Tuesday, October 17, 2006

Cars and the environment

If you've scanned this blog a bit, you'll quickly realize that I'm a wee bit interested in cars.

This post by Our Man In Hanoi, titled "Four Wheels Bad" piqued my interest. It is also, in part, wrong. Here is the bit:
Well the bikes are the lesser of the evils as far as I can see compared to cars.
While we probably 'agree to disagree' with respect to other parts of the post (industry is the engine of the future and tourism is a nice diversion; a full belly and rubbish on the road is better than hungry cleanliness), and while passenger vehicles may overwhelm the roads, they certainly stress the environment less in comparison to the teeming motos.

How clean are car emissions these days? Well, as one would typically answer a complicated question: "It depends."

Assuming that you chose one of the cleanest (non-hybrid) new passenger vehicle, the emissions output is roughly 1.04 grams* per mile, per this source from Clean Car Campaign. That asterisk is important - it denotes that I am not well versed on this issue. Emissions is a complicated matter, because what's coming out of the tailpipe is a stream of complicated gases. The four general categories are Hydro Carbons (HC), Carbon Monoxide (CO), Nitrous Oxides (NOx), and Particulate Matters (PM). From my limited research, there seems to be genuine debate on which category is the "worse" for the environment - an important debate to resolve because certain current engine technology can reduce one type of emissions while increasing another. Suffice to say, I don't know enough, so my emissions output metric combines all four categories.

So what exactly is one of the cleanest new passenger vehicle? For the more car-minded folks, it would be a SULEV certified car. Or in other words, something as radical as a Toyota Camry 4-cylinder sedan, with an automatic. See EPA numbers here. No need for vehicles with 80 lbs of batteries (which, incidentally, like a Toyota Prius, would be cleaner still).

So how do motorbikes do? Again, the short answer is: "It depends (but it's worse than the Toyota)."

As this 2000 World Bank study of South Asia (nee India, Bangladesh, Pakistan, Nepal, Bhutan and Sri Lanka) (.pdf file) demonstrates, two stroke engines pollute (~ 20 grams/km) much more than four stroke moto engines (~ 15 grams/km), but both would pollute more than SULEV cars. Note also that if one were to convert to grams/mile, the numbers would be ~ 33 grams/mile and ~24 grams/mile respectively. The study also points out that emissions performance would be severely negatively impacted due to poor quality fuels and lack of engine maintenance.

Even with more advanced engine designs, such as those offered in Europe or the U.S., motorcycles and motorbikes pollute more than cars. Here is the text of the new, more stringent EPA standards (.pdf file) for motorcyles and motorbikes, issued Dec. 2003. These new standards are more lax than SULEV passenger vehicles, and there are difficulties experienced by manufacturers in meeting these lower standards.

So in short, how do motorbikes do? 4 strokes are better than 2; 125cc's are better than 50 cc's. The Toyota is much better than all the above.

For those who are shopping, here is a list, offered by DriveClean.ca.gov, from which you can pick out cleaner passenger vehicles - note also that PZEV (Partial Zero Emissions Vehicle) is cleaner than SULEVs, and that there are a bunch of PZEV cars out there.


HanoiMark said...

I'm certainly no expert on cars or emissions but here are my thoughts. First, on the environment: you can clean up the tailpipe but ultimately the thing that will bring us all down are the greenhouses gases and it seems clear that cars burn way more of these (I used my moto a fair bit in Hanoi and it costs me about $2 in gas each week; cars on the other hand guzzle gas). The other thing is the huge cost of cars on the infrastructure of Vietnam. Cars will destroy the cities of Vietnam because Vietnam is not built for cars. Already we are seeing huge demolition of neighbourhoods in order to widen streets to accommodate the increased traffic - as as OMIH points out, it's largely the cars that cause the traffic jams which end up being the reason for road widenings. See Antidote to Burnout for a recent posting on streetwidenings. Most people in Vietnamese cities live in very narrow and dense alleyways (ngo in the North, hem in the South). You cannot drive into them and you certainly can't park there. If cars are accommodated in a big way you will see massive clearings for the purposes of parking. This will seriously compromise the integrity of Vietnamese cities. Next, when it comes to safety, the most dangerous thing is a mix of speeds and vehicles - esp. when cars operate on a different traffic logic than motobikes. I can't see much good in the way of the proliferation of the car in Vietnam. In North America our addiction to cars is creating huge environmental and geopolitical problems (and I would argue social problems). I think it would be a huge loss if Vietnam refashioned itself to accommodate cars, just when we are starting to see the benefits of trying to break our own addiction to them.

D. said...


First, a bit of correction. You wrote "you can clean up the tailpipe but ultimately the thing that will bring us all down are the greenhouses gases and it seems clear that cars burn way more of these..."

You are confusing and conflating two things. Greenhouse gases are created when you use fossil fuels. It is true that motos *use* less fossil fuel per mile than cars. But it is certainly *not* true that motos create less greenhouse gases - that was the whole point of my post and the studies and data that back up the post. By cleaning up the tailpipe, you reduce the creation of greenhouse gases (i.e. all those HC's, CO's - the carbon output that turns into greenhouse gases, but don't forget NOx and Particulates in your concerns!)

In short, motos use less fuel but create more greenhouse gases per mile. Why? Because the engine design is inherently less clean (wrt to 2 strokers) and because emissions control equipment is less developed and proportionally more expensive on the motos and therefore not in the marketplace. $100 worth of emissions control is more easily incorporated and accepted by the market on a $20k vehicle than a $1k vehicle.

As I wrote, I agree that cars lead to traffic issues and the entire eminent domain issue that Mel brought up strikes me as problematic - but certainly less problematic than that issue in the U.S. (witness all the grief Justice Souter received for his eminent domain ruling in "Kelo v. City of New London"). However, there are more than one solution to this - one could (and should) keep the hệm the way they are, narrow and car free. New urban planning should incorporate roads that handle four-wheeled traffic. You can have a car free urban center with rings around the city being designed to accomodate the forthcoming traffic. This is similar to what many European cities have or are doing.

The discussion is important, but let's get the facts straight first.