Friday, December 24, 2010

Advocate safer, robust, and efficient transportation for better cycling

What should cyclists advocate?  As an avid cyclist who enjoys such discussions, it is a question that comes up in one form or another.  In many ways, the same discussion arises during conversations with non-cyclists who simply want to get around in a convenient manner, have safe neighborhoods, and enjoy their lives.  That is the direction that I want to take advocacy.  Or more generally, a lot of "us" -- everyone in a neighborhood instead of simply cyclists -- want safe, vibrant, and livable neighborhoods and as Charles Marohn writes,
When you can't let your kids play in the yard, let alone ride their bike to the store, because you know the street is dangerous, then the engineering profession is not providing society any real value. It's time to stand up and demand a change.  It's time we demand that engineers build us Strong Towns.
The point is that instead of talking about what cyclists want, how great cycling is, or the many other benefits that it can give, we should recognize that a lot of what is good for strong neighborhoods is good for cyclists. 

My conclusion in a nutshell: slower road speeds are the easiest and most effective way to improve the cycling/pedestrian environment and a huge improvement for livable neighborhoods in general.  Underlying the idea is that a modest level of uncertainty is good since it requires drivers, cyclists and pedestrians to remain aware of their surroundings to successfully navigate the environment.  Instead of calling this bicycle or pedestrian advocacy, I think that we should push for safer, robust, and more efficient transportation network since we can make transportation safer, give people more acceptable options, as well as make driving trips shorter (make the same trip in less time).  We can make everyone better off regardless of their transportation choice.

Slower is safer for everyone

The claim that slower speeds are safer on local roads is probably accepted by just about everyone.  As one drives faster the distance covered before reacting and stopping increases; controlling a vehicle becomes more difficult; and damage increases in the event of a collision.  How much more dangerous is probably something that remains quite fuzzy for most people.  Given that an alert driver takes about 1.5 second to react and a few assumptions about the rate of deceleration we can determine the following:


Breaking Stopping Distances
MPHReaction
Distance
Total
Distance
204463
3066109
4088164
50110229

Relative to 20 mph, traveling 30 or 40 mph increases stopping distance by ~70% and 160%.  Clearly as one travels faster, the ability of an alert driver to slow their vehicle decreases at an increasing rate. Even a slightly distracted driver -- say it takes three seconds to react doubling the distance in the table above -- would significantly exacerbate the issue.  As expected, vehicle speed is highly correlated with pedestrian and cyclist injury/mortality.
From DOT HS 809 021 October 1999
A pedestrian hit by a vehicle traveling in the low 30s instead of low 20s has almost a three to fourfold increase in mortalityA statistic that is perhaps more surprising for many is that the risk to the driver is significant too

Injuries per 100 Occupants by Change in Speed (deltaV) at Impact
delta VModerate InjurySerious Injury
mi/hAIS 2+AIS 3+
1-104.51
11-2010.62.6
21-3029.211.1
31-4053.427.9
Bowie and Waltz (1994)
 
Mortality for drivers also follows a similar pattern: velocity changes of 20, 30 , and 40 mph are estimated to have a 0.6, 3.2, and 10.1% fatality rate (Joksch, 1993).  Clearly, cyclists, pedestrians and drivers are all better off at moderate residential speeds in the event of a collision.  Perhaps more important is that the traffic calming literature -- see the same FHWA synthesis -- strongly supports that collisions are reduced as well.  A recent traffic calming success on Lawyers Road in Fairfax County demonstrates the concept.  Consequently, pushing for roads designed for slower velocities and greater user awareness, as opposed to roads built like freeways with lower speed limits, is likely to produce fewer and less serious collisions/crashes. 

A more robust transportation system

A transportation network that gives people several acceptable transportation options is more robust than one that emphasizes driving only and can benefit even those that typically drive.  This is most obvious during major events such as the recent snow storms ("Snowmageddon") or "Tractor Man" where people were forced to choose alternatives due to their cars being trapped by snow or restrictions that made driving unreasonable.  More transportation options, however, are useful for far more mundane problems such as poverty -- cars are expensive to own and maintain: greater than $5K annually for a Ford Focus -- vehicle downtime, or as an alternative for a household second or third vehicle. 

Let me briefly emphasize that last point.  Parents often purchase (or let their teenagers use their vehicle) another car for a teenager because few alternatives exist and chauffeuring him/her around becomes a burden.  In short, teens are terrible drivers.  Giving parents alternatives to letting their teenager drive or greater leverage in limiting driving until a teenager demonstrates greater maturity and skill could literally save their life.  For instance, legislative changes that limit teenager driving have resulted in fewer fatal collisions.    

Naturally, there are people who would actively choose to cycle or walk more if they felt conditions were better.  As I demonstrated above, a strategy that lowers road speeds would make a given road safer and likely more acceptable.  Mind you, I believe virtually any road can be cycled on with a reasonable level of safety by applying a few rules and riding according to the rules of the road.  Based on my conversations with people of varying levels of interest in bicycling, however, when motorized traffic on a road crosses some threshold of volume and speed it is classified as too dangerous (or simply undesirable) regardless of the evidence.  Adopting a paradigm where slower but better flowing traffic becomes the norm clearly makes more roads accessible to average citizens.  

Yet typically one can simply look at a map in combination with some local knowledge to identify "high stress" areas or other obstruction that would limit cycling and walking for many even with some measure of traffic calming.  If these areas represent major connecting points in a local transportation grid, then addressing desirability via some smart engineering is probably worthwhile.  That is, if the cycling and pedestrian transportation network is meaningfully expanded with some thoughtful changes, then it should be seriously considered and pursued.   "Thoughtful" is the operative word here since careless application of bicycle treatments can create perverse situations for cyclists and other road users by increasing the risk of collision at with crossing traffic (intersections) which represents the greatest risk of collision to the cyclist.  While this is supported by observations in the U.S. as well as overseas, there are studies that find little correlation between facilities and collision risk but that facilities are also correlated with increased use and an overall improved safety that many attribute to safety in numbers.  Overall, my take on the literature is that it doubles my emphasis on the "thoughtful" adjective used earlier.  Over-engineering our roads can not only decrease safety directly, but facilities often remove driver/cyclist responsibility from actively thinking about their actions.  But in many cases, the engineering solution is the easiest way to connect sections of the transportation grid for many cyclists and pedestrians.  If one is looking to expand the acceptable cycling transportation grid through high stress areas, pick places with little or no crossing traffic, long ascents on roads with moderate to high traffic volumes, and so on.

More efficient and slower?

Clearly we all expect road diets and traffic calming to be safer however, their effect on vehicle capacity and travel duration is often minimal.
Under most annual average daily traffic conditions tested, road diets appeared to have minimal effects on vehicle capacity because left-turning vehicles were moved into a common two-way left-turn lane. (FHWA)
For instance, the Lawyers Road diet referenced earlier pulled back extreme speeds but only lowered average speed from 45 to 44 mph.  Moreover, distances are generally much shorter for local travel consequently the absolute change in travel duration will be small: a 5-mile trip without any stop lights driven at 30 versus 40 mph takes 10 and 7.5  minutes respectively.  Traffic signals clearly decrease the percentage difference between the two.  But we can actually slow traffic, decrease collisions, and improve travel times with a simple traffic device: the roundabout.

Many Washington DC locals shudder when they think about the high speed traffic circles that litter the area.  Modern roundabouts are not traffic circles nor rotaries!  Roundabouts have much more deflection, are much smaller than circles, and consequently have slower speeds.  Some of the benefits of modern roundabouts include:
  • Reduces injury accidents by 75 percent and fatal accidents by 90 percent.
  • Increases efficient traffic flow up to 50 percent.
  • Helps the environment by reducing carbon emissions by double digits.
  • Decreases fuel consumption by as much as 30 percent.
  • Costs less than traffic signals and does not require expensive equipment or maintenance.
Roundabouts never have a "dead time" like traffic signals where no traffic is in the intersection.  Roundabouts avoid long vehicle waits during off hours.  By design, entering traffic yields to traffic already in the circle and pedestrians traveling on the outside.  Consequently, successfully navigating the roundabout requires that the driver pay attention instead of mindlessly zipping through a green light.  As demonstrated by the red dots, roundabouts have far fewer conflict points than a signalized intersection.

The standard signalized intersection has 32 vehicle-to-vehicle conflict points

The roundabout has 8 vehicle-to-vehicle conflict points.
Not all intersections are appropriate for roundabouts and the literature has mixed reviews for cyclists since some of the early designs put bike lanes in the "circle".  Nonetheless, for the typical local trip, a few well placed roundabouts could easily reduce travel time to offset slower velocities and newer designs either encourage cyclists to behave as a vehicle or provide easy access to behave as a pedestrian


Conclusion

I know several cyclists that think fondly of European facilities.  While they look like a lot of fun and could work in some areas, even Copenhagen facilities show some warts and, to be frank, I have doubts that many would be willing to pay the price to have them.  Moreover, bike safety and ridership in many Netherlands cities likely experience a positive effect from strict liability and slow road speeds.  So the concept of building livable neighborhoods takes into account the European experience.   

Broadly speaking, here in the United States we spent a lot of energy and resources pursuing a strategy of safe crashing.  While seatbelts and other technological achievements are true advancements that help prevent injury and death in the car, we should also consider how people drive when they are in a protective cocoon and the effect on neighborhood livability.  Local streets should be for local travel which includes cycling and walking.  What this means is that for better neighborhoods we need to design our roads for slower travel that require greater driver attention.  Moreover, we need to stop building roads like freeways and simply slapping a 30 mph speed limit on the road.  We should consider innovative and efficient ways to enforce speed limits such as the speed camera lottery or ordinary automated cameras where engineering a slow road proves too costly for various reasons.

Thanks for reading!

Post Script

Just to be clear, I breezed through many details of the safety literature that might be important to particular individuals.  Moreover, I omitted many interesting studies and articles that could be related to various points discussed in the post.  My objective here is to give a broader outline but provide links that an interested individual could follow to obtain a foothold in the literature.  I'm also trying to reach a broader audience that might know little or only one side of the safety literature as well as a much broader community that could support pro-neighborhood policies that would find a more in depth discussion tedious.

Monday, November 8, 2010

DA Hurlbert has a perverse sense of what constitutes a felony

DA Mark Hurlbert decided to drop felony charges against a driver Mr. Erzinger who allegedly ...
Erzinger allegedly veered onto the side of the road and hit Milo from behind. Milo was thrown to the pavement, while Erzinger struck a culvert and kept driving, according to court documents.

Erzinger drove all the way through Avon, the town's roundabouts, under I-70 and stopped in the Pizza Hut parking lot where he called the Mercedes auto assistance service to report damage to his vehicle, and asked that his car be towed, records show. He did not ask for law enforcement assistance, according to court records.
What is particularly offensive is that the impact on Mr. Erzinger's job was considered despite the victim's objections.
“Felony convictions have some pretty serious job implications for someone in Mr. Erzinger's profession, and that entered into it,” Hurlbert said. “When you're talking about restitution, you don't want to take away his ability to pay.”
Of course, the reasonable person realizes that Mr. Erzinger who manages over a billion dollars in assets for Morgan Stanley already possesses more than enough assets to compensate the victim even if he had a take a pay cut as the result of a felony charge.

As bad as this is, it turns out the DA Hurlbert has a history of prosecuting some "interesting" things as felonies ...
  1. Andrew Thistleton was charged with third-degree assault and harassment for throwing a snowball at a coworker.  
  2. Wendy Lyall and Katie Brazelton were charged with felony criminal impersonation for swapping racing material after an injury for the Leadville Mountain Bike Race. 
Now in the end, the ludicrous nature of these two cases were realized and charges were eventually dropped.  Mr. Milo, the cyclist struck in this case, however, suffered serious life-altering injuries from an alleged hit-and-run collision.


“He will have lifetime pain,” Haddon wrote. “His ability to deal with the physical challenges of his profession — liver transplant surgery — has been seriously jeopardized.”
It appears to me and others that DA Hurlbert exercises a serious lack of judgement and a perverse sense of justice.

Added November 9:

DA Hurlbert responds to the criticism.  He claims that his point about the defendent's income and ability to pay were exagerrated and had nothing to do with the charges.  He makes a case why two misdemeanors will be a long lasting penalty which could still include the defendent being incarcerated. 

Wednesday, October 20, 2010

Safety in Numbers in Jacobsen's paper

EDITED on October 21, 2010

An interesting discussion on "Safety in Numbers" (SIN) at the Washcycle forced me to think more clearly about the Jacobsen paper supporting the hypothesis.  Long story short, by my assessment, the regressions in Jacobsen's paper are consistent with SIN but falls short of convincing evidence.  That is, given the form of his model one could easily estimate a slope parameter less than 1 without more cyclists leading to decreased risk of accidents/injuries.  

Let's consider Jacobsen's model of California bicyclists where he regresses ...

log ACC - log POP = a + b ( log CYC - log COM )

where ACC is number of accidents/injuries, POP is total population, CYC is number of cyclists, and COM is number of commuters.  Jacobsen claims that an estimated b parameters above means that as the proportion of cyclists in a city increases, proxied by the proportion of cycling commuters among all commuters, the risk of an accident/injury decreases.  A simple model of the underlying data can be described in the following manner:

log POPi ~ N ( u , s )

log CYCi = a1 + b1 log POPi + e1
log ACCi = a2 + b2 log CYCi + e2
log COMi = a3 + b3 log POPi + e3

For simplicity, lets assume that everything is distributed normal -- i.e., the linear transformation of the variables are lognormal -- and independent.  Suppose we are in a world where everything is proportional to population such that b1 = b2 = b3 = 1.  Applied to the California regression in the Jacobsen paper and dropping subscripts for cities we get ...

Left Hand Side ...
log ACC - log POP = a2 + a1 + e1 + e2

Right Hand Side ...
log CYC - log COM = a1 - a3 + e1 - e3

Now suppose we follow Jacobsen's paper and do a regression of ...

left-hand side = A + B right-hand side

... and consider the effects of the variability the error terms on an estimate of B.  The accident error term, e2, functions just like the error term of classic regression.  Consequently, increasing/decreasing the variability of that parameter should do little to the estimated regression coefficient B.

This leaves us with e1 and e3.  Increasing the relative variability of e1 and e3 will affect the estimate of B.  Increasing relative variability of e1 increases the efficiency of the regression since the term appears on both sides we will get estimates of B close to 1.  Increasing the relative variability of e3 and we get something synonymous with a classic errors-invariables problem where the estimate of B is biased towards zero.  This is straightforward to simulate and have done so with an EXCEL spreadsheet.  Unfortunately, I don't have an opportunity to play with the Google docs spreadsheet software to upload it and make it directly available.  However, I am more than happy to share with anyone that contacts me.  In the case where the variance -- the percentage variability since we're dealing with logarithms -- is equal, I observe estimates of B approximately 0.5. 

I've put some effort into working this out analytically and allowing more complex relationships, but at this rate the boy will be mashing a 52/11 chainring/cog combination by the time I get something sensible.  Consequently, I produced the example above to demonstrate that we should have some skepticism regarding the estimates.  Just to be clear, there are other ways one could (reasonably) produce a biased estimate signalling SIN.  But the given example is analytically straight forward, easy to simulate, and, in my opinion, quite plausible in the real world. 

Some general comments ...

I want to think Jim Titus and Jonathan Krall for continuuing to object.  It made me use some brain matter that has been getting dusty.  Interestingly, as I worked through the issue, I'm less convinced by John Forester's argument that the regression is tainted (inherantly) by the relationship between population and cyclists.  Interestingly, a paper on pedestrian SIN in Oakland addressed the regression issue too -- they cited Brindle (1994) as presenting the argument that randomly generated data with no relationship could produce an apparent SIN effect -- and found that when properly weighted, the "faulty" regression yielded consistent parameter estimates of the simulated data.  I'm convinced that if done carefully, one could estimate a ratio model and get appropriate results.  Although I think that there are better ways to get at SIN. 

With that in mind, I've downloaded the California data in the Jacobsen paper.  We -- Robin Fisher and I -- are still wrapping up re-analyzing the Wachtel and Lewiston paper on intersections.  But my over-the-weekend thoughts suggest that this should be straight forward. 

Special thanks to ...

Robin Fisher.  Some of the work here is the result of his insights.

Footnote ...

The the predictor's nubmerator in Jacobsen's model is actually the number of commuter cyclists.  But as one can see, adding another equation that conditions cycling commuters to all commuters would make the model more complex without adding any insights.

If one is wondering, when I simulated my model ...

a1 = a2 = log(0.1)
a3 = log(0.6)

all of the variance terms were ~ N( 0 , 0.01 )

Tuesday, August 31, 2010

My Letter to VDOT concerning the widening of I-66

To Whom It May Concern:


Let me begin by writing that I truly sympathize with commuters and travelers that need to drive through Arlington. Congestion can be awful on I-66 and it is the case that people often have poor alternatives to driving. Regardless, when I look at the present details of projects #1 and #3, I am pretty skeptical that any improvements are being made with respect to travel time. Given the general local opposition to the project -- I think that there are some valid points among the vitriol ... there are points that I see as more of a rant -- it appears to me that some more thought is needed to address the transportation issue. Consequently, I am opposed to the present plan.

My understanding of queuing theory is that people switching lanes creates more chaotic motion which increases travel times. I think that given the congestion on I-66 that aggressive drivers will use the long auxiliary lane to leave the regular travel lane, advance in the queue, and re-enter the travel lane at some point creating an effect that will -- on the margin -- increase travel times. Now from a conversation with the traffic management person at the 10/27 meeting, the creation of an auxiliary lane gives drivers that enter/exit the highway more space to negotiate their entrance/exit which would decrease travel times. His simulations suggested that the net effect is to decrease travel times.

One problem with the conclusion is that it appears to lack measures of robustness. For instance, if I ask what is the confidence interval of the average difference in travel times, the simulations do not support such analysis. The issue here is that there are competing effects and everyone agrees that the simulations contain considerable uncertainty, but we have zero measures of that uncertainty. Given the aforementioned competing effects, it would not be surprising if a confidence interval existed, it would include zero, as well as, a range of positive values. From the perspective of science, the conclusion that projects #1 and #3 represent an improvement is pretty weak.

A second problem with the conclusion is that according to the researcher, it fails to account for any changes in the number of accidents. More generally, his response was that traffic engineering's models for accident prediction is rough at best. Reading between the lines, his response was more along the lines of accident prediction models are "pretty darn bad." In my casual reading of traffic engineering articles and books, there seems to be a line of thought that aggressive driving is a major cause of accidents. Well, people are going to have these runways to zip ahead -- over one mile in heavy traffic! -- in an attempt to cut in line. However, my experience is that people cutting in line tends to irritate others resulting in more aggression in return. My take is that omitting these accidents from the simulations creates a downward bias in the travel times that would bias any comparison made when choosing projects in the first place. Moreover, it also opens up the possibility that even if the project results in a net decrease in average travel times, it might increase the empirical variance of travel times since an accident can create a real travel quagmire. In other words, the projects might make an ordinary day a little better but make it more likely that a commuter gets stuck in a nightmare. Whether that would represent an improvement is dependent on preferences but would be a turn for the worse in by my standards. Let's remember that people do get hurt in accidents. What the tradeoff is between travel time and personal injury is unclear to me. That travel times could get worse and we have more people getting hurt is obscene in my opinion.

At least based on intuition, I have less objection to project #2. That is, I can see how it decreases travel times. I guess it might help with traffic closer to the District by relieving later bottlenecks; although I suspect not. Whether it is worth the money and impact on residents nearby I-66 is another issue and others have written extensively on it. I have little to add other than it is my opinion that you should ensure that the plan is aesthetically and environmentally acceptable to a majority of those affected. At the moment, it is unclear whether VDOT has satisfactorily addressed local concerns.

My last point is that I am a believer in, "If you build it, they will overuse it." That is, if by chance the engineering changes represents an improvement in travel times, a subset of people using an alternative will substitute away from their present choice and drive. Or alternatively people will recognize the improvements and be more likely to reside/work in a location that takes advantage of this new improvement. This will occur until no advantage exists relative to any other alternative. I find it hard to believe that these projects are really addressing the big issue in a meaningful way. I would rather that my tax dollars be better used on something that truly represents -- or at least something that we have a high degree of confidence -- an improvement in a time where state and federal governments need to be more conscious of its dollars.

Saturday, August 28, 2010

So you're interested in a child trailer for your bicycle? My general thoughts, experience, and advice regarding trailers.

The good news is that there are several excellent models of trailers out there.  The bad news is that well defined guidelines for when a child is ready for a trailer are nonexistent.
So let's deal with the bad news ...

Roughly, you will find a few references that recommend waiting until a child is one year of age.  Precisely what that recommendation is based on is vague.  From what I can gather, the direct evidence is virtually nil such that it is more of a conservative educated guess.   We decided to take Henry for a few short rides at around eight-nine months since he developed good neck control at that age.  Moreover, since he was in an aluminum crash cage, we didn't bother with a helmet which would only add more weight to head and make the experience less satisfying.  Anecdotally, among cycling enthusiasts, I have read experiences with children from six months to about one year for the starting date.  But as I imply above, I would worry little about age instead of the child's physical development and their ability to enjoy the experience.  For instance, even at one year, Henry would have a hard time touching the floor of the trailer.  He was unable to use his feet and legs to support himself and would slowly slide forward into what appeared to be an uncomfortable slouch.  He never complained; but I imagined that it would not be particularly comfortable.  I ended up arranging a cardboard box to effectively raise the floor to his feet. 

The good news is that there are several excellent models out there.  After some investigation, I focused on three brands: Baby Jogger, Chariot, and Burley.  There are cheaper models which in truth are fine for a majority of uses.  However, we observed lower quality wheels -- the rims would only support low PSI tires for instance --, poor insulation, less comfortable seats, worse storage options, and less features.  Nonetheless, I am pretty confident in saying that they are almost certainly just as safe and acceptable for short rides. And assuming that any interested reader will do a little price shopping on his or her own, like bicycle components in general, one will pay a disproportionately large amount of money for an increase in quality/features.  Note that I only looked at models with 20" (ERTO 406) wheel as this is the common BMX size.  Consequently there are lots of quality tires and tubes available. If you decide to go with a model without suspension, you can find great street tires in this size that will roll well at -- the Schwalbe Big Apple is a famous example -- ridiculously low PSI. 

Baby Jogger has an awesome and quick fold.  It also converts from one mode to another in a fast fashion.  It is pretty expensive and heavy.  However, like many products if you are patient, you can find them on sale.

The Chariot has a lot of accessories and it features a suspension.  Unlike road/path cyclists where suspension adds little value, in the case of someone sitting down without an ability to use their legs to help absorb impacts, I think that the additional suspension will make a much more comfortable ride for the passenger in the back.  Wherever you ride, there are occasional holes, curbs, and so on that will result in big bumps.  This helps smooth it all out.  Realize that the base carrier does NOT come with the bike hitch accessory which I recall is non trivial.  Chariot is carried by REI which has a ridiculously good return policy and offers 20% off coupons that can be used on any single product.  With an REI credit card, there is also an additional percentage of the purchase added to your annual rebate.  

The Burley D'Lite also has tons of accessories and features a suspension.  Unlike the Chariot, it comes with the bike hitch.  Consequently, it is less expensive than the Chariot.  It used to be carried by REI, but I believe they only carry the Chariot line of trailers now.  

If you plan on having a second child as we were, then I suggest going with the double model.  There is a weight and width penalty to getting a two child trailer.  Although to date, the width of the two-child trailer has not been an issue for me.  This is the model -- the double seat Burley D'Lite -- we purchased.  I waited until the fall sale, got ~25% off, and still got 5% added to my annual rebate.  I know that Burley also offers an infant seat among its accessories which provides more support for babies.

Now I referenced relatively expensive models.  From memory, I believe both Chariot and Burley offer less expensive models that have fewer features.  For instance, at the time we shopped for trailers, the model one tier down the Burley line lacked a suspension.  The good thing about these expensive trailers is that there is a large used market for them.  One can often find a used model in Craigslist or recoup a decent percentage of a new purchase down the road.  Although before purchasing a used model, do realize that the models have changed over time.  For instance, Burley D'Lites from a few years ago do not have a suspension. 

Henry and I have done several 30-mile rides together.  So far, he seems to really enjoy the rides and is excited when I mention a trailer ride.  My rules of thumb are that I try to let him out of the cage every 60-90 minutes where he gets to play, do something interesting, eat with daddy, and so on for 15-20 minutes.  That seems to keep the rides lively enough for him to want to do it again.  Also ... realize that the damn thing is heavy.  The Burley trailer (double) is 33 pounds; plus 28 pounds for Henry; plus whatever supplies I have for the bike, me, and a two-year old; plus the fact that I ride a recumbent which is close to 30 pounds.  Picking appropriate gearing and routes makes the experience a lot better. Also, an upgrade that I wholeheartedly recommend if one is sticking with roads and paths is swapping the tires.  Not only will rolling resistance decrease but I suspect that the ride becomes more comfortable for the passenger as well.  I base this on rides with my recumbent which is designed with a passive suspension.  That is, the steel frame is designed to flex.  When I hit large bumps I'll hear the trailer hitch and the rear arm make some noise.  When I switched to Primo Comets -- virtually zero tread road tires that come in a wide variety of widths -- that sound decreased considerably. If one is patient, Primo Comets can often be found at a discount or used.

Feel free to ask questions and report your own experiences.

Friday, August 27, 2010

Am I the only one who thinks that this sign is going to kill someone?

While walking down Pennsylvania Avenue today, I tripped on the supports for a construction sign located at the Northeast corner of 20th St.  Traffic is coming from your left such that a pedestrians traveling east will typically be looking to the left.


1

As you can observe, the supports are quite long and easy to miss.  The supports also cross the direct path onto the crosswalk.  Besides the actual danger from tripping and falling, notice that there is a good chance that someone could fall onto the road and in front of vehicular traffic.

Sunday, August 8, 2010

former slave Jourdon Anderson letter

A bud recently passed a letter from a former slave named Jourdon Anderson to his former owner Colonel P.H. Anderson.  The background is that the P.H. wrote to Jourdon asking whether he would like to come back.  Jourdon's reply is quite witty and entertaining.  Being a natural skeptic, I wondered about its provenance and did a quick web search on the topic.  Low and behold, it appears that many others have asked the same question. 

One can search for Jourdon Anderson in Ohio and P.H. Anderson in Big Spring Tennessee in decennial Census records and find...
  1. a Jourdon Anderson in the 1880 Census born in Tennessee and married to Amanda with several children.
  2. a P.H. Anderson in Wilson County Tennessee -- according to the site there was a Big Spring in Wilson County -- who was a farmer aged 37 in the 1860 Census.   
Another individual, LE, found stronger corroborating evidence through the decennial census.  

The letter itself was published in a book titled the Freedman's Book -- see page 265 -- and reprinted in several newspapers of the day.  The NY Daily Tribune writes that it was dictated by Jourdon Anderson whereas other sources suggest that he wrote it.  Nonetheless, in short, the letter appears to be genuine and I am pleased that George Carter took the pistol away too.


Dayton, Ohio, August 7, 1865

To My Old Master, Colonel P. H. Anderson
Big Spring, Tennessee

Sir: I got your letter and was glad to find you had not forgotten Jourdon, and that you wanted me to come back and live with you again, promising to do better for me than anybody else can. I have often felt uneasy about you. I thought the Yankees would have hung you long before this for harboring Rebs they found at your house. I suppose they never heard about your going to Col. Martin's to kill the Union soldier that was left by his company in their stable. Although you shot at me twice before I left you, I did not want to hear of your being hurt, and am glad you are still living. It would do me good to go back to the dear old home again and see Miss Mary and Miss Martha and Allen, Esther, Green, and Lee. Give my love to them all, and tell them I hope we will meet in the better world, if not in this. I would have come back to see you all when I was working in Nashville, but one of the neighbors told me Henry intended to shoot me if he ever got a chance.

I want to know particularly what the good chance is you propose to give me. I am doing tolerably well here; I get $25 a month, with victuals and clothing; have a comfortable home for Mandy (the folks here call her Mrs. Anderson), and the children, Milly, Jane and Grundy, go to school and are learning well; the teacher says Grundy has a head for a preacher. They go to Sunday-School, and Mandy and me attend church regularly. We are kindly treated; sometimes we overhear others saying, "Them colored people were slaves" down in Tennessee. The children feel hurt when they hear such remarks, but I tell them it was no disgrace in Tennessee to belong to Col. Anderson. Many darkies would have been proud, as I used to was, to call you master. Now, if you will write and say what wages you will give me, I will be better able to decide whether it would be to my advantage to move back again.

As to my freedom, which you say I can have, there is nothing to be gained on that score, as I got my free-papers in 1864 from the Provost-Marshal-General of the Department at Nashville. Mandy says she would be afraid to go back without some proof that you are sincerely disposed to treat us justly and kindly -- and we have concluded to test your sincerity by asking you to send us our wages for the time we served you. This will make us forget and forgive old scores, and rely on your justice and friendship in the future. I served you faithfully for thirty-two years and Mandy twenty years. At $25 a month for me, and $2 a week for Mandy, our earnings would amount to $11,680. Add to this the interest for the time our wages has been kept back and deduct what you paid for our clothing and three doctor's visits to me, and pulling a tooth for Mandy, and the balance will show what we are in justice entitled to. Please send the money by Adams Express, in care of V. Winters, esq, Dayton, Ohio. If you fail to pay us for faithful labors in the past we can have little faith in your promises in the future. We trust the good Maker has opened your eyes to the wrongs which you and your fathers have done to me and my fathers, in making us toil for you for generations without recompense. Here I draw my wages every Saturday night, but in Tennessee there was never any pay day for the negroes any more than for the horses and cows. Surely there will be a day of reckoning for those who defraud the laborer of his hire.

In answering this letter please state if there would be any safety for my Milly and Jane, who are now grown up and both good-looking girls. You know how it was with poor Matilda and Catherine. I would rather stay here and starve and die if it comes to that than have my girls brought to shame by the violence and wickedness of their young masters. You will also please state if there has been any schools opened for the colored children in your neighborhood, the great desire of my life now is to give my children an education, and have them form virtuous habits.

Say howdy to George Carter, and thank him for taking the pistol from you when you were shooting at me.

From your old servant,

Jourdon Anderson

Sunday, July 25, 2010

George Washington on Religious Tolerance



In reference to recent remarks on the proposed Cordorba House near the World Trade Center site, bloggers have shared this letter written by George Washington "



to the Hebrew Congregation of Newport, Rhode Island. In this letter, the first American President assured the Congregation--as he had, in separate letters to each, assured the United Baptist churches in Virginia, the General Assembly of Presbyterian churches, the Methodists, the Congregational ministers, and the Roman Catholics--that this brand-new nation would be a place of inclusiveness and religious tolerance, where everyone could enjoy 'liberty of conscience'."




Gentlemen:

While I received with much satisfaction your address replete with expressions of esteem, I rejoice in the opportunity of assuring you that I shall always retain grateful remembrance of the cordial welcome I experienced on my visit to Newport from all classes of citizens.

The reflection on the days of difficulty and danger which are past is rendered the more sweet from a consciousness that they are succeeded by days of uncommon prosperity and security.

If we have wisdom to make the best use of the advantages with which we are now favored, we cannot fail, under the just administration of a good government, to become a great and happy people.

The citizens of the United States of America have a right to applaud themselves for having given to mankind examples of an enlarged and liberal policy—a policy worthy of imitation. All possess alike liberty of conscience and immunities of citizenship.

It is now no more that toleration is spoken of as if it were the indulgence of one class of people that another enjoyed the exercise of their inherent natural rights, for, happily, the Government of the United States, which gives to bigotry no sanction, to persecution no assistance, requires only that they who live under its protection should demean themselves as good citizens in giving it on all occasions their effectual support.

It would be inconsistent with the frankness of my character not to avow that I am pleased with your favorable opinion of my administration and fervent wishes for my felicity.

May the children of the stock of Abraham who dwell in this land continue to merit and enjoy the good will of the other inhabitants—while every one shall sit in safety under his own vine and fig tree and there shall be none to make him afraid.

May the father of all mercies scatter light, and not darkness, upon our paths, and make us all in our several vocations useful here, and in His own due time and way everlastingly happy.

G. Washington

August 18, 1790



Long story short, (1) Newt's comparison to Saudi Arabia only makes sense if one believes we should be like Saudi Arabia and (2) being tolerant means tolerating things that one doesn't like.     


Saturday, June 12, 2010

Looking for a helmet/bike cam


With some local and national incidents on the road, my interest in a helmet/bike video cam has peaked recently.  In addition to documenting some cool rides, using footage for online cue sheets, and some random stuff, I'd like to use the camera as evidence in the event of a collision, near miss, or harassment.  If you have not seen these incidents, the video has proven helpful in some collisions or near collisions ...

http://tinyurl.com/3yrnfxj

Some thought, research, and conversation led to the following video cam characteristics to target.

1. waterproof
2. small and lightweight
3. use commercially available memory and batteries
4. take footage for several hours
5. shockproof ... the ability to take steady footage when being shaken
6. robust enough for cycling
7. have mounts for helmets, handlebars, and so on
8. take video sharp enough for license plates

Now, I still have yet to decide whether to mount it on the bike or a helmet.  Mounting it on a helmet will help steady the cam during rides and reflect what I see.  However, I suspect that a lot of people look away when they are going to be hit or hit something such that some important scenes would be missed.  Also, having stuff mounted on your body naturally gets a little tiresome; but if it is light enough then it is probably ignorable.  There are a few standard cameras with video capacity, but appear to be a little too fragile for regular outdoor use.  Moreover finding helmet mounts for regular cameras appears to have its own issues.

I began with looking at ...

Tachyon XC Micro
Drift X170

    Both are reasonably priced and satisfy #1-7.  The Drift also has a LCD screen that allows you to view your shots immediately, a wider lens (which is good and bad), and more mounts.  It also costs a bit more.  However, I determined that while their resolution is excellent for a lot of purposes -- 720x480 -- from a few examples on the web it became clear that one would be unable to reliably get license plates and other fine details.  Below is a screen capture at 720p posted by a Bikeforums.Net member CyciumX.


    As you can see, the license plate of this truck on a 50 mph speed limit road can be read.  Based on comparisons between 480p and 720p, I think that this is the minimum resolution needed to identify plates unless the traffic is going relatively slow.  Note that I also looked at "super resolution" programs that borrow power across multiple shots of the same object to form a single high-resolution image.  Most are some sort of compilable code in C(+), Matlab, and so on.  There is a commercial product with good reviews named Photo Acute.  At this stage of my life, I think that the easiest way of getting higher resolution photos is to simply get a better video cam.  For a frame of reference, in early June 2010, I could find the two for $130-160 from Amazon.  

    I evaluated the following HD cameras ...

    Contour HD (1080p)
    Go Pro HD
    Drift HD170
      Literally, the Drift HD170 was announced earlier in the week and should be available July 10.  Assuming that the Drift lives up to its specs, the short story is that any of the three cameras are more than acceptable.  The Drift is the only one with a zoom function, remote control, and LCD screen that lets one view shots immediately.  It can also take 5 Megapixel still photos.  The Contour HD gets praise for its easy use and laser guide to line up shots; although it does not take photos and is limited to only 16 GB of memory.  The Drift and Go Pro have a 32 GB capacity.  The Go Pro HD also takes 5 Megapixel still photos and lots of accessories.  But the only way to check your camera alignment is to take your shot, download it to a computer, and verify that you have the right perspective.  

      At this point, I think that waiting for the Drift HD -- and perhaps a drop in price -- makes the most sense for me since I'm not in a rush.  But I'm hoping that more information comes out and could easily change my mind.  As of July 12, the Go Pro HD and Contour HD 1080p is available for $250 and $300 respectively.  Note that Contour also has another HD model with a maximum 720p resolution instead of 1080p which one can purchase for less than $200 at Amazon with a bonus $50 Amazon gift certificate.  The Drift HD has a retail price of $320.

      Notes:

      Here is a comparison of the Go Pro HD and the Drift X170

      http://www.youtube.com/watch?v=yZqXldNcfp4

      Here are some informative threads on Bikeforums.Net