Tuesday, December 29, 2009
Around the Kingston news lately (from CB):
Drive-thrus are valuable to the elderly, the immobile, parents with small children and, believe it or not, are actually better for the environment than cars in parking lots — or so says TDL, the parent company of Tim Horton’s.
Early last month, Polowin presented the RWDI report to Kingston council. Its conclusion — that drive-thrus create fewer emissions than parking lots — is based on a finding that when parkers turn off their cars, the catalytic converter cools and is less efficient at reducing emissions. And so, when the customer restarts the car, a larger, initial spurt of emissions is released. There are a lot of variables to consider when comparing the emissions generated by a parking lot and a drive-thru. While drive-thrus are generally thought of as bad for the environment because people tend to idle their cars, Michael Lepage, a principal with RWDI, says, "the one thing people have missed is how much time people spend idling in the parking lot."
Well, that is a load of shit. Ok, let’s narrow down the factors.
Type of vehicle.
All have to do with the catalytic converter.
Let’s just keep the vehicle type constant over the average.
What about idle times from start? I.e. the pollution effects controlled by the catalytic converter.
So, why is the catalytic converter so important, and why does it need to get to a certain temperature to work?
Ok, here’s the chemical equation for what the converter does:
- Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx→ xO2 + N2
- Oxidation of carbon monoxide to carbon dioxide: 2CO + O2→ 2CO2
- Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2→ xCO2 + (x+1)H2O
Basically, it turns nitrogen oxide into carbon dioxide and water, reducing nitrogen oxide emissions by as much as 70%! Why is nitrogen oxide bad? NO (and NxOx) destroys the ozone layer, reacts with organic chemicals and leads to biological mutations, acid rain, and respiratory issues.
Ok, but there is a catch with the catalytic converters; they need to be warm to work. Most estimates I’ve found seem to be around the 400-600 degrees Fahrenheit. The catalytic convert warms up because it is close to the running engine.
Now, ambient temperatures.
We see two things from this paper. One, that ambient temperature does effect catalytic warm-up times, and two, that these warm up times are linear. Times to complete warm up seem to be in between 12 to 30 minutes. Wow.. 30 minutes? Ok.. from this we’re starting to learn that catalytic converters are meant to reduce emissions for longer, more often than not highway related, drives.
Somehow I don’t see the 5 minutes taken to go inside a Tim Horton’s long enough to totally cool down your catalytic converter. Moreover, I doubt many catalytic converters would be warmed up when entering the drive-thru.
National Resources Canada suggests the 10-seconds rule: if you are idling for more than 10 seconds, it is more efficient to turn your engine off. I found this rule employed quite often in Tokyo when I was there, with drivers typically turning their vehicles off at stop lights.
Ok, after that tangent on catalytic converters, back to the original article. So, I was talking to Jeremy about this, and he mentioned, as the article did, that that an additional, more prominent reason for this drive thru ban would be that people just don’t want the traffic in their back yard.
From another article on the Tim Horton’s subject from The Whig Standard:
"Specifically, the company takes exception to the 50-metre setbacks for drive-thrus from nearby residential properties.
Polowin said those regulations are usually based on issues of noise, most often emanating from the drive-thru speaker box. He said the company is working on making that technology better.
Another issue is how drive-thrus might interfere with pedestrians, and particularly in downtown heritage areas of cities.
Polowin said the City of Ottawa recently adopted his wording on their official plan that sets down more precise guidelines for building esthetics in the downtown core but could still allow for a drive-thru to be built…
Schmolka said the official plan is mainly concerned with traffic flow, pedestrian safety and proximity to residences and that staff may ask for extra studies to deal with concerns."
One final point on that TDL (Tim Horton’s) study.
In an e-mail message, Mr. Glover (a Kingston city councilor) disputed those findings:
In support of their case, they have prepared a report suggesting that drive-throughs are more environmentally friendly than parking lots. Unfortunately, at their presentation to the Planning Committee last Thursday, they said it was based on a sample of 52 cars, which does not seem to me to be a sufficiently large sample to carry much weight. By contrast, the city’s by-law against idling vehicles was based on the science available from Environment Canada. The presentation also seemed to incorporate a number of assumptions that may not be valid.
Basically, Tim Horton’s feels the need to put money toward changing the public perception behind idling because they make so much money from their drive-thrus. I’m not sure how much, but if McDonald’s is making 65% of its cash from drive-thrus, I would bet that Tim’s is over 80%.
As discussed in an older National Post article,
A ban on new drive-thrus was debated in the city of North Vancouver but was rejected in March by city councillors. Coun. Sam Schechter said he proposed the ban as one step towards orienting his city towards more sustainable design.
"It was simply part of better urban design for building cities that are less car reliant," Mr. Schechter said. "You’re orienting your community away from the automobile and towards pedestrian and more sustainable transportation."
Wow… this post is all over the place! Too much information, too little time…
at 5:55 PM