General Motors isn't the only automaker to have a problem with ignition switches that could shut off the engine at highway speeds.
Just a few years ago, Chrysler recalled nearly 250,000 minivans and crossovers over switches that could pop into accessory mode if the key was accidentally nudged by the driver's knee or a rut in the road.
But taking the key out of the equation hasn't been a perfect solution either. Automakers have had safety problems with push-button ignition systems, too, as drivers have struggled to adjust to the interface and the fact that a vehicle can keep running after they leave with the key.
Five years ago, at the height of Toyota's unintended-acceleration crisis, a USA Today headline posed this question: "Is the power start-stop button the most dangerous new feature in cars?"
The newspaper noted that a driver needed to press the start/stop button for three seconds -- "an eternity in a panic situation" -- to turn off the vehicle.
Toyota's reasoning for the three-second rule was to prevent an unintentional button press from shutting down the engine on the road, just as an inadvertent bumping of the key might in a faulty Chevy Cobalt or Saturn Ion.
People have also been hit by vehicles that were left running when the driver walked away with the key fob without putting the vehicle in park. And in one 2012 accident in Boca Raton, Fla., a man and a woman died of carbon monoxide poisoning after leaving their Mercedes-Benz with a keyless ignition idling in the garage.
"There's no question that [keyless ignition] is here to stay. It's not going away," said Sean Kane, president of Safety Research & Strategies Inc., a Massachusetts consulting firm. "But we're upending the human interface with the machine, and that has risks."
The National Highway Traffic Safety Administration proposed new rules for keyless ignitions in 2011 to address these concerns, but hasn't finalized them.
Meanwhile, push-button start systems are rapidly replacing metal keys. Of the 2014 models tracked by Edmunds, 246 of 345 -- about 71 percent, up from 6 percent in 2005 -- had a push-button system as a standard or available feature.
"It's becoming like Bluetooth," says Jake Fisher, testing director at Consumer Reports. "You expect it on every new car now."
Kane said metal keys are tried, tested and effective. It's when they are poorly designed that they can become dangerous.
In the fall of 2010, Chrysler Group started an inquiry into the Chrysler Town & Country and Dodge Grand Caravan for a problem similar to the one GM found in cars such as the Chevrolet Cobalt and Saturn Ion. Chrysler had received dozens of complaints about stalling, it later told regulators.
The company quickly found the problem: The ignition could get stuck between positions. If nudged, it could move into "accessory" mode and shut off the engine.
Seven months after its investigation started, Chrysler recalled 248,437 vehicles from the 2010 model year.
Two rear-end crashes had been linked to the defect, but no one had been injured or killed, the company said in a defect notice at the time.
As GM did this year, Chrysler told customers then to use their keys with nothing attached until the fix was complete.
Because keyed ignitions have been generally reliable over the decades, safety advocates say, GM should have connected the dots earlier on its ignition defect.
"Traditional ignition switches have been fairly well-vetted as a technology," Kane says of GM's defect. "What we had here was just a bad design."