Sunday, February 17, 2013

Adding Sound to EVs - Pedestrian Safety or Naivety?

For several years now, the government has been idly threatening to force car manufacturers to include a sound effect on all electric vehicles and hybrids.  The reasoning focuses around pedestrian safety, especially those that are blind or visually impaired.  Certainly, if that is a true concern, I would totally support the addition of artificial noise to EVs and hybrids.  But I would argue that the problem isn't centered around blind and visually impaired pedestrians; it's stupid pedestrians.  It's the people listening to their iPods or talking on their smart phones, totally disengaged and unaware of their surroundings.  Indeed, these people are the best candidates for being jumped and mugged, and I would be willing to bet, these people are the most likely "victims" of car accidents involving pedestrians. 

The claim that hybrids cause more pedestrian injuries and deaths than ICE vehicles doesn't go without merit; there is one study that, with the limited data set and questionable data collection aside, does accurately show a statistically significant difference in pedestrian accidents between hybrids and internal combustion engine (ICE) vehicles.  After several searches, I found the original study and checked over the numbers to convince myself that, besides the aforementioned flaws, the results are correct, assuming the data wasn't purposefully skewed.  (Find the study here:

Please note there is a statistically significant difference, but the scale we're talking about is miniscule.  Less than 1% of all cars, whether they are ICE vehicles, hybrids or EVs, are actually involved in a pedestrian accident.  That means less than 1% of hybrids, and less than 1% of ICE vehicles.  So even though there is a statistically significant difference, this difference is very slight.  This will be an important point that I will come back to later.

The problem with the study is that it doesn't consider any of the factors that are most obvious to me: (1) Which accidents involved pedestrians that were blind or hearing impaired? (2) Which accidents were found to be the drivers' faults, which were found to be the pedestrians' faults, and which were found to be shared or undetermined faults? (3) Were the pedestrians wearing headphones or talking on the phone?

Here's an interesting statistic I found on another site ( 50% of pedestrian accidents were judged to be the fault of the pedestrians, versus 39% judged to be the fault of the drivers, with the balance being shared or unknown.  Additionally, 37% of fatally injured pedestrians had blood alcohol concentrations (BACs) at or above .08 percent, while only 15% of pedestrian deaths involved drivers with BACs at or above .08 percent.  These two facts lead me to believe that it is not the cars we need to fix, it is the pedestrian habits. 

Let's look deeper at the primary study.  One factor the study did cover (and rightly so) is the light condition.  Interestingly, the proportions of accidents from hybrids and ICE vehicles are the same proportions in the daylight.  In all other lighting conditions, however, the hybrids had much higher proportions of pedestrian accidents.

I think this begs the question, are pedestrians expected to watch out for cars (or listen for, in the case of our blind and visually impaired)?  Or are drivers expected to watch out for pedestrians?  This discussion centers around low speed accidents, so we're talking about neighborhoods, intersections with walkways, etc.  These are places where it is the responsibility of the drivers to watch for pedestrians.  So frankly, adding artificial sound shouldn't be an issue at all, because the sound is to alert pedestrians.  An artificial sound doesn't help drivers avoid pedestrians. 

Now, I don't want to come off insensitive, but I just want to stop here and state that the blind don't discriminate against daylight and darkness.  If this was about the blind pedestrians not hearing hybrids, I would think the proportions of daylight accidents vs. accidents in the dark would be about the same.  So again, these statistics lead me to believe that drivers need to watch for pedestrians, not the other way around. 

But wait, if it's the drivers responsibility to watch for pedestrians, does this imply that hybrid drivers are more reckless than ICE vehicle drivers?  No, because more of these accidents are the fault of the pedestrians than of the drivers. 

I think I've confused the situation even more, so let's break it down. 

  • A pedestrian crossing at an intersection when they have the walk signal absolutely has the right of way, and the driver should be watching for them.  In this case, the artificial sound wouldn't really help, because the knowledge of a car's presence doesn't change the fact that pedestrians have the right of way and that they should be able to cross.  If a driver is going to blow through the light and plow over the pedestrian, I don't think a blind person (or for that matter, a seeing person) could necessarily jump out of the way to avoid it. 
  • A pedestrian J-walking or otherwise crossing illegally is purposefully putting him/herself in danger.  Hopefully blind and visually impaired people are not doing this, and everyone else should be watching, not just listening, for cars coming.   Obviously, this is a stupid thing to do, and could result in an unnecessary tragedy.  People with earbuds make the proposed artificial sound even more useless. 

Either way, I do not see the need to add noise pollution to a technology that otherwise eliminates it.  Instead, and I may be going a little survival-of-the-fittest here, our society must adapt to quieter cars and become more aware of their surroundings. 

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