As the car crept up to them, the students didn’t react. It wasn’t until it was about to run them over that they even knew it was there. And that was only because it hit their white canes.
The hybrid car’s electric motor had kicked in. And the students, all of whom are blind, couldn’t hear it.
“It came up, and it was right there. We had no idea it was even coming,” said Chad Wilburn, one of students, who took part in a demonstration of the new hazard posed by the quiet hybrid vehicles earlier this year in Salt Lake City by the Utah Center for the Blind.
Advocates for the sight-impaired say the vroom of a conventional engine is the only sure way a blind pedestrian can know that he or she may be walking into the path of an approaching car. They have been pushing for safety measures for several years, and Congress is considering a bill that would order the Transportation Department to make sure hybrids and the coming generation of all-electric vehicles make enough noise to be heard.
But they’re not the only ones worried about the silence. Emergency workers are raising the alarm, too, saying it can be hard to tell whether a hybrid’s engine is still running at the scene of an accident.
“If it’s in gear, it can lurch forward and injure someone,” said James Surrell, a physician at Marquette General Hospital in Michigan, who teaches hybrid safety classes for rescue workers and emergency medical technicians.
Hybrids’ electronic motors offer several other challenges for emergency workers at the scene of an accident. The biggest is that they are electronic motors.
In addition to a standard 12-volt battery under the hood, a typical hybrid engine uses another battery under the back seat that packs as many as 600 volts — more than enough to cause instantaneous death.
There have been no documented reports of any emergency worker’s having been electrocuted by a hybrid battery in the United States. But in literature they publish for emergency responders, nearly all manufacturers include vivid warnings like this one in the first-response manual for the Nissan Altima Hybrid: “Failure to disable the high voltage electrical system before emergency response procedures are performed may result in serious injury or death from electrical shock.”
First puzzle: Is it a hybrid?
On the road, government safety tests indicate that hybrid vehicles are just as safe as their gas-powered counterparts. Any concerns come from what to do once one of them has been in an accident.
The high-voltage batteries are thoroughly sealed in protective metal, and there is little chance that they could leak or explode. In fact, hybrid engines are packed with automatic sensors designed to stop the flow of electricity on impact or whenever the side-impact air bags deploy.
But that assumes the sensors themselves haven’t been damaged.
In its guide for emergency responders, Toyota, whose Prius popularized hybrids in the United States, warns crews to “never assume the Prius is shut off simply because it is silent.”
Emergency agencies across the nation have added specialized training for workers responding to accident scenes involving hybrids, like a hybrid safety seminar last month at the Lamar Institute of Technology in Beaumont, Texas. That’s because “we’re worried about forced entry into a hybrid and using the jaws of life,” said Brad Pennison, a captain with the Beaumont Fire Department.
At these seminars, crews learn that the first difficulty is recognizing that a vehicle is, in fact, a hybrid, which calls for different procedures.
Most contemporary hybrids are built to resemble their conventional counterparts — a design philosophy the industry calls “mainstreaming.” Many can be identified only by a badge or a small logo; if that’s damaged or hidden by debris or another vehicle, rescue crews may have no obvious clue that there’s a high-voltage battery lurking in the wreckage.
If the “hybrid” badge is missing from the door of its Silverado and Sierra trucks, Chevrolet details a four-step inspection process that crews should follow to determine whether they’re dealing with a hybrid or a conventional engine. Steps 3 and 4 require opening the hood, assuming the emergency workers can get to it.
Saturn, meanwhile, suggests finding the vehicle identification number on its Vue sport utility. “If the eighth digit is a five (5), this signifies the vehicle is a Hybrid,” its responder guide says.
Just how do you turn this thing off?
Once crews know they’re dealing with a hybrid, the next step is to make sure it’s turned off. All manufacturers say simply switching off the ignition and removing the key is the best way to disable the system. But that’s not foolproof.
For example, even when the motors are disabled, “power remains in the high voltage electrical system for 5 minutes after the HV electrical system is shut off” in the Prius, Toyota says. On the Lexus GS450h, it can be as long as 10 minutes.
And those instructions assume that the key or the ignition system is accessible. If it isn’t, the next option is to disable the standard 12-volt battery, blocking power to the bigger, more dangerous battery.
Different vehicles have different ways to do that, information that rescuers must either know when they arrive at the scene of an accident or be able to quickly retrieve.
On Honda hybrids, crews are advised to remove the main fuse (they must have a Phillips-head screwdriver handy) and cut both cables on the 12-volt battery.
On Lexus’ GS450h, however, they have to remove a yellow fuse in the engine junction compartment block. On the Lexus RX400h, it’s a red fuse. But on the Lexus LH600h L, they should remove the IG2 relay.
Other hybrids call for non-intuitive steps that crews must take before they can even try to disconnect the 12-volt battery. In the Nissan Altima, for instance, they first have to move the power seats and operate the power trunk release.
‘You need to know these little things’
If, in the worst case, emergency workers have to go near the big battery cables, they’re generally in luck. Nearly all hybrids color-code their battery lines in orange, an easy visual clue. But in some Saturns, some of the cables are blue.
The color isn’t set by any law, meaning not only that there isn’t 100 percent consistency, but there’s no guarantee that manufacturers planning to enter the market will observe the unofficial orange standard.
Complications like that mean emergency crews have to take extra time to assess an accident scene, even if injured victims need rescuing.
“There’s this tremendous amount of electrical energy,” said Surrell, of Marquette General Hospital. “You need to know these little things about hybrids because of the potential electrical danger to the victim of the accident and the rescuer alike.”