by Eleanor Cummins / illustration by Sinelab 13
Car-free levels
Getting commuters out of cars is key to
avoiding overtaxed spans, but bridges
aren’t exactly friendly to bikes or our own
two feet. Contemporary designers
advocate for lifting parklike promenades
above traffic and filling them with public
art, health-boosting greenery, ample
shading, and even cafes for socializing.Robot-only zones
Humans hesitate when accelerating
or changing lanes, but self-driving cars
won’t have our delayed reactions: When
the light turns green, they’ll move in
unison. That’s why graduate students at
UC Berkeley propose an autonomous-
only 100 mph “hyperlane” to help traffic
quickly clear overpasses.Quake-resistant supports
Bridges shake under normal conditions,
giving a little to keep from shattering,
and a quake is the ultimate test. To stay
upright, engineers dig towers into the
bedrock, install dampers throughout the
structures to absorb tremors, and outfit
spans with seismic and traffic sensors
that alert authorities to any danger.NOW
- Wider lanes
- Car-free levels [ 1 ]
- Robot-only zones [ 2 ]
- Regular maintenance
- Quake-resistant supports [ 3 ]
make bridges,
not death
traps
THERE ARE 614,0 00 BRIDGES IN THE U.S., AND NEARLY 1-IN-10 OF THEM IS FALLING
apart. When Eisenhower signed the 1956 Federal-Aid Highway Act,
estab lishing a 41,000-mile system of roads and bridges, there was roughly
one car for every three people. Today, it’s almost 1-to-1. This infl ux of ve-
hicles, plus shoddy maintenance, has taxed spans to the brink of collapse.
This bridge is the sum of our worst missteps, and how to make them right.FRANKENBUILD