Choosing Your Ride

August 7, 2017

In a recent post I extolled public transit as a way to cut personal fuel use, emissions and expenses, for those few Americans who can use it. But I had to think hard about that view after reading two well reasoned rebuttals, from Paul in Madison, Wisconsin, and Vince in Austin, Texas.

Vince pointed out that transit buses use more fuel and generate more emissions per passenger-mile than automobiles, and recommended car pooling as the best all-round approach for most Americans. Paul decried the inconvenience of using public transit, and noted that it was mostly financed by taxes rather than fares.

Both readers said average car ownership expenses were higher than necessary, exaggerating the “Car Tax” (the nearly mandatory expense of operating an automobile.) Paul concluded that car ownership wasn’t that much more expensive than using transit- if available- and was well worth the extra cost. Vince reported his auto expenses, commuting in a 1995 Oldsmobile, as much lower than any transit alternative.

Let’s look at these points in detail, with this key question in mind: What’s the best transport choice for an individual American who wants to make the necessary trips but also wants to conserve fuel and reduce emissions- without moving house, without selling or trading cars, using the existing road network and existing transit systems?

Obviously, most of us need access to an automobile for the daily necessities of life. A few can get by with walking or cycling. A minority, in major metropolitan areas, can use extensive public transit systems with frequent, reliable service. Outside those areas, many cities have transit systems, usually bus lines, providing limited service.

Transit buses use more fuel and generate more emissions than passenger cars or personal trucks, on a passenger-mile basis, as shown in the following table. (Emissions are not shown here, but fuel use is a close analog.)

The light loading of transit buses- nine passengers on average- kills their efficiency. Loads were higher in the 1970s and 1980s, averaging 12-13 passengers. If buses were always fully loaded- in some hypothetical world- they could achieve about 160 passenger miles per gallon (Note 1). But an average car with four passengers- typical for commuters in a car pool- gets around 95 passenger-mpg.

Car pooling takes significant organization, but is a vast improvement over driving alone (like 90% of auto commuters today). And it’s potentially available to every auto commuter. It eliminates travel to and from the transit stop, saving some trouble during bad weather. Vince called it “..the absolute cleanest, most efficient and economic mode of commuting..”

But if you can conveniently use public transit for a given trip- whether to work or some other errand- it makes an even better choice. A scheduled bus is going to run, whether you ride it or not. If you choose it over your automobile, you save all the fuel you would have used and the emissions you would have generated. With one more passenger, the bus will burn a little more fuel, but only a tiny fraction of what your car would have burned.

If you choose public transit over a car pool, the same considerations apply: you’re saving a large fraction of the fuel the car would have used and the emissions it would have generated, at the cost of a minuscule increase in the buses’ fuel use.

This logic only fails if you happen to be that one additional passenger who convinces management to put a second bus on the route. It’s highly unlikely- there’s always room for jello, and for one more passenger on a transit bus. In actuality, buses tend to be lightly loaded, and every additional passenger makes them more efficient per passenger mile.

Both car pools and public transit help to reduce traffic congestion. The bane of the traffic engineer is the single occupant vehicle. A bus passenger, with his “share” of the buses’ footprint, takes up 4 times the space of a pedestrian on the roadway. A parked car takes up 70 times as much. (For moving vehicles, the multiples increase.)

Buses cause more wear and tear on highways than cars, but if a large segment of auto commuters changed to public transit (or car pooling), it would reduce the need for road and bridge expansions. It may be cheaper to do extra maintenance on a six-lane highway than to enlarge it to eight lanes.

Can you save a bundle by not paying the Car Tax? Paul thought my value for the yearly cost of operating a car was high, though it came from a well documented survey. Vince demonstrated with his own figures that he could keep his car expenses at about $1,000 a year. The national average is about $9,000. And as Paul demonstrated, if you allow for more than a minimal number of rides a week- say 16, for eight round trips- the typical $2 fares will cost nearly $6,000 a year. So the savings are not fantastic.

However, a few thousand makes a big difference if you’re in the same income bracket as the average transit commuter in my county or in Orlando: under $15,000 a year. So does the reduced risk: if the bus breaks down, you won’t have to fix it or pay for the repairs.

Are you depending too much on other taxpayers if you use public transit? On the average, fares pay for only 36% of the cost of public transit; taxpayers cover the rest.

This “farebox ratio” is better in more heavily used systems. The best in the US is San Francisco’s BART system, 75% financed by fares. Some of the highest in the world, 100% or more are found in Hong Kong and Singapore, densely populated cities where nearly everyone uses the transit systems.

Our transit systems have a lot of room for farebox ratio improvement, with an average of nine passengers riding a 50-passenger bus. If the ratio is 36%, just increasing the average load to 13 passengers, like it was in the 1970s, would raise the farebox ratio to 52%. Hypothetically, if the buses were half full on average, the ratio would be 100%.

We depend on taxpayers for streets and highways, too. The average household pays about $1,100 a year in state and local taxes for road construction and maintenance. They also pay about $980 a year in gasoline taxes, mostly federal. Though there’s some overlap in those numbers, if you think of gas taxes as our “fare” for using the system, the highway system’s farebox ratio may be around 50%. Certainly it’s nowhere near BART’s. (Transit buses use the system too, of course. And pay plenty in gas taxes.)

Toll roads vary, from some that pay for themselves to others that don’t even earn back the cost of collecting the tolls. I haven’t found any national averages.

Is public transit too inconvenient for practical use? Maybe “inconvenient” is too mild a term. Paul complained of “..the staggering non-monetary cost of transit”:

“It takes 60-120 minutes including walking, random waits and transfers with more and lengthy waits, to make a 20-minute trip. It crawls along with an interminable stop every couple of blocks. It leaves the rider drenched and sticky from hiking in blistering July heat, or, conversely, at risk of breaking bones on slick January ice.”

It depends on your situation, your local transit system, and how much inconvenience you’re willing to put up with. When biking or walking, the cool of the morning is a big asset. In years past, I would bike to work if there was no rain in the area, in a long sleeved shirt and slacks, and arrive after a 20 minute ride with no significant sweat. On the way home, it didn’t matter if I got sweaty or even rain-soaked. I could change clothes at home.

I don’t count my time walking or cycling to a bus stop as lost. If I get some aerobic exercise in the course of my travels, it’s that much less time I need to set aside elsewhere in my schedule.

Ice on the sidewalks? I’ll leave that discussion to the Madisonians. (Though when I lived there, I walked a mile or two to classes most days, often in an Air Force “snorkel” parka.)

In spite of the drawbacks of the transit bus, I still see small-city bus systems as nuclei that could grow in coverage and service frequency to become viable systems for commuters and shoppers. In a small way, it’s already happening. In a recent survey of riders on our little county bus system, half of whom either don’t own a car or can’t drive, one passenger in five was using the bus for its convenience, rather than necessity.

Vince mentioned the private “dollar vans” that started carrying passengers in New York City during a transit strike in the 1980s, and still operate today: “These guys operate at a profit against heavily subsidized government buses. Their customer base is mostly poor immigrants.”

Maybe relaxing the laws on “common carriers” would help to promote more such systems. I wonder if the dollar vans helped inspire the Megabus private intercity bus system. It operates without official bus stops or, apparently, any real estate. Its fares start at $1, for the first passengers to book.

Note 1: In previous posts, I’ve cited a figure of 360 passenger-miles per gallon as a potential maximum for US buses, based on a DOT reported average fuel economy of 7.2 mpg. Transit buses, driving in city traffic and making frequent stops, get less than half that many miles per gallon. I’m not distinguishing gasoline and diesel powered buses here; the numbers are roughly similar.


US Public Interest Reserch Group, “Who Pays for Roads?”, 2015,

Seattle Times, “How Much of Transit Operating Costs do Riders Actually Pay?”, 2017,

Wikipedia, “Fuel Taxes in the United States”,

Federal Highway Administration, Travel Profile of US, 2009,

Hartford Courant, “Federal Law Gives Tax Break For Transit Commuters”, 2016,

US DOT, Commuting Mode Share (figure), 2015,

US DOT, “Overview of Transit Vehicles,”, “Public Transportation Demographics: Ridership Data for Cities”,

US Oak Ridge National Laboratory, Transportation Energy Data Book, 2016, Download at

Space Coast Area Transit Rider Survey Report, included toward the end of this package of materials:

Interesting study of Seattle’s tranportation taxes and fees from taxpayer’s point of view: “Transportation Revenues from the Taxpayer,”

Contrary view from another Paul in Madison, “Do Buses Save Gas?”, 2008,

Revisions to this post:
August 6: Added note about exercise,link to SCAT rider survey

Featured image via Jim Joel, at Wikimedia Commons. Creative Commons 4.0.,_taxis,_private_cars,_bodabodas,_bicycles_and_pedestrians_in_downtown_Kampala.jpg

Bob Wise

Robert Wise brings a lifetime of eclectic experience to inform his Eclectications Blog—field artillery, graduate study in geography and meteorology, mapmaking, college teaching, computer programming in scientific applications, boatbuilding, and developing maps and imagery to support a workstation that could deploy anywhere on earth.

Tags: Cars, greenhouse gas emissions, public transit, sustainable transport