When you think of road construction, you probably
think of concrete, massive bridges, and year-long delays, all to make wider, faster roads. But this
project took a completely different approach. This intersection might look pretty typical, but
it proved to be problematic for a few reasons, and something needed to be done. The first problem
was the size. This wide turning radius encouraged drivers to take this turn at high speeds and
became a dangerous spot for crashes. It was also only controlled by a single stop sign for this
direction and had visibility problems for cars trying to turn. Not only was this dangerous,
but it also delayed cars trying to turn, most of which were turning left. However, due to
limited funding and a lack of available space, options were limited to fix the problem,
so the city tried an innovative solution: a mini roundabout made of plastic. This roundabout
was constructed by installing plastic panels made of recycled milk jugs onto the existing road,
changing the entire configuration in the same amount of space. It was built as a pilot project,
meaning it could be easily modified or removed if they found it to be unsuccessful or kept to
become permanent if desired. Construction began on installing the plastic panels, and the project was
completed in only four days. The roundabout opened to traffic, and the test began to see if it would
prove to be successful. Due to the small size, the center island had to be clear of obstacles
and traversable to allow for large vehicles to drive over it, as they wouldn't be able to make
the small turning radius. So, while anyone could technically drive straight through the middle,
it would be a pretty abrupt bump, especially at higher speeds. Drivers seem to respect the panels
and follow the roundabout as designed. This setup causes everyone to slow down and yield to traffic
within the roundabout, creating a slower, safer, and more efficient intersection, solving the
problems this intersection previously had. It was completed for a very low cost compared to
building a traditional roundabout and didn't require any additional land. Despite the
unconventional construction materials used, it has created real results by improving safety
and efficiency in a matter of days. And it turns out this mini roundabout is just one piece of a
toolkit that can be used on roads everywhere to implement small changes in design that slow down
drivers and save lives. When people drive, they drive according to their perception of danger.
If we perceive less risk, we'll drive faster, and if we perceive more risk, we drive slower.
This is a crucial part of road design and has a massive impact on speeds. Straight, clear roads
with wide lanes signal to drivers that higher speeds are acceptable, whereas curvy, narrow roads
with obstacles and visual obstructions signal to drivers that they need to slow down. It might
sound counterintuitive, but sometimes perceiving more risk can actually be a good thing for safety,
due to the fact that drivers slow down and pay attention on streets where cars should be going
slow. Elements that reduce the amount of space where drivers can make mistakes and force them to
pay attention can actually end up being safer than a straight, wide-open street. This is especially
important in places where pedestrians are present, such as residential streets, as that difference
in speed can mean life or death if a crash occurs with a pedestrian. And unfortunately, pedestrian
deaths are on the rise in the US. There are many contributing reasons that will require policy
change or a societal mindset change to fix, such as the ever-increasing size of vehicles or
distracted driving, but speed is definitely a key factor in this problem, and thankfully, we can
use design to help reduce speeds. One road in Cincinnati, Ohio, had a huge problem with speed,
with recorded speeds reaching 89 mph on this road full of homes, families, and schools. Thankfully,
they decided to do something about it, and their solution has already prevented crashes and saved
millions of dollars in only a matter of months. We'll take a deeper look at what they did in a
bit, but since speed is such a critical factor in safety, what tools can be used in communities
everywhere to decrease speed? The first tool is pretty simple: landscaping. Streets lined
with trees and shrubs not only look nice, provide shade, and improve air quality, but they
also function as a tool to slow down drivers. They create the perception of a narrower roadway,
and drivers become aware there is less room for error. When trees are placed between
vehicle lanes and a sidewalk, they also function as a physical boundary between the two,
making it an all-around win for better streets. Curb extensions, also called all sorts of other
things, extend the curb at intersections further into the road to narrow the roadway. This visual
narrowing of the roadway can slow down drivers, and the smaller turning radius reduces the speed
at which drivers make turns. Curb extensions also reduce crossing distances for pedestrians and can
increase their visibility within the intersection. This can have a huge impact on pedestrian safety
because of a concept called daylighting. On streets with parked cars, any cars parked up to
an intersection can block the view of pedestrians, creating blind spots. By bringing the curb further
out and eliminating parking next to the crosswalk, sight lines are greatly improved for both
drivers and pedestrians. Some cities have done this just using paint, cones, or
flexible bollards as a low-cost way to improve safety and show that it can work
before installing a more permanent solution. Curbs can be modified at other points in
the streets too. A chicane is where the roadway intentionally curves by modifying
the curb to force drivers to slow down in order to take the turns at a safe speed.
This example in Charlotte, North Carolina, used to be a standard straight residential street
but was modified to add curves and slow down drivers. They also added these median islands
to the middle of the road for this project, which are another common tool used for traffic
calming. The median island creates a physical obstacle in what would otherwise be a wide-open
road. If you haven't noticed a common theme yet, this gives the visual appearance of narrowed lanes
and encourages drivers to slow down to ensure they can safely make it through the space between the
side of the road and the median island. When used with a crosswalk, they reduce crossing distances
and function as a refuge for pedestrians to wait and cross each direction of the street separately.
While most of these tools so far rely on a level of perception or turning movements, there are some
tools that can physically stop speeding. If you've driven anywhere, you've likely been over a speed
bump, and while I don't think anyone really likes driving over them, they're cheap to install
and can be effective in slowing down drivers to very low speeds. But the speed bump has some
variations for when we don't need cars to be at crawling speeds but still need to keep speeds in
check. A speed hump is essentially a longer speed bump. It isn't quite as an abrupt bump and allows
for slightly higher vehicle speeds. This makes it more appropriate for residential streets. It also
provides a more comfortable experience provided drivers are traveling at the designed speed.
Many times speed humps are placed in a series, ensuring vehicle speeds stay low on the entire
road rather than just at a single point. Speed humps aren't without their issues,
though; they can delay emergency vehicles, which is less than ideal. However, these larger
vehicles have a built-in advantage that makes for an incredibly simple solution: make some gaps
in the speed hump. These are speed cushions, and they're designed to reduce delays for
emergency vehicles. These larger vehicles have a wider wheelbase than regular cars,
meaning they can fit perfectly through the gaps between the speed cushions and don't have
to slow down. Cyclists are also unaffected as they can go between the gaps. Regular cars
will still end up hitting some part of the speed cushion even if they aim for the gap.
Speed tables are even longer than speed humps, with a flat section on top, and
they're designed for streets with even higher speeds. These can be paired with
a crosswalk to create a raised crosswalk, which forces drivers to slow down and brings
awareness to pedestrians within the crosswalk, since they are higher in the sightline of drivers.
This can also be applied to entire intersections, creating raised intersections. This keeps vehicle
speed slow throughout the intersection and allows for level crossings since the crosswalk and the
road are at the same height. Typically, there are physical barriers like bollards or planters to
prevent drivers from entering the sidewalk area. A lot of these tools can be combined as well,
creating things like speed tables with median islands or landscape curb extensions. However,
it's important to ensure traffic calming tools match the use of the road. While a speed hump
might be appropriate to slow down traffic in a residential area, you wouldn't want to put
one on a highway. That's because a residential street is made for homes and people,
while a highway is for vehicles to get between places quickly. That might seem pretty
self-explanatory, but many roads in the US are mismatched in terms of their purpose and their
design speed, leading to the infamous stroad. A stroad is a mix of a street, which is
designed for places and people and homes, and a road, which is designed for cars to
quickly drive between places. Combining those two ends up with a mix of high-speed cars,
several conflict points from turning vehicles, and pedestrians living, shopping, or working
at places along the stroad. This combination has proven to be incredibly dangerous for
everyone. All of the problems regarding stroads have been discussed in depth by many
great creators already and could be discussed further in a future video. But let's take a look
at what happened with this stroad in Cincinnati, Ohio, and how this fix is already proven
to improve safety and connectivity by using the final and most versatile tool in our
traffic calming toolkit: the road diet. A road diet is the conversion of an existing road
to function differently through the reduction of vehicle travel lanes. This can result in a
wide variety of outcomes ranging from the most common four-lane to three-lane conversion
to bike lane additions to dedicated transit lanes. There are tons of possibilities
as to what can be done with a road diet, but one common motive behind any road diet is
safety. In the typical 4-to-3 lane conversion, safety improvements are accomplished in a few
ways. When we look at an undivided four-lane road like this, these left lanes function as both
passing lanes as well as turning lanes for traffic turning left. This means large differences in
speed, which can lead to rear-end collisions or drivers having to weave around turning traffic.
Having a passing lane available also leads to higher speeds in general, since drivers aren't
limited to the speed of the car in front of them. Visibility is also a huge problem for traffic
turning left. If two cars are waiting to turn at an intersection, they block the view of
any traffic that might be in the rightmost lanes. Meanwhile, in a three-lane setup with
two driving lanes and a center turning lane, it allows for all turning traffic to move out
of the driving lanes, lowering the risk of rear-end collisions and increasing visibility
at crosswalks. The center turning lane can be built as a median island, creating a pedestrian
refuge and shortening the crossing distance. These median islands alone have been shown to
reduce pedestrian-related crashes by up to 46%. All of these safety improvements are calculated
using a blend of math, data, and engineering. And while concepts in those fields can sometimes
feel intimidating or complicated, there's a free and easy way to learn more about concepts in
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start learning something new, check out Brilliant. When vehicle lanes are removed and more space
is available, it allows us to completely rethink how people can get around the area and
decide if we want it to truly be a road or a street. And in Cincinnati, they decided they
were going to turn this road into a street, but it most definitely wasn't
before as it had a major problem: speeding. This 4-lane road had a 35 mph
speed limit, but traffic studies revealed that over half of drivers exceeded the speed
limit and 20% of drivers exceeded 60 mph. The highest recorded speed was 89 mph, and
unfortunately, it was proving to be deadly. These roads were basically built as highways
through the heart of the neighborhood. This is Matt Butler, president
of the Devou Good Foundation, who was a key part of transforming this street. They were experiencing a lot of reckless
driving, so much so that many of them were afraid to walk. Neighbors had also complained
about drivers driving up into their yards, striking their parked vehicles, crashing into
rock walls, trees. We met with the neighborhood and we listened to their concerns. We
went and walked the streets, we put up radar devices to really get a quantitative
measurement of what's going on on the streets, and we came up with some conceptual designs.
They wanted to slow traffic down. The best way to slow traffic down is to reduce the lane
width. And so what we did was we removed two of the drive lanes and repurposed them for either
full-time parking or full-time bike lane. And so these countermeasures, like the bike lane,
are actually making drivers and people in cars a lot safer because they're reducing the
speed of all the other drivers around. The other great thing about the bike lane is it's
usable infrastructure that everybody can use. And the project has already
shown that it's working. Roadway data shows that reckless speeding
over 50 mph has been reduced by 90%, crashes overall have decreased by 30%, and the
severity of those crashes has greatly decreased with a 93% reduction in injury. This project was
done as an interim solution to show what can be done with less expensive construction materials
while still creating real results. It's designed to last at least five to seven years, and we
figured that would give not only College Hill but other communities an opportunity to see
these in action. We wanted to make sure that it functioned really well, that people were
really safe, and that it was low maintenance. There's a huge backlog of maintenance on
all of our roads, billions of dollars, and unfortunately, as a society, we've
prioritized just building new things at the expense of maintaining what we already have.
So, we should be fixing it first. In this case, communities can do this pretty quickly without a
lot of money. The other advantage of it is that if something isn't working exactly right, then
you can make adjustments on the fly. And we did that because we needed to accommodate school bus
turning movements. And if this was made out of, say, permanent poured concrete, that would
have been an extremely costly fix. Instead, it was just the contractor basically
working with the engineer to kind of move things around a little bit, and they
were able to make modifications in a day. Not only has this project improved the street, but
it's essentially already paid itself off just from how much money has been saved with the cost of
crashes. The federal government assigns a monetary value to each different type of crash. Many
factors go into the total cost of a crash, from the obvious vehicle repair cost to hospital bills
to lost wages, and the list goes on. With that data, they were able to look at crash data from
before and after the improvements and calculate the money saved. In our case, we just looked at
it over a few months, but that was enough time to kind of give us a sense. So, our $500,000 that
we spent saved about $5 million just in a short few months, according to the federal government's
calculations. Since we were able to basically just place these on top of the street, our costs were
extremely low, so our payback for the neighborhood was within a matter of like a month and a half or
something like that, so it was pretty astounding. With the changes they were able to create, I
asked Matt what the next step should look like for anyone wanting change in their own community.
They need to be persistent and they need to, at least in the city of Cincinnati, get
involved in their Community Council, speak to their elected officials, go to Council
meetings, and speak up and say that these are the type of things that they want. And there's
a lot of changes that need to happen. When we started this about four years ago, the budget
at the city of Cincinnati for traffic calming was about $500,000, and now it's $10 million.
It's still a very small amount, but it's much, much bigger than what it was just four
years ago. So, I think change is possible, but people have to speak up and
organize themselves with others, and don't be discouraged if you get a no; then
go back and find out how can we get to a yes. So, whether it's a plastic roundabout
or a total street renovation, change is happening in communities all over,
and it's important to keep fighting for safer streets for all. This next video reimagines
what streets in the suburbs could look like and dives deeper into some of the problems
they currently have. If you liked this video, be sure to subscribe and check out our Patreon
to help support creating more videos like this.
