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:
https://www.youtube.com/watch?v=FRIFG3ipgUc
https://www.youtube.com/watch?v=2rfuAL7XDzs
https://youtu.be/rlJv_6pJbzo?t=4m10s
https://www.youtube.com/watch?v=5GAPu7tdGHQ&t=7m0s
https://www.youtube.com/watch?v=Au1ubzT1AWA
https://www.youtube.com/watch?v=aZp2Ml5nYz8
https://youtu.be/deRQ4x2WUtc?t=3m50s
https://vimeo.com/109317447

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.”)

I was just in Mountain View for most of a week on business, biking to and from work and to work dinners in the evening. The roads are much smoother than here near Boston, the weather was warmer, it did rain once, but wimpily, and it’s flat as a board in Silicon Valley. Biking there ought to be great.

Links go to short YouTube videos illustrating claims/points

However, they blow it. If you need to cover any particular distance, it’s easy to find yourself with no choice but a four-lane road with a door zone bike lane that waxes and wanes with the whim of whoever laid out the road, and parking is prioritized enough that you often find yourself squeezed towards traffic.

One shared use path is designed with the apparent assumption that bicycles are OMFG deadly dangerous to pedestrians, so it’s considered appropriate to encourage lower speeds by installing barriers that make high speeds deadly, and that also makes larger bikes (bakfiets, trailers) difficult to pass through, and that guarantee conflicts whenever people are traveling in opposite directions or if there’s a pedestrian and a bike traveling in the same direction. Imagine, for cars, that a crosswalk was made safe not just by installing a narrowing bumpout in each lane, but by narrowing the road to a single lane for both directions.

Note that this is on a straight path where everything is completely visible, so all that’s really needed in most cases is a “slow for pedestrians” sign. Not all people will go as slow as they should, but not all people will negotiate those gates without injury or conflict, either. Later on, a blind intersection with plenty of cross traffic on the Google Campus goes completely unremarked, and several curves past that are gratuitously blind, either because of untrimmed vegetation, or because bicycles were routed between two chain link fences, and for no particular reason one side (the one that matters) is intentionally made opaque by slatting installed in the fence so that it’s impossible to see oncoming bicycle or pedestrian traffic on the fence-narrowed path.

Incomprehensibly, an underpass with over 7 feet of clearance (I reached a hand up to measure as I passed under, so that’s an estimate – apparently they couldn’t be tasked with actual measurement, but I ride quite tall and cleared easily) was declared to be dangerously low, and thus we’re told to walk our bikes there, as if.

Actual road crossings are designed with zero thought to the convenience of cyclists. At one there’s a gate to force a U-turn to enter it, then a beg button that imposes an interminable wait despite large gaps in motor traffic (I didn’t wait). A cyclist obeying traffic laws to the letter could not ride back that same way – the returning lane slips onto San Antonio, and returning on the sidewalk instead one is greeted with a WRONG WAY sign specific to bicycles (and the sidewalk is clearly intended for bicycles, else the sign would read “no bike riding”). It’s not much wonder that I just wing it.

At another crossing on the Permanente Creek trail, cyclists are vaguely directed to enter traffic and then make a u-turn at the light, as if that is preferable to looking for a gap (which we’d need to look for anyway, to enter traffic to make that u-turn) and just crossing on foot. There’s a sidewalk, but it’s twisty and too narrow for two-way traffic. Crossing on foot is necessary because there’s a big-ass curb in the middle of the road. The same can be seen on parts of Middlefield, where children crossing to/from school have worn goat paths in the median strip, far from any crosswalk. (Video is not great; there were kids, they were waiting to cross, and the median is cut by little footpaths.)

At a larger level, multilane Alma/Central and the RR tracks make a nasty barrier to traveling (peninsula-compass) east-west in Mountain View. Crossings are not well signed, Google Maps doesn’t seem to know about them, the entry is tight, the mirrors at the bottom make it clear the bicycles are known/expected to be there, but the ramps are quite narrow, guaranteeing conflict if there’s 2-way traffic or pedestrians.

This is all doubly annoying because it could be so nice. Remember, flat topography and a mild climate. If there were good, comfortable, safe routes that led anywhere interesting, lots of people could and almost certainly would use them. But right now, Mountain View is failing both in the small (annoying and insulting inattention to details of intersections and safety) and in the large (arteries are for cars – wide, fast, and with varying-width door-zone bike lanes, sometimes very fast).

And yeah, I know, “reasons”. Y’all ought to look at yourselves, a 10-lane highway jammed up every morning, even with thousands of employees delivered by buses instead of single-occupancy vehicles. I rode a bike to dinner after work and beat the people driving. Here’s two free clues as to why Mountain View ought to install a ton of really nice bicycle infrastructure. #1, no matter what you do about traffic, more cars will always arrive to fill the voids that you create, and with high tech salaries I’m not sure even congestion charges would do the job. #2, if you install really nice bicycle infrastructure, if you need to get around your own town, you won’t care about that traffic, and because the land is so flat and the climate so mild, that’ll be true all year. You might want to knock out a few parking spaces and replace them with bike corrals to make this really be true, but I managed to find bicycle parking a lot closer to the restaurant than anyone driving there.

Subway capacities

May 7, 2016

I recall once figuring that the capacity of a single track of subway was substantially higher than a lane of traffic. This is how that is calculated for a real live subway (the MBTA Red Line, also roughly applies to Orange and Blue lines which run similar equipment.)

redline_cars_per_train = 6

Source: Wikipedia red line article

redline_trains_per_hour = 60/4.5 = 13.3

Source: 2014 MBTA Blue Book, page 17.
Headway is 8 or 9 minutes at rush hour on each of the Alewife/Ashmont and Alewife/Braintree lines, or 4.5 minutes on average on the shared portion of the line.

redline_ppl_per_car_policy = 167
redline_ppl_per_car_crush = (267*74+260*58+277*86)/(74+58+86)
redline_ppl_per_car_seated=(63*74+62*58+52*86)/(74+58+86)

Source: 2014 MBTA Blue Book, page 18.
167 is the policy people-per-car. Seated and crush capacities are averages over the red line fleet.

seated_rush_cap = redline_ppl_per_car_seated * redline_cars_per_train
policy_rush_cap = redline_ppl_per_car_policy * redline_cars_per_train
crush_rush_cap = redline_ppl_per_car_crush * redline_cars_per_train

seated_rush_cap * redline_trains_per_hour => 4,671.5596
policy_rush_cap * redline_trains_per_hour => 13,360
crush_rush_cap * redline_trains_per_hour => 21,526.6055

Compare this with a lane of traffic. Rule of thumb is that you get one car every two seconds, or 1800 cars per hour, and an average of 1.2 people per automobile, or 2160 people per lane per hour. Simple seated subway capacity at rush hour is double that, so-called “policy” capacity is 6 times that. Crush capacity, which I’ve seen and not much liked (“nobody takes the subway, it’s too crowded”) is just shy of 10 times the capacity of a lane of traffic.

And understand, this is far from the theoretical capacity of a subway line, it’s just what is actually obtained on a real subway in a real city at rush hour. Run longer trains (requires longer platforms, a completely doable thing) and you can add capacity. Run trains more frequently, and you raise capacity – the London Underground appears to manage 24 trains per hour at rush hour on the Northern Line or not quite double the Red Line’s frequency.

Re-doing the numbers at the London Underground’s rate for scheduling trains:

seated_rush_cap * underground_trains_per_hour => 8,408.8073
policy_rush_cap * underground_trains_per_hour => 24,048
crush_rush_cap * underground_trains_per_hour => 38,747.8899

At the Underground rate, “policy” train packing carries 11% more people than “crush” packing in the current system. And the theoretical “crush” capacity is the equivalent of 18 lanes of traffic.

Earlier this week, I was riding my bike home on a road with a bike lane, and came up to an intersection where the car at the front looked like it was planning to turn right (based on position in lane and angle of wheels) but was not signaling a right turn. The intersection has no advanced stop line for bicycles, just a plain old stop line and crosswalk. And understand, me going first is a completely legal thing, there are two lanes, straight traffic has right-of-way over turning traffic.

This presented several choices. I could stop far enough back that if the driver intended to turn right, they could easily do so (except that they would probably get hung up by pedestrians in the crosswalk and would stop midway, blocking the bike lane and delaying me). If they did manage to turn right quickly, there’s no guarantee that the driver behind might not try to barge on through with their own right turn; that’s happened, I even have video of someone doing this. Or, I could pull up to the stop line, and hope that if they did decide to turn, that they’d notice my presence in time not to hit me, and also not try to just make their turn through intimidation. Or, (and this is what I did) I could stop a little bit in front of the stop line – technically illegal, though I’ve never, ever seen this particular law enforced and drivers violate it constantly – and position myself so that the driver could hardly help seeing me, and even if he didn’t or if he decided to go anyway and there was a collision, I’d land on the hood of the car – relatively safe for me as collisions go, relatively damaging to the hood of the (expensive) car.

I hope it’s clear that this is no way for a normal person to ride a bicycle. I do so because I’ve learned it over the years and it’s no longer difficult, but to think that I would explain this to someone else as “useful tips for riding in traffic” is insane. This is similar to knowing that “it’s okay to ride closer to parked cars in a residential permit parking zone, because people move those cars only about once a day”. Or, “practice riding through potholes no-hands, so you get really good at controlling your bike on our crappy crappy roads”. I’m not making any of this stuff up, I do these crazy things, our roads are messed-up enough that it helps.

I’m not sure how this gets fixed. Safety-in-numbers is some mitigation; with enough people on bicycles, it becomes obvious that there’s bike traffic to the right and bike traffic through intersections and bike traffic past car doors, and the normal distribution of aggression among bicyclists insures that a few of them will help carve out space for the rest. I don’t put much stock in driver education; there’s not that much in it for the drivers, and it’s work to constantly be looking around for bikes. We could pretend to do more enforcement, but in practice the majority has zero appetite for that (evidence: we don’t vote for more enforcement, despite continual infractions and drivers killing thousands of themselves and other people every year). I think I’d like it if we adopted some modern Dutch infrastructure; a lot of that is designed to get rid of these designed-in conflicts and make it easier to see what’s going on. I have some hope that robot cars might be helpful; tedious rules like “always signal a turn at least 10 seconds or 3 car lengths before the turn” are what computers are for, as is “look for bikes in all directions always”.

I both drive cars and ride bikes, and for years I didn’t think much about how much driving a car impairs all your senses, as well as your ability to communicate. To hear how other people talk about traffic and safety, I think I’m not the only person to miss this.

Where this usually comes up is in discussions of rolling stops, and stop-then-go at red lights. The claim from cyclists (and this claim is absolutely true, which is why I’m writing this) is that they generally can see and hear better than people in cars, and thus are in a better position to judge if it is safe to go or not. This is one of the several justifications for the Idaho Stop Law.

So, vision. Someone riding a bike is as tall as they are standing up, if not taller. To stop, most people must hop off the saddle because they sit too high to reach the ground with their feet. Modern sedans tend to be about 4-and-a-half-feet tall (I just measured a Civic and a Camry), so whoever is sitting in them is shorter than that. On a bicycle, seated, your head is about 3 feet back from the front edge of the bicycle, but it’s easy to lean forward to within about a foot of the front. In a car, leaning forward gets you to the windshield, which is five feet back from the front of the car. Add to that whatever fog or dirt happens to be on the windshield and the windows, plus the various pillars and mirrors and fuzzy dice, and I hope it’s clear that the cyclist has a far better view of what’s around.

Next, hearing. Luxury cars are actually marketed for their ability to make you deaf to the world. That ought to be enough right there, but I’ve actually mentioned this to a degreed+prestigious colleague whose snap reaction was “no, I can hear okay in a car”. No, really, you can’t. Even without luxury soundproofing, cars have noisy engines, ventilation fans, tire noise, often a stereo, and quite often their windows are up. All these things act to block exterior sound. On a bicycle, the default is that you hear everything. There’s wind noise when you’re moving, but stopped at an intersection there’s nothing between you and the world and the bike is silent.

And you might like to think that maybe hearing doesn’t matter–after all, we let people who are deaf drive and ride bikes–but it certainly does. When I approach intersections, I can hear cross traffic coming before I can see it; that’s redundant safety information, which is a good thing. I can hear cars approaching from behind, and tell if they’re slowing or swinging out into traffic to pass, and I can judge the size of the car or truck as well (big trucks without sideguards are very dangerous). For pedestrian safety being able to hear matters, because I can carry on a conversation with the people around me. “I see you”, “go ahead, it’s a crosswalk, I’m stopping”, and of course “oops, sorry”. I can communicate with other cyclists, “there’s a blind woman walking ahead of you” (in the dark). All the sound signals that we’re supposed to legally make when approaching pedestrians are useless when approaching cars because drivers are effectively deaf. All the communication that’s easy with people around us is impossible with people in cars.

People on bikes also see more because of their ability to always position themselves near an intersection before stopping. That means we always get to see the light cycles and light timings, and even if we haven’t learned them all yet ourselves, we can see how other cyclists react to them. We don’t need to catch sight of landmarks as we drive through the intersection, because we always have plenty of time to look around at the front. Once you know the usual timing for a light (easily derived from countdown pedestrian timers on the street and cross street – which you can see because you are stopped at the intersection) you can also judge from quite a distance the appropriate speed to make the next light, which allows you to moderate your speed to only what is adequate to catch the green. Lower speeds make for easier pedalling, and are also safer.

I had meant to make a much longer rant about “windshield vision”, but I think this is good enough for a start. You might ask yourself, if you could drive and fool yourself into thinking that you weren’t half-blind and mostly-deaf, and not realize what you were missing stuck back in a line of traffic, if you might not be self-fooled about some other things. If your reaction to the facts stated here is that they’re the crazy opinions of one of “those cyclists” – don’t forget, I am a licensed driver, I drive often enough, I own a car, and this is true of most adults riding bicycles (knowing this stuff makes driving a lot less fun. Don’t expect any auto advertising to mention this ever).

Bonus sensory deprivation video, in case you still don’t believe me: watch the second driver in this video roll right over a bicycle and a bicyclist’s foot, and not be able to believe she did it. Said bicyclist has right of way, in clear daylight, riding straight on a straight road, wearing a dayglo-yellow jacket, with a front flashing light. The second driver did not see, did not hear the crash, did not hear the crunch of the bike as she drove over it, did not hear the guy she was running over yelling at her.

It occurred to me a few days after posting this that “people on bikes behave unpredictably” is consistent with “people on bikes make decisions based on information I don’t have”. Probably not the only explanation, but worth thinking about before jumping to pejorative conclusions.

Most times you see discussions on the internet of global warming, traffic congestion, and road safety, the advocates of the status quo are quick to claim that “we cannot ban cars, because [reasons]”. I’ve got no respect for this style of arguing the point because #1, even pseudo-serious calls to actually “ban all cars” are quite rare ( this recent article is the strongest statement I’ve seen, and that’s just one writer at Gizmodo ), #2 the reasons all assume that we’d do nothing to adapt and when possible remedies are proposed, new reasons are concocted (we can play this game all day), and #3, there’s real live reasons to reduce car use by quite a lot, and those cheerfully get ignored.

Just to motivate this, here are some very good reasons to drive a whole lot less. It’s also helpful to keep this in mind when considering alternatives; if they’ve got the same problems, then maybe they’re not good alternatives.

  • Cars kill thousands of people in crashes, including over 4000 pedestrians per year.
  • Cars kill their drivers through lack of exercise, enough to raise their annual mortality risk by about 25-30% 

    (summed over the population of car commuters, this is probably more early death than results from cigarette smoking ).  As long as exercise is its own separate activity, you’re unlikely to get enough of it.

  • Ignoring the less-death part of the equation, the regular exercise that you get from not-driving to work and results in just plain better health; you get more wind, more stamina, more flexible joints. It tends to help you keep weight off, tends to help blood pressure, tends to help blood levels of cholesterol and triglycerides, tends to ward off type 2 diabetes.  None of this is guaranteed for any one person, but it’s a really good bet.
  • Cars are a source of both particulate and noise pollution, which both contribute to poor health. Noise pollution from cars makes public spaces more annoying and less useful; you can’t hear as well.
  • Cars use roads very inefficiently. In urban areas the resulting congestion is so serious that one additional car added to Manhattan traffic is calculated to have an aggregate cost of $160 through delays to others on the roads.
  • Cars are a major source of CO2 emissions which contribute to global warming and climate change.
  • Paying for fuel for cars puts money into the pockets of nations and groups that do not share our values. Al Qaeda was mostly funded from oil money. Daesh is funded from oil money. Iraq would have been a non-issue without oil money (murderous dictators of poor nations don’t get much attention from us). Iran, officially an enemy of the US and ally of our enemy in Syria, runs on oil money.
  • From an economic-theory point-of-view, cars are a poster child for market failure. Their use is not independent of other people’s choices; if I want to take the bus, traffic from cars makes my bus ride slower and more expensive. If I want to ride my bike, cars can make the ride so much more unpleasant that many people won’t ride a bike. Even if I want to compromise and just drive a smaller car, the mass of larger cars makes me less safe in any collision; even for cars, it is a safety arms race. These externalities (pollution, noise, risk) are not accounted for in gas taxes. Even the direct costs of driving itself–repair and expansion of the roads–is not fully paid by the gas tax. The one reason that economic theory says ought to motivate people not to drive–that driving is very bad for your health–falls victim to human over-optimism about their good intentions and future luck; we won’t invest rationally in our (near-) future health, because we think we’re “healthy” and don’t need to do more. All this means that you can’t use hand-waving appeals to popularity and market outcomes to prove that profligate driving is what happens in the best of all possible worlds.

Given this motivation, let’s suppose we did ban cars. The question I’d like to see thought about and answered is not “why is this impossible?” but rather “what changes do we need to get by in a hypothetical car-less future? What changes would a lack of cars allow us to make?” My hope is that we would make some of those changes now, so that more of us won’t feel like driving a car is our only option. If the assumption is “cars are banned”, that removes the option of not thinking about a problem by assuming “well of course, for that we would use a car”.

One problem with using the thought experiment for this purpose is that there’s a difference between cars-banned and cars-reduced. If we actually banned cars, we wouldn’t need “bike lanes” because we’ve already got bike lanes. They’re called “roads”, but right now they’re full of cars. But if there’s still many cars on the road, we don’t get those “bike lanes” for free.. So keep that caveat in mind; if we’re planning to use tools from the hypothetical world in the real world, because some might not survive translation.

Another problem is: “what about the car-like things?” This might mean delivery trucks, golf carts, buses, trikes. What about self-driving cars? What about really big “bicycles”? Are those cars? Do we ban them too? I think what makes sense is to look at the costs of each and how they interact with what’s around them. Anything heavy tends to impose unusual wear-and-tear on the roads; this includes city buses. Anything human-guided has the potential for inept or careless use, so there should be some combination of small size, low speed, and/or safeguards to mitigate that risk. Inefficient transportation will produce excess CO2 until our energy supply is properly carbon-free. Even if a motorized robot-guided chair is carbon-free, safe for others, and kind to roads, it is still a motorized chair and will have the same detrimental health effects for its passenger.

 

So, to consider some of the problems:

There are people who cannot ride a walk long distances or ride a bike.

Anything that assumes bike riding or increased use of transit by default assumes some basic fitness, and some people lack that. How should they get around? In practice I think quite a few of them would use mobility scooters of some sort; modern electric wheelchairs travel as fast as 5mph (according to a wheelchair user I asked) but if they could be made stable we’d want more than that. I think they could be made stable. A larger, faster real-world example is a golf cart, though this is cheating slightly on the “ban cars” assumption. For people who lose their balance a tricycle sometimes works.

There are people with very long commutes.

Back before cars were so popular we tended to use a lot more rail; people would take the train in to urban areas to work. Would we restore our train networks? If the rail line doesn’t pass close by home and work, how are those endpoints connected? My default answer is “bicycles”. Another answer is to modify the zoning regulations that prevent people from living close to transit and work; artificially restricting that supply drives up prices and forces longer commutes. I expect this is one of the harder changes to make because it involves change near where people live; allowing greater density near transit would financially benefit anyone owning that property, and it would also provide an advantage to those somewhat near transit who wanted to use it (higher density allows transit to function efficiently allows better service). However, widespread density increases closer to urban centers might have the effect of reducing property values sufficiently far out as a simple consequence of increased near-urban supply reducing far-suburban demand.

For an all-bicycle commute, from personal experience I’d say 6-7 urban miles is fine, but 10 miles is pushing it, though that depends on conditions. The median commute is nearly 9 miles, which means that half might be done on bikes, but half also almost certainly will not. It’s possible to make biking somewhat faster — current bike routes often contain many gratuitous stops or are far from direct, and bikes with aerodynamic fairing or modest electric assist can cruise at 20mph (a human doing this without “cheating” is likely to get very sweaty) which reduces the time for a 10-mile ride to 30 minutes, which is about what my 6-mile commute-with-stops-and-old-legs takes.

There’s weather.

Sometimes it rains, sometimes it snows, sometimes it’s hot. As a general rule the only truly difficult weather is hot weather; we can add rain coats, umbrellas, gloves, boots, and hats for the wet and cold. Some cities have building codes that allow for pedestrian awnings, and those help with sun, snow, and rain. We’d probably do more of that in a car-less world. One useful thing about banning cars is that you no longer need to deal with your car and the weather; no need for car washes, no need for digging cars out of the snow. A pedestrian or a bicycle can fit down a narrow lane, or if in a hurry, can simply push through/over a snow pile rather than shovel out a wide path.

There’s kids.

It turns out bikes work pretty well for hauling tiny kids, and once they’re too large to haul, they can ride their own bikes.  With cars banned it’s vastly safer for little kids to ride bikes (turns out a ban isn’t even necessary if you design your infrastructure right).

Grocery shopping.

Not much need to adapt here. People who walk already use folding carts. My old retired now-deceased neighbor just carried his bags. People riding bicycles have many options, everything from backpacks to huge messenger bags to front racks to baskets and panniers mounted on racks. Even on a “normal” bike proper equipment allows six bags of groceries (2 front panniers, 2 rear panniers, 2 in basket). Actual intended-for-cargo bikes carry more.

There are heavy things that require heavy machinery to deliver.

True, but this is far from the common case. Delivery vans nowadays are large to amortize the cost of the driver who guides them, and then they drive as fast as allowed to also amortize the cost of that driver. The van is large, but the delivery generally is not. Consider the potential capabilities of self-driving delivery vehicles that need not to be large and fast. We can estimate this somewhat by looking at what humans on bicycles and tricycles are able to deliver. The point is not “this is what humans should be doing” or “look at those crazy people”, but rather, with a small vehicle and a small motor, it is possible to deliver this much stuff if you aren’t in a terrific hurry. Examples: Haley Trike and 400 lbs of sand (video); a chicken coop; a trailer full of Citibikes; a ludicrously large pile of stuff; a mattress, table, chair, and box. Robots could deliver loads of this size, and if it becomes economical for self-driving cars to ferry people around, then it will also be economical for self-driving carts to ferry cargo around in smaller batches.

Emergency vehicles

Well of course, for that we would use a car.  With all the other cars and trucks banned, they should be able to move really quickly through the traffic that’s not there.  (Bikes don’t take up much space and you can haul them completely off the road if you need to clear a path for an ambulance.)

Steep Hills

There is already (one) cable-lift assist for bicycles.  E-assist also helps, if a hill must be crossed regularly.  For one-shot annoying hills, walking works.

Rural Areas

No good answers here yet.  Horses?  Even electric vehicles are dicey, for sufficiently cold and remote values of rural.

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