Recent studies have found hybrids to represent a mixed blessing of increased safety for their drivers, but potentially increased hazard for pedestrians.
Analyzing such data for the first time, the Highway Loss Data Institute found hybrid versions of vehicles compared to an internal combustion-powered counterpart version of the same model in their makers’ lineup are 25 percent less likely to be injured.
The study scrutinized only same-make sibling vehicles, not cars sold strictly as hybrids or electrics such as the Toyota Prius, Honda Insight, Nissan Leaf, Ford Focus Electric and Chevy Volt.
Although they were not looked at, crash test data from these latter vehicles otherwise shows them to be high-scoring as well for the same reason.
What is the reason hybrids are safer to occupants? Extra mass. A hybrid has more weight due to the extra bulk of battery and related components of its sophisticated drivetrain.
“Hybrids on average are 10 percent heavier than their standard counterparts,” said Matt Moore, the data institute’s vice president and author of the study today. “This extra mass gives them an advantage in crashes that their conventional twins don’t have.”
The analysis by the data institute – an affiliate of the Insurance Institute for Highway Safety – examined over 25 hybrid and conventional vehicle pairs made between 2003-2011.
Its findings could be considered empirically obvious to people with a good intuitive grasp of mechanical/spatial relationships. Extra weight carries extra kinetic energy. It is the same principle used to sell heavy SUVs, as their weight is a safety advantage.
Keep in mind the data institute conducted a fairly limited analysis. Also outside its scope were such comparisons as between a mid-sized vehicle and a compact, or compact versus subcompact, etc.
Cars also not studied, like the mid-sized-heavy, but compact-sized Volt for example, have similarly been found to top safety charts among compact class vehicles. The battery alone in the 3,700-plus-pound car weighs around 400 pounds, and extra bulk provides a margin of safety in impacts. The same is true for the Nissan Leaf which weighs over 3,300 pounds.
While safety for those inside the car is statistically improved, a second study by the data institute found hybrids could be up to 20 percent more likely than conventional counterparts to injure pedestrians.
Here the cause was their very quiet running.
“When hybrids operate in electric-only mode, pedestrians can’t hear them approaching,” Moore said.
Again, this was with ICE/hybrid sibling pairs, but one could reasonably infer similar concerns for any hybrid or all-electric car for that matter.
In fact, that has already been officially done by way of a congressional mandate to the National Highway Traffic Safety Administration. This ruling was decreed prior to any study such as we are now reporting, and was instead based on lobbied concerns and what some considered common sense.
NHTSA has three years to devise sound alerting standards to make now- near-silent electrified vehicles more noticeable.
The lobbying for this was first started by the National Federation of the Blind whose members noticed a number of near-miss incidents and began pushing years ago for legislation.
Thus far, only Japan has sound-emitting rules in place. The Japanese market 2010 Prius for example has an electric-motor-like humming sound which rises and falls in pitch relative to speed. This equipment is expected to come with the U.S. market 2012 Prius V.
Presently, this sound emitting issue has been approached voluntarily in a few ways by manufacturers. The Volt has a light horn sound meant not to startle, but sound “friendly.” The Nissan Leaf electric car also has a sound to alert pedestrians when it is approaching. Other makers have done similarly.
A unified U.S. standard is expected to be law in a few years. Automakers concerned with liability issues have said they will comply with the federal government’s decision when required, if not before.
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