Guest blogger Greg Kushmerek continues his series of articles on bike commuting:
I am the parent of young children, one of which has recently started at public school. As with many working parents, I need to juggle my work schedule with their school schedules.
This week I tried a little experiment: compare a car-based vs. bike-based commute while doing school drop-off for a 15-mile commute.
Bike Day
- Put bike seat on back of bike.
- Load child on bike.
- Ride to school (5 blocks).
- Lock bike to fence (no bike racks).
- Drop-off
- Ride back home and deposit bike seat.
- Bike to work
Bicycle: Dahon Cadenza (my slower, heavier bike). Arrive at work: 9:28
I was showered and working before 10AM. Had the work VPN been up that morning, I’d have had 30 extra minutes at home to check and respond to messages.
Drive Day
- Walk child to school
- Drop-off
- Walk back home
- Drive car
Car commute conditions were a touch heavier than normal, but within the mean. Arrive at work: 9:10
Conclusion
Sacrificing the bike for the car (or forsaking the bike for the car — your call) doesn’t yield major gains, at least not for me. Had it been inclement weather or a good deal colder the car puts in a more obvious advantage. The time gains from the car are even a bit inflated when you consider that on car-day, I arrived at the school five minutes earlier. One could argue that less traffic would lead to bigger time gains, but I know I can get to work faster on my Felt (about 3mph / 5min faster).
Given a flexible work environment where some on-line work or staying a touch later is allowed, the time difference isn’t enough to warrant giving up the bike for the car.
For some people arriving 18 minutes later and sweaty is just a no-go. For those who live a lot closer to where they work, that time gap could practically vanish, and one might not even need to clean up.
Posted: September 18th, 2009 | Filed under: Cycling, Transportation | 2 Comments »
Solar cars designed specifically to race in competitions such as the North American Solar Challenge or the Green Global Challenge (previously the World Solar Challenge) must somehow move at freeway speeds with less power than a typical hairdryer. Building these vehicles is a grand exercise in energy efficient design, and demonstrates what’s possible when engineers focus on producing maximum results with very limited power consumption. This is the third installment in a series that discusses several strategies solar car designers use to squeeze the most performance out of a vehicle-sized solar array. As with the larger energy system that powers our homes, vehicles, and factories, the best solution is not necessarily to focus only on producing more (ideally renewable) power, but also to identify and eliminate waste in systems that use energy. Designing for energy efficiency is a very cost-effective strategy to addressing energy problems.
One significant source of energy consumption in cars is tire rolling resistance. Basically, it takes some amount of force to roll a tire forward, even if you are not accelerating or going uphill. A simplified model of rolling resistance is:
This equation describes how much force is required to roll a tire forward at a constant speed on a flat road; this force is called rolling resistance 
. It depends on two things: the vertical load supported by the tire (i.e., the normal force 
), and the coefficient of rolling resistance 
. The normal force depends on how weight is distributed in your car, and the rolling resistance is a function of tire design (and is also influenced by things like temperature, speed, and tire slip). Rolling resistance goes up proportionately with both normal force and with . We would like to reduce rolling resistance in order to reduce the energy consumed while driving. It’s easy to see that one way to do this is to reduce how much a car weighs, which reduces . Suppose we’ve eliminated as much vehicle mass as possible, and still want to reduce rolling resistance further. How do we reduce ? To understand this, let’s have a look at where rolling resistance comes from.
When rubber tires roll over the road they deform. The spot that touches the road (the contact patch) is flattened just a little due to the force of the car pushing down. Imagine what happens to one piece of rubber in your tire as the tire rolls on the ground. Looking at the drawing below, at position 1, the piece of rubber is slightly curved. As the tire rolls, the piece of rubber moves into position 2, and it starts to deform. By the time it gets to position 3, it’s pretty much flat, and then as it moves through position 4 to position 5, it returns to its original shape.
All the rubber in the tire tread and sidewalls goes through some type of deformation with each revolution of the tire. It takes energy to deform rubber. We get most of that energy back when the rubber ’springs’ back into shape. But rubber is not exactly like a spring; you don’t get back all the energy you put into it. Rubber is what we call viscoelastic. The elastic part of viscoelastic is the springy part. Something has elastic behavior if it springs back into shape after being deformed. The viscous part means that when something is deformed, energy is lost, and resistance to deformation increases with how fast you try to deform it. Think of stirring a pot of honey; if you stir it slowly it doesn’t take much effort, but if you try to stir it fast the viscosity of the honey makes it harder to stir. Where does all the energy go from stirring? The honey doesn’t ’spring back’, so you can’t recover the energy like you can with a spring. The energy from stirring was converted to heat; the honey became a little bit warmer.
Tires exhibit both viscous and elastic behavior. Some of the energy is recovered when the rubber springs back into shape after rolling through the contact patch (point 3). Due to the viscous nature of rubber, there is extra resistance to deformation, as well as resistance to returning to its normal shape. The energy used to overcome this extra resistance is converted to heat; bending rubber back and forth makes it heat up (sort of like stirring the honey). Have you ever noticed how tires get warm after driving? The energy that warms your tires is energy lost. How can we minimize this lost energy (and reduce rolling resistance)? There are three main approaches:
- Reduce tire deformation: if tire rubber is deformed less, then less energy will be consumed. This can be accomplished by increasing tire pressure (one important reason to make sure your tires are inflated properly). It’s important not to over-inflate tires, however, as this could degrade handling and ride quality, compromise safety, and accelerate tire wear. Tire deformation can also be reduced by adjusting tire design, that is, changing its shape and what it’s made of.
- Reduce how much tire is deformed: narrower tires and tires with thinner tread have less rubber that moves in and out of the contact patch, reducing how much energy is lost from tire deformation. There are tradeoffs, however. Narrow tires may not handle as well, and thinner tread reduces durability.
- Reduce rubber ‘viscosity’: using a harder rubber compound can help shift tire behavior closer to purely elastic, meaning that a greater proportion of energy that goes into deforming rubber is elastically recovered. Again, there is a tradeoff. Harder rubber compounds may not grip the road as well as softer compounds.
Some tire manufactures have created tire specifically for solar cars, with emphasis on ultra-low rolling resistance. Solar car tires are thin, high-pressure tires with hard rubber compounds. They have rolling resistance coefficients as low as 0.0025, whereas high efficiency passenger car tires have coefficients near 0.006, and typical passenger car and light truck tires have coefficients much higher than that. To give you a sense of the legendary efficiency of solar car tires, I was contacted by engineers interested in using solar car tires on bicycles they were developing for breaking human-powered speed records. Solar car tires are more efficient than racing bicycle tires.
Below is a photo of a solar car tire along with a view of the suspension (this is a photo of the Stanford solar car from several years ago). Notice the electric hub motor just to the right of the wheel. There is a direct connection between electric motor and wheel; no drive shafts, gears, belts or chains to sap energy.
The next photo shows a pile of solar car tires. Since these tires are optimized for energy efficiency, they don’t last very long. They must be replaced frequently, and it takes a large pile of tires to make it through a long cross-country solar car race.
Solar car tires are intended for specialized racing vehicles, and are obviously impractical for passenger vehicle applications. Nevertheless, we can take lessons from their design to help improve efficiency of production vehicles. Maybe we could move toward higher pressure tires, and use more advanced suspension design to help counteract the harsher ride from stiffer, high pressure tires. As we make other vehicle aspects more efficient (such as aerodynamics or powertrain design), the energy lost through rolling resistance will become an increasingly important factor, and is an opportunity for improvement.
Posted: August 11th, 2009 | Filed under: Design, Energy, Sustainability, Transportation | 5 Comments »
Guest blogger Greg Kushmerek continues his series of articles on bike commuting:
Someone I like to follow on-line is Andy Kessler. He’s a financial journalist and author of sorts who’s written a few books and used to run a hedge fund. He’s very practical, has an excellent sense of the arbitrary nature of “value”, and I’ve come to realize as I’ve followed him that he seems to hate cyclists, or at least cycling evangelists.
Andy’s made a few comments denigrating, really almost fearing, a vision of the future where cars are not dominant and cyclists such as me have “won”. He has a real distaste of a future where everyone lives in densely populated areas in order to make a greener place. If I’ve read him correctly, he thinks that would attack the very nature of what it means to be American — that having onerous burdens that force people to live in cities would create a society devoid of innovation.
There are some great areas for discussion in that position, the first and foremost being that it’s a real concern shared by many people who would rather not have to face arriving at work sweaty from a summer ride with dirty hands from trying to rebuild a snapped chain. That little saddle doesn’t sound as appealing as a cushy leather seat and air conditioning (or heat in winter). How do you reach these people? If you can’t, are you going to force them towards that vision via government regulation?
Now Andy has a sharp wit and it’s very tempting to point out that the proper market-oriented answer is that rich people like him would ultimately pay teams of people like me to come out to his vast estate and cart him around in our little cycling paradise. The ruling class could grow to a race of Jaba-The-Hut proportions and lord it over the rest of us.
However it’s at this point I think one should step back and look at this from a more practical standpoint: could the cycling vision really work in America? I’ve previously mentioned that The Netherlands only oriented itself to cycling in the 1960s, which implies that with enough will the same kind of thing can happen elsewhere. The problem with that position is that it ignores what 40 years of infrastructure development in the USA have created: a population spread out over a wide area, much bigger than tiny Holland.
Think about it: if the Feds suddenly put out bike friendly infrastructure and created an economic environment more favorable to cycling, what would it mean? My city condo would go up in value as some people would find my dense neighborhood more attractive, but plenty of people in the suburbs and exurbs would neither want to move or appreciate a reduction in their own property values. The houses in far flung places won’t magically disappear and the communities won’t just transplant themselves. Some people hate dense areas and generations have grown up in spacious suburbs. People will still live in places with long roads in between their destinations. They’ll start driving more efficient four-wheeled vehicles before they move. You don’t have to be especially bright to see the real implications.
In this kind of environment, what do you do to make cycling more attractive in suburban areas? Bike lanes are ridiculous on most roads since they’re plenty wide enough. It’s the main connecting roads that you have to think about. Should there be bike lanes on those? Should there be more “bike stops” so people can duck out of the rain? One policy I like, that would make some people howl, is to reduce the percentage of car use on those main arterial roads by 40%. Shove cars in narrower lanes in the middle, put up some raised granite separators on the outside, and make the space from the granite to the side of the road exclusive to cyclists and mopeds.
Maybe you could buy them out? The Great Smokies National Park used to be plots of private farmland until the 1930’s. We spent the 60’s using eminent domain to raze the center of cities and put in highways. Should we now use those same policies to reverse engineer what’s in place?
In the end, this only confirms Andy’s fear. The houses won’t get any closer if you force the roads to be more cycling friendly. Not everyone will leave and those who do will not do it all at once. Some business will not want to expand into suburban areas if the government creates market conditions more favorable to denser cities or exurbs. While I think that this kind of environment won’t stifle innovation — it will enhance it as people rush to fill voids that a new market condition creates — that’s cold comfort to Andy’s point of view.
Still, I am vexed over what to do with all of those suburbs. You can’t simply say “too bad”. The political backlash would kill pro-cycling integration policies if those policies became onerous to suburban living. Yes you can create market conditions that encourage people to give that existence up, but you need to think of ways to accommodate those who do not switch. After all, even the most avid suburban cyclist is likely to have a car for errands.
I’d like to know what you think?
Posted: August 5th, 2009 | Filed under: Cycling, Policy, Transportation | No Comments »
Guest blogger Greg Kushmerek continues his series of articles on bike commuting:
A key design tip in the world of print is consistency: keep consistent design elements in place. People recognize a designed page as “belonging” to the overall product. Apply this to the physical world and you get predictability, and that’s good for something like traffic management.
We don’t have enough predictability on today’s roads, however, for drivers or cyclists. For example: should bikes be subject to all rules of the road, or should they have their own set? Aside from the fact that some cyclists create their own rules, I have seen plenty of examples where bikes have been given the right to do things that cars cannot.
For example: it’s the law in Massachusetts that bikes can pass cars on the right so long as the local town or city hasn’t explicitly outlawed the practice. Pass someone on the right in a car, and you’re subject to a ticket (it was the first one I ever got when I was a teen). Of course, few people know this — I once had someone try to use his car as a rolling roadblock to prevent me from going down the right side.
More signage would help as would other aids to navigation. Intersections can have bike traffic lights or bike signs explicitly dictating what cyclists may do. Signs in advance of major intersections could warn cyclists and drivers that the road is about the change and thus the dynamics are about to be different.
Consider bike lanes again: the non-uniformity of how they appear, how long they last, on what kinds of roads you’ll see them all lead to ambiguity. Ambiguity in traffic is bad. When are they solid lines? When are they dashed lines that allow cars in them? And, as I previously mentioned, how close to the side of the road are they? I personally prefer the idea of redefining the idea of a road to be partly a place where cars travel and then partly a place where “other things” happen. Some roads are generously wide enough that you can cut out eight feet from the side, leave six feet for parking, a foot of space, and the last foot be available for bike lanes. Consistent marking would make it clear where moving cars do and do not belong, and people would form new habits.
What about sidewalks? Any cyclist who’s spent enough time on the road has been asked, rhetorically, “Why don’t you go back on the sidewalk where you belong?” (Presumably, the thought of a cyclist rapidly sneaking up on a baby stroller is more appealing to these drivers than having to share the road.) Just when is it a good time to be on a sidewalk? Ever? Never? I think they’re even more dangerous for cyclists than most roads, but the laws here are also quite mixed even encouraging cyclists to use sidewalks.
I think it’s time to consider a federal-level set of guidelines tied to highway and road funding. Signage, lane width, location, requirements on which kinds of roads should have bike lanes, consistent rules — all of this can come right down and level the playing field to create the predictability we need on the roads. It won’t stop cars from complaining about bikes on the roads, but hopefully it will move their complaints over how someone is biking on the roads and not whether someone should be biking on the road.
Posted: July 22nd, 2009 | Filed under: Cycling, Policy, Transportation | No Comments »
Last summer Americans had a taste of high fuel prices, and our driving habits and vehicle choices actually started to change. Substantially higher prices certainly would cause a lot of pain, particularly in the short term, but what benefits might we realize? Chris Steiner, Forbes columnist and author of $20 Per Gallon: How the Inevitable Rise in the Price of Gasoline Will Change Our Lives for the Better, explained in a recent NPR interview that dramatically higher prices could lead to a better way of living.
Steiner predicts that as fuel prices climb, we will become less of a disposable society, and migrate to denser, more interactive living arrangements. Air travel may not be economically viable for most of us, and travel by rail will grow in popularity (look at nations in Europe or Asia with high-speed rail infrastructure for examples). Other positive changes include more exercise in people-centered (as opposed to car-centered) communities, cleaner air, better (local) food, and improved health. And let’s not forget one of my favorite impacts: increased popularity of cycling.
In addition to environmental and health benefits, curbing petroleum consumption is a national security issue. This video features retired generals and others discussing a recent report from CNA that ‘explores the impact of America’s energy choices on our national security policies’. Vice Admiral Richard Truly, USN (Ret.), discussed the urgency of helping improve public knowledge about energy use, and the importance of resolving our energy situation. General Chuck Wald, USAF (Ret.), explained that Americans must realize that our energy situation is not going to take care of itself without us being a part of it. The link to national security alone could be motivation enough to take action.
The transition to higher fuel prices and lower consumption will certainly be painful, and hurt more for certain segments of the population than others. Should we wait for fuel prices to rise due to market forces and adapt then, or should we take some preemptive action to ease the transition? A phased-in fuel tax could be used to fund required infrastructure changes, as well as investments in technology that will enable us to enjoy a high standard of living on far less petroleum. Revenues could also be used to assist those struggling most with the transition to higher fuel prices. Instituting a U.S. fuel tax would funnel revenue into infrastructure and investments that benefit Americans, whereas waiting for market forces to drive up fuel prices will instead boost revenue for oil producers. Automakers actually support a fuel tax, hoping that it will stabilize fuel prices so they can invest in advanced technologies with more confidence in future demand for energy efficient vehicles. The main question here is not whether fuel prices will increase, but would we rather transition with foresight and a strategy, or just wait until we are forced into reacting. The former option would certainly be less painful, and would leave us in a much better position after the transition.
A strategic transition would require a substantial fuel tax (or a price floor), but this appears to be politically impossible right now. What do you think it would take for U.S. citizens to support an appropriate fuel tax?
Posted: July 17th, 2009 | Filed under: Energy, Policy, Sustainability, Transportation | 1 Comment »
Guest blogger Greg Kushmerek continues his series of articles on bike commuting:
There’s a lot of arguments out there about whether bike lanes are good or bad, and a lot of the arguments against them seem to come down to “They create more problems for cyclists than they solve”. Perhaps that’s an oversimplification, but it’s an opinion I agree with with when looking at many implementations of bike lanes in my own area.
Consider Boston. Boston really should be a great biking city. It’s not that small, has lots of parks, fairly wide roads, and isn’t all that hilly right in the city area. However, biking in the city feels risky. The few attempts to put in bike lanes have simply stunk. The first bike lane I’m aware of is behind Jamaica Pond on Perkins Street. There’s some parking between the curb and the bike lane, and then the parking lane ends and the bike lane takes over. What happens is this: people fill up all the parking spaces and then just park right over the bike lane when parking runs out.
Now you can point your fingers at the Boston Transportation Department or Boston Police Department and say that they should be out there doing more ticketing, but that ignores the larger point. The implementation stinks. The bike lane competes with parking in a highly desirable location. The bike lane could have been one foot further out, eating into the regular road. This would make it clearer that there’s a real lane there. The lane could be using different paint than the simple white lines that, everywhere else in the city, denotes the shoulder.
Worse still is that the placement of the bike lane puts cyclists in a zone of danger. People come in and out of that area with their cars all the time to go walk around the park (yes, they drive to the pond to go jogging, but I’m not going there today — at least Massachusetts has the 2nd lowest rate of obesity in the country today). In other words, the risk of a cyclist getting doored is pretty good.
Imagine if the federal government had a law giving states and municipalities the incentive to put in bike lanes only if those lanes had little boxes all alongside them that randomly punched out at passing cyclists? That’s kind of what’s happening today. If you are resurfacing a road, you can ask the feds to chip in on the cost, which they’ll gladly consider if you agree to spray on some bike lanes.
So here we are: you have local transportation departments taking the cash and laying down lines about as close to the side of the road as they can get it, regardless of the parking situation. In Cambridge, MA, this led to a cyclist’s death a couple of years ago when a female cyclist in her lane on Mass Ave was doored and fell to the ground in front of a passing bus.
I don’t think this automatically makes all bike lanes bad. I think that bike lanes are a really good thing when they’re done correctly. I point to The Netherlands as one such example of doing these things well frequently, but this time I don’t have to look so far. Right in Newton, on Beacon Street, the town effectively cut the road in half by making a shoulder out of what was an unofficial second lane. It’s not now considered a bona fide bike lane, but that’s how it’s frequently used by many commuters and college students. Parking is limited and where there is parking, a passing cyclist has enough space to get around the car and not be in traffic.
I’d like to see more of this, and I’d like to see the feds put in some guidelines on just how a bike lane gets implemented rather than having them simply hand over a check.
What do you think makes a successful bike lane? How can the policy be better?
Posted: July 8th, 2009 | Filed under: Cycling, Policy, Transportation | 2 Comments »
U-Haul is jumping on the low-carbon bandwagon by promoting their ‘clean gasoline’ moving trucks over ‘dirty diesel’, but this blatant corporate greenwash is endorsing choices that actually lead to increased carbon emissions. Have a look at a screenshot from this U-haul webpage:
U-haul is telling us here that using a gasoline-powered truck instead of a diesel truck would reduce CO2 emissions. This campaign is actually doing more harm than good. It may garner more business for U-Haul, but switching from a diesel truck to a gasoline U-Haul truck will actually increase carbon emissions. This advertising campaign will also lead to indirect carbon emission increases by perpetuating misconceptions about diesel. Let’s have a more careful look at the numbers used here.
The core of U-Haul’s claim of lower carbon emissions is that the amount of CO2 emitted by burning a gallon of diesel fuel (22.2 lb) is somewhat larger than the amount released by burning a gallon of gasoline (19.4 lb) [Data source: EPA]. So what is wrong with U-Haul’s claim? It is based on the (incorrect) assumption that diesel and gasoline trucks get the same fuel economy. What U-Haul doesn’t explain is that you can do a lot more work with a gallon of diesel than you can with a gallon of gasoline. Diesel fuel efficiency is typically 40% better than for gasoline engines. That’s a huge difference!
The better fuel economy is a result of two main factors: diesel has 11% higher volumetric energy density than gasoline, and the Diesel cycle allows for much higher compression ratios than the Otto cycle used in gasoline engines (which makes for a more efficient engine). In other words, diesel fuel has more energy packed into it per gallon (which is part of why it has higher carbon content), and diesel engines do a better job of converting that chemical energy into mechanical energy used to move the truck.
A valid comparison between gasoline and diesel trucks would be based on equal amounts of work, not equal mpg—this is what really matters to the customer. Consider a potential rental truck customer that has a set amount of stuff that needs to be moved from a specific start location to a specific end location. What we should be comparing is how much CO2 is emitted from a gasoline truck vs. a diesel truck for moving the same amount of stuff along the same route. If you account for the substantially better fuel economy, the diesel truck will emit far less CO2 than the gasoline truck. The U-Haul comparison assumes both diesel and gasoline trucks get 8 mpg. For this to happen, the customer would have to remove some of his load from the gasoline truck to improve its fuel economy so that it equals the fuel economy of the diesel truck (which is carrying the full load). In this case the gasoline truck is doing far less work, and is not moving all of the customer’s stuff. The U-Haul comparison strategy is unrealistic and deceptive. Readers who are unaware of diesel’s inherently better efficiency may be misled into believing that choosing U-Haul would actually reduce carbon emissions.
In the fine print above, U-Haul states that ‘actual gas mileage may vary’. The fact that actual gas mileage does vary, in favor of diesel by a large margin, destroys U-Haul’s claim that gasoline trucks are better with respect to carbon emissions. The ‘various reliable sources’ statement in the fine print should raise another red flag: U-Haul is not the least bit transparent about these distorted claims.
In the fine print you will also find links to articles about new regulations for diesel particulate, sulfur, and NOx emissions, which are unrelated to the comparison of CO2 emissions between diesel and gasoline. Ironically, these articles explain how diesel-powered vehicles will be improved significantly in the near future.
The statement in this advertisement that diesel trucks emit more carbon than gasoline trucks (per gallon) may be deceptive, but it is technically correct given all the stated (but unreasonable) assumptions. The running tally of ‘CO2 emissions kept out of the atmosphere by choosing U-Haul’, however, is flat-out wrong (flying in the face of the Truth in Advertising Act). Whoever did these calculations didn’t do their homework. Correct calculations would result in a negative value here; that is, switching to U-Haul would increase CO2 emissions.
On U-Haul’s Corporate Sustainability page you can read:
Avoid “dirty” diesel
Mile for mile, diesel trucks release more toxic air contaminants, cancer-causing soot, and smog-forming emissions than gasoline-powered trucks. Greenhouse gas emissions from a gallon of diesel are 15 percent higher than those from a gallon of gasoline. That’s why all U-Haul rental trucks use cleaner-burning unleaded fuel.
The first two sentences, taken independently, are technically correct. Diesels do emit more particulates and other toxic gasses than gasoline engines on a mileage basis (at least with current emission control standards). And as I explained before, a gallon of gasoline does emit more CO2 than a gallon of diesel (14.4% more). However, putting these two statements together without clarification may lead people to believe that diesel trucks emit more CO2 on a mileage basis than gasoline, which is an incorrect conclusion. I roll my eyes at the third sentence. If U-Haul truly was concerned about carbon emissions, they would have transitioned their fleet to more efficient diesel trucks.
The financial savings claim in this ad is also incorrect. Not only do diesel trucks burn less fuel, but diesel is now less expensive than gasoline on average in the U.S. (gasoline: $2.691/gal, diesel: $2.616/gal, Source: EIA, June 25, 2009).
U-Haul is working hard to perpetuate incorrect negative stereotypes about diesel fuel and engines. An anti-diesel campaign magnifies their negative impact by delaying diesel adoption in the U.S. market. Switching to diesel-powered passenger cars could be a practical near-term solution to reducing carbon emissions and reducing dependence on foreign oil. We need to encourage the U.S. market to embrace diesel, not shun it. I want to note that diesel-powered transportation is not a long-term solution; we need to develop (as quickly as possible) a fossil-fuel free transportation system as a long-term solution.
What do you think of U-Haul’s CO2 marketing campaign? Why don’t you let them know (1-800-789-3638), and see what they have to say about it. Or, you could let others know (like these folks).
As an aside, if you want the ultimate in ‘green’ moving options, and you are moving locally and are feeling athletic, perhaps you would be interested in getting a few friends together for a ‘bike move‘.
Posted: June 25th, 2009 | Filed under: Green FAIL, Transportation | 1 Comment »
Guest blogger Greg Kushmerek continues his series of articles on bike commuting:
Last time I discussed how much something seemingly simple, parking, can have a strong effect on whether people cycle to work. Today I want to argue for the second seemingly simple thing that can make a big difference in whether someone cycles to work: having a convenient place to shower.
If you’re an American reading this, it might seem awfully obvious and almost a given. I say this as an American: people don’t like to smell your stink and you don’t like people smelling yours. On this basis alone, many people put biking as a non-starter. No place to clean up? No bike ride to work.
There are people who go through heroic motions. I read once about a guy who works out in San Francisco and cycle commutes. He’s got his place to park the bike, in a room in the basement of the building, and he also has adult-sized wet wipes to clean up from his ride. It makes for an interesting read, but I doubt that’s inspiring enough to spark a movement.
I’m fortunate: my employer has a gym on-site that includes a locker room with clean showers and towel service. I use this every time I come in. I keep a set of clothes at work that regularly go through a dry cleaning service (that I pay for) and I ride in with my shirt nicely rolled up — rolling helps prevent wrinkles. This makes riding in exceptionally easy from a logistics standpoint. I skip the shower at home and heck I save on hot water too. I consider this arrangement ideal.
So what could we do in designing our workplaces to make this available to more people? Many larger business have on-site gyms; if they provided safe bike parking then it’s easy enough to make the commute workable. It’s the medium and smaller places that are harder to manage.
One idea is to engineer change through the tax code. Businesses could receive tax credits if they provide a parking/shower package for cycle commuters. Sound outlandish? Businesses already receive tax breaks if they close down a building. That’s why some places stay empty for years but don’t get sold (I once worked at a place that redecorated a floor and then moved everyone out to claim the credit). A counterargument that nags at me is that the tax code is already so tortured that it’s become inefficient and costs society in a myriad of other ways.
What else? Well there’s the simple but blunt approach of making car commuting more expensive. The last time I checked, gas taxes didn’t even cover 60% of the cost of maintaining roads meaning that non-drivers are continuously subsidizing the roads that they don’t use. Here again is where I have some sympathy with the Libertarian point of view: if people find the service is worthwhile, then make people pay for it. I don’t want to privatize the Fire Department, but I do think the subsidy to car drivers is ridiculous and they should pay more for the roads they use as well as for the times they use them (look up “congestion charging” for more on this idea).
Whether through congestion charging (design) or market forces (demand as in $4 gas when the world economy was humming), a smart business will see the advantages of putting in more parking and showers to attract tenants. After all, once companies start to hire again, how better to burnish Green credentials than to promote their friendliness to cycle commuters?
Posted: June 24th, 2009 | Filed under: Cycling, Transportation | 1 Comment »
Please welcome the newest Design Impact guest blogger: Sterling Anderson. Sterling is a Ph.D. student at MIT working in the Robotic Mobility Group. In today’s article, Sterling writes about his work in the next generation of vehicle stability and hazard avoidance control, and how it relates to vehicle sustainability.
Today I’d like to briefly discuss exciting new developments in a field not commonly associated with or considered a critical component of vehicle sustainability. That field is vehicle safety. The connection I’d like to draw between safety and sustainability goes as follows: no matter what its energy source (gas, hybrid, electric, etc), a vehicle may be made more efficient by removing or otherwise lightening its structural elements. Many of these elements, however, such as secure seat belt harnesses, large airbag systems, sturdy roll cages, and large crumple zones, cannot be removed without increasing the risk of injury to vehicle occupants in the event of a collision. This limits the degree to which vehicles can be made smaller (which reduces drag), and lighter (less mass) without forfeiting the structural protection provided by larger and more massive vehicles.
Enter driver assistance systems. In recent years, the historical focus on passenger safety in human-controlled motor vehicles has shifted from collision mitigation systems such as seat belts, airbags, roll cages, and crumple zones to collision avoidance systems, which include anti-lock brakes, yaw stability control, roll stability control, and traction control. Whereas collision mitigation systems seek to reduce the effects of collisions on passengers, active collision avoidance systems seek to prepare for and avoid accidents altogether. This accident avoidance reduces – and may one day eliminate – the additional mass and design constraints required by passive safety systems.
But while existing collision avoidance systems are effective at reducing accident frequency, they are still limited in one respect: their avoidance methods are fundamentally “reactive” in nature. In the majority of these systems, controller intervention is based solely on current vehicle conditions, and thus cannot anticipate and prepare for future threats. For example, an anti-lock brake system seeks to help the driver avoid accidents by more intelligently applying his intended braking command – it does not preview the road ahead and decide to apply the brakes of its own accord. Ditto with stability and traction controllers; neither preemptively seeks to avoid hazards – each simply responds to the driver’s command. Thus, a drowsy, distracted, or otherwise inattentive driver receives very little benefit from such a system as it does not engage until he begins his own evasive maneuver.
Recent developments in onboard sensing (cameras, radar, laser-based sensing, vehicle-to-vehicle communication, etc.) and drive-by-wire technology have facilitated the development of collision avoidance systems that use information about the vehicle’s surroundings, along with predictive computer models to determine the best course of action to avoid an accident. If needed, such systems intervene and share steering and/or braking control with the driver. These “predictive” systems generally attempt to honor driver intentions, opposing them only when doing otherwise would lead to a collision or loss of control. By constantly monitoring a vehicle’s surroundings and predicting a safe path through them, they may warn the driver and take control of the vehicle steering and/or braking to avoid accidents before it is too late. Much like a copilot or driving instructor, this controller intervention should strike a necessary balance between the level and frequency of intervention: not altering the driver’s steering and braking inputs “too much”, “too soon”, or “too often” while still guaranteeing that the vehicle avoid hazards independent of that driver input.
In my work with MIT’s Robotic Mobility Group, we are currently developing a predictive active safety system that predicts the “best-case” trajectory through the environment, assesses the threat this trajectory poses, and intervenes as necessary to avoid accidents. We’ve tested this system in both simulation and experiment with excellent results. As the patent is still pending, I’ll defer details until my next post. Until then, you can see a demonstration of its performance in a few simulation videos posted here. In the mean time, and before I’ve biased your creativity with our solution, please brainstorm your own possible solutions. We have the technology to identify hazardous conditions and help the driver avoid collisions. What would you think of driving a car with a system like this? How do we know when intervention is “too much” or “too soon”? Feel free to discuss these ideas with others via the comment section below.
Sterling Anderson
MIT Robotic Mobility Group
sterlinganderson.synthasite.com
Posted: June 23rd, 2009 | Filed under: Design, Sustainability, Transportation | 2 Comments »
My earlier post, What Cycling Can Teach us About Better Driving, addressed how spending some time biking can help us become safer and more fuel-efficient drivers. This article prompted some insightful feedback from readers via blog comments, email, and LinkedIn. Here is a summary of what I heard from you:
- Interaction: Cyclists learn to establish communication with motorists around them to ensure drivers are aware of their intentions, and vice versa. Drivers with experience cycling tend to be more vigilant with things like using turn signals, since they appreciate the importance of informing other road users what they plan to do. A motorist failing to use a turn signal can in some cases be a severe hazard to cyclists. One reader suggests always driving with lights on to help cyclists who use mirrors, particularly in foggy conditions. Another reader observed that establishing eye contact is ‘an important mode of communication’ for both cyclists and motorists.
- Awareness: Cyclists develop the habit of being very aware of what’s going on around them. The habit of checking to see who is around you and what they are doing carries over to driving, as well as being extra alert for cyclists. Experience cycling gives drivers some insight into where to look for cyclists and what to expect from them.
- Interpretation: It’s possible to discern much of what a driver is planning to do by paying attention to ‘body’ language, whether the actual behavior or facial expressions of the driver, or vehicle positioning, movement, or even what direction a car’s wheels are pointing. Cyclists develop these skills by necessity; drivers with enhanced anticipation and interpretation skills can drive more defensively and safely.
- Appreciation: Exprience cycling helps motorists understand just how much space cyclists need while being passed, and the wide variation in speeds cyclists can travel at. It’s important for motorists not to assume all cyclists are travelling slowly; underestimating speed can lead to trouble. In addition, minor road hazards that might not mean anything to a motorist (like some road grates) are significant obstacles for cyclists; if driver’s can recognize this they can anticipate cyclist actions better. One reader ‘would like to see laws requiring cycling skills as part of driver’s licensure’ to help drivers gain a deeper appreciation for the dangers and challenges faced by cyclists. Another reader pointed out that drivers in the Netherlands are ‘far more considerate of cyclists’ because so many drivers also cycle.
Posted: June 22nd, 2009 | Filed under: Cycling, Education, Transportation | No Comments »
