Motorcycles Create More Greenhouse Gas Emissions than SUVs

Hi Romedeiros1970,

I agree, that motorcycles and SUVs are both "huge offenders" in terms of GHG emissions.

The study used a occupancy rate of 1.46 passengers for SUVs. You can find this number on page 10 of the report under the LDDT column on the chart. In the beginning of the report they state that SUVS are assumed to have the same characteristics as light duty diesel trucks (LDDTs). All the data is normalized by the value for cross-comparison purposes.

With that being said, you do make a really good point. When I see SUVs on the road they are often only transporting 1 person and from what I observe, there usually isn't a bunch of cargo from the Home Improvement Store or Costco in the back to justify the explicit use of the vehicle class!

Passenger Miles Travelled figures are published by the department of transportation and those values are used by this study.

If the study had used the 1 passenger per vehicle value for SUVs like they used for sport bikes, then SUVs would have come out much much worse on the charts.

Thanks for your observations,

Matt

You have good point Simplefulllife.

Motorcycle riders in N. America, especially sport bike riders, tend to drive very aggressively.

Sport bikes are primarily used for recreation and are produced in relatively low numbers compared to sedans or popular SUV models. Therefore, the bikes can't spread their production footprint across large production volumes.

Like many things eco, economies of scale often yields great efficiency.

-CarbonPig

Hello UndeadByDawn,

Here are a few articles that reference the dog study you were likely referring to:

http://www.newscientist.com/article/mg20427311.600-how-green-is-your-pet...

http://www.google.com/hostednews/afp/article/ALeqM5iff46ra1X3B9m0rMediJS...

http://news.yahoo.com/s/afp/20091220/sc_afp/lifestyleclimatewarminganima...

Thanks for the heads up, 

Matt

The "lifetime" estimates include a whole group of factors additional to tailpipe emissions. These factors include vehicle manufacture, along with less obvious things like assessments for roadway construction and highway lighting.

Even the operating emissions are curious and make sense only in light of differences in use patterns determined by the Berkely authors. For example, greenhouse gas emissions associated with driving a motorcyle over its lifetime were 15 mt for the 2-cyl bike and 16 mt for the sport bike (pages 34 & 36). How could they be so close? The 2-cyl was driven 75,000 miles, while the sport bike only went 60,000 miles, and the 2-cyl got 45 mpg while the sport bike got 33 mpg (pages 8 & 9). So 1666 lifetime gallons of gas for the 2-cyl and 1818 gallons for the sport bike, which makes the lifetime emissions from driving closer than I would have suspected. If you said the 2-cyl got 60 mpg and the sport bike 40, the difference would be larger but not much larger.

The inclusion of non-operating emissions makes this an interesting report, and I was happy to see it linked here.

Hi vw-traveller and Lars2885, 

The title of the chart gives the units of the y-axis, which are in mg/PMT. Sorry the graph doesn't contain the units. I think the font is the same color as the background of the chart, so you can't see them.

Anyhow, you bring up an interesting point about fuel injection. How would fuel injection change the emissions profile? Forgive my lack of knowledge on this aspect.

Motorcycles do get good mileage on a per gallon basis. A lot of the life cycle emissions come in at the manufacturing stage. 

I think that it would be great if we moved towards widespread use of light electric vehicles that were battery powered and charged by renewable resources like wind. 

Thanks for the comment, 

Matt

Hi Motorcyclist!

True: Motorcycles do get driven much less; generally.

I really like your point about pushing the manufacturers to improve their operations; especially on the manufacturing process, where a significant portion of the life-cycle emissions are accounted for.

We don't want to give up our freedom in the long-term, but maybe in the short term we'll have to limit our use of motorcycles to send a message to the manufacturers.

Ride On,
CP

Hello Just an Island Girl, 

Mopeds emit more greenhouse gases (GHGs) than motorcycles believe it or not!

Despite getting really great mileage, the way that they burn fuel is highly inefficient and polluting. In an article titled Air Pollution: Asia's Two-Stroke Engine Dilemma, published via the National Institute of Environmental Health Services, Carol Potera points out that, "...two-stroke engines burn an oil–gasoline mixture, they emit more smoke, carbon monoxide, hydrocarbons, and particulate matter than the gas-only four-stroke engines found in newer motorcycles."

Aminu Jalal, an engineer for the Nigerian National Automotive Council, presented some to-the-point power point slides on the technical disadvantages of two-stroke engines compared to four-stroke engines at the the Nigerian Conference on Clean Air, Clean Fuels and Vehicles, which was hosted in Abuja during May of 2006, that are easy to understand for non-technical folks.

You mentioned you know me. Who are you Island Girl? Contact me. 

Eco-Mindedly, 

Matt