarely, if ever, discussed within the commuting debate.

It’s also clear that based on the data, I5 south in Vancouver will recover more quickly from a bridge lift than I5 north in Portland will. Within approximately 60 minutes of a bridge lift I5 south has completely corrected itself. In Portland, I5 north, doesn’t correct itself until Rush Time is over (on July 21st this doesn’t occur until 8:15 PM).

What causes this? I don’t have any data to support my suppositions so I honestly don’t know. If I were to take a wild guess it would be that the arterials on I5 north are poorly designed and this causes and inordinate amount of merging. Merging usually results in some slow down and in turn this slow down translates into a traffic shockwave that can reverberate for miles. I5 north in Portland is not the only culprit, the entrance to SR-14 eastbound in Vancouver is too close and requires drives to slow down to make the turn. During peak times, this slowdown will extend all the way to the Hayden Island entrance on I5 in Portland (this is the last entrance to I5 north from Portland) and essentially turns I5 north from a 3 lane Interstate into a 2 lane Interstate.

For those that are curious as to what happens before and after the bridge lift, I’ve create a time lapse image from the hours of 5 AM to 9 PM.

It’s official. Humans are terrible at driving in traffic. A recent study by researchers from several Japanese universities observed a phenomenon referred to as a “traffic shockwave” in a live traffic simulation. They setup a 230 meter circular track and had 22 vehicles drive around in a circle at 30 km/h (around 19 mph). At first, everything is free flowing and then, out of nowhere, “pockets” of congestion begin to appear. It’s amazing to watch (see Youtube video below).

The recent study lends credence to Dear GF’s theory that cars should be computer controlled. This would effectively remove the human element and lapses in judgment that cause “traffic shockwaves.” However, I think it’s unrealistic to think that humans would give up their control of driving altogether, but I do think that a hybrid system would eventually work.

The system would work very similarly to how driving works in the 2004 movie I, Robot. When you leave your house, the vehicle would be manually controlled. When approaching large metropolitan freeways (interstates and highways, etc.) an autopilot would activate and take you to your destination exit. Once reached, you would once again regain manual control of your vehicle and travel to your final destination.

For those that wish to rebel, there would still be the option of manually driving on the freeways…for a charge and it would be restricted to one or two lanes (I can’t imagine that anyone would want to drive manually on the freeways).

You can imagine the benefits of this type of system. Pollution and fuel reduction (the vehicle could be magnetically propelled) come to mind and of course there are the time savings by reducing traffic congestion. A 30 minute trip to work wouldn’t be so bad if you could watch a show, read a book, or play a game while the vehicle drove itself to your designated exit. It could be the perfect marriage between public transportation and driving. Combining the best of both worlds.

But let’s be honest, at this point that’s just wishful thinking and fantasy, but I’m sure that there are ways to increase the efficiency of our automotive transportation system.

Most of my commute to and from work takes me through the worst traffic in the Portland metro area, so I’ve recently become fascinated with traffic analysis; the hows and whys of how traffic congestion occurs and how it can be solved. So much so that I’ve added a set of books The Road More Traveled: Why the Congestion Crisis Matters More Than You THink, and What We Can Do About It, Stuck in Traffic: Coping with Peak-Hour Traffic Congestion, and 21st Century Highways: Innovative Solutions to America’s Transportation Needs to my Amazon wishlist to eventually read.

Coming from an IT world, where static values are usually frowned upon, I’m frustrated by the fact that freeways, bridges, etc. are still built with this mentality without giving a thought to the dynamic nature of traffic.

For example, Interstate 5 (I5) in North Portland has three lanes going north and three (sometimes it cuts down to two) going south. As people commute to downtown Portland in the morning, I5 south is a complete mess and in the afternoon, I5 north (as people commute home to Southwest Washington) is a complete mess.

One can easily imagine a dynamic system of traffic distribution that “takes away” lanes from an unused part of the highway and “gives them” to the part that needs it. Now, I understand that comparing packets and routers to vehicles and physical infrastructure is like comparing apples to oranges, but let me explain where I got this idea from.

Last summer, my family and I went to Vancouver BC where we did the normal tourist things. While coming back from Stanley Park, I drove us over the Lions’ Gate Bridge and I noticed that traffic on the bridge can be dynamically adjusted by a series of lights (red, green, and yellow). In fact, this actually happened while I was going across the bridge. When the lane that I was driving in started flashing yellow, I had to do a double-take. After a few seconds of confusion, it made total sense. My lane was being repurposed to allow cars to come the other way.

It would be interesting if something like this is being considered for the replacement of the I5 Interstate Bridge (the total cost is in the billions of dollars) that is scheduled to take place in 2010. Until then, I’ll just have to keep my sanity by listening to podcasts and music while going to and fro.

I’ve lived in Oregon for a while now (although I still refuse to
call myself an Oregonian) and all throughout, I’ve lived on the west
side of town.

With the exception of my first job, all of my other jobs have been
on the east side of town. This is good and it’s also bad. I love the
west side of town, but that’s just because I’ma ‘burb boy and that’s
all I’ve really known. The bad is US Highway 26.US Highway 26 is the
freeway that runs from the west side of town to the east side of town
is US Highway 26.

Historically, and I’m only counting since I’ve been here (~ 1997),
US Highway 26 (referred to as 26 from here on out), has been a complete
disaster.

If you wereheading east bound after work, you could expect to see a
complete clusterfuck of traffic before the first off ramp (the zoo off
ramp). To make this easier for people that don’t live here to
understand, I’ve grabbed some satellite images from google. Here is the
first image, which is what I was just describing.

That’s a terrible place for a slow down considering that you still
havevery long ways to go to get to the where the bulk of the burbs are
as evident by the next two images here and here.

What does this have to do with Vancouver? Well, since Vancouver has
been “the place” to live 26 no longer slows at image 1, it actually
slows down at image 3. Image 2 is just a filler to give you a scope of size.

That’s great for me. Unfortunately, the traffic has just shifted
somewhere else because I5 North is a complete disaster and is
un-drivable until approximately 7-8 PM.

Thanks Vancouverites!

It’s no surprise that I hate driving in nowadays. Traffic is a mess
where ever you go and the roads are littered with people that learned
how to drive by driving the bumper cars at a carnival. Imagine my glee
when I found a blog that has a whole category devoted to Traffic
Assholes. He takes photos and describes situations where jerks on the road have made his life a living hell. I think that this post is the best though; you have no idea how many times I have thought what this guy is thinking. Here’s a snip:

If it’s busy traffic and you accidentally turn into the wrong lane, suck it up and deal with it. Accept the consequences of your stupid actions and just go.

Oh, and if the guy behind you lays on the horn because you’ve stopped in the middle of the fucking road, you have absolutely zero right to be pissed off. You’re the one fucking up. Accept it, apologize, and drive your Goddamn car. You are, singlehandedly, the reason we have traffic.

I couldn’t have written it any better myself.