Home > Policy > The end of the pollution argument

The end of the pollution argument

Urban cycling advocacy is about to lose one of its biggest arguments for increased riding.  For years, advocacy has relied on the idea that cycling mitigates three problems: pollution, public health, and traffic. But the handwriting is on the wall for the pollution argument, in my estimation the most compelling of the three, the one that often makes politicians sit up and notice. Consider these trends:

Now, it’s true that the full impact of these trends won’t be felt for years, even decades. Electric cars now account for less than one-percent of overall sales, and renewable electric generation still comes in less than fifteen-percent of total production. But if history is any guide, politicians looking for excuses not to support cycling will find them where they can. For instance, the City of Beverly Hills is betting on a fleet of self-driving cars to solve the subway’s last-mile problem, even though such technology is still in development, and may not happen for as long as thirty years, and against arguments that the bicycle solves the last-mile problem cheaply. Similarly, I expect we’ll soon hear of politicians dismissing cycling’s ability to clean up our air, given how fast the car is approaching parity.

Cycling advocacy still has many arrows in its quiver. In any case, the loss of the pollution argument will also mean winning on the issue of cleaner cities, an improvement all around. But when our best arguments now often give us gains measured in signs and paint, we need to find other compelling reasons for city action. Will traffic congestion be enough? Is public health enough? Will other arguments for cycling infrastructure — like complete streets, vision zero, and quality of life improvements  — be enough?

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  1. livinginabox
    August 11, 2016 at 12:56 PM

    This subject is more complex than it appears. Electric vehicles emit more particulate pollution than equivalent ICE cars (1). Plus more fuel efficient vehicles and self-driving vehicles (2) are likely to increase mileage driven. I failed to find a reference for the relationship between more fuel efficient vehicles ind increased driving, but I do recall seeing one, but I can’t remember the specifics.

    One way to reduce emissions is to reduce vehicle mass, except bicycles, where improved aerodynamics (velomobile / streamliner) would probably outweigh the resultant increased mass, provided that cycling infrastructure would reduce / eliminate unnecessary forced stops. Also, every unnecessary forced-stop increase increases the effective journey length (3) for the typical cyclist by approximately 100 metres. It isn’t unusual for a commute to include, say a half-dozen to twice as many forced unnecessary stops. These can be particularly unpleasant in hot weather.


    (1) Non-exhaust PM emissions from electric vehicles
    Victor R.J.H. Timmersa, , , Peter A.J. Achtenb
    • A positive relationship exists between vehicle weight and non-exhaust emissions.
    • Electric vehicles are 24% heavier than their conventional counterparts.
    • Electric vehicle PM emissions are comparable to those of conventional vehicles.
    • Non-exhaust sources account for 90% of PM10 and 85% of PM2.5 from traffic.
    • Future policy should focus on reducing vehicle weight.
    Particulate matter (PM) exposure has been linked to adverse health effects by numerous studies. Therefore, governments have been heavily incentivising the market to switch to electric passenger cars in order to reduce air pollution. However, this literature review suggests that electric vehicles may not reduce levels of PM as much as expected, because of their relatively high weight. By analysing the existing literature on non-exhaust emissions of different vehicle categories, this review found that there is a positive relationship between weight and non-exhaust PM emission factors. In addition, electric vehicles (EVs) were found to be 24% heavier than equivalent internal combustion engine vehicles (ICEVs). As a result, total PM10 emissions from EVs were found to be equal to those of modern ICEVs. PM2.5 emissions were only 1–3% lower for EVs compared to modern ICEVs. Therefore, it could be concluded that the increased popularity of electric vehicles will likely not have a great effect on PM levels. Non-exhaust emissions already account for over 90% of PM10 and 85% of PM2.5 emissions from traffic. These proportions will continue to increase as exhaust standards improve and average vehicle weight increases. Future policy should consequently focus on setting standards for non-exhaust emissions and encouraging weight reduction of all vehicles to significantly reduce PM emissions from traffic.
    (2)February 25, 2016
    Driverless cars could increase reliance on roads
    (3) Why cyclists won’t stop – Chris Juden, CTC Technical Officer

    • August 11, 2016 at 1:15 PM

      The first article is behind a paywall. Is the particulate matter coming from dust stirred up as heavier electric cars travel? From increased tire replacement costs? Something else? Or is it the long tailpipe argument?

      I think cheaper driving costs will mean more driving, that relationship seems clear.

      • livinginabox
        August 11, 2016 at 11:32 PM

        I too only have the abstract. As to “Is the particulate matter coming from dust stirred up as heavier electric cars travel?”, I doubt it, since that’s not additional pollution released, merely redistribution of pollutants already in the environment. Plus the volume of air moved per distance travelled, would surely not be significantly different between an EV and its ICEV counterpart.
        Presumably, the pollution is particulates derived from the vehicle’s operation, from the transmission, steering, suspension, tyres, brakes etc., which are necessarily scaled to meet the demands of starting, steering and stopping the greater mass. It’s likely that the road-surface abrasion also plays a part in this pollution,

        What the paper suggests is that the pollution argument has likely not gone away. Nor does it seem likely that it will, anytime soon.

        Meanwhile, although off-topic, but related to this side-discussion involving vehicle mass. These EVs will present a greater hazard to other road users by virtue of their greater mass. Of course with regard to a cyclist or a pedestrian hit by a vehicle, this is a moot argument. It matters not whether the vehicle is a tiny car or a massive truck. Dead is dead.

        Michael Anderson
        Maximilian Auffhammer
        Working Paper 17170
        1050 Massachusetts Avenue
        Cambridge, MA 02138
        June 2011
        Heavier vehicles are safer for their own occupants but more hazardous for the occupants of other vehicles.
        In this paper we estimate the increased probability of fatalities from being hit by a heavier vehicle
        in a collision. We show that, controlling for own-vehicle weight, being hit by a vehicle that is 1,000
        pounds heavier results in a 47% increase in the baseline fatality probability. Estimation results further
        suggest that the fatality risk is even higher if the striking vehicle is a light truck (SUV, pickup truck,
        or minivan). We calculate that the value of the external risk generated by the gain in fleet weight since
        1989 is approximately 27 cents per gallon of gasoline. We further calculate that the total fatality externality
        is roughly equivalent to a gas tax of $1.08 per gallon. We consider two policy options for internalizing
        this external cost: a gas tax and an optimal weight varying mileage tax. Comparing these options, we
        find that the cost is similar for most vehicles

  2. livinginabox
    August 12, 2016 at 12:01 AM

    I don’t believe the particulate matter is related to the long tailpipe argument. Looking at http://naei.defra.gov.uk/data/gis-mapping, the UK Emissions Interactive Map, It’s pretty obvious that the road network is readily discernible from the Road transport emissions of PM10, PM2.5 and PM 0.1 emissions, So the primary hazard to health must derive from being close to a source – a busy road used by vehicles. I didn’t directly establish the distance that PMs can travel, but given the fact that that roads are visible via the particulates emitted by vehicles, it seems reasonable to infer that the particulates cannot travel very far. The long tailpipe argument is essentially a side issue.

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