I don’t doubt that buses are efficient during rush hour, filled to the brim with commuters who would each be going in their own cars if the bus weren’t there, but during off-peak hours, which is most of the day, driving along circuitous routes in a vehicle designed to hold 100 people but only actually holding maybe 8 - that’s got to be a pretty big fuel waster, right? I’ve just had a really busy week, taking the bus at least twice a day to some place or another, which prompted this question. How much fuel do buses really save? Trains?
Fun fact! FlyingRamenMonster has now been on several gas buses. But what she really wants to try is one of her city’s newfangled HYDROGEN buses. Vroom!
I don’t know the factual answer, but given that most people choose to drive alone I wouldn’t think it would take too many riders to make a gas bus more efficient than a car.
I think it might be based on averages; I know that the train system I’ll be using eventually will run more trains during ‘rush hours’ and less during ‘off peak’ times.
When I calculate my per-tank mileage, I’ll get high MPG with good highway driving, low MPG with bad highway or stop-and-go driving; on mixed tanks it will be in the middle.
So maybe in that sense it’s fuel-efficient - on average with high and low use balanced to maximise the fuel that is used, it might be as fuel-efficient as it reasonably can be. And hopefully more generally fuel-efficient than all of those people driving individual cars in a larger congestion model they contribute to.
As to how the fuel-efficiency varies on a per-vehicle basis, I don’t know. My pickup got decent mileage unless you filled it up; then it was horrid. But my pop’s truck got middlin’ mileage - empty or full. I would imagine that the weight added by the commuters doesn’t necessarily make the vehicle operation significantly less efficient or steady.
In Vancouver, B.C. the buses are electric, using overhead lines for power. The electricity also powers air compressors for their brakes. What a change from L.A., which has noisy, smelly, smoke-belchers! I don’t know if the Vancouver buses have back-up diesels.
Not necessarily. The figures I’ve typically seen say that seven riders is actually a little above the breakeven point for fuel use for a typical bus as compared to single-occupancy cars. That is, a given trip on a bus uses less fuel than seven cars would use for the same trip.
Averaged out over the whole daily schedule, therefore, riding the bus generally saves a lot of fuel over individual automobile use. You also have to take into account the fact that buses, being more compact, take up a lot less room on the road than the seven or seventy cars their riders would require, so they save additional fuel for other cars by making the roads less congested. (However, they also stop more often than cars, which slightly offsets the de-congesting effect.)
I think the Consumer’s Guide to Effective Environmental Choices has a table showing comparable emissions and fuel use for automobiles versus other forms of transit, but I can’t find it online.
In my experience, they tune the trains pretty well to capacity so I don’t think this is a big problem there. At night, they might only run a couple of cars once an hour.
When’s the last time you were down here? Most of the older, black-smoke belching buses have been replaced. I think the newer buses mostly still run on diesel, but they do seem to be a lot cleaner.
Still you’re right about the trolley buses of Vancouver. Electrically powered transit vehicles, whether on track or off, seem to accelerate so much more smoothly and quickly than a motor bus. It would appear that the trolley buses have some batteries of their own; our tour bus driver in Vancouver told us that someone had once hijacked a trolley bus and turned off the route, away from the wires. He managed to cover quite some distance before the power in the bus died.
On a bigger scale, having good off-hour bus service makes it viable not to own a car. Which means that more people walk/carpool/bike because they have no car to rely on and they know they can fall back on the bus if they need to. So you can count in more than just the people physically present on the bus.
Also, don’t forget to factor in the traffic jams (wasted gas) busses tend to create as they stop every 3 blocks. That’s how often the one on the road I drive seems to stop.
I think there’s two questions to be answered here:
Are Mass Transit vehicles more fuel-efficient on the whole than cars?
and
Do Mass Transit vehicles pollute less on the whole than cars?
Each is a very different question and it’s not certain that the answer will necessarily be Yes or No to both.
Here in Chicago the L runs on electric which is certainly better form a pollution standpoint than cars. Ditto for all cities which use electric bus systems. However, it’s probably a more complicated question when you debate the energy usage from both a Joules standpoint and a cost standpoint. Additionally, the political side of it comes into play.
Generally speaking the more we run off electricity (powered with nukes or coal instead of foreign oil) the better we are.
So if you want to simplify the question to just diesel buses versus cars, you can see where the answer lies. I personally don’t have the answer, but I’m guessing that a bus is only about 3-4 times less efficient than a car from a gas milage standpoint so as long as the riders/mile measure is better than 4 to 1 the buses are going to be better.
Oh, good. That means I can feel good about pumping great masses of money into the public transport system now.
Johnny - I used to live in Vancouver, I seem to remember that the electric buses were old and the new ones ran on diesel or some other non-electric source. Is my memory just wrong?
Find me another person that works in/around the Merrimack NH area, and lives in/around the Sandown NH area, that would be willing to wait around if I’m reqired to work late, or come in early.
Otherwise, I have no CHOICE.
That said, if I was commuting into the big city of Boston, and it was possible to get a convienent schedule of public transit, AND find parking at a commuter rail station, I’d use public transit.
Years ago, I lived at the end of one of the lines headed into Boston. I had a choice of being either 1 hour early for work every day, or 1 hour late, pretty much the same choices going home. It took less time (work + commute) to drive into Boston (horrible traffic) than it did to take the train.
Just because it works for you, doesn’t mean it can work for everyone.
If Vancouver’s transit system has been growing and evolving like San Francisco’s, your memory is just fine. Muni’s somewhere in the final phases of replacing old trolley coaches with new models. The ones they’re replacing were fairly old and decrepit 15 years ago. They’ve not improved since then. The new ones are larger and have a few blocks worth of reserve battery power so they can drop poles and scoot around double-parked trucks, accidents and construction. The old TCs would drop dead within a foot or two of losing the line.
Where the neighborhoods are amenable to the idea of having overhead wires installed so they can get rid of noisy diesels grinding up the hills and putting out soot and smells, Muni has been electrifying routes and getting rid of some stinky old diesels.
An additional aspect of bus fuel consumption and emissions is that it gets started in the morning, warms up once, and then runs all day, as opposed to a commuter car that normally have 2-3 warm-up cycles per day. (Driving to lunch or running errands accounts for the 3)
Did you put them back when you were done with them?
I’m also thinking that with fewer vehicles on the road, you get fewer accidents, fewer ambulances and emergency services running around after minor or major dust ups.
On a more long-term scale, a community built around public transport would need much less area for parking lots and roads. That means a higher density of houses and businesses, which can result in shorter average commuting distance.
even sven is right – simply put, a mass transit system is greater (more efficient) than the sum of its parts. Like any other industrial process with an economy of scale, the big picture is where you make your savings.
Even if the bus isn’t nearly full, it leaves on time instead of waiting for enough passengers to break even – because reliably scheduled buses can be planned for, often simply from memory. One wasted trip isn’t as big a waste as alienating frustrated commuters – unreliable and irregular service immediately makes me look for another solution, and I might never return to using the bus. The buses have to run on schedule even if only carrying one person, or risk being ignored by commuters.
Where I live, county buses feed commuters to the Washington, DC Metro subway system. They are tributaries to that great river. The subway is, in turn, even more efficient than buses, so the buses feeding the Metro would be saving highway space and energy even if they themselves ran at a loss (up to a point).
Sometimes, when I miss the bus that’s within walkingdistance, I’ll drive to the Park & Ride (basically a staging lot all the buses pass through on their way to the Metro). Even though some of the bus routes wouldn’t go to the Park & Ride if they were optimially planned, sending all the buses through the P&R means that I, the commutrer, know I can get one there pretty quickly, even if I missed my usual bus, so I have incentive to use the P&R and not just drive in.
Even with the economy of scale, the whole bus – > Metro system has its inefficiencies. Still, individual cars are comparatively even more inefficient – and much moreso when tens of thousands of individual drivers are making bad or self-serving decisions al at once on our overtaxed road system. I’ve seen people slowed by buses, sure, but in terms of individual dumbass decisions costing everyone commuting time, the variable that counts IMHO is number of drivers: more drivers inevitably raises the odds of a dumbass collision locking up the Beltway for seven hours.
A bus has the minimum number of drivers, no matter how many passengers it has.
There’s also the matter that, even aside from the number of bus drivers, they’re all professionals, and thus (I would hope) less likely per-driver to be involved in accidents or other inefficient forms of poor driving.
Most of the older, black-smoke belching buses have been replaced. I think the newer buses mostly still run on diesel, but they do seem to be a lot cleaner.
Compressed Natural Gas. They are a little stinky, but no soot. Very clean burning.