Parklet: win-win or win-lose?

Near the right side of the photo below is a “parklet,” a seating area which replaces a couple of parking spaces on Somerville Avenue in Somerville, Massachusetts, USA. A parklet may also contain a planting, as this one does.

Parklet on Somerville Avenue, Somervill, Massachusetts, USA
Parklet on Somerville Avenue, Somerville, Massachusetts, USA

A parklet can be installed only on a street which is wider than it needs to be for travel – typically, where curbside parking is an established reality. In the early part of the 20th century, parking might have been only sporadic for deliveries and pickups of goods, and for buses and taxis to pick up and discharge passengers. Over time, private motor vehicles became more affordable and popular. They increasingly came to occupy the  sides of streets, and for longer time periods.  Merchants demanded curbside parking; residents also may use it and may value it as traffic calming.

So, a lane on one or both sides of the street has gone out of use for travel, to be used for car storage.  The parklet looks like a clever way to reduce parking and avoid increasing travel space for motor vehicles  – a double win.

The claim is commonly made for parklets that the street space is being taken back for the use of the people – but which people? People also use the parking spaces, an issue also brought up in another post on this blog. The issue can come down to a locals-vs.-outsiders conflict. That can go either way. Residents object to the loss of parking spaces. Or on the other hand, residents  may be unhappy with a deluge of parked vehicles coming in from elsewhere, and there may be a shortage of public space in the neighborhood. Most support I’ve seen for parklets in the Boston area comes from anti-car activists, notably the Livable Streets Alliance. A restaurateur may be willing to trade off the loss of parking spaces for the additional seating, especially if most customers are local.

Sign on Someville, Massachusetts parklet
Sign on Somerville, Massachusetts parklet

The latter is the case with the Somerville parklet. A restaurateur actually paid for it – and so, it amounts to a repurposing of public street space for private use. though certainly, the same may be said about  car storage. One private use of public space gets traded off for another, which is seen as more friendly to the neighborhood. The sign attached to the parklet, shown in the photo above, reads “Somerville’s first Public Parklet, brought to you by the Forge Baking Company.” The Forge Baking company is in the mini-mall upon which the parklet fronts.

Let’s also consider the consequences if a lane on one side of the street has to be closed off to repair underground sewer or water lines. Without a parklet, and if there is parking on the other side, temporary “no parking” signs can be posted and traffic moves over by one lane. Traffic can continue to use as many lanes as before, at the cost of a few parking spaces. The flexibility to  convert non-travel space on the street into travel space is very helpful in maintaining the functionality of the street for travel.

When a parklet is installed, the parking spaces can no longer be repurposed as travel space, at least, not without tearing out the parklet. And let’s hope against hope that the parklet doesn’t have to be torn out to replace underground pipes.

A parking space ahead of the Somerville parklet has been repurposed as bicycle parking. This may work to the restaurateur’s advantage, at least in good weather. The bicycle parking would be easier to take out temporarily if required for a construction or street-maintenance project. All in all, there are better places — more secure, sheltered — to park bicycles than in street parking places. But this placement also constitutes a symbolic victory, taking space away from cars for bicycles.

In the case of the Somerville parklet, I’ll actively question how much thought was given to safe traffic operation. Somerville Avenue has typical Boston-area bike lanes, in the door zone of parked vehicles. The parklet here extends nearly to the edge of the bike lane before a parking space, then a driveway, and the wall  is high enough to block cyclists’ view of pedestrians and vehicles entering from the right. The two cyclists in the photo at the top of this article know enough to avoid edge-riding risks but not all do.

Anti-car activists relish their symbolic victories but often don’t care to address hard questions of safety, mobility and maintenance.  The Somerville parklet is, in my opinion, a case in point.

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Bruce Epperson’s examination of bike-share legalities

Bruce Epperson is a lawyer and bicycle historian in Florida, USA. Bruce’s comment on a previous post drew my attention.

Several years back (2014 or 2015) I wrote a detailed analysis of the legal status of bike-share operations in Florida. It ran to about 30 pages. It covered everything from answering the question “what is the legal relation between a bikeshare operator and a government (depends on the form of the contract) to risk management, procurement, labor law and open records laws. I can send it if you want (it’s a public record). The very thought of giving permission to allow a firm to use the city’s public ways to rent scooter conveyances, but without a vendor contract, makes my lawyer’s hair stand on end.

I e-mailed Bruce and asked him whether I could post the analysis. He agreed and sent it to me, with the following warning:

Two cautions: 1) It’s breathtakingly boring; 2) It’s obsolete – no doubt, somewhere in there, the law has been supplanted or amended, so don’t rely on it unless you have me check out a particular point of law.

Bruce’s analysis also refers specifically to Florida laws. Laws differ outside the USA, but also among states in the USA. One of the genius aspects of the US federal system, and also a headache, is that some states may enact pioneering laws, successful or not, and the others get to observe the outcomes before they take action, or decline to.

In case you would like to read a breathtakingly boring — but perhaps highly significant — legal analysis, it is here:

http://john-s-allen.com/pdfs/Florida Bike Sharing Law.pdf

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Mighk Wilson’s report on Orlando bicycle crashes

Mighk Wilson, who works for the Orlando, Florida metropolitan planning organization, has prepared a very interesting study of bicycle crashes in the Orlando area based on a database of 5,000 crashes, 2011-2017. The study is important in that it distinguishes between urban, suburban and rural areas, and identifies major differences in the rates of different crash types between these areas. His PowerPoint presentation about the study is online. View it in file edit mode to see the speaker notes, which explain the content of the slides. Also, Mighk describes the study in a series of three article on the Savvy Cyclist blog.

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Simultaneous greens: bicycle roundabout?

An article on the UKrant.nl Web site describes an intersection in the Netherlands with simultaneous green lights in all directions for bicyclists. This works the same in theory as an exclusive pedestrian phase. The headline, “How to Survive Simultaneous Greens” misrepresents the installation (not all greens actually are simultaneous) and tends to promote a spirit of support for careless innovation.

The video below appears at the top of the article. The featured still image looks benign enough. When you click on the image to set it into motion you’ll see that bicyclists are crossing at right angles to others, and some are taking odd routes across the intersection.

Alle Richtingen Tegelijk Groen from UKrantvideo on Vimeo.

How to survive simultaneous green lights? Same way we survive any uncontrolled intersection: yield to traffic already in the intersection and yield to traffic coming from your right. Note in the photo that the simultaneous green lights are only for bicyclists, who have special bicycle signals. Motor vehicles are shown waiting for red lights.

There is no legal right turn on red either, so the motorists may not enter the intersection. Bicyclists enter from a narrow channel to the right of the waiting motor vehicles and so the intersection works more or less like a roundabout during the all-green bicycle phase. This treatment solves the problems with right-hook and left-cross conflicts, at the cost of increased delay for everyone because of the additional signal phase.

Couple quotes from the article:

In the subhead; “It might look chaotic, but in fact – it’s the safest way to do things.”

A couple of paragraphs in: “When the city of Rotterdam tried to implement a similar system, there were two accidents in the first two minutes, and the alderman quickly cancelled the experiment.”

If people understand to circulate as in a roundabout, then it is going to be reasonably safe. If not — chaos, of which there is much in the video.

The article mentions two problems in Rotterdam: the intersection was too small, and people weren’t used to it. The article makes no mention of any rules for circulating in this intersection or education in how to use it — essential to improve the survival rate — and I can add, there is no mention either of how pedestrian traffic is addressed. (The video, however, does show pedestrians crossing during the bicycle phase — so the rules for them during the bicycle phase are also the same as in an uncontrolled intersection: cross in any direction at any time, and drivers  — bicyclists — must yield) The claims that this is the safest arrangement is unsubstantiated in the article and undercut by the Rotterdam experience.

Here is another video, of a bicycle roundabout on the campus of the University of California, Davis:

I think that a bicycle roundabout is a valid concept where bicycle traffic is heavy enough and motor traffic light enough to justify it. The Davis installation, which prevents chaos by channelizing the bicycle traffic, is better than the Groningen one, where bicyclists — and moped riders, who also use the bikeways —  ride straight across from one corner of the intersection to another, and take shortcuts that put them into conflicts. Whether that kind of traffic flow could be achieved without physical barriers, allowing heavier motor traffic between the bicycle-only signal intervals, is another question, though.

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Some comments on electric scooters

Electric scooter -- Photo fro mthe Washington Post
Electric scooter — Photo from the Washington Post

At various dates in 2018, companies Bird, Lime, Skip and Spin have released dockless electrically-powered scooters  into a number of US cities — sometimes with approval from the city government, sometimes without. These scooters represent more or less a third wave in the advent of shared two-wheel personal transportation. First came docking bike share, then dockless bike share, and now we have dockless electrically-powered platform scooters.

Published articles have addressed the general social aspects of the scooter phenomenon, for example an article in the Washington Post from which the photo above has been copied, and one by blogger Bike Snob in Outside magazine. The article I am writing here has a different emphasis, safety and vehicle performance.

Certain hazards are inherent with any type of vehicle, but let’s make a comparison of these scooters with bicycles.

The bicycle’s design reflects a compromise between the risk of a stopping-type crash and the bicycle’s practicality and convenience. Avoiding the risk of a “header” or “endo” (over-the-handlebars crash) with a conventional bicycle, electrified or not, is largely a function of cyclist skill, in avoiding stopping hazards such as potholes and parallel-bar storm grates, and in using the brakes. A long-wheelbase recumbent bicycle avoids the risk of this type of crash, though with a tradeoff in convenience and eye height. Recumbents have been easily available for decades, but have never gained a large market share. All in all, the hazards resulting from bicycle geometry are tolerated, and studies point out that bicyclists, on average, live longer than other people. The benefits of exercise outweigh the risk of an injury or fatality.

A platform scooter has a much worse problem with stability than a modern bicycle. The vector from the center of mass to the front wheel contact patch is nearly as vertical as on an 1880s high-wheeler bicycle, only the front wheel is much smaller and pothole-prone. Also there is little benefit of exercise.

Bike Snob is generally pleased with scooters as an additional transportation option but he gives a paragraph to safety issues:

At one point, I rode down the gentle slope of SE Sandy Boulevard in the bike lane when a driver crossed my path. On a bike, I would have feathered the brakes and thought little of it, but on the scooter I immediately locked up the wheel, causing it to fishtail. I put a foot down and recovered quickly because I’m awesome, but it was a good lesson in how much faster you’ll hit the limits of a scooter than those of a bicycle. There’s also the fact that a bike is better suited to carrying heavy loads. You’d have a much easier time making a grocery run on a bike than on a scooter. And perhaps most crucially, due to the geometry of the scooters, it’s very difficult to ride them one-handed. Forget glancing at your phone or adjusting your bag; even hand signals are pretty much out of the question.

That pretty much says it about the limitations on braking. I can’t comment on steering with both hands on the handlebars other than to say that the short wheelbase makes steering quicker. But the situation is easier to define when one hand is on the handlebar: there is no saddle, and so, no point of reference for upper-body position. Forward/rearward rocking of the rider due to pavement irregularities, braking etc. will then abruptly steer the scooter out from under the rider. Also: better handlebar geometry on a bicycle places the hand position well ahead of the steering axis, so that placing weight on one hand while leaning slightly to the other side results in stable steering. The Lime scooters shown in the  video embedded in the Washington Post’s article have the handlebar directly in line with the steering axis. Hanging baggage over the handlebar doesn’t help with steering stability either, and these scooters offer no other option for baggage other than a backpack..

Steven Goodridge, CyclingSavvy instructor and engineer, has done some experimentation on scooter handling, and describes it at length in a comment on a Facebook post. Scroll down to his comment which begins “my takeaways.” Briefly,  his observations about steering confirm my speculation. Goodridge finds that front-wheel braking of the Bird scooter he tested is limited to prevent pitchover — though of course, only when due to braking and not when due to surface hazards or abrupt steering. Rear-wheel braking can cause fishtailing, even though it appears to be automatically modulated in some way. Maximum braking is barely within the limit possible on a bicycle which has only a rear-wheel brake, typically also the legal requirement: 15 feet from 15 mph.

Goodridge also finds that motor power of the Lime scooter is “insufficient for even the slightest hills…it couldn’t handle a number of the short hills at more than walking speed. Acceleration into traffic is slower than manual kicking.” By way of comparison, bicycle  speed is less than that of most motor vehicles, but a bicyclist is able to sprint rather smartly from a stop.

Goodridge, in a later comment on the same Facebook post, argues that electric scooters have fundamentally the maneuvering characteristics of vehicles, and so should be allowed on streets, prohibited from sidewalks but to some extent, be allowed in parklike settings, same as bicycles. I have some concern with this conclusion. Signaling turns is required by law, but it is possible on an electric scooter only at great risk of losing balance and taking a fall. Any vehicle which travels on streets should allow the full range of control options required under the law, including signaling. But,  with these scooters, hand signaling is impractical and  the very small height and width of the rear-wheel and fender assembly make turn signal lights impractical.

The electrical scooter phenomenon, all in all, is one more example of technology getting ahead of government management and regulation, a phenomenon which is occurring on many different fronts at the time of this writing.

 

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New York Bike Lane Promotional Video

This video is long on promotion and unbalanced, weak on anything which approaches a description of a comprehensive bicycle program. Parking? Enforcement? Education? Other infrastructure?

0:00 Leads with fear and hyperbole. “Let’s be honest. For many people, the thought of cycling in a city was terrifying.”

0:06 — picture of a door zone bike lane, just like most in NYC, cyclist risks dooring from the left and then is doored from the right. A perfect example of how not to ride. The hazard is obvious to anyone with an elementary understanding, so why did the bicyclist ride right into this trap?

0:24, Picture of a gauntlet, Sadik-Khan says “it was almost like being a cast member from Escape from New York.” Maybe if you were an extreme sport person, it was a great place for you because you were dodging cars (picture of traffic jam, dubbed-in sound of car horns.). Well, yeah, that’s fiction, but as Sadik-Khan uses it, it’s hyperbole.

1:10 “We put down 400 miles of on-street bike lanes.” (Note, all bike lanes are on-street, by definition.) Bicyclist is shown riding in a door zone bike lane, like most in New York, like the one the cyclist at 0:06 was doored in and like the one where a cyclist was killed a few weeks ago when a livery vehicle pulled out, collided with her and dumped her under a truck.

1:20 Claims that the 9th Avenue lane is much less stressful are buttressed by running video clips in slow motion, and with calm music.

1:32 Cyclist is shown avoiding the bike lane.

2:15 Staggered traffic signal timing: The 9th-Avenue bikeway was the first, and well-designed to avoid conflict if everyone obeys the rules, but the video neglects to mention that the staggered timing reduces green time for bicyclists, and the timing still favors motorists (green wave originally at 30 mph, now down to 25 due to city-wide speed limit reduction).

2:20 More slow motion.

2:23 Injury claim is for all users, not bicyclists. This is not stated. “Win” claim is vague, different for each type of user. The win claim for motorists is only that they got a separate turn lane, not that capacity was increased. It was reduced. Claim for bicyclists is of reduced stress, not of reduction in travel time: it was increased. And again, safety claim is an overall claim, not one for bicyclists.

2:50 The 9th Avenue lane was carefully designed. Later ones were done on the cheap without separate signal phases and other amenities. Saying only that more were constructed avoids the issue of their quality.

3:35 “You can’t just paint sharrows on a street and expect that people are just going to, voilà…” Shared lane marking shown is in the door zone.

4:00 Roger Geller’s categories of cyclists are not from a survey. They are a categorization he created out of thin air.

4:25 “If you want to build a better city, you can start by building better bike lanes.” — That’s what the closed caption says. Sadik-Khan says only “building bike lanes.” Conveys that the only thing a city needs to do for bicycling is to build bike lanes.

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The definitive paper about loop detectors, published 1986

The City of San Diego, California, USA published its Traffic Signal Bicycle Detection Study Final Report in 1986. I have scanned a copy of the document and posted it online.

Cover of the San Deigo Traffic signal Bicycle Detection Study Final Report
Cover of the San Diego Traffic Signal Bicycle Detection Study Final Report

This report’s main topic is inductive-loop traffic-signal detectors. These are metal detectors with their antennas, loops of wire, spread out just below the surface of streets. The detectors serve to trigger traffic signals when vehicles are overhead.

Detection increases efficiency of traffic flow. A small street that crosses a main street can, for example, get a green light only when a vehicle is waiting. A timer does not have to stop traffic on the main street every minute or two, whether or not anyone is waiting in the side street.

An earlier type of vehicle detector was a pressure-sensitive device embedded in the street. From approximately 1970 onward, though, loop detectors came increasingly into use, having become practical with the advent of transistorized electronics. The traffic-engineering literature mentions them as early as 1966.

Pressure-sensitive detectors responded to bicycles, but many loop detectors were not sensitive enough to detect bicycles, as reported as early as 1975 by bicycling author John Forester. By 1985, several California communities had addressed this issue in one way or another. The report describes these efforts, and offers suggestions both for new installations and for retrofits.

The report includes several pages of research data establishing the sensitivity necessary to detect bicycles. Detection was easily achieved with the correct setting of the electronics in the signal control box, but raising the sensitivity of the detector would result in unwanted triggering by a vehicle in the next lane. Commonly, a vehicle exiting an intersection could trigger a signal. Installation crews addressed this problem by turning the sensitivity down as low as possible while still detecting a passenger car in the lane directly over the actuator loop.

The detector, so adjusted, will not detect a bicycle and often not a motorcycle. This deficiency encourages — in some cases forces — bicyclists and motorcyclists to run red lights. Most bicyclists, probably also most motorcyclists, do not understand why the lights stay red, fostering disrespect for traffic signals. Entering an intersection on the red can, as is well-known, result in crashes.

Making the loop detector antenna more directional — so it responds much more strongly to vehicles in the lane directly overhead than to ones in adjacent lanes — allows the sensitivity to be raised so that bicycles and motorcycles are detected reliably. The San Diego report shows how to accomplish this.

The San Diego report describes a workable, very low-cost solution: all that is needed is to lay the wire in a different pattern, adjust the sensitivity of the electronics, and in some cases, paint a marking showing where bicyclists need to wait. There was nothing new to on its topic to say for decades, until evolving technology brought detection using video cameras, light-emitting diodes, microwaves and ultrasonic sound emitters into consideration.

Nonetheless, implementation of reliable detection can be described as, at best, spotty, even 30 years after publication of the report. I address that history in another post.

References:

MGA Associates, City of San Diego, Traffic Signal Detection Study Final Report, ca. 1986. (The document does not list a publication date, but the latest dates mentioned in the document are in 1985.)

Forester, John, Effective Cycling, Second Edition, 1975, page 3.4-2

Tranoff, P. J. and P.S. Parsonson, Selecting Traffic Signal Control at Individual Intersections. See for example references 18, 30, 31, 49, 52, 58, 63 (1974, which also mentions treadle detectors), 77, 114, 115 (the earliest reference to loop detectors, 1966).

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Counterrotating spins about blind spots, from Germany

This post is a translation of an article on the site of the ADFC (German bicyclists’ association), to which I have added comments, in indented italics as here. The German original is at https://adfc-berlin.de/radverkehr/sicherheit/information-und-analyse/121-fahrradunfaelle-in-berlin-unfallstatistik/222-exkurs-der-tote-winkel.html. For a different approach which could save your life is you are a cyclist, please see the following video.

Side discussion: the blind spot

ADFC: there are no blind spots around large trucks.

(A rather bold assertion)

(Lines below the picture are translations of the annotations)

Mirrors on a large truck
Mirrors on a large truck

ADFC: A truck which conforms has six mirrors, making it possible to see all around the truck. Correct adjustment of mirrors is essential. In the photo, the slip-road mirror is incorrectly adjusted; half of its area shows the truck rather than the area next to the truck.

(JSA comment: so this truck has a blind spot. Also,  mirrors must be adjusted to suit the height of the driver. )

Fields of view required by the EU
Fields of view required by the EU
  • Class 2, class 4, class 5, class 6, danger zone.
  • Source: MEKRA Lang company (rear-view mirror manufacturer), 2008

All areas ahead of and next to the cabs of large trucks are visible in mirrors prescribed everywhere in the EU.

That can be confirmed easily in practice by looking at the mirrors from the outside of the truck. If you see the steering wheel and the window in the driver’s side door, then the driver can also see you in the mirrors.

(JSA note: the driver also must be looking into the mirror.)

Example of fields of view
The “blind spot” is within the field of view
  • A cyclist next to the truck is visible in both the side window and the wide-angle (convex) mirror.
  • Photo: ADFC

JSA note: The photo was taken from the same height as the mirror and window, which are about two meters above the road surface. The bicyclist is not tall enough to be visible in the window and can be ahead of or below the field of view of the convex mirror.)

Bagged front and wide-angle mirrors
Bagged front and wide-angle mirrors
  • Bagged front and wide-angle mirrors
  • Source: http://www.toter.winkel.de

“Explanation” of the “blind spot” by the police and trucker’s association

Bagged frame (Rahmen) mirrors: (should be Rampen, slip-road, mirrors, as in photo caption). Source: http://www.transportbotschafter.de

ADFC: in explanations of the “blind spot”, the wide-angle mirrors are often bagged. A truck is, however, not driven with its wide-angle mirrors bagged. The explanations are contrary to practice.

ADFC: the view in the wide-angle mirror: in fact, the supposed “blind spot” is seen in the wide-angle mirror.
Source: http://www.vsbb-verkehrssicherheit.de/

(JSA comment: The reference is to an article by the truckers. The video at the bottom of the article starts by showing a young child riding into the danger zone to the right of a large truck.)

ADFC: The explanations are often strongly supported by trucking companies or truck manufacturers. An example of this is the „Verkehrssicherheit Berlin-Brandenburg GmbH“ (VSBB), (Berlin-Brandenburg Traffic Safety Corporation) , a 100% subsidiary of the Berlin-Brandenburg truckers’ association.

Driver’s assistant

The ADFC demands the addition of a driver’s assistant as a measure to counter the main reason for fatal bicycle crashes.

EU requirements and German traffic law

Since January 2007, the EU has required newly registered trucks to have mirrors for gap-free views in all directions. Since March, 2009, existing trucks have had to be retrofitted with these mirrors.

The German traffic law requires

§ 56 Mirrors and other arrangements for indirect vision:
(1) Motor vehicles must, as described in paragraphs 2 and 3, have mirrors or other arrangements for indirect vision, constructed and installed so that the the driver can see all essential traffic activity to the rear, the side and immediately ahead of the vehicle – also when pulling a trailer.

ADFC: Vehicles with a “blind spot” do not, therefore, conform to the German traffic law.

Latest update; February 2, 2018

(JSA comment: there isn’t a view in all directions unless there is a backup camera, not mentioned in this article. No driver can look into six mirrors and directly ahead, at the same time.)

 

 

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About dockless bike share

  • Your bike: you own it and look after it.
  • Docking bike share: the company owns it and it is secured at the dock when not being ridden. If you lose it, you bought it.
  • Dockless bike: once it is locked up (only immobilized, not secured to anything) and lying around, anyone can come vandalize it or throw it into the water, or a dumpster, and won’t be caught.

Faulty business model…doesn’t work in China — mountains of abandoned bikes; doesn’t work here. Can work for the company if the bikes are so cheap that they recoup their cost in a few trips, before being vandalized or disappearing. But then the community bears the cost of retrieving and disposing of these throwaway bikes.

I’m reminded of the “yellow bikes” schemes of decades ago where idealistic, naive people would put bikes out for free, all painted a distinctive color. Surprise: they disappeared. Dockless bikes are unrideable unless they have communicated someone’s credit card number to the mother ship, so the way they disappear is a bit different.

The bike in the photo below has sat untouched outside a house in my community for several months. The company left town and didn’t retrieve it. Once the battery dies and the bike no longer sends a GPS signal, the company can’t locate it.

Abandoned dockless bike
Abandoned dockless bike

Update: I came into possession of this bicycle, got to ride it and review it.

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Fewer roads in the future?

I’m responding to a comment on the facebook post which started with the sharing of the 13-lane animation on which I commented in my previous post on this blog. A commenter stated:

I don’t think it oversells the space because that assumption operates on the premise that cars need to be able to go EVERYWHERE. They don’t. So while one single road may not have 13 lanes to give up, two or three collectively certainly might. Take them away, at least from through traffic. They’ll become access-only, which effectively makes them pretty empty.

Well, yes, access. Roads have gone nearly everywhere the wheel was known, for thousands of years, because motor vehicles, or wagons drawn by animals, have to go everywhere except where people and supplies are to be transported on foot, on the backs of animals, by bicycle, railroad or boat, all of which are more expensive or impractical for many destinations, loads and trips. Oh, I left out elephants, which require as much road width as motor vehicles, but you get the idea. Inefficient (largely single-occupant) use of motor vehicles, requiring enormous amounts of space for multi-lane arterial roads and for parking, is the space issue — not the existence of motor vehicles or where they can go. Overpopulation and land use also play into this problem.

Be ready for a surprise if you live long enough to see it. People who are thinking about autonomous vehicles are saying that traffic volume will actually be higher, though parking demand will be much lower because these vehicles will be in use much more of the time. Traffic, they say, will be slower but steadier. Road capacity will increase both due to reduction in parking and to more efficient use of travel space (shorter following distances, better traffic management).

I could be surprised too because I’m not sure that this is more utopian than reality will turn out to be. In particular, travel demand varies enormously at different times of day, so parking will still be needed (though fewer parking spaces per vehicle, to be sure). We can see some of the parking issue playing out with bike-share systems having to rebalance for commutes in opposite directions, morning and evening. With driverless cars, that would amount to either extra cars and parking, or extra travel. I remain unconvinced that people will be happy to carpool in driverless cars, that overall cost reduction will outweigh that consideration or the tragedy of the commons/convenience to the individual of having a personal vehicle. Urban/suburban/rural conditions will of course differ.

Where do bicycles fit into this? That not a question whose answer I know to give. I may speculate on it later.

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