This video was made possible by Blue Apron. The first 100 people to sign up using the
link in the description get three free delicious, fresh meals from Blue Apron. In 2004 the American Highway Users Alliance
published an article claiming that the Katy freeway in Houston, Texas was the second most
congested road in America. Drivers spent a combined 25.4 million hours
every year sitting in traffic on that road. That’s 36 lifetimes worth. It was an absolute embarrassment of a road
for Texas so they decided to spend $2.8 billion to expand it to 28 lanes making it the widest
highway in the world. All this extra capacity would surely fix the
problem—more lanes means more room for more cars which means shorter travel times... right? Unfortunately not. Between 2011 and 2014 alone, travel times
on the Katy freeway increased by up to 55%. It now takes an average of 64 minutes to drive
the 28 miles between downtown Houston and Katyland during the afternoon rush hour. That’s up from 41 minutes in 2011. The problem with this project was that the
solution violated the fundamental law of road congestion—more lanes mean more traffic. This probably seems counterintuitive. The more lanes there are the higher the capacity
a road has so cars should be able to drive faster... but that’s a very narrow analysis
of the problem. You can’t just think about how this would
work on one road, you have to think about it in the context of a whole city. Many people choose not to drive places because
of how long it takes. If the traffic is bad, they can take public
transit or wait until a less busy time, or just not travel at all. When a road is expanded, travel times initially
decrease so all those people who chose not to drive or to take an alternate route or
whatever decide to switch to using that newly expanded road. What’s fascinating about roads is that this
happens at a perfect 1 to 1 ratio. If the capacity of a road doubles, the amount
of people using that road will also double. If it doubles again, the amount will again
double. Of course if you kept doing this over and
over again you would eventually build a big enough road that there wouldn’t be any more
cars to fill the road, but in the real world where demand for roads far outstrips supply,
drivers will adjust to any change in road capacity. So does that mean that it’s hopeless? Is there no way to solve traffic? No way to make our roads better and safer
and more efficient? Well... no. There’s plenty we can do. Here’s the thing about traffic—it slows
down exponentially. The 20,000 car on the road slows down traffic
overall significantly more than the 5,000 car. This is a major driver for a lot of jams—a
small addition of cars leads to a large addition in congestion—but it also makes solving
traffic a bit easier since you only need to remove a small amount of cars from the road
and that’s just what ramp meters do. Ramp meters are set up on the on-ramps of
highways to restrict the amount of people getting on the highway. They usually let one car on every five or
six seconds. Since the amount of cars actually on the highway
is kept down, the highway stays at its most efficient speed. Minnesota did an experiment where they shut
down their long-used ramp meters for eight weeks in order to see if they actually worked
and they found that the highway capacity decreased by 9%, travel times increased by 22%, speeds
dropped by 7%, and crashes increased by 26%. Stockholm, Sweden used that exponential nature
of traffic to decrease travel times by up to 40% in 2006. Stockholm as a city lies across 14 islands
which means that all the bridges act as huge chokepoints. Traffic, therefore, was historically horrible
for the relatively small city. On January 3rd, 2006, Stockholm started to
charge drivers who entered this central perimeter—the busiest area. The charge wasn’t much—between 10 and
20 krona, the equivalent of 1 and 2 US dollars— but it was enough to persuade 20% of drivers
to not enter the central perimeter. They either went downtown on public transport
or walked or didn’t go at all. These are the amounts of daily drivers in
the perimeter in the years leading up to the charge. As soon as the charge was implemented in 2006,
the daily amount dropped down to here. It wasn’t a fluke. After the 6 month initial trial period driving
in the central core became free again and the amount of daily drivers increased to nearly
the level it was before. When the charge became permanent in 2007,
daily numbers once again plummeted. Even though the charge was minuscule, it was
enough to dissuade 10s of thousands of people from using those roads. There are really two costs of driving—the
money and the time. When the time it takes to drive isn’t enough
of a cost to prevent people from driving, these charges increase the overall cost to
a level where some people will decide not to drive. But what about safety? Roads are still unbelievably dangerous. In any given year, 1 out of every 10,000 people
in the US die in a car accident. Just think about how high of a proportion
that is. If you go to a Redskins game at FedEx field
near Washington, DC, eight of the people sitting in the stands with you will die in the next
year in a car accident. It turns out one of the best ways to prevent
accidents is with something you’ve almost certainly already seen or used—the roundabout. There’s a reason you see these more and
more. Roundabouts reduce deaths and serious injuries
by 90%. That is not an error. With roundabouts, there’s almost no opportunity
for the worst type of collision—the head on full speed crash. In a traditional intersection, cars come within
feet of each other while going at a relative speed of up to 100 mph. A head-on crash at that speed is undoubtedly
catastrophic. With roundabouts, cars naturally slow down
to about 15-25 miles per hour since they’re going around a curve. Also, if there were to be a collision, it
would either be a side-impact collision if a car failed to turn into the circle or a
side-to-side collision if a car misjudged the curve. Both of these collisions happen at a low relative
speed so fatalities are low. But what about capacity? Surely the lower-speed roundabouts cause horrible
traffic problems. Well... they don’t. A single lane roundabout can handle a maximum
of 1800 vehicles per hour which is exactly the same as a traditional two-lane signaled
intersection. While cars will move through a signaled intersection
at a much higher speed, they have to wait both for the light to change and left-turning
cars. With roundabouts, you have a smooth, consistent,
albeit slower, flow. So what’s the problem? Why haven’t we replaced every intersection
with a roundabout? Well there are disadvantages—they’re more
difficult for pedestrians, especially those who are deaf or blind, they require a larger
footprint, they’re more expensive to maintain—but the real reason roundabouts are not ubiquitous
nowadays is because of the biggest fallacy in road design—that drivers need rules. Poynton, just outside of Manchester, UK, used
to have a typical, rather dreary intersection and nobody really liked it. Cars would back up for miles, pedestrians
had to wait forever for the light to change, and it essentially split the town apart. So someone had the idea to remove the traffic
lights, remove the zebra crossings, the curbs, remove almost every safety device in the intersection
and just set up two adjoining roundabouts. Surely this would wreak havoc, but it didn’t. Turns out, when people are uncomfortable,
when people aren’t really sure what’s going on, they pay more attention. The green light was a signal to people that
the road was clear, that it was safe to speed, that they could let their guard down, but
after the change the cars were able to flow freely, albeit at a slow pace, instead of
waiting for the lights to change. Pedestrian incidents went down, collisions
went down, traffic flowed faster, and the city center finally had some character. So, all around the world cities are replicating
what Poynton did. They’re removing curbs, traffic lights,
and pedestrian crossings to make one shared space. All around the world, these streets are resulting
in fewer accidents and more pedestrian space. Discomfort is saving lives. On a larger scale, there’s one more innovative
intersection design that’s beginning to save lives—the diverging diamond interchange. This interchange is designed as a way to get
more cars on and off highways faster. After the on-ramp to the right side, the road
crosses over so cars never have to traverse active lanes to get onto the highway. A car heading north can effortlessly join
the on-ramp without crossing traffic, and a car heading south will cross over so it
drives on the left side and can effortlessly join the on-ramp to head south. Not only is this easier for drivers, it improves
safety. The dangerousness of an intersection is often
rated by determining the number of conflict points—possible points where accidents could
happen under normal circumstances. With a traditional on-ramp intersection there
are 26. With a diverging diamond intersection, only
14. And they’re faster too. The US Department of Transportation found
in a study that universally, whether the traffic was light or heavy, diverging diamond interchanges
let more cars through faster. It costs less too. A traditional on-ramp intersection requires
$11.3 million to build; a diverging diamond intersection, only $5.7 million. There are really no major disadvantages to
this intersection so nearly 100 of them have been built to date and more and more are being
installed each month. As good as these solutions sound, there’s
no one way to solve traffic. The difference between cities with chronic
traffic problems and those without is a combination of smart policies and designs that mitigate
the effects of having more road demand than supply. But traffic won’t just fix itself so until
cities at least experiment with solutions we’re all condemned to traffic, forever. This video was made possible by Blue Apron. Fixing traffic is all about saving time and
improving the environment and so is Blue Apron. They ship pre-apportioned meals strait to
your doorstep sourced directly from sustainable farms and fisheries. Blue Apron sent me a box to try out and it
was a fantastic meal. You’re shipped the exact amount of everything
you need so you don’t have do any measuring. Not only does this save time, it also minimizes
food waste. They give you these clear, concise instructions
so even the least experienced chefs can work with their recipes. So here’s the meal I made. It was healthy, quick, filling, and delicious
and the good news is that you can get a meal just like this for free. Blue Apron is offering the first 100 Wendover
Productions viewers that sign up with the link in the description three free meals so
you can try Blue Apron. Not only will signing up support Wendover
Productions, you’ll also get a chance to try these truly delicious meals. Aside from that, please be sure to check out
my podcast Showmakers and subscribe to this channel to get all my future videos right
when they come out. Thanks again for watching and I’ll see you
in two weeks for another Wendover Productions video.
That damn moron in the van at 2:25... Starts turning barely after signalling with like 1 car length.
How to Fix Traffic Forever
"...there is no one way to solve traffic."
Oh... ok.
Ribbing aside, good analysis of modern traffic constructions that both do and don't help traffic issues. Though I know many would argue that the roads and intersections are only half the issue. It is interesting to see those European setups with little to know marking proving to be safer. Goes to show a little attention to the road and those around it goes a long way.
I work in Traffic Consulting and this is a very good introduction to the solutions being worked on for traffic problems. One thing I wanted to add is the problem with roundabouts are at high demand intersections these become huge gridlock issues especially when you have a multi-lane roundabout. People cannot lane change effectively to their exit point and end up spinning a few times ie. UK and Davis, CA. Add that in with peds and cyclists and you're looking at circles for minutes. Not all intersections benefit from a roundabout installation but for a majority of smaller intersections, it works out.
A few other solutions to traffic issues are adaptive ramp metering, HOV (Carpool) to HOT (high occupancy toll) lane conversions, and general infrastructure upgrades. People may not know this but a very large portion of signal and ramp light technologies in the US haven't been upgraded from the 60's and 70's and they still use switch board computers. So with new systems we could have better ways to detour cars and mitigate traffic incidents.
Overall very impressive video that would show regular people the issues surrounding my field of work.
Hey I made this so let me know if you have any questions!
I highly recommend doing a wikipedia binge through all the different intersection designs that I didn't cover in this video. This topic could probably turn into a full length documentary if it covered everything.
Step 1: Add lights to slow people getting onto the highway.
Step 2: Add diverging diamond intersections to make it quicker and easier for drivers to get onto the highway.
Is it really any surprise that charging people for driving results in less driving? Also, I found it odd that you call a $2 charge to drive on a road minuscule. That's a hell of a lot of money to drive on a road especially if you drive on it often.
I think that autonomous driving is the best way to handle congestion. Most traffic jams are caused by humans driving poorly. They overreact and brake too often, they brake before getting off a major road forcing everyone behind them to brake, and they don't leave enough following distance between them and the car in front of them which means they have little buffer to absorb small speed differences which means they need to brake more. I'm sure with autonomous driving the capacity of our road ways would go up quite a bit.
I thought relative speed doesn't matter. Two cars hitting each other at 50 mph is not the same as one car going 100 mph. Pretty sure mythbusters did an episode on this.
What's the reason for the diverging diamond interchange being almost 50% cheaper than the traditional system? Seems like it take up more space and would consist of more road.
From an Econ 101 perspective, it would seem that "more lanes means more traffic" isn't some innate "law", but instead represents both pent up demand and a trade-off between substitute goods (highways/arterial roads/surface roads). For example, on a microeconomic scale, Jim needs to get from point A to point B. Because the old highway was so busy, Jim chose to work from home most days, where he was slightly less productive and didn't make quite as much as if he'd commuted on the highway. In this case, Jim's demand for transportation is restricted by the capacity of the highway. Now that the new highway is built, the supply of transportation is increased and Jim can commute, earning a bit more income. Also, when commuting from point A to point B, Jim has a choice of routes using the highway, an arterial road, or a surface road. Because the old highway is so busy, Jim chose to use the arterial and surface roads, but once the new highway was built, Jim used the new highway instead. In this case, the increased usage of the new highway doesn't create more traffic, it just shifts it from the surface roads.
TL;DR: It should come as no surprise that increased capacity leads to increased use when demand far exceeds supply and the cost of use is stable or essentially free.