I guess people think I am tedious on this subject (people on Facebook think I am tedious on this subject), but bike share is very safe. By design, it can count the number of trips. We’re pretty good at counting deaths, too. In over 100 million trips there have been two deaths. (Death #1)

On “normal” bicycles, we’d expect to see 20 deaths in that many trips. In cars, we’d expect to see 9 deaths in that many trips. Instead, two. (As a sanity check on those rates, Canadian statistics are similar.)

If driving doesn’t need helmets, then bike share doesn’t need helmets. Don’t be distracted by “look at all the safety devices on cars, look at the safe metal cage” — with all those devices, driving is still 4 times as likely to kill you, and we don’t think it needs helmets (TBI is the cause or co-cause of death in about 40% of car crashes; car crashes are a leading cause of TBI hospitalization and death).

There are several reasons why this might be true.
Bike share bikes come with daytime running lights.
Upright posture appears to put your head at lower risk in a crash.
Bike share tends to require a credit card, and the bikes are sized for adults. Small children don’t have credit cards and thus don’t ride bike share.
Bike share tends to occur in cities and biking is safer in cities (“but wait”, you say, “driving is also safer in cities!” Yes, and that means it is more dangerous than the driving average in suburbs and rural areas, where we still don’t even discuss the need for driving helmets. If that’s not dangerous enough for helmets, then neither is bike share.) People riding bike share are almost never bombing down a mountainside, and almost never engaged in head-down bicycle racing or race training.

If you claim to pay the slightest attention to math, if you claim to take a rational approach to risk, this ought to be the end of the discussion. Does the CDC collect biased statistics? Two separate studies found similar car and bicycle crash-death rates for the US and Canada (with Canada slightly safer, as one might expect if they’d ever driven or biked in both places).

I’ll just put these articles out here.
Note that we count overdose deaths per 100,000, Europe counts them per million.
Our best state in 2015, Nebraska, had 69 overdose deaths per million, or back of the pack for Europe. Portugal, with decriminalized drugs, had 3 per million.
Here’s the European stats referenced in that article.

Estonia, the European country with the highest overdose rate (127 per million) would sit at 13th among US states, tied with Georgia. 8 states (New Mexico, Massachusetts, Pennsylvania, Rhode Island, Kentucky, Ohio, New Hampshire, and West Virginia) had an overdose death rate about double that in 2015.

And of course, there’s all the violence that comes from pushing drugs into the criminal economy.

Portugal did the experiment, they’re not an especially wealthy nation, and they got great results. We study what they did and copy it exactly; we’ve never had a “War on Drugs” that came anywhere close to their results, and their approach didn’t require jail sentences, corrupted police forces, or no-knock warrants to “preserve evidence”. The humane choice is humane, AND it works.

Reading List

June 2, 2017

Normal Accidents, Charles Perrow
How complex systems go wrong, or not.

Influence, Robert Cialdini
How we get conned / how to con.

The Control of Nature, John McPhee
Hubris wins, but it’s close.

Waves and Beaches, Willard Bascom
For mitigation of hubris, and there’s interesting mathematics happening right in front of us at the beach.

Bicycling Science, David Gordon Wilson
More than you’d ever want to know about the most efficient means of travel.

Roxana’s Children, Bonfield and Morrison
“Because they’re always writing about the men”, and reverse nepotism. Roxana’s my great-great-great-grandmother, married twice, raised nine of her own kids and two stepkids, all lived long enough to marry. (Morrison is my great-aunt).

To Say Nothing of the Dog, Connie Willis
Because I keep re-reading it and enjoying it. Time travel with bits of Christie, Sayers, and Wodehouse.

The March North, A Succession of Bad Days, Safely You Deliver, Graydon Saunders
Because I keep re-reading and enjoying them.

Yesteryear I Lived in Paradise, Myrtle Scharrer Betz
Florida before air conditioning and the crowds it has now. I grew up sometimes messing around in boats in St. Joseph’s Sound behind Caladesi Island, where she grew up.

Cradle to Cradle: Remaking the Way We Make Things, Braungart and McDonough
Read it once at the recommendation of my uncle, it made a real impression on me, and got me permanently thinking about the asymptote, after we’ve sucked up all the cheap-and-easy resources.

The Winner-Take-All Society, Luxury Fever, Robert Frank
Introduces you to tournament economies and relative-status utility functions (deriving satisfaction from your status relative to others screws up the mathematics of market economics; free markets can yield suboptimal results under those conditions).

There’s probably other books that I’ve forgotten, and at least one that hasn’t been written, about how flaky and weird our mental engines are, and why we shouldn’t just be content with how we’ve made ourselves, and how we could be better people (not smarter people, not longer-living people, but more considerate, less biased, more careful).

Biking and cold weather

April 1, 2017

One thing I didn’t understand growing up in Florida was how people could bike in cold weather.  Now that I live near Boston, I do it all the time, and I understand how.  I will share these secrets with you.

The two most important things to know are that you need to shield your extremities (toes, fingers, ears) from cold wind, and that even moderate cycling generates an enormous amount of heat.  Humans are not efficient motors; for each 100 watts we deliver to the pedals, we leave 300 in our legs, to be swept into the rest of our body by our remarkably effective circulatory system. Most people can pedal at 100 watts once they are in any kind of shape at all. The heat isn’t all there right away, so you also have to get used to the idea that rides start “brisk”, but use layers because you’ll warm up.  Wind blocks and sweaters that unzip down the front (as opposed to pull overs) are a good thing because your thighs and torso will be warmest by far. And by layers, I don’t necessarily mean thick ones; it’s easy to overdress for a trip of more than a couple of miles, and then you’re sweaty, in the winter, which is dumb.

Another thing that helps is learning to personally quantify what is or is not endurable.  For example (note, I seem to run warm, especially after ten years of biking in the winter) above 45F, I can ride barehanded, below 45F I need gloves or some sort of a wind shield.  With “baggies” or “pogies” to shield my hands, I can ride barehanded down to 15F (you try it, and if it doesn’t work, you put on gloves).  Without a beard I need to do something for my face below 30F, with a beard I am comfortable down to 20F. It turns out that with a wool long-sleeve T-shirt and a wind block (and gloves) I can endure 40F raining or 20F dry. (“endure” means parts of me may be cold, but not painful, and my torso and legs are warm enough to keep it that way).  I don’t have a lot of experience biking in single digit temperatures, but a balaclava appears to solve the cold-face problem pretty well and that appears to be the main problem; gloves in pogies and two layers of socks handle the rest.  

People will live in electric vans

Reading an article about people in Silicon Valley living in cars (didn’t save the reference, go look for it) and noticing that there was no plan to build new housing fast enough to meet demand, it occurred to me that (necessity being the mother of invention) there would be innovation in the world of cars-for-living-in.

I thought about this a little more, and realized that electric vans (camper vans, minivans, step vans, not sure exactly what) were likely to hit the sweet spot for this. So many things go better with electricity, especially nowadays. Electricity runs lights, computers, fans, phones, electric blankets, in a pinch it can even run air conditioning. And it does all this quietly, with no smells. Gas powered cars can supply a little power for a little while from their batteries, but they’re small, and the usual way to recharge them is to run the engine when there is otherwise no need. Mechanical constraints to get power to the wheels usually force the floor of the car (or van) relatively high above the ground, reducing interior headroom.

Electric cars have comparatively huge batteries, and will certainly be able to refill at charging stations (and some employers even provide these for free, at least for a little while more), or at relatively low cost from someone else’s electric power, and there is always the option of solar (especially in sunny places like Silicon Valley), especially on the squarish roof of a van. Rooftop solar wouldn’t provide enough energy for a lot of driving, but it would cover consumption by electric amenities. Because power can be distributed to the wheels through wires instead of mechanical axles, the floor of the van can be relatively low to the ground (this is a really good idea anyway for a delivery van) which provides a lot more headroom inside.

It’s possible that a self-driving van could also dodge overnight parking restrictions by driving very slowly on low-traffic streets, automatically pulling over whenever faster traffic approached from behind (5mph or less, to conserve energy, minimize motion for sleeping passengers, and maximize safety).

If I can think of this, I’m sure someone else is already working on this. Anywhere that artificial restrictions on housing supply cause prices to spike, this could be an option.

After a little more thought, this: “Neighborhood Electric Vehicles”. A weight budget of 3000lbs, but no need for a high-strength frame or collision crumple zones gives you room to work with (old VW vans weighed much less than that).

On June 22 Cambridge held a public meeting on traffic in Inman Square. I did not attend. I did receive a pointer to the presentation. The next day, a woman on a bicycle was killed in Inman Square, perhaps first doored, certainly run over by a landscaper’s truck.

Preliminary comments.

Slide 4, I see counts of “traffic volumes” measured in “vehicles per day”.
Which of the following is “vehicles”:

  • bicycles only?
  • cars and trucks only?
  • bicycles and cars and trucks?

I see no pedestrian counts, which seems like a major omission.
I also see no breakdown by turns, which makes it difficult to know how much of a priority to place on turning traffic.
I also don’t see any information about existing light timings.

For slide 13, the only group for whom “increase efficiency” is a concern is “Vehicle”, and I suspect that really means “Motor vehicle” since “Bicycle” is a separate category. This seems like a major omission, since you have apparently not measured either the bicycle traffic or the pedestrian traffic, we don’t know if optimizing motor vehicle efficiency reduces the total time wasted at this intersection, and it might well compromise safety. Lacking any other information, I think we must assume that each person traversing this intersection is equally important.

It’s also important to notice that attempts to “increase efficiency” for motor vehicles here could be pointless. This intersection doesn’t exist in isolation; it is connected to the rest of Cambridge, which is also filled with traffic jams. In contrast, both bicycles and pedestrians flow freely through the rest of Cambridge (I bicycle commute on Broadway or Hampshire every working day of the year, I have video) so impediments removed here would result in actual gains.

One efficiency problem that could be addressed with no infrastructural changes is locally-greedy misbehavior by drivers; people frequently enter the intersection without a clear path to exit it, resulting in a blocked box when the light changes (bicycles are less affected by this; again, I have video). Drivers also speed fruitlessly (later to be passed in a line of stopped traffic by a fat old man on a huge heavy bicycle, so truly useless speeding), endangering everyone. In both cases, the remedy for locally-greedy misbehavior is enforcement; tickets for blocking the box, tickets for speeding, tickets for running red lights. Automated enforcement is probably more cost-effective than staffing the intersection every day at rush hour.

Another thing I saw no mention of was the role of parking in reducing safety. The door zone is a constant worry to cyclists, and the space allocated to parked cars also reduces options for creating safe places for cyclists to ride.

Other questions that need answering:

  • I know that buses use Hampshire. How many people use those buses, and how much delay (summed over all the bus passengers) results from that delay? That’s another thing we should optimize.
  • There’s a lot of bike traffic on Hampshire, especially at rush hour. If we knew the range of trip distances for people traversing Inman Square in cars (especially at rush hour), we might get some idea of the potential number of bicycle commuters that would use Inman Square if were less dangerous and more pleasant (it is one of the more significant unpleasantness bottlenecks in Cambridge).

Given what looks like a severe case of car-centric tunnel vision by whoever prepared these slides, I think that someone needs to start over again, perhaps doing the mental exercise of banning cars and seeing what sort of intersection results. (That’s not quite a serious proposal for an intersection design, but it is definitely a serious proposal for being sure that something other than cars-cars-cars is considered.)

My choice for a starting point would be to de-emphasize traffic “efficiency” for single-occupancy vehicles since those are the least-efficient users of scarce road space, the most needy in terms of a clear path to travel, and relatively dangerous to other people on the roads. Buses are space-efficient, very safe for their passengers, necessary for the less-able, and a good backup choice in nasty weather. They’re not a good thing to crash into, but their drivers are trained professionals, and risk-to-others is amortized over all the passengers on the bus and thus is not that large per passenger. We should remove enough cars from the road to ensure that buses are not impeded. Both bicycles and pedestrians are very space-efficient and though neither mode is risk-free, they are very safe for other people, and they’re also able to cope with narrow paths and impediments that completely block automobiles. I would therefore do as much as possible to make those two modes attractive. When I look at all the somewhat-unused space in Inman Square, my reaction is to try to find ways to use that space make things better for pedestrians and cyclists, instead of trying to use it as more places for cars to drive on.

Videos of Inman Square:

Hypothesized mechanisms for “safety in numbers”

Safety in numbers is a cycling safety rule that says that the more people ride bikes, the safer each rider will be. Hypothesized mechanisms include (1) driver familiarity – because drivers more often see bikes on the road, they become better-trained to see them on the road and (2) driver empathy – because so many drivers also ride bikes, they are more aware-of/concerned-about bicycle safety issues. (Here’s a nice pile of pointers to papers, tracked down by a real live researcher.)

I think both of these mechanisms are entirely possible, but riding an actual bike in actual traffic in actual crowds of cyclists, I’ve noticed what looks like other ways that greater numbers provide safety. In at least one case I’ve captured it on video. The difference between these mechanisms and the others that are hypothesized is that they are extremely short term – “safety in numbers” can appear whenever there is a biking crowd and disappear as soon as it disperses. These are also somewhat more likely in crowded urban areas and depend somewhat on the existence of traffic jams.

The first mechanism I might call “schooling” (after Bike Snob’s “shoaling” and “salmoning”). Bikes riding in a line are schooling, and for several common cycling hazards, most of the risk is borne by the lead fish, and the rest get a free ride. If someone in a parked car is not looking for bikes and is about to open their door, but then a bike zips by, it’s not unreasonable that they would be startled, and maybe then look to see if it was clear – and if the bikes are schooling, all the followers get the benefit of that. The dooring risk is almost entirely on the lead cyclist. Similarly, cars pulling into or across traffic represent a threat only to the lead cyclist, and very little to the ones in the rear. A line of bikes is also somewhat protective against right hooks, since those usually occur when a driver thinks they can overtake a bike and turn right, or forgets the presence of a single bike. With a line of bikes, once the first is across the side street, it is obvious to the driver that a right turn is not possible.

A second method is less obvious, but safety decreases markedly in the range of speeds between the slowest and fastest typical commuters. A low-speed (below 10mph) crash is stupidly survivable; you can almost step off your bike as it falls down. A high-speed crash (above 20mph) is far more likely to send you to the hospital or worse. Bike lanes at rush hour tend to run single file for some distance, usually because the bikes are hemmed in between parked cars on the right and “parked” cars on the left. Inevitably, some riders will be slower than others, and the inability to pass then compels the would-be-faster riders behind to slow down until they can pass. This makes them safer, whether they like it or not. This, I’ve seen on video, where I play the role of impatient rider. The probability of this delay and the difficulty of passing both rise pretty quickly once there’s more than a couple of riders delayed behind a slow leader.

After dark, a school-of-fish also multiplies the effectiveness of any lights that cyclists might be using. Just considering use of lights and not, if an unlit cyclist pairs up with one using lights, they can obtain most of the safety benefit of the lights. When two cyclists both have lights, the variations in their movement or in the flashing style of their different lights will create additional visibility over a single cyclist; for example, one cyclist’s flashing light might draw attention, but the other’s steady light might allow a driver to accurately locate the pair. Not nearly as many cyclists ride at night, but bicycle lighting use in the US is not nearly as good as it should be, so there’s plenty of room for this to help.

I don’t know if I’m typical, but if I’m riding at night and overtake another cyclist without lights who’s not too much slower than me, I’ll slow down to give them the benefit of my lights. I’ve even done this with a (impressively fast and competent) rollerblader caught out too late on the local multi-use path.

The interesting (to me) thing about these is that they can work in the US, they take no time to work, and they take no change in driver empathy or enlightenment. And if a crowd of bikes disassembles, then the safety effects do as well. The effects should appear most often at rush hours, when the largest number of bikes are on the road and when they are most hemmed in by traffic.

A historical/hysterical note is where the idea for safety-in-numbers comes from, and why we assume its existence even when we’re not entirely sure how it works. Once upon a time, when Effective Cyclists were peddling their prescriptions for safer cycling (ride in the road, in traffic, just like the “vehicle” that bicycles legally are, and that legal status is a good thing for which the EC movement certainly deserves some credit) the counterexamples of “the Dutch” and “the Danes” came up, where many people often ride bikes on lanes entirely separate from auto traffic, with crash fatality rates 5 times lower than ours. The EC people were very good at finding and/or interpreting studies that “proved” that if only the Dutch would get rid of their separate facilities, they would be even safer than they are now, that in fact their extraordinary safety must have some other cause. (This might even be true, but nobody’s ever managed to get more than about 1% of the population to bike in an “Effective” style.)

And what was the obvious difference that might be the cause of that anomalous safety? “Numbers”. It must be “Safety in Numbers”, assumed to exist to fill a (huge) gap between theory and reality. This was convenient for the Effective Cyclists because they got to continue to feel correct about their prescriptions (“just you wait, once everyone here rides bikes, we’ll be the safest cyclists on the planet!”) but now this same hypothesized mechanism is used to justify creation of cycling-specific infrastructure that Effective Cyclists hate (“we’re tired of waiting, EC is phenomenally unpopular and we’ll never get the numbers that give us the safety we want if we do it your way. And by-the-way, global warming, particulate pollution, pedestrian deaths, urban congestion delays, traffic noise, and public health, we need this now. Infrastructure will get butts in saddles and safety-in-numbers ‘proves’ that they’ll be safe.”)