PlanoFuji

A common claim when advocating non-car mode choices is "40% of all trips are 2 miles or less." such as made here; https://www.bikesbelong.org/resources...on-statistics/

I suspected that this was a misinterpretation of the data, so I looked a little further and determined the claim is based upon a publicly available household travel survey, the NHTS 2009. This means the actual analysis can be replicated. The following is results from my statistical analysis of the NHTS data directly.



First I calculated an arithmetic mean (average) and median calculations for the 'trip' distances and obtained the following; mean = 9.8 miles and median = 4 miles. The median is the point at which half the 'trips' are shorter than that value and the other half are longer. This gives some credence to the claim. So I looked at the data definition for the table and determined that 'trip' in this case does not really mean what is implied by the claim. For instance if you made the following 'trip'; leave home, stop at starbucks, go to work. Most folks would call that a single 'trip', but the data analyzed classified it as two trips. Its easy to see how the difference in interpretation could make a pretty big difference in the validity of the original claim.

Some additional research turned up that the government had already addressed this issue and compiled a table representing what are called trip chains. The home-starbucks-work example would be a single trip chain. The idea is illustrated here where a complete set of three trip chains for a single person on a single day is represented.



I then performed the same set of calculations on the trip chain data that I had previously performed on the trip segment data and obtained a mean of 13.5 miles and a median of 6 miles. With a trip distribution as shown here:




Now this is starting to tell a different story. The distances are getting a bit longer. Of particular relevance is that we still aren't really addressing the real problem. Which is that what is important is the total distance traveled from the time one leaves home, until the time one gets home. The data to answer the question is not readily available, but I am working on processing the NHTS to obtain it. I am making this post, because if one truly wants to advocate travel modes other than a car, we need to understand the real issues that drive people to use motor vehicles in the first place. One of which is that the distances are not as trivial as some advocates try to make it.

surreal

I see what you're trying to say, and those other metrics are still useful and representative of important data. But, most trips are less than 2 miles. Sure, the mean and median would go up, even if we're talking about 9 trips of 1mile each and one trip of 20miles. The sad fact is, a lot of Americans take the car to the corner store to buy some Twinkies and a gallon of milk. However you feel about the politics behind it, that sort of trip is wasteful and helps no one.

But, even the Home>Starbucks>Work>Home trip, on the microlevel, amounts to something we oughta do by bike. I live less than 1 mile from Starbucks. Work is about 3.5 miles from Starbucks. Getting home is another 4 miles or so. Even if i need to stop for some groceries, a market is only one block out of my way on the return trip. This is definitely the sort of trip that can and should be made by bicycle, even if the whole ordeal is a bit less than 9miles.

I kinda feel like, if you live in a location that is very far from coffee, groceries, and work, then you probably ought to move to a more sensible location. Obviously, there are circumstances where this is problematic or even impossible: the spouse works just as far from home in the opposite direction, or you lost your job that was near your house & you can't sell the house in today's market without taking a loss, etc. But to live a life that's unbikeable, even if you still choose to drive, is a wasteful lifestyle. The exurban motorist will pay for this choice in higher insurance premiums, fuel costs, time wasted in commute, and increased risk (dwell time) during his/her commute, but the truth is, we all pay the price for rampant waste of resources.

PlanoFuji

Yes 40% of trip segments are less than 2 miles. As I said, that isn't a particularly relevant problem. Though it is in fact the source of the benefit that bike sharing brings to a community. Driving to work, may be necessary (or taking transit), but bike shares allow people to use a bike for trips to lunch or the post office that they would have used their car for (since walking seems abhorrent to most Americans).

Many (if not most) Americans need to travel longer distances than you do for Starbucks, work, etc. The average (arithmetic mean) distance traveled from home to work is about 11-12 miles in the U.S. That distance is certainly doable by bike in most places; however, we don't convince people of that when we focus on partial trips (trip segments) of 2 miles or less. The average person hears that statement and is correct that it doesn't apply to them... Since they correctly think in terms of the total distance they travel each day.

Slowhead

Look for an overview of the town you currently live in, on-line. General info like the length of commute are usually listed. You may find some different mileage statistics and how the people around you live.

PlanoFuji

The data referenced contains information to isolate those records associated with specific communities. The larger your community the larger the number of records in the data set to represent it. At least some of the larger areas will also have additional household travel surveys as well.

Mobile 155

What people could do and what they do most often are two different things. People could walk five feet from the easy chair and change the channel on their TV. But I can't remember the last TV I ever saw with a manual changer.

More to the point there are very few places in this country where an adult can't bike. The problem is easier than that. The vast majority of people simply don't want to bike, anymore than they wanted to walk over to change the channel on a TV. And then in reality doesn't everyone have the right to decide what they want to pay for? Exurban and Suburban environmentalists seem to question the wisdom of creating large Urban Heat Islands because we all pay for the effect it has on the environment. And yes urban heat islands are measureable. There something people can do about their carbon foot print. But I do agree, if you don't like where you live then move.

enigmaT120

" I am making this post, because if one truly wants to advocate travel modes other than a car, we need to understand the real issues that drive people to use motor vehicles in the first place. One of which is that the distances are not as trivial as some advocates try to make it."

I like what you're doing. Do I understand you correctly to be saying that half of the trips (trip-chains, whatever) are under 6 miles (but the average is higher)? Are you in some position where you could publish your findings and have any attention paid to them, except by us?

I'm guilty of everything Surreal says. I live 50 miles from work, but my house on 32 acres of forest land is paid for and I do not want to move. When all I did was drive my little car, Realage.com added to my age significantly for my commute. They didn't even have an entry for all the miles I ride motorcycles.... So I pay the price for my stubborness, and will retire as soon as I can afford to. I'm just lucky that I can ride my bike 9 miles to catch a commuter bus the rest of the way to work. It helps that my employer pays for my bus pass.

Roody

I commend you for finding a cleaner way to commute that long distance. But it probably isn't really your employer paying for your bus pass. They likely get a tax credit on their federal taxes to pay for this. I believe this credit is set to expire soon, if I'm not mistaken. You might want to check this out, or maybe somebody else will post reliable info. (My memory is a little rusty on something I was reading a couple months ago.)

good luck, I hope you get to retire soon and spend more time at your home in the forest.

Roody

Talking about trip segments vs. trips-- one problem is that many people do tend to make several separate short trips. Usually it's more efficient to combine trips. This is even more true if you can plan ahead several days to make the most efficient use of your travel time.

over the years, a lot of people have commented on this forum that they become much better at planning and combining trips after they become carfree. It's good to use transportation that's a a little slower or a little more effortful because this does discourage wasteful trips.

Of course, if you're a good bike rider, you can make spontaneous trips that don't cost a lot of money or harm the environment.

surreal

Re: heat islands and other environmental concerns-- it is virtually impossible for humans to have no impact on their environment. The truth is, all of the other human behaviors that cause what many (myself included) consider to be environmental problems are exacerbated by overpopulation. If there were only a dozen ppl on earth, we could cruise around for days on end in nuclear-powered humvees, and it'd have less impact than a million vegan luddite pedestrians would have during a 3-day fast.

Most environmentalists have their favorite cross to bear. The cyclist-enviromentalist criticizes the car. The vegan-environmentalist criticizes the carnivore. The locavore despises big agribusiness. The non-breeder-environmentalist despises population growth. The truly committed tree-hugger despises pretty much everything. And, all of these ppl have valid arguments, replete with good points. But, sad fact is, most ppl won't pay heed til more pressing realities (cost, total unavailability, disaster) force them to make adjustments.

As for me, I make my choices like a recovering addict. I take things one day at a time. Any day that I can keep myself from driving, eating meat, buying tropical fruits, and knocking ppl up is a good one. Like any addict, I have relapses from time to time, but I try not to beat myself up about it. Tomorrow is another day, with better choices to be made.

I suspect that, if more urban ppl made choices that led to less heat-production, those heat islands wouldn't be as much of a problem. But, I think we're a good ways off from that happening, barring some sort of disaster that leads to higher prices and less availability of petroleum/electricity/etc....

alhedges

I think this is very useful; trips are different from "trip segments", and quite different from trip segments that are done at the far end of a longer trip segment. I.e., if I travel 20 miles to work, drive 1 mile for lunch from work, and then stop at a grocery store 2 miles from work on the way home, the old data would show that I had trips of 1, 2, and 20 miles, which would suggest that I could easily do two of these trips by bike. But of course that's not true because those trips are only short from a place I had to drive 20 miles to reach. (Of course I could take my bike to work with me, but that adds additional complexity and doesn't help much with the stop on the way home).

Roody

But to me the sad thing is that many of the necessary changes could be made almost painlessly if they were well thought out and planned for. For example, the suggestion to "walk or ride a bike for all trips under two miles" is not the big hardship that most people think it is. I don't have to tell this to you guys (and gals), but most people just plain don't know that a two mile human powered trip is easy to accomplish. It would help explain it if Planet Earth had an advertising budget as big as the auto and oil companies!

kmv2

What does that equate to in Strava segments?

gerv 

Hope you realize this is a totally car-centric pattern for provisioning your home. You can easily do make 3 stops on a 5 miles car trip. (and it's probably a great way to use a car...)

But if you were obtaining provisions by bike or on foot, you probably couldn't carry all that stuff. Instead you tend to make one trip and bring your goods back home. That's exactly how I do it on a bike. Get 50 pounds of food from the grocery store, then next day make a trip for hardware and maybe a trip to the health food store next day. I wouldn't want to lug all that stuff on one trip.

So, guessing that this data really depends on how your city is laid out and also on your preferred method of traveling.

PlanoFuji

That is not what the data says. It is pretty clear that people do combine trips. That was the crux of the analysis in the first post.

surreal

The link to the NHTS 2009 linked from the bikes-belong page is a dead-end. I get a "page not found" message. Going off of my observation of others, as well as my own experiences as a committed driver in my late teens/early 20s, I believe that ppl exhibit both behaviors. Some drivers may tend towards one over the other, but I feel confident that both the there-and-back-single-destination-<2miles-trip and the multi-destination-tour-of-several-local-stops-trip are represented on our roadways, by users of various kinds of vehicles.

Personally, I still do both, but the single-destination local trips are always done by bike, unless I'm hauling a lot of stuff. (eg, donated bikes to the bike share. I've never been able to "ghost-ride" more than one add'l bike at a time.) When I'm making several stops on the same outing, I may opt to drive if there's a very great total distance or, again, if I'm going to be carrying something heavy. I also make these multi-destination trips on a bike, but I need to plan it out a little better. As I live in some very dense suburbs, it's pretty easy to plan out a convenient trip, if one's not too picky about particular destinations (eg, settling for home depot b/c it's near the grocery, even if I'd prefer to shop at the small, independent hardware store that's a few miles in the opposite direction.)

PlanoFuji, while I do find your data interesting, I don't know how valuable it is in terms of promoting cycling as transportation. Even if the 40%<2miles stat is misleading (and I'm not convinced that it is), if we get ppl to make this ultra-short trips (at whatever %) by bicycle, it'll be an introduction to transportation cycling. If they like that, they can start going further afield by bike, or make several stops for a round trip total of 5, 10, 20 miles. If they still like it, well, then I guess that possibly misleading stat has still done it's job, by "misleading" ppl in the right direction.

PlanoFuji

I posted a link (which is active) to the NHTS in the second paragraph of my first post. or you could google; https://www.google.com/search?source...le.9caiZIY3Zcs

The point is that these 'ultra short' trips are not occurring in isolation. They are occurring as part of much longer trips. Biking isn't going to be an option unless people carry their bikes with them on transit or their cars.

That is why I specifically addresses bike shares. This examination of the data serves to make the concept of bike share much more viable than usually assumed by those who prefer their own bikes. It allows for the provision of readily available bikes in those areas where these 'short trips' are most likely to occur. That combined with shifting the emphasis of traditional advocacy to the ease with which longer trips can be made by bicycle (average home to work commute about 11-12 miles). As I said, telling people that they can use bikes for 40% of their trips (as Bike belong has) isn't going to cut it. Most folks correctly realize that the claim doesn't apply to them.

Oh, and just to clarify it isn't my data. It is one more example of your tax dollars at work.

surreal

But... those trips DO happen. I watch them happen. They happen every day. The 40% figure may be misleading, but the fact is, my neighbor routinely drives 3 blocks and back to get a loaf of bread or a gallon of milk. My wife will actually drive the 2 blocks to the trainstation, park there, and drive the 2 blocks back home, when it's raining.

Absolutely, ppl will tend to run some errands while they're out, and stop at destination X on their way to destination Y, and then hit up destination Z on their way back. If you're driving anyway, that only makes sense b/c it saves time and fuel. If you're biking, you can often do the same thing.

But, to suggest that short there-n-back trips don't occur is simply not true. We can question the prevalence of such trips, but we cannot deny their existence. Sometimes, ppl hit up destination X on a Sunday, and come right home. They might work at destination Y, but they might want to go home to change their clothes before they head out to destination Z Monday evening.

PlanoFuji

Of possible interest; https://www.policy.rutgers.edu/facult.../2001-2009.pdf

Table 1 on page 3 is a nice summary.

PlanoFuji

Nothing I am saying (nor what the data is saying) is meant to say such trips don't occur. BUT, the travel survey specifically cited (and travel surveys in general) are designed to obtain a statistically valid representation of the travel behaviours of an entire population, not an anecdotal sample by an individual. And the data indicates that your perception about the frequency of such short trips (I believe you described them as a majority of trips) is not supportable.

Roody

Right. And there's nothing stopping cyclists from combining trips like some motorists do. If I have a doctor appointment, I go to Sam's Club which is less than a mile from the appointment. Then I go to a nearby bookstore also.

Many of the car owners I know are constantly making single purpose trips. My own son used to bike everywher, and made 5 or 6 short trips a day. Now he drives, but still makes 5 or 6 short trips per day. Most of my co-workers drive out to buy a burger or salad on their breaks--single purpose trips of less than two miles. I pick up a salad on my way into work on bike or bus, saving a trip.

It takes a lot of convincing to get people to change old habits. The "two mile" goal was considered a low hanging fruit. The thinking was that if you could get people to substitute human power for their shortest trips, they would later develop the habit of walking or cycling on longer trips. Will this ever happen? We will never know if we don't try. I am seeing very little money going into public service messages that try to change driving habits, so I'm pessimistic at this point.

What people need to realize is that making these simple lifestyle changes is not really optional. We must change our wasteful habits or our lifestyle won't be changed voluntarily, it will be extinct. People can use denial all they want, but things are only getting worse.

Roody

Yes, but this data only describes driving habits. Presumably people change their habits when they switch to cycling. That is, they change the frequency, distance and number of segments of their trips.

PlanoFuji

Once again you are making a false assumption. The NHTS covers all modes, and if anything tends to over estimate non-auto modes (from conversations and conferences with the FTA). The numbers and chart I derived from the data include those who made trips by walking, cycling, and taking transit as well as those who drive. Perhaps you should look at the rutgers report I posted above. It is derived from the NHTS data. You might find it interesting.

Simply changing to bicycling does not mean that the style of trips will (or even need to) change. As you said, nothing prevents cyclists from making multi-purpose trips...

Roody

As you point out in your first sentence, I'm pretty stupid. Could you then explain in simpler terms, what are the practical or policy implications of your findings that you reported in the first post? It seems to me that a great many of these "trip tours" are still under five miles. This is very doable on bike, but not so much on foot. So are you saying the emphasis should be on cycling rather than walking? Or are you saying that no efforts should be made because people travel too far to even consider non-motor transportation?

also can you explain why the other experts use the single trip definition? while you use your trip tour definition?

PlanoFuji

I never made any such claim. I simply pointed out that you were once again making unfounded assumptions.

I believe I have. The emphasis should be on either how folks can make ALL (or at least complete home to home tours) of their days trips by bicycle or how bicycles (but not necessarily personal ones) can be used for parts of those daily trips. Think easily portable folding bikes or even better bike shares. I have seen on here many derisive comments about bike shares from cyclists who didn't see the purpose of these programs for themselves. When the data indicates that these programs may be pivotal in getting folks to use active modes

As I noted in the first post, even trip tours are not really the issue either. What really matters is the total distance travelled from the time one leaves home until one returns home, at least in reference to personally owned bicycles replacing cars. With an average home-work commute distance of between 11 and 12 miles in the U.S. many folks could replace their entire commute with the use of bicycles. Advocacy would be better served talking about that, rather then replacing the mythical 2 mile or less trips.

Haven't seen a single expert use the trip segments in the context of this post. The errors were performed by bicycle advocates, like the bike belong site mentioned in OP. Also it isn't my tour trip definition. The tour data and the definition used were directly from the NHTS site... You do seem to have made it clear that you didn't bother to read any of the actual facts or reports in the links cited. Guess you are afraid they might contradict your preconceptions and stereotypes.