Soft walls
‘Soft walls’ actually hard to perfect The concrete walls that surround virtually every race track in America are designed to do one thing: keep cars from going into the stands. But they do little to protect drivers who slam into them at nearly 200 m.p.h. In an effort to reduce driver injuries, engineers have started working on energy-absorbing barriers (so-called “soft walls”) for race tracks. To date, however, they have yet to build the perfect barrier: a wall that protects drivers and fans from every accident.
Hitting a concrete wall 1 Direct hits: Concrete walls are extremely
unforgiving when hit at sharp angles, stopping a speeding race car so quickly—and violently—that drivers stand little chance of escaping without serious injuries.
1 2
2 Glancing blows: When hit at less steep angles, however, these walls actually help the driver: They gradually slow the car’s forward momentum and keep it along the outside of the track, away from oncoming traffic. PROS
Oncoming car
e
rfac
su ack
Tr
Deadly in head-on accidents
Hitting a soft wall
1
1 Direct hits: Unlike
concrete walls, which absorb little or no energy when hit head-on, energy-absorbing barriers help dissipate some of the car’s momentum. In theory, a wall could be designed to reduce the stress on the driver’s body by about 40 percent.
2
Oncoming car 12" diameter secondary impact cylinder
2 Glancing blows: Soft walls
can reduce the impact of glancing blows as well, but they can also “pocket” and snag the car, bringing it to an abrupt halt and redirecting it into the path of other cars. Safer in head-on crashes
rier
te bar
e Concr
CONS
Relatively inexpensive Already in place Very durable
PROS
Traditional concrete barrier
CONS Expensive Need to be installed Can shatter on impact, sending debris into stands or onto track
Inside a soft wall
PEDS-2 barrier
Cable restraint system ing
lapp
over hick te t " 2 1/ ct pla impa
Existing concrete barrier
ce
urfa
ck s Tra
16" diameter The PEDS-2 Barrier (Polyethylene Energy Dissipating System) is primary impact considered the most advanced soft wall designed for race tracks. cylinder Developed by the Indy Racing League and the University of Nebraska, it uses a series of hard plastic cylinders to soften the blow of a crash; the cylinders are then covered with an impact plate and attached to the front of an existing wall. The PEDS-2 has been used at only one track, Indianapolis Motor Speedway, on a small stretch of wall on the inside of Turn 4. Engineers are now working on a third generation of the PEDS, which uses high-density foam instead of cylinders. Sources: Indy Racing League, University of Nebraska
Chicago Tribune/Drew Sottardi and Phil Geib
Hitting a concrete wall 1 Direct hits: Concrete walls are extremely
unforgiving when hit at sharp angles, stopping a speeding race car so quickly—and violently—that drivers stand little chance of escaping without serious injuries.
1 2
2 Glancing blows: When hit at less steep angles, however, these walls actually help the driver: They gradually slow the car’s forward momentum and keep it along the outside of the track, away from oncoming traffic. PROS
Oncoming car
e
rfac
su ack
Tr
Deadly in head-on accidents
Hitting a soft wall
1
1 Direct hits: Unlike
concrete walls, which absorb little or no energy when hit head-on, energy-absorbing barriers help dissipate some of the car’s momentum. In theory, a wall could be designed to reduce the stress on the driver’s body by about 40 percent.
2
Oncoming car 12" diameter secondary impact cylinder
2 Glancing blows: Soft walls
can reduce the impact of glancing blows as well, but they can also “pocket” and snag the car, bringing it to an abrupt halt and redirecting it into the path of other cars. Safer in head-on crashes
rier
te bar
e Concr
CONS
Relatively inexpensive Already in place Very durable
PROS
Traditional concrete barrier
CONS Expensive Need to be installed Can shatter on impact, sending debris into stands or onto track
Inside a soft wall
PEDS-2 barrier
Cable restraint system ing
lapp
over hick te t " 2 1/ ct pla impa
Existing concrete barrier
ce
urfa
ck s Tra
16" diameter The PEDS-2 Barrier (Polyethylene Energy Dissipating System) is primary impact considered the most advanced soft wall designed for race tracks. cylinder Developed by the Indy Racing League and the University of Nebraska, it uses a series of hard plastic cylinders to soften the blow of a crash; the cylinders are then covered with an impact plate and attached to the front of an existing wall. The PEDS-2 has been used at only one track, Indianapolis Motor Speedway, on a small stretch of wall on the inside of Turn 4. Engineers are now working on a third generation of the PEDS, which uses high-density foam instead of cylinders. Sources: Indy Racing League, University of Nebraska
Chicago Tribune/Drew Sottardi and Phil Geib
