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Comment by Torkel | Hacker News Reader

Speaking to a founder to a competing company (https://www.edeva.se/en/) I found out that there has been many attempts at solving the problems of speed bumps:

- Everybody gets bumped, not only high speed vehicles - Emergency vehicles need to slow down - Bus drivers and others can get back problems from speed bumps

Most solutions break down because the forces and the wear and tear is so tremendous. The solution from Edeva seemed clever to me because the swing a trap door down so the bump comes from the solid ground and not from a moving part.

I'm curious how this liquid solution handles emergency vehicles and the wear+tear. A mechanical solution is good but very expensive. A liquid solution seems like it could be made cheaper.

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I've always wondered what it would look like to tie one of those roadside speed monitoring trailers (they have a sign telling you the speed limit, and your speed) which were in contact with a 'speed bump' filled with hydraulic fluid. The faster you go over the limit, the harder and taller the speed bump :-)

If you did this with a camera system you could avoid penalizing emergency vehicles.

> If you did this with a camera

Yeah I've always felt like speed cameras should have been the "disruptive technology" for speed bumps but we're lagging behind for some reason, instead choosing to penalize everyone using the road.

How often are speed bumps not doable at the speed the street allows, e.g. having to go 15-20kmh over the bump in a 30 zone, or more extreme, 5kmh in a 50 zone when they want you to watch out for drunk pedestrians during events when said pedestrians aren't there (or drunk) yet/anymore...

Speed cameras are slightly more expensive than a speedbump and way easier to sabotage. It's enough with some paint to disable it temporarily or just cut it down if you want it disabled a bit longer.

The ones out on the highway here have just tended to get shot at I think.

Only because of the hurricane that used them as a shield.

The main issue is that everything movable or deformable is going to get absolutely wrecked by vehicles, in short order.

Even old-fashioned speed bumps get severe ridges worn into them by vehicles that go too fast. They need to be repaired after a year or two. And even if that doesn't happen, they experience severe forces from wheels, every single day.

You (and the non-newtonian bump mentioned in the article) suggest basically a rubber bag filled with fluid. Instead of getting ridges worn into them, they're going to get punctured and destroyed.

There's a reason the system mentioned in the article is only shown in parking garages. It only works indoors (because of UV), and it only works at relatively low speeds, where the forces are lower, and the risk of undercarriage hits is very small.

I hate speed bumps, but it's extremely hard to find a workable alternative. Personally, I prefer chicanes.

Fair enough, although if you were using a hydraulic system you could be raising and lowering a concrete berm with your system which would take the wear and tear.

In Las Vegas they had very deep 'gullys' on either side of a street to facilitate flash floodwater and where those 'flood streets' crossed others there were 'speed ditches' :-) They were very effective as the wear and tear occurred on the car that was grounding out after going over them too quickly.

Chicanes are ok but people who try to go through them too fast and get stuck after colliding with one side or the other cause problems.

Ah, I learned a new word. These serpentine roadways are used to slow the advance of cars on a guarded gate or outpost in military situations. They're pretty annoying to drive through but that probably means they working correctly.

Or a significantly more expensive (and correspondingly reliable) infrastructure investment in two traffic lights, where speeding past the first one triggers the second. Also requires: two intersections; cameras and/or law enforcement to enforce an actual penalty.

Why wouldn't you just put up a speed camera at that point?

Speed cameras, they earn themselves back easily. If they add warnings that there will be a speed camera it'll have the same slowing effect as speed bumps. Doesn't need to be a real camera even.

That sounds like a great way to kill someone.

Not easy to find a video of how it works on the site, but here it is:

https://www.youtube.com/watch?v=eRHphB-YqN8

Here are three problems I see:

- it has electronics and actuated parts - will be a maintenance issue

- it can be overridden remotely - yet another thing in the city to hack for fun or profit

- there's a distance between speed measuring zone and the bump zone that's big enough the device might react confusingly in dense traffic

the live edge looks like can ding a rim of a poorly inflated tire.

Here's some additional information on Edeva's first export order:

https://www.highways.today/2017/09/08/dynamic-speed-bumps-cr...

David saw a surge in web-traffic and traced it back to this HN thread, and then pinged me about this :)

Regarding bus drivers: I've seen speed bumps which don't cover whole width of the road - they are just wide enough so that cars can't avoid them, but buses (which are wider) can pass them freely. Obviously this assumes that buses and other large vehicles are not the ones speeding.

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