Faster Cars = Better Air Quality?

One of the fundamental “claims” of the Columbia River Crossing is that by reducing backed up traffic, air quality will improve. This week’s PSU seminar tackles whether that assumption in transportation projects holds true.

Portland State University
Center for Transportation Studies
Spring 2011 Transportation Seminar Series

Speaker: Alex Bigazzi, Portland State University

Topic: Can Congestion Mitigation Reduce Emissions?

Abstract: Policy-makers, researchers, and activists often assume that traffic congestion mitigation results in reduced motor vehicle emissions without proper justification or quantification. This research investigates under which conditions that assumption is valid by comparing trade-offs between increased efficiency and induced travel. Analyses include investigation of varying vehicle fleets – including advanced-drivetrain vehicles. Results demonstrate that higher levels of congestion do not necessarily increase emissions, nor will congestion mitigation inevitably reduce emissions. These results apply for both roadway capacity expansions and traffic flow improvement projects. We compare the emissions effects of various congestion and emissions mitigation strategies, with particular attention to the roll of trucks and the potential of truck-only facilities. Congestion performance measures are also compared for applicability to emissions trends.

When: Friday, June 3, 2011, 12:00 – 1:00pm

Where: PSU Urban Center Building, SW 6th and Mill, Room 204


6 responses to “Faster Cars = Better Air Quality?”

  1. No, such measures may not dramatically improve air quality. But there are a lot of emerging technologies in the pipeline that will. Check out the Green Car Congress for hundreds of them:

    We need a sensible rail freight plan for long haul delivery (which would improve the safety of our interstate system)—– and environmentally-friendly solutions for local commercial vehicles. To me, something worse than the exhaust of diesel engines ( as they are presently configured for our commercial fleets) is the NOISE, which unless you are several floors above the street, can be a real drawback to living in an urban environment. BTW the lead article today on GCC is about a methane-diesel Volvo truck engine, but I thought Ford Co. was moving ahead on their fuel efficient gas engine, the “BobCat” which I’m sure would be far quieter than ANY diesel engine.

    As far as a congestion strategy, there is something to be said for added road capacity. Even if emissions are not reduced, a person’s time is still valuable, and that goes for people who might be riding a public transit bus, too. The saying “can’t build your way out of congestion” would hold a lot more credence within a slower growth strategy. Then it wouldn’t make a lot of sense to put in roadways that would end up seeing little use.

    I have no idea of how EPA regulations affect cleaner-technology commercial engines. I’m still trying to get to the bottom of why fuel-efficient engines sold in other parts of the world can’t break into the US market. I guess it is not only the EPA, but state enacted restrictions such as in California and New York.

  2. Ron,

    For diesel engines, yes, you are correct. The U.S. does not have consistent policy, so European makers have to modify engines for the U.S. market. For gas engines, I believe it is simply the market. Consumer preference is starting to shift, but it’s going to take a while. Horse Power and associated male compensation are still driving factors here.

  3. And not only is it that the governmental policy of states like CA and NY would restrict vehicles that while fairly clean do not meet the ppm standards, it is also the factor that these are huge consumer markets, so manufacturers don’t want to promote a product that cannot be sold there.

    However, I am seeing now that the new Volvo plug in hybrid diesel –the V 60—is claiming 124 mpg?? and a 36 mile full electric range. Shouldn’t state laws and EPA regs accomodate this?

  4. New EPA regs just coming out allow for plug-in vehicle mileage ratings and comparisons.

    Note that when a plug-in hybrid or full electric vehicle claims “124mpg”, what they usually mean is “124 miles per gallon equivalent” in the test driving cycle, with the electricity consumed and gas consumed converted to BTU and then stated as though the total BTU came entirely from “gallons” of fuel.

    Although this seems convoluted and is not without it’s problems, it does allow ballpark conversions between different types of vehicles in terms of total energy usage, if you don’t care much about the source of that energy.

    As to why we don’t see many Diesel hybrids here, it may just be that the cost payoff isn’t there yet. Building a “clean Diesel” engine costs more than a “dirty” one, and building a “hybrid” of any variety of engine costs more. So a clean Diesel hybrid has a lot more up-front cost than either a clean Diesel-only, or than a gasoline hybrid.

    In terms of lifetime costs justifying the up-front expense, a number of (but not all) gasoline hybrids became viable based just on costs when gas approached the $3 range. We may not be there yet for clean-Diesel hybrids.

    (There’s other factors to consider beyond merely cost of engine and cost of gas when it comes to the benefits of hybrids, but unlike the early days of hybrids, more than one or two models are able to make legitimate lifetime cost savings claims.)

  5. How the fuel economy is rated is different than the parts per million standards for the exhaust emissions. Which, to my non-expert knowledge, is currently a stumbling block. But I’m not the expert on how all of those regs. (including the state ones) might be limiting the saleability of high mpg European cars in the US—-or discouraging Ford from selling their 65 mpg diesel Fiesta here. It is being sold in Europe and Australia, but there are also safety regs. in the US that apparently have an effect, too.

    The new Ford Fiesta is good-sized, though, comparable to the Focus of the last several years. The new Focus is being evaluated for several modes—-so it is probably just a matter of time when they bring a high mpg version on the US market.

    (But if I ever bought one it would have to be from the auto wreckers—and not a brand new one. Just like my “new” 2004 Saab SS–that had been in a front ender.)

    I did know about the equivalency rating. Battery tech. seems to be progressing as my post in the open thread covered some new German technology that powered a small Audi-like car for 450 km. We’re getting there—as the Green Car Congress articles show. Any car owner would have to evaluate how the potential fuel savings would benefit them. Some people might be in electric mode the vast majority of the time—so there equivalency rating would be pretty high.

    The plug in diesel hybrid is only one of the new innovative configurations. Split cycle, Scuderi design is supposed to a fuel saver. Then, there is the “shock-wave” internal combustion engine:

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