Curb Cuts | Hacker News Reader

Curb Cuts

99percentinvisible.org

185 pointsGW15091457 comments

I just became aware of the possibility of raised crosswalks, which seem like a fantastic idea -- no gradient for pedestrians, and a speed bump to slow cars -- https://sf.streetsblog.org/2018/05/22/walk-sf-campaigns-for-...

I imagine a raised crosswalk would also be more expensive than a curb cut. Are there any advantages or disadvantages relative to curb cuts for various disabilities?

Pedestrians are able to negotiate gradients more easily than cars, so this seems inefficient.

The inefficiency for cars is a feature. It means drivers will slow down and thus kill less.

https://www.strongtowns.org/journal/2018/1/25/speed-kills-so...

Some pedestrians can manage a sloped curb at a crosswalk. Others may have a more difficult time of it.

By contrast, all cars must be able to drive up and down a short slope. They must do so to enter most parking lots, for instance, so performing a similar maneuver at an intersection is no big deal.

So many of our problems with regard to urbanism are rooted in making things efficient for cars over other users.

One objection to omnipresent speed bumps would be their effect on ambulances. Unless one were to outfit ambulances with those nifty active electromagnetic suspensions, so that you could actually speed to the hospital without slamming the patient into the ceiling...

In denser city environments where this would be installed, ambulances are already impeded in their speed and you likely wouldnt install this along a thoroughfare.

At typical E-series based ambulance as found in the US spend 50,000 miles bombing down potholed gravel roads before needing major service and that major service is more preventative than anything else.

People bouncing around inside and the ambulance box deteriorating are probably your first two limitations when it comes to ambulances driving fast over speed bumps.

It's interesting how much of this is just about visual design. make it look like the cars have to cross the sidewalk rather that pedestrians crossing roads.

In my experience, crosswalks are counter-productive. They are typically placed in terrible locations, with poor lines of sight, or at otherwise busy and attention-demanding intersections. It is far safer to avoid the hell out of marked crosswalks, and cross the street in other locations, where you can clearly see the flow of traffic, and pick a slot to cross that is safe.

Unfortunately, the blind and visually impaired rely heavily on crosswalks to cross the road. Attempting to cross without the safety of a crosswalk will certainly result in death.

The problem is that mid-block crossing only works if traffic is slow and there are appropriate gaps in traffic. As an example, most of America lives in places that have streets that are eight to eleven lanes wide, with posted speed limits of 55-65 MPH and effective speed limits ten miles an hour above that. In the suburbs, crossing a busy road is essentially a death sentence, and coincidentally these are also the areas that are generally the most poorly equipped with crossing facilities.

Well yeah, you don't cross highways. Most streets are not 8-11 lanes wide, particularly in places where anyone would ever be walking along them. Places where pedestrians are common are in-town, low-speed (25-30 mph posted) streets.

The problem is we design our environments to be fundamentally hostile to walking between suburban neighborhoods, so only those who are desperate enough will walk. Usually this means the suburban poor, because cars can be prohibitively expensive.

This usually results in scenarios that beggar disbelief, like this one: https://www.huffingtonpost.com/radley-balko/raquel-nelson-ja...

>As an example, most of America lives in places that have streets that are eight to eleven lanes wide

Get out of your SF bubble. Not even the suburban sprawl in the south is built like that. You're exaggerating literally every detail you mentioned by a factor of two or more.

Two to four total lanes, with additional turn lanes at intersections is representative of the typical "suburban sprawl". You don't usually have to cross more than two lanes at a time because most places like that have raised medians. For non-major roads two lanes with occasionally a shared left turn lane is very common.

While I she agree that 8-11 is an exaggeration, it is easy to get up to 7: 1 right turn lane, 2 though lanes, 2 left turn lanes, and then 2 more through lanes in the opposite direction. Those aren't common in areas with lots of pedestrians, but I do see them all the time in other areas which do have cross walks (with traffic lights, if course) which I have seen used on occasion. Sometimes these even cross highways with 60 MPH (100 KPH) speed limits.

It's also not uncommon for major arterials to have shoulders, which are equivalent in crossing distance and safety to a road lane.

A couple of places in the South:

Atlanta: https://www.google.com/maps/place/Buford+Hwy+NE,+Georgia/@33...

Tampa: https://www.google.com/maps/place/Tampa,+FL/@27.9494221,-82....

Charlotte: https://www.google.com/maps/place/Charlotte,+NC/@35.2023214,...

Raleigh: https://www.google.com/maps/place/Charlotte,+NC/@35.7310989,...

Louisville: https://www.google.com/maps/place/Charlotte,+NC/@38.2154225,...

These are rather extreme examples (I said 8-11 based on my experiences in Long Island, NY), but things like this are not uncommon.

Most of these medians are basically nonexistent, and even if they did exist, there usually aren't any physical barriers that can stop a car above 50MPH, so they're just marginally safer than standing in the shoulders next to moving traffic.

> You don't usually have to cross more than two lanes at a time because most places like that have raised medians.

This can actually be a disadvantage, because in my experience, it has been rare where a crossing light on these types of roads gives you enough time to cross the entire road all at once, which can add a few minutes waiting for long, car-focused light cycles even for an able-bodied person. When crossing the street, the total distance and time it takes to go from one side to the other is what matters in terms of pedestrian comfort and convenience.

In fact, the ideas is thousands of years old. The ancient Romans had a concept of raised crosswalks in Pompeii:

> Blocks raised on the road allowed pedestrians to cross the street without having to step onto the road itself which doubled up as Pompeii's drainage and sewage disposal system. The spaces between the blocks allowed horse-drawn carts to pass along the road.

https://en.wikipedia.org/wiki/Pedestrian_crossing#History

That's awesome, thanks! Were raised crossing with spaces for cart wheels common around the world? Haven't cities everywhere had the sewage in the streets problem to varying extents for most of the time cities have existed?

Reykjavík has a few of those, but they are amazing. They are one of the few places where cars actually stop for pedestrians almost immediately (way more effective then simple painted crosswalk). They also do wonders in slowing down the traffic as it reaches downtown (way more effectively then simple speed bumps).

Imagine making a right turn at an intersection where you have to cross two of these, one after the other. Your car's tires are not going to make nearly as good contact with the road, making your brakes less effective should you need to use them.

Turning, of course, puts lateral forces on the tires, making traction worse.

Sounds like a feature, not a bug - you'd better slow down quite a bit to make navigating that situation safe and make sure you aren't exceeding the safe speed for that intersection.

In the kind of dense urban areas where raised crosswalks have the most potential to make a difference in safety just by virtue of the raw number of people who use those street features, pretty much every improvement in some way contributes to lowering and moderating motor vehicle speed.

Tokyo is pretty darn dense and the normal, legal speed of traffic in most areas with crowded crosswalks exceeds speed bump speeds.

City and traffic planners are sure to be concerned with increased congestion and reduced road throughput by adding speed bumps to intersections that are already in the most congested spots..

I disagree that making it less safe to navigate intersections at currently observed speeds is a good way forward. I also believe that if speed reduction is a identified goal there are ways to accomplish this without making navigation at current speeds more dangerous; such as psychological speed bumps.

>pretty much every improvement in some way contributes to lowering and moderating motor vehicle speed.

Such as dedicated bike lanes that are divided from the rest of the road, raised sidewalks and other methods of traffic control that keep different classes of traffic from interacting? /s

If you were to do all crosswalks at an intersection like this, it's much more common to just raise the entire intersection as a massive speed table. https://nacto.org/publication/urban-street-design-guide/inte...

Curb extensions are an alternative which may be more practical. Maybe that in combination with smart road humps[1] which respond to speed, would deter speeders down oak and feel streets in SF.

[1]https://hackaday.com/2017/08/14/smart-speed-bumps-slow-only-...

Curb extensions are awful for bicycles.

Speed tables have the side benefit of being fun for specific minority of vehicle drivers when pedestrians aren't using them.[1]

[1] http://image.fourwheeler.com/f/75606874+w660+h440+re0+cr1+ar...

Tangentially related, but important if you do any sidewalk work… Those bumps on the ramps are not for traction, they are tactile clues for the blind.

Do not use the bumped pavers decoratively to make interesting patterns! They come in a variety of patterns, but those all have specific meaning, they are not there to make your walk look interesting.

I can appreciate that purpose, but they're also really annoying to traverse for other kinds of vehicles, including small-wheeled strollers, children's scooters, longboards, etc. It's appreciated when the curb cut can be a bit wider so that there's a section which is smooth all the way down.

With my powered longboard (Boosted), I'm usually on the road, but there's a section of my commute where I'm on a multi-use pathway adjacent to a busy road and need to use curb cuts to navigate crossings at a pair of roundabout— having the bumps there (with limited way to avoid them) adds instability exactly when I'm about to cross traffic and need to be able to focus on which non-signalling, unaware drivers are about to swerve out of the roundabout and plow me over.

I'm obviously a tiny minority in this, and the accessibility argument is huge, but OTOH crossing these roundabouts in their current condition would be pretty much impossible anyway for a non-sighted person.

As annoying as being blind? I understand you're inconvenienced by the bumps but, c'mon, have some perspective.

"crossing these roundabouts in their current condition would be pretty much impossible anyway for a non-sighted person"

They are more than annoying for bicycles - they're an outright hazard for bicycles. They become slippery as ice when wet.

A nearby bike trail uses them at every intersection, and when it's been raining I dread having to maneuver on them.

As someone who has to push a stroller around these days, I’ve come to appreciate how much improved accessibility for disabled people means improved accessibility for everyone.

Came here to mention the stroller thing. Making cities more accessible to wheelchairs has had a lot of happy side effects.

Curb cuts are wonderful all around - in addition to the obvious benefits for wheelchair bound people, they are great for strollers, deliveries, people with reduced mobility who can walk but have trouble negotiating full curbs, and just as a guideline for helping people with full mobility cross the street safely.

For people with reduced mobility who can walk, slopes are often worse than steps. It is common for old people to lose sensation. This includes the ability to be confident of the angle of the ankle, the ability to sense pressure under the foot, and the ability to quickly sense motion via the inner ear. The slope can make these people tip right over, falling and then breaking bones. It can be fatal.

This is one of the more subtle reasons I dislike the euphemism "differently abled". It makes it sound like accessibility measures are at the expense of regular people's comfort, but that could not be further from the truth. There are some hoops society wants all people to jump through, and disabled people cannot jump through a subset of those. Accessibility measures means removing hoops people are forced to jump through. Everyone benefits from fewer hoops.

Navigating my city’s public transport with a stroller also gave me new appreciation of how difficult it must be for people in a wheelchair. There are only a handful of step free stations in my city.

Curb cuts in LA also include a sheet of small yellow nubs right before the street. The ADA calls these “detectable warning systems” [1], intended for sight-impaired folks. I feel bad because I always assumed they were there to interfere with skateboarders on the sidewalk!

[1] https://www.access-board.gov/guidelines-and-standards/street...

Skateboarders don't need curb cuts, they can go off and on curbs in ways that wheelchairs can't easily do. And if they're using a longboard, well, that's their own fault :)

You’re right, but I doubt the people making such hypothetical laws have ever ollied a curb ;)

For what it’s worth, people shouldn’t use the sidewalks for riding their skateboards or longboards.

In the UK they are different colours and patterns so blind and partially sighted folks can tell what they're near.

They're red near pedestrian controlled lights and yellow near uncontrolled lights or crossings with no lights. There's different patterns of the raised dots/lines for some uses - like steps or platform edges.

None of this had I noticed until someone pointed out there was a method at work. :)

People don't know about the spinners under the PELICAN / TOUCAN boxes either. They aren't on all boxes, but they are on lots. https://www.bbc.co.uk/news/blogs-ouch-22706881

99percent invisible had a blog post about really poorly laid out pavers fairly recently.

https://99percentinvisible.org/article/death-tactile-paving-...

Amazing.

That said, recently my father had a stroke. As the person who has spent plenty of time pushing him in his wheelchair (until his balance and strenght returns) I can tell you there are still plenty of instances where things are "non-inclusive."

p.s. If anyone is looking for a startup idea, having a sensors to tell the person using it whether __both__ breaks have been engaged would be helpful. Without the breaks engaged pushing up and out of the chair actually leads to pushing the chair out and back.

Similar can be said a walker. There's no feedback. It's all trial & error. T&E is great for an 8 month old learning to walk for the first time. T&E for an 80 y/o is dangerous.

Even adding say $50 - $100 to the cost of either - if that investment lowered doctor / hospital visits - I think the cost could be easily justified (read: beneficial and insurane company approved).

*brakes

Yeah. Oops. Thx

99pi is always one of my first recommendations for podcasts. Roman Mars and team do a really good job of talking about the built / designed world in a way that is accessable and interesting to outsiders.

Ironically, this episode didn't have him in it.

Yes it does: he comes on at approximately 31:30

Either way, the praise was directed to Roman and the team.

I knew I should have finished the podcast before commenting..

And yes of course.

See also this article by Rory Sutherland about the more general benefits of accessible design.

https://www.spectator.co.uk/2017/12/design-everything-for-th...

These, like speed bumps, would be a pain in winter for snow removal. There is a reason a lot of folks in the northland are buying removable speed bumps so they don’t have issues in the winter.

Curb cuts are cut into the sidewalk, which is normally cleared by manual shoveling anyways, t least in the US. Shoveling a curb cut is really not all that different from shoveling any other piece of sidewalk.

Reply on news.ycombinator.com