Start Stop Technology

The last year or so I’ve noticed when sitting at a stop light or walking on the bike trail near a stoplight what I thought were people turning off their engines until the light turned green. Assuming the driver was actually turning the ignition off and back on I thought to myself, that is interesting I wonder why they do that? This week I took my car to the dealership for some work and was given a loaner car to drive around until mine is ready. Sure enough this car turns itself off when I come to stop and restarts when I let my foot off the brake and it’s not a Hybrid, but an regular SUV.  My gut reaction is to find this kind of unsettling but knowing that there must be a reason for this I decided to look into it.

What I have found it there is really not a lot written in Start Stop Technology as it pertains to environmental impacts. Perhaps because it is fairly new in the US in non-hybrid vehicles there isn’t a lot of data to measure yet. Nonetheless, the reason for Start Stop technology is precisely that, to reduce CO2 emissions. When the engine is turned off rather than idling it uses less gasoline and produces less emissions. Idling cars waste some 3.9 billion gallons of gas per year in the US. Currently less than 50% of new vehicles in the US are equipped with this technology, and with lots of older vehicles on the road the effect on this is probably fairly small at this point. While the actual gas and emissions savings vary depending on how you are using the vehicle, sources estimate that the reduction in each of these factors is somewhere in the neighborhood of 5-15% with higher reductions being associated with city driving and 6% being average. While this definitely isn’t as environmentally impactful as an investment in a hybrid or electric car, it seems to be a small move in the right direction by automakers.

I don’t think I will be running out to buy a new car based on this technology alone whereas I would be inclined to consider a new hybrid or electric car. I am interested to see how this technology pans out over the next several years. Because I’m not the type of person to buy a new car and drive it a couple years and trade it in on another new car reliability and durability are important to me. The thought of my car having to start 5 or 10 times more than what a normal car does concerns me because of the possibility that something could fail (while I’m sitting in traffic) and it wouldn’t restart. Start Stop equipped vehicles have larger battery requirements as well which at least partially offset the positive environmental impacts related to emissions.

What do you think about Start Stop Technology? Would this influence your decision on what car to purchase?