BYU Group Designs Software That Could Help Cities Map Growth

PROVO —
Imagine life if
city planners
didn’t plan.
Downtown Salt
Lake City
might be a
jumble of strip
malls and a
maze of
one-way
streets, or oil
refineries might
be nestled next
to office
complexes.

BY VINCE
HORIUCHI
THE SALT LAKE
TRIBUNE

Not likely,
but even the
slightest
changes in a
city’s
development
can have big
ramifications
for citizens.
Some
Brigham Young
University
engineering
professors and
students think
they have discovered a better way of mapping things
out.
They are developing software that can
automatically search for the best future plans for a
city by figuring out how it should change and grow
as it gets more populated.
The software takes a city’s existing map of
land-use zones and figures out whether any
changes should be made in the zoning. It decides
which streets should be widened as more people
move in.
Just input the data about a city, press a button,
sit back and let the computer do its thing.
"I see this project as the future direction in city
planning," said professor Richard Balling, who leads
the project.
The eight-year project, financed by two grants
from the National Science Foundation, ends next
year. But Balling and his group are using the
software to search for the best plans for the
Provo/Orem metropolitan area and will share them
with city engineers this summer. They also are
finding the best plans for the whole Wasatch Front.
"They won’t take our plans and implement them
at face value. This is university pie-in-the-sky stuff,"
Balling said. "But it may influence their thinking in
some way."
First, the city engineer using the program would
input the city’s projected population growth over the
next two or three decades as well as a map of the
city’s various residential and commercial zones.
Then the software looks for ways to allocate
enough land for housing and commercial
businesses, ways to reduce traffic congestion, and
ways to do all of this with as little change and
heartache as possible.
To find the best city plans without computer
assistance would be mind-boggling. For just the
Provo/Orem area, the number of different plans
would equal a one with 203 zeroes.
To help narrow that down, members of the group
turned to evolution, not engineering.
They use a "genetic algorithm" to find the best
city plans, a formula based on how two parents
produce a child with their characteristics. Airplane
manufacturers use genetic algorithms to help find
the best designs, and researchers even use them to
create art and music.
"First, the computer generates a couple of [plans]
randomly. Most of them would be really bad, like
turning 1300 East into a freeway or tearing
downtown Salt Lake City down and turning it into a
farm," said Michael R. Brown, a former BYU student
who worked on the project and now is a
transportation engineer. "You cross one plan with
the other plan and odds are the child is going to be
better than its parents were."
The computer will go through "generations" of
plans before it settles on the best hundred or so,
which takes a personal computer about three days
of continuous cranking to accomplish.
"You run through a hundred million years of
evolution in six hours with the computer," said
Brown, who wrote the initial genetic algorithm code
for the software. "At the end, you have an entirely
new population where all of the plans it’s creating
now are infinitely better than the ones they began
with."
Balling said city engineers ordinarily use
computers to analyze the efficiency of a handful of
city plans, but "we’re different because we use
computers to search for plans among hundreds of
thousands."
But with all of the computing horsepower and
brainpower behind this project, there are still a
couple of things the software can’t figure out — such
as unpredictable politicians or that one angry
activist who doesn’t want the freeway running
through his property.
"We produce a starting point," Balling said. "And
with it, we think they are looking at good plans to
start with and not just pieces of junk."
Vern Keeslar, long-range planner for Provo, is
impressed with what Balling and his group are
accomplishing.
"It helps us look at things like air quality and
mass transit options. It would provide housing that
is of a better quality," he said. "It shows wonderful
trends and the impact that one development in one
city may have on neighboring communities."
While this is strictly a research project and not
for commercial use, Balling is convinced city
planners one day will use the software to help shape
the future.
"In 10 years," he said, "this will be a standard
way of doing things."

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