Swedish automaker, Volvo, recalled 65,000 cars due a software problem related to side impact airbags. I spoke with Volvo spokesperson, Maria Bohlin, who told me the problem was discovered by Euro NCAP, a European automotive testing agency, which found the "inflatable curtain deployed milliseconds too late." She added that Volvo would examine whether their software and testing routines are sufficiently robust.
Firehouse.com offers excellent technical information about Volvo inflatable curtain (IC):
The IC is a long, flat airbag which deploys down from the roof rail and extends from the A-pillar to the C-pillar, covering the front and rear side window areas from the roof to the top edge of the door. One side-impact crash sensor is mounted low on the inside of the B-pillar. A second crash sensor is mounted low on the C-pillar at the seat-cushion level. The IC inflates only on the side where impact takes place. A pressurized gas cylinder contains 95% argon and 5% helium gas that fills the Inflatable Curtain airbag.
This photo shows the actual stored gas cylinder used in the Volvo system:
Airbags are complex devices that must deploy within a fraction of a second, between the time a vehicle strikes an external object and the rider hits the front or side of the car interior. This diagram illustrates the kind of logic used in airbag software:
This is not the first time an auto maker recalled cars based on software issues. Earlier this year, Ford recalled 470,000 Mustangs because the "passenger-side frontal airbag could potentially deploy with greater-than-allowable force for a petite, unrestrained passenger."
Software permeates our lives in the most unexpected places and sometimes it goes awry. Volvo and Ford have learned that lesson the hard way.