Am I the only one who kind of always assumed city block meant a standard size?
Well, it might seem obvious now,
but city blocks come in a lot of different sizes,
which makes you wonder what the ideal size is for a city block.
Let's go for a walk,
say, here in Manhattan.
If I want to meet my co-worker for a coffee,
and he's 10 blocks uptown,
that's 2,500 feet, half a mile.
In that case, I'll say, "Yeah. No sweat.
The walk feels like a breeze."
But if I'm in Atlanta at the Perimeter Center Mall,
and my friend is the same distance away,
I'd be more tempted to drive or I'd walk, but grudgingly.
This is the comparison that prominent architect and urbanist,
David Green uses to illustrate walkability.
Generally, we say something is walkable when it offers
destinations to walk to and when pedestrians feel safe and comfortable walking there.
So, when you're walking across that super block,
its massive scale means you don't get the sense you're making progress through space.
As a puny little human on
a vast asphalt plain where the buildings are hulking and set far away from the roads,
you don't feel safe and comfortable.
But when you walk that same half mile in New York City,
you're crossing all these perpendicular streets.
You sense that you're making progress.
Your senses are engaged by the rich tapestry of city life unfolding all around you,
and you've got so many different ways to traverse this grid.
Zigging and zagging, you could take a new route and discover something new each time.
Portland, Oregon has small blocks and is the darling of the urban planning world.
Urbanists love Portland because those small blocks make a city more walkable.
Planners and urbanists care so much about walkability because
walkability is part of what makes an urban space feel like a place,
someplace where you want to visit and spend money.
That said, smaller isn't always better,
because the smaller the blocks,
the more time you spend crossing streets
and the more time cars and trucks spend at stop signs,
and there's an economic trade-off for cities.
As block size shrinks,
you end up with more streets.
Streets cost money to maintain,
as opposed to a retail occupied plot of land which generates tax revenue.
According to some very impressive complicated math by this team at Harvard,
when it comes to block size,
smaller isn't automatically better.
By their math, New York City's grid,
laid out in 1811,
is nearly ideal in terms of walkability and accessibility to the most destinations.
Its blocks have been able to accommodate everything from farmhouses to skyscrapers,
and there are countless destinations easily accessible within a five-minute walk.
So, by that measure,
it's one of the most walkable cities in the world.
David Green, our urbanist friend,
says his ideal block size,
based on his years of experience,
is 240 feet by 360 feet.
That's right in between Portland's 200 by
200 blocks and Manhattan's bigger oblong blocks.
He says this is accommodating to most types of buildings including parking,
which needs a lot of space.
But it's still small enough to feel walkable to pedestrians.
But, as the Harvard team notes,
there's not one Goldilocks block size for every city.
Part of the ideal size depends on how big
the parcel sizes are plus the street width and the depth of the plots.
But, their formula can help planners find
that sweet spot between walkability and efficiency.
Hey, thanks for watching.
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