Think Motorcycles and Scooters are Great for the Environment? Wrong!

by Benjamin Jones on September 1, 2008

A lot of well-intentioned people have hopped on to motorcycles and scooters recently in an effort to do their part to help out the environment. Sadly, they’re actually polluting a lot more on even the smallest of scooters than they would be driving a car. It seems counter-intuitive because there are so many reasons why two wheels should be better than four:

  • Scooters and motorcycles get better gas mileage
  • They’re smaller, so they use less materials to produce and ship
  • They’re extremely popular in European countries and Japan, which are more eco-friendly than the US

While these things are true and often advertised, they don’t quite paint the whole picture when it comes to the environmental impact of 2-wheeled, motorized transportation.

Scooters and motorcycles can pollute 90 times as much as SUVs

Yes, you read correctly. It doesn’t seem to make sense because of the wildly different sizes and fuel consumption of the two vehicles. In fact, it was the EPA that tested a Yamaha YZR R6 and found that it emitted 90 times more hydrocarbons than a Dodge Durango SUV. Hydrocarbons are the pollutants responsible for forming ozone and smog, which is both a serious health risk as well as an extreme eyesore.

The reason why scooters and motorcycles pollute so much more is because there is much less regulation when it comes to these vehicles. Technical and market restrictions have made it difficult to pass legislation cleaning up motorcycle tailpipes for years. For example, because most motorcycles and scooters are smaller and cheaper than cars, adding modern catalytic converters and emissions systems would add a tremendous amount of weight and cost to most 2-wheeled vehicles. This means that, unlike cars’, motorcycle and scooter exhaust is heavily polluted.

Another consideration is the large amount of two-strokes that are still used and sold. Many manufacturers, like Honda, have made plans to completely phase out the use of two-strokes, but because they are cheaper they will continue to be sold in quantity until legislation can be passed banning them from use. Two-strokes pollute so much more because they run on a gas/oil mix, meaning that every combustion cycle is burning motor oil as well as gasoline. Similarly, the engine’s design allows unburnt fuel to escape through the exhaust and into the air.

Many wealthier nations are starting to place tighter restrictions on motorcycles and scooters as the technology becomes cheaper and their emissions make up a greater percent of total vehicle emissions. However, in countries like Canada new 2-wheeled vehicles can still pollute up to 14 times as much as automobiles, so there still is no perfect solution.

To scoot or not to scoot: a balancing act

If you’re a diehard environmentalist you’re going to want to stay away from scooters. I know from my time as a Honda Metropolitan owner that most riders would get between 90-110 mpg, but I also know that they exhaust was pretty smelly, even though it was a four-stroke Honda.

On the other hand, however, you’d be getting 2-4 times the fuel economy and emitting fewer green house gases. However, the magnitude that these are reduced is tremendously outweighed by the magnitude that smog-forming pollutants are increased. Nevertheless, you will save money on gas, but riding a scooter isn’t quite as safe or air-conditioned as a car.

Personally, I ditched the scooter in favor of my bike for shorter trips and a car with good fuel economy for longer ones. You’ll have to make your own choice, but make no mistake, scooters and motorcycles are not the most environmentally sound transportation choice.

For more on the issue, check out this LATimes article.

EDIT: Thanks for the heads up from a commenter, because I obviously didn’t make my intention clear enough. As the commenter points out, there are clearly more ecofriendly scooters out there than others, just as there is a huge variety in cars. Hell, you can even get electric scooters (just as you can get electric cars), so it’s not that 2-wheels is evil.

Rather, I wanted to point out that emissions regulations are clearly lagging and that, in studies, 2-wheeled transport contributes more smog-forming pollution than it’s share of actual vehicle miles traveled because the average motorcycle/scoot has worse emissions than the average car.

If you liked this post, sign up for out RSS Feed for automatic updates.

Popularity: 30% [?]

{ 75 comments… read them below or add one }

51 Claude September 3, 2008 at 8:21 pm

Another problem with the catalytic converter is the heavy metal compunds released as vapors when they get hot. Eventually they lose too much and the matrix breaks down, then the cat has to be replaced.
This problem doesn’t apply to the stratified combustion engines like the Honda CVCC. It might apply to the CRX, which has been out of production since ’91, so it’s probably a pretty dirty engine by modern standards.
So what’s the difference in total emmisions by weight per mile, rather than parts per million? I push a lot fewer millions than a Hummer.

52 Christopher Harley September 4, 2008 at 9:58 am

Honda’s GX35 and GX50, 4-stroke engines, reduce hydrocarbon emissions to 1/7 those of typical 2-strokes. At work in a motorized bicycle (not a moped or scooter) this incredibly efficient and ultimately cleaner engine can deliver both rider and payload. The future of commuting deserves practical designs that strive for optimal efficiency. That’s why I’m building-out an Electra Townie, stretched with the ExtraCycle, driven by the Honda GX35 to a NuVinci CVP Hub.

53 Ricky Willems September 4, 2008 at 11:19 am

Most catylitic converters are now straight through pipes, and on cars with 200 horsepower, cost only 2 horsepower to have in place.

When they first made their way into cars, the exhaust had to push through a mesh of catalyst, which caused a huge increase in back pressure. Now catalytic converter technology has evolved to the point where it has -minimal- (not non existent) impact on performance. Performance in this regard can be directly related to economy, so lets say it has a grand impact of 1%.

As for weight, a series of catalytic converters weighs at most 50 pounds, which would have very minimal impact in an average 3000 pound vehicle.

As for emissions from catalytic converts, the catalyst does slowly exit the tailpipe to some degree, but not in the form of noxious gases. There have actually been organizations who go to road ways to harvest the expelled platinum from peoples tail pipes.

In regard to lean burning cars, there are stumbling blocks to them, but not ones that can’t be overcome. Also, their is no reason that Catalytic converters for lean burning engines could not be developed.

Anyway, I stand by the fact that a Catylitic Converter does not make a -sizable- impact in performance, and that with the engines companies are running today, they are well worth the very, and unnoticeable small drop in economy.

54 Neil September 5, 2008 at 3:27 pm

Moderator , my sincere apologies I have noticed another mistake, this will be my last attempt to get this post right. (please remove this paragraph!)

Re. Catalytic converters. Cats are only straight through pipes if you consider a ‘honeycomb’ of pipes, straight through? This honeycomb massively increases the amount of surface area in contact with the gasses with a concomitant rise in drag (see the Coanda effect and fluid shear) This also completely ignores the fact that it is given a rough coating to further increase surface area which then also produces turbulence with a proportional rise in drag. This honeycomb also has a deleterious effect on the standing wave and other useful harmonics in the exhaust pipe which would otherwise be tuned to more effectively scavenge exhaust gasses at the most useful engine RPMs and reduce the work imparted by the flywheel thereby freeing more energy available at the crank for propulsion.
THE INTERESTING BIT
But anyway let’s take your optimistic, 2 horsepower 1% figure on your 200hp family? car, Average mileage 12000 miles per annum at an optimistic 40mpg this works out at an extra 3 gallons a year burnt just because of the drop in engine efficiency (there is more loss I’ll get to) so with America as an example having: 62 million registered vehicles and 6.4 million unregistered functioning vehicles (total 68.4 million) ok, you see where this is going? Let’s be really conservative and half this number to 34 million and multiply by our three gallons we get 102 million gallons burnt just BECAUSE OF CATS in the US alone (remember we have been conservative every where here).
Now your 50lb cat on your 3000lb vehicle equates to one and a half percent of the vehicle’s weight (rounded considerably down) and if you ever watch your economy meter in instantaneous mode, cruising at constant speed on the flat gives say 100mpg, due to wind resistance and friction, so our 40mpg average is due to acceleration of the vehicle mass, in other words 60% of the fuel is used for acceleration, so on our 12000 mile 40 mpg car (300gall/year) 60% goes on acceleration (180gall) and 1.5% of this is a further 2.7 gall. So let’s say 2.5 gall times our super conservative 34 million vehicles is a further 85 million gallons just because of the weight of the cat. We now have a super conservative ABSOLUTE MINIMUM 187 Million Gallons of fuel burnt in the US alone JUST BECAUSE OF CATS!!!!!!!!
This does not take into account manufacturing and disposing of the cats (remember the environmental study mentioned in my previous post?) so this figure is almost certainly higher in reality and could be several times higher???
There are also all sorts of other polluting issues with cats due to how they work and the metals used, which if you like we can go into on another occasion? As I am sure you are wearying of this as am I.
Any way do you still think cats are better than going lean burn and less of everything (only if you profit from cats you do!) As I said in my previous post cats are to do with big business and profit, and nothing to do with environmental issues, this is merely the lie used to sell them because superficially they can easily be made to sound good and it is difficult to explain why they don’t really work!

55 Ricky Willems September 5, 2008 at 11:09 pm

Neil,
This is really becoming an interesting conversation, but I think its getting out of hand for a board like this. I’d rather not post an email here, but its my name at gmail. I wouldn’t mind turning this into an article.

Anyway, here are a few other things to think about. Firstly, think about the junk that people tend to carry in their cars, the extra 20 pounds around the waist, the stereo systems, the air conditioners, the 6 way climate control. All of these have considerably more impact on both weight and fuel consumption that a catalytic converter system.

As for exhaust inefficiencies, although high performance exhausts are nice, smooth, free flowing pipes, average automobiles are not equipped as such, and the straight through (though still slightly drag inducing) cat is the least of their worries. A new muffler would have far greater impact.

Also, unfortunately very few vehicles get 100 miles to the gallon out on the open road, or even 40 for that matter. Having driven many different cars at constant highway speed for hours at a time, lets say a 40mpg car would get 50mpg out on the highway, and for the whole trip might average 48mpg. But that’s just an aside.

Now as for lean burn tech. Again, it’s great, I’m not knocking it. But something I find very ironic is that lean burn engines, while they take less fuel to operate, produce far more NOX emissions, and require more complicated catalytic converter systems than regular engines to operate with similar emissions.

The other thing I find interesting, though I’m speculating here, is that I would imagine that a lean burn system, while being more efficient and using less gas for a given output, would require a larger engine for a similar amount of power to be produced. That may be a non issue with regard to the benefits, but it would certainly mean more weight to carry around in the vehicle.

Again, it’s not a matter of whether cats hurt fuel economy, they do, but less than under inflating your tires or rolling down your windows would. The question is, for the sake of gas mileage, is it worth it to spew millions of extra tons of toxins into the air? Isn’t a 85% drop in exhaust emmisions worth the little extra gas? (and yes, I am saying that on a grand scale, 187 million gallons of gas a year is “a little” since we use 3.8 billion gallons per -day-. That 1/100th of a percent difference in gas you know )

56 douglogic September 6, 2008 at 9:00 am

I think if you like driving an SUV, drive it. If you like riding a scooter, ride it. If you enjoy riding a bicycle, ride it! However, please do not make those choices based on the false impression that you are somehow saving the planet. Global warming is a hoax perpetuated by people like AlGore who fly around in their G5 corporate jet while guilting you to ring your hands over whether you should drive a car, ride a scooter or ride a bike. Go enjoy your life and free yourself from the fantasies of charlatans.

57 Reality bytes September 6, 2008 at 1:16 pm

Douglogic,

Global warming is a hoax? Wow. What makes you say that?

58 Neil September 6, 2008 at 4:15 pm

Ricky,
You are still missing the point. the cats are burning fuel that does not need to be burnt. and there is the problem of the cats themselves, you keep ignoring the environmental impact of making and disposing of those too, and they by legislation are fitted to every car, your rather facile argument of people carrying an extra 20 lbs of weight around their middle is kind of stupid, as there are a lot of underweight or small people too but besides that the point is the vehicle is their transport, that is what it is for, to carry them and their fat around! then you have the cheek to finish the paragraph saying: “All of these have considerably more impact on both weight and fuel consumption that a catalytic converter system.” Aircon does, 20lb exta weight doesn’t. Aircon although extravagent is there for the comfort of the passengers, which is what the car is there for too, they dont have to have a car, it just makes life so much easier.
As to the high performance exhaust statement, cars are fitted with high performance exhausts because manufacturers are competing against each other for fuel economy and performance, so exhaust systems usually have an expansion box type silencer, which acts almost like the end of the pipe (pressure wave reflecting off free air) this is the same reason that air intake boxes are so big, and the Cat has to be fitted much closer to the engine than the first box is which is another reason it mucks up the resonance.
So Im sorry the new muffler will not have a far bigger impact than a Cat, quite the reverse.
Sorry didn’t understand what you meant when you said very few vehicle get 40 mpg but that it averaged 48?
You keep refering to lean burn, as though it is somehow deficient! The technology already exists fully fledged! and does not require bigger or heavier or noisier or strange engines in any way, it just requires the appropriate legislation.
Re. the Nox emmissions, yes all high temp combustion produces it, are you going to fit Cats to jet engines?(which makes the amount cars use look silly) Also lean burn engines produce negligable amounts of the highly toxic carbon monoxide less carbon dioxide and negligable amounts of unburnt hydrocarbons, so when you tell the whole story, it doesn’t sound quite so ironic does it? Also as I said in a previous post, lean burn engine (NOx) emmissions are not nearly as bad as the pro cat lobby implied. And Cats give off hydrogen sulphide and ammonia amongst other things, so choose your poison, Quite apart from the large list of heavy metals that they contain!
And your final comment about what cats use being a drop in the ocean with the implication so why worry, is exactly the sort of attitude that got the world in the mess it is in, so leave those lightbulbs burning in the rooms you are not in, after all what difference does a 60 watt lightbulb make, I mean, it would have to be on for nearly seventeen hours just to use one unit of electricity, such an insignificant amount?

59 Ricky Willems September 7, 2008 at 10:10 pm

Hey Neil,
Again, I’d like to continue this, but I think email might be a more appropriate way to do it? If you email me at my name (rickywillems) at google mail then we can continue without highjacking this poor guys post any further.

60 Charles Overstreet September 8, 2008 at 2:33 pm

I think your nuts. Your can’t put all scooters in the same classification. Have you ever heard of a Vectrix Electric Scooters. No exhaust, no oil use, no belts. No hydrocarbons.

61 marvingalaxy September 9, 2008 at 2:48 am

I live in Hawaii and 4-stroke scooters are rare. Oddly, the only one I have found for sale was a generic Chinese model. Except for the almost non-existent larger scooter-body motorcycles, all the <50cc scooters here seem to be oil burners (2-stroke) and about half of the thousands of these on the road every day have loud muffler modifications.

Perhaps California has different regulations, but we have thousands of these 2-stroke nightmares here keeping people up at night and stinking up the city.

62 ravinglunatic September 13, 2008 at 10:25 pm

Perhaps it bears repeating that if we were cut particulate emissions too quickly, it is possible to lose the cushioning effect that global dimming has had. This may eliminate or reduce its estimated climate forcing effect of ~−2.7 ± 0.9 W/m against the Forcing effect of global warming @ ~4.3 ± 0.6 W/m2, or net effect of ~1.6 ± 1.1 W/m2. In layman’s terms, this means a significant loss or reduction in the dimming forces can result in accelerated warming, as those emissions are easier to eliminate than warming forces. I have included a link to article I have based my comments on.

http://www.pnas.org/content/98/26/14778.full

63 Neil September 14, 2008 at 12:58 pm

That is a very interesting point, and is born out by the instantaneous temp rise that occurred after 9/11 when the majority of air flight was cut!

64 Bart Jannis September 17, 2008 at 5:14 am

Al motorcycles that are sold in Europe have to be EURO3 and from 2010 they have to be EURO4. The Californian emision standards aren’t even EURO2

65 Wayne October 11, 2008 at 12:03 pm

I didn’t read all 68 replies, so someone may have already pointed it out.

While HC and CO emissions may be higher, because of the lack of a catalytic converter on many models, CO2 (greenhouse gas) emissions, are much lower per mile travelled, as compared to a automobile with a single occupant.

66 Allan Hardy October 14, 2008 at 12:53 pm

Electric vehicles are the way forward. Okay cars are not there yet, but electric scooters can match their gasoline counterparts. They now go up to 62 miles per hour and have a range of between 30 and 60 miles. I guess what we really need is for ‘battery stations’ where you can swap your dead battery for a live one. They’re already trying this in Denmark and there’s a scheme to be launched in Hawaii.

67 Alex January 28, 2009 at 10:56 am

I had no idea how much motorcycles had such a big impact towards r earth…i always wanted 2 ride 1 be4 and i finally did it was fun..but is it worth it. There dangerous towards accidents and the enviroment :0 i’m doing a project on how motorcycles have a impact on the enviroment… and they really do…thanks 4 the info :)

68 Basisrente March 24, 2009 at 9:10 am

Really nice scooter! ;)

69 Charles April 18, 2009 at 10:03 pm

The President is only interested in the CO2 emissions and not the other pollutants that come from motorcycles. CO2 emissions cause global warming. Automobiles are a major problem to CO2 emissions. If the President thought more CO2 emissions was created by scooters, well he would be stricter on scooter manufacturers. But he is not.. Why is this? Could be because in 2010 all motorcycles and scooters manufacturered will have catylatic converters on them? That the EPA has already made this mandatoy? In 2006, my Bali 250 was required by the EPA to have a catylatic converter on it. If this be true, my scooter is cleaner burning than a car. Read it on the EPA under motorcycles and scooters. Now a 2 stroke engine is bad on the enviroment, but my Bali 250 is a 4 stroke. So to say the scooter is worse than a car maybe actually false. And I get better gas milage than the 2010 Chevy Volt hybrid on my Bali 250. The Chevy Volt on the electric end only travels 40 miles per charge and converts to gas getting 30 mph or better( but I bet most Chevy Volt’s get 30 mpg).

70 Your worst nightmare June 10, 2009 at 7:47 am

hi
WHAT IS YOUR PROBLEM!!!!!
i am a hardcore motorcycle rider! a two stroke rider as a matter of fact.
i have done studies. many many studies. Two strokes aren’t as bad as you think!
yes they burn oil, but its a special oil. not motor oil.

SO IF YOUR GOING TO MAKE A WHOLE f@#$ING ARTICLE ABOUT MOTORCYLES.. LEARN THE FACTS BEFORE YOU POST!!!!!

if you have any complaints or would like to tell me why motorcycles are soo bad.. i would love to hear about it. please e-mail me if you think you can prove me wrong.
speedydemond05@yahoo.com
ps: stop closing down my trails!!!!

71 Austin Tucker June 10, 2009 at 8:54 am

hi
i really think who ever wrote out this article, has very little idea of what he/she is talking about. Yes, two strokes are more pollutant than four strokes. Will not deny this fact. I ride a two stroke.(two smoker) I have seen the smoke/exuahst it puts into the air, but i think the writer is missing the point. If my dirt bike (2005 honda cr 85r) can get around 40 mpg and an suv around 15-20mpg’s… can you please tell me who is more pollutant? Im 15 but when i was 3 i knew that 40 is bigger than 20.
A scooter that is 2cycle gets around 60 mph’s. I ride a racing motorcycle, but i dont ride it every day. A SUV will be driven almost every day. So please correct me if im wrong but, SUVs are using ALOT more gasoline than motorcyles.

So the part in the article that says two strokes are so pollutant because they burn motor oil. Thats about 50% accurate. Yes they burn oil, but it is a special kind of mixing oil, not motor oil. The 2 cycle mixing oil is (not a 100%accurate guess but pretty dang close) 60% less pollutant, it is a cleaner/leaner burner than motor oil.

And to the writer of this article, please email me where you found your information. I would love to correct them to.

ps: To the offroad riders and anybody else that wants to help the issue please help me in keeping our orv parks and our riding trails open. Lets beat these people that have stolen our riding areas. OUR RIGHTFUL RIDING AREAS. So if you want to help me save our areas and SHUT THESE ENVIORMENTALISTS UP! please visit any website or club to help keep us on the trails!
If you have any questions or arguments, i would love to hear em.
speedydemond05@yahoo.com
thanks

72 Jacob Aziza August 19, 2009 at 10:53 pm

This was mentioned once among the 70 something comments, but I’m not sure how well it was understood.

The standard test for auto exhaust does not measure the “amount” of pollution an engine emits.
It measures the percentage
ppm stands for parts per million; in other words, of 1 million units of air, how many units of a given pollutant.

The test does not take into account how much total exhaust is flowing.

If a vehicle gets twice the mpg an another, but also produces twice as much pollution in ppm, then driven over a given distance both will emit the exact same total amount of pollutants.

Therefor, the larger the engine, the more total pollutants it can emit while still having low numbers on the test.

73 J.Nicol December 8, 2009 at 3:52 am

bikes and scooters are far better for the environment than cars as cars take up more space and have larger fuel tanks which means that cars give out more CO2 emissions as they consume more fuel. the people who say that bikes are bad for the environment are WRONG, it also helps to resolve the hunt for parking spaces big enough for wide cars or people carriers. i thinkpeople need to reconsider how they see the environment being impacted first before judging what affects it and what doesn’t. at the end of the day everything affects the environment in some way but bikes and scooters are the least ones that affect it. i would know, my dad was a bike mechanic and my sister is one now, i’ve been on bikes since i was 8 years old and am now 19, i know a bike inside out, and my mum is also a biker, we have friends who are bikers and bike mechanics as well. BIKES ARE THE LEAST THINGS FOR AFFECTING THE ENVIRONMENT. end of.

74 ritasloan November 18, 2010 at 11:40 pm

E-scooters are more enjoyable and fun fetching that even elders finds the chance to use it, as it is adjustable to any height. Now we can say it is the desire of the man of any age. With these scooters, one can ride on the plane roads or off roads; it has added one more kind of fun in life’s of today’s trend. Electric Scooter is smaller, light in weight and requires less parking place.

75 donate car canada November 22, 2010 at 4:30 pm

why don’t you just guys jog or do bicycle for a change… you talk about pollution control and emission lessening tool but in real life you drive a drinker and a belcher… scoot or car you still smoke, except those electric one and hybrids but the point is, still carbon footprint is emitted by these…

Leave a Comment

{ 6 trackbacks }