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.
Steve Goodridge has now posted a thoughtful article about these scooters: https://www.bikewalknc.org/2018/09/rules-of-the-road-for-electric-scooters/
Not to mention, I suspect a lot of scooters will be ridden by people with limited bicycling experience. What can possibly go wrong?
In Minnesota we are not required to signal if we need our hand to control our bicycle/scooter.
Also in Minnesota these e-scooters are not permitted to make vehicular-style left turns.
Hokan — indeed, in most jurisdictions, bicyclists are not required to signal when both hands are required for control of the bicycle. But on a bicycle, with a reasonably competent rider, this is only when braking or standing out of the saddle — not so much of the time as to make signaling impractical. When operating a slow vehicle, signaling is needed as a request to merge into line, when a lane narrows, to pass an obstruction — not only to make one’s way to a vehicular left-turn position. Interesting reverse logic: if signaling isn’t possible, none of these actions is possible, and as a consequence, consistent rules for travel are possible only on segregated facilities, with turning traffic yielding to the slow through traffic, and two-stage left turns — which leads to increased calls for segregated facilities, and restrictive laws, and bikelash due to inconvenience for motorists. But, segregated facilities can’t be built everywhere, and on streets without them, motorists must have the expectation that bicyclists and scooterists incapable of signaling and merging will unpredictably swerve out in front of them. That is the rabbit hole we are being led down by advocacy for the wonderfully inclusive-sounding call for cycling by people of all ages and abilities, and by the legality of vehicles which do not permit signaling.
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 (its 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.
Bruce Epperson sent me his analysis and it is online, linked from a more recent post on this blog.
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I’m a cyclist (and a personal injury lawyer), and I was recently in San Diego, where I tried out Bird and Lime scooters. A couple observations:
1) The app tells you to wear a helmet, but of course literally no one does. This is in contrast to bicycles where, thankfully, helmet usage is common (though not universal).
2) I was struck by how, when turning, the scooter combines the worst parts of cars and bicycles. A car turns by changing the direction of the front wheels, whereas a bicycle at any real speed turns by leaning to the side. The scooters have fat tires, presumably for better stability at low speeds, but, with just one front wheel and one back wheel and a high center of gravity, if you’re above 3-5mph, they inevitably turn in part by leaning. People seem to adapt quickly to it, but it’s inherently problematic–you can never really get good at turning at anything other than really low speed.
3) A consequence is that scooters do one thing well — go in a straight line — and do everything else poorly. In some circumstances, that is fine. San Diego has a grid downtown and, outside of that, long and straight business-heavy streets and boardwalks. It’s also really flat, and generally has really wide sidewalks. A scooter can perform well in most of the dense areas of San Diego. In other cities, with more elongated curves or hills or narrow sidewalks, a scooter will be way out of its element.
Gary Cziko has road-tested a Lime electric scooter. It has the handling issues described the post, but it is powerful enough to climb a 7.5% grade. Gary is a bit light in commenting on the handling, but he is a highly-skilled cyclist. See Gary’s video at https://www.youtube.com/watch?v=bu5VkvANsmg