boundaries, and one with no markings or apparent rules at all — which one would look safer

to you?

Towns all over Europe are starting to experiment with streets like this: where cars, bikes,

buses, and people can travel freely in the same space.

I think this looks like an accident waiting to happen.

But I know someone who would know a lot more about this than I do.

I'm Roman Mars from 99 Percent Invisible.

And that's what urban planners often refer to as a “shared space” design strategy.

It seems counterintuitive, but there's evidence that getting rid of all signs and barriers

might make our streets a lot safer.

So — how does it work?

There's a spot in Google street view where you can witness a town undergoing this exact

transformation.

This is Poynton, England — about 20 minutes away from Manchester.

Here's the city center in May 2011: there's a mess of signs and lights, a few small sidewalks,

and some haphazard guardrails to keep pedestrians safe.

And here it is in July 2015.

Traffic lights, road signs, curbs — all gone.

“Something very strange is happening on the streets of Britain — I don't know

if you've noticed, but in some places, pavements and roads have been blurring into one with

cars, buses, and pedestrians all sharing the same space.”

The town spent 4 million pounds to expand sidewalk space and strip the city center of

traditional demarcations.

Now, the only marker left is this little sign: Poynton shared space village.

The concept is that the absence of separation will make everyone more cautious — so commuters

slow down, make eye contact, and negotiate.

Watch what happens when a boy in Poynton is encouraged to cross the street without waiting

for the cars to clear the intersection.

Because cars don't spend time waiting at traffic lights, it takes less time on average

for them to get through the crossing.

Even when bikers and pedestrians are absent, cars drive slow due to a concept called “edge

friction.”

It's the idea that nearby vertical elements in a driver's peripheral vision — like

trees or lamps, create a visual cue for how fast they're going.

On a highway, those are often totally absent, so the sidelines blur.

In a shared space, those lines play an important mental trick to slow down drivers.

In theory, shared space works well for pedestrians, allowing them to follow their desired path

while walking.

Instead of being limited to a strict path, they can walk exactly in the direction they

want to go.

n In practice, that doesn't always seem to

be the case.

Video footage of a shared space at Elwick Square in Ashford, England shows that pedestrians'

mostly still stick to crosswalks, or where a crosswalk would be.

That's largely because these layouts are stressful: The majority of a survey group

asked about crossing Elwick Square reported feeling anxious about it.

And those pedestrians frequently report that they prefer things the way they used to be.

But the “way things used to be” is relative.

If you look at old footage of city streets in the early 1900s, cars mixed freely with

pedestrians, bicyclists, and streetcars.

Vehicles couldn't go very fast back then, so there wasn't a huge concern about separating

them from walkers and bikers.

With plenty of city streets, that's still the case without any intentional urban planning.

But the big question is whether these deliberately stripped-down designs actually make people

safer.

It seems that in many cases, they do.

For one thing, we know that the number of accidents drops after shared spaces are installed.

In Ipswich, rates of accidents involving injuries fell from 23 over three years to just one

per year.

In London's Kensington High Street, the number of pedestrians injured dropped by nearly

60 percent.

And in Drachten in the Netherlands, accidents at one intersection fell from 36 in four years

to two in two years.

We also know that shared spaces are quantifiably more free-flowing based on analysis of traffic

conflicts.

With video footage like this from Exhibition Road in London, analysts can rate the severity

of a traffic conflict based on participants' speed and change of course.

Before the shared space renovation, one pedestrian had to step back onto the sidewalk to avoid

a departing car.

Another broke out into a sprint to avoid getting hit by an oncoming van.

After the shared space installation, traffic conflicts were less frequent and less severe on

average — like this, where pedestrians wait for a cab to cross before continuing.

Or this one, where a cyclist changes course to avoid pedestrians.

But that doesn't mean these designs work for everyone.

“I think it's the most ludicrous idea I've ever heard.

What about blind people?

Children?”

From the beginning, shared space designs have been under fire for providing insufficient

protections for disabled pedestrians, especially the visually impaired.

“The family of a pensioner who died a month after being hit by a bus have called for traffic

lights to be reinstalled at the junction.”

“Traffic lights here were recently removed to make way for a so-called shared space, but it's

a move that has angered David's family”

“I'm sure if the traffic lights were there,

this wouldn't have happened”

A 2015 House of Lords report called for a temporary ban on shared space designs.

And in August 2016 a select committee of the House of Commons launched an inquiry into

the accessibility of such environments.

Their final report in April 2017 asked the government to put all shared space schemes

on hold until they improved the process of consulting disabled communities.

Preliminary designs like these by the Danish Building Research Institute give us an idea

of what that balance might look like.

They include both the mixed traffic of shared space and the raised street textures and button-activated

crosswalks that disabled users are used to.

Shared spaces can be effective, but for this kind of plan to work across communities, it

will require a lot more research to determine what will work in different places and what will serve

the needs of all the people sharing the streets.