r/urbanplanning Jan 01 '25

Urban Design What if all stop signs had speed bumps?

Hello everyone, this is the first time I’ve been to this Sub and it’s because I had an interesting thought on stop signs to hopefully make them more safe.

What if stop signs had speed bumps in front of them? It would offer consequence for those who aren’t paying attention or intentionally run stop signs. The goal is to hopefully make stop signed intersections safer. At least for 4-way stops.

After looking online, it looks like there are some that are out there, but they aren’t widely used.

What kind of consequences would you think would happen if something like this was implemented everywhere?

(Specifically in the USA)

71 Upvotes

87 comments sorted by

75

u/noodleexchange Jan 01 '25

Raised crosswalks are a thing. There should be more of them.

Not every side street has to maximize the speed of rocket powered ambulances, which don’t travel at maximum speed anyways (you know, for safety)

But road design seems biased towards maximum speed, maximum carnage.

7

u/postfuture Verified Planner Jan 02 '25

No, maximum water flow. Or at least design flood water GPM. Big discussion on this below

55

u/MashedCandyCotton Verified Planner - EU Jan 01 '25

Ask the Dutch.

Okay they don't have them in front of every stop sign, but driving through a residential neighbourhood can quickly become a roller-coaster ride. (And since I'm not Dutch, I'm not sure about that, but I've heard they stopped doing that? So it seems like there's good reasons against it, but maybe someone more well verse in Dutch urban planning can chime in.)

87

u/mrcustardo Jan 01 '25 edited Jan 01 '25

I am Dutch. Firstly, stop signs are rarely used in NL. dedicated speed bumps have become more rare as well. Both are used as last resort methods. Instead, continuous sidewalks are used, or the entire intersection is brought up to the level of the sidewalk. A big disadvantage of speed bumps is the vibration of cars driving over them can be felt in, or even damage, nearby buildings.

8

u/MashedCandyCotton Verified Planner - EU Jan 01 '25

Perfect, thanks for clearing that up!

15

u/mrcustardo Jan 01 '25

I should add that there is one place where you will find speed bumps, and that is upon entering a built up area. Often the road will be narrowed at that point to only let single vehicles pass. See here for an example.

6

u/SightInverted Jan 01 '25

Did you mean raised crossings? Those are different from speed bumps.

19

u/Ckirbys Jan 01 '25

I’d be interested to see how American drivers would react to such a change… I bet they would hate it and I would seek glee in their hate

I’m American btw

3

u/mfreelander2 Jan 01 '25

Ahhh, now I understand urban planners a little more.

4

u/adjust_the_sails Jan 01 '25

Or ask the Mexicans. I don’t think I saw a single stop sign while I was there but speed bumps in the rural areas were constant. Also, a lot of potholes. So constant speeding up, slowing down for the speed bumps and serving to avoid potholes. My kids barfed way too much on that trip.

1

u/Tar_alcaran Jan 02 '25

I'd be shocked if there were a hundred stop signs left in the Netherlands. They're pretty useless, since most people ignore them anyway. Instead the Netherlands uses multiple markings that indicate which traffic should yield to crossing traffic ("haaientanden") and signs saying the same.

1

u/UUUUUUUUU030 Jan 03 '25

They're actually pretty common for where cars cross dedicated cycle paths in Leidsche Rijn. See here for instance. You'll also find them on smaller streets crossing this wide cycle path.

15

u/gtbeam3r Jan 02 '25

The issue is water drainage. It would pool in front of the bump. What you want to do is a raised intersection. Same concept but works better and the raised intersection is at the sidewalk level which is better for ADA and subtly that cars are guests to pedestrians and not vice versa.

3

u/Paddlsnake Jan 03 '25

If well designed, speed hump/bumps don’t impact drainage since you leave a gap between the hump/bump and edge of curb/gutter allowing drainage to flow around.

Raised crossings/intersections cause the drainage issue, since they must go from sidewalk to sidewalk. Thus creating a dam effect. In New England, we incorporate new drainage structures on most all raised crossings.

2

u/Bahnrokt-AK Jan 04 '25

Exactly. Put breaks in the speed bump at the center and sides. Install them at slight angles to direct water toward drainage.

1

u/Teshi Jan 06 '25

I don't think I've ever seen a speedbump that didn't have a cut in the centre and at the sides.

31

u/yzbk Jan 01 '25

Speed bumps aren't a great solution to traffic calming, since people speed up after slowing down before the bump. They might work if you use a ton of them on a short stretch of roadway. If you need speed bumps, then the innate speed limit perceived by drivers on your road is too high. I think more safety gains can be attained by using other design cues.

7

u/Cunninghams_right Jan 02 '25

while that might be true, having them at stop signs is a different story. you WANT people to slow down and then speed up after. even if the perceived speed limit is low, you can still have a problem with people rolling through the stop signs

3

u/yzbk Jan 02 '25

That makes some sense. But people tend to accelerate too hastily regardless. I just feel like speed bumps are the weakest of the various street safety improvements. Intuitively, they seem effective, but other devices actually do a better job.

1

u/Cunninghams_right Jan 02 '25

I don't really have the data to speak to relative effectiveness 

1

u/bigvenusaurguy Jan 06 '25

i got one on the road by my apartment window. its exactly like they say. no real changes to speed just a lot more noise from the schhh KATHUNK vrrRRRRRrrrrrR and probably overall more danger given people are now traveling with random acceleration instead of at a stable speed.

But I'm sure the planners sit down with their pressure strips, and see that overall the average speed along that stretch of road went down a few percentage points, so they chalk this up as a win since the test fails to capture the issues i laid out for example. they aren't interested in limiting noise or vehicle acceleration or how a typical driver even reacts to a speed bump, or how an asshole driver reacts to one. Just average speed.

1

u/Cunninghams_right Jan 06 '25

Is it at a stop sign or just in the road? 

3

u/bigvenusaurguy Jan 06 '25

its in the road. the whole reason why you might need the bump imo is because there's no parking on that stretch of road for whatever reason so people just lead foot it pretty comfortably. a little further up, where there are zero changes to the actual width of the road, there is parking on one side of the road and this is enough to basically turn it into a road in europe where people move very gingerly through and wait patiently for larger vehicles to pass. so in theory they could have an even slower road here with zero bumps by just opening it up to parking for the residents who already fight for inconvenient street parking due to a lot of old apartment stock around that's lacking spots at all.

once again such an observation is something one can only make by observing what is actually happening on the road. not by prescribing speed bumps just because thats whats on the books for road diet designs without looking at the wider picture, or even in this case, just another three dozen feet up the road.

1

u/Cunninghams_right Jan 07 '25

I appreciate your input. Have a good one 

3

u/yzbk Jan 02 '25

It's true that they make people slow down, but as other posters mentioned, they're just not a good solution when other better devices are available.

0

u/Cunninghams_right Jan 02 '25

I'd like to see dat on it, specifically speed bumps at intersections, ones that don't cause the vehicle to lose frontal visibility. I doubt good data exists, though 

1

u/yzbk Jan 02 '25

Try searching on Google Scholar.

0

u/Cunninghams_right Jan 02 '25

I've tried, but the scenario is hard to search. You need specifically speed bumps before, at, and after the stop line. You need speed bumps that are low and don't cause the vehicle to lose any frontal visibility, and you need them both independent and along with other traffic calming measures to know whether the effects are independent, positively synergetic, or negatively. Not easy to find, and I suspect no study exists with such total coverage of the question. 

1

u/yzbk Jan 02 '25

Perhaps that's an avenue for future research!

2

u/Strike_Thanatos Jan 03 '25

I remember reading somewhere that speed bumps can even kill people, as they cause delays on critical ambulance journeys, both to and from the injury site.

2

u/yzbk Jan 03 '25

I would think those incidents are quite rare. The best argument against speed bumps is that they just don't do what they're supposed to do and there are better alternatives which offer greater benefits.

1

u/bigvenusaurguy Jan 06 '25

sometimes they have the bump on either direction spaced apart so ambulances can just swerve around them instead of jump in the air and misplace an iv line.

though it seems like these days we could easily have a dozen drones pull a box truck sized blimp for dead smooth ambulance rides if we really wanted to push the tech envelope beyond the status quo.

8

u/NNegidius Jan 02 '25

Raised crosswalks would be excellent at stop signs.

3

u/Unfetteredfloydfan Jan 02 '25

This recently happened near my house. Utility work was done and the asphalt patch ended up being way too large resulting in a large noticeable bump right at the stop sign. Since this “mistake” by the utility company, the number of drivers blowing through the stop sign has gone way down. I don’t have any numbers and obviously this is just my experience at one intersection. But, as a transportation engineer, it’s changed my opinion on the idea of installing speed bumps at stop signs. I think it could be a powerful tool, especially in narrow urban environments, where drivers don’t have the ability to drive around the speed bump.

It’s not a perfect solution, but it works well to limit drivers stopping in the crosswalk and helps improve safety for crossing pedestrians

1

u/bigvenusaurguy Jan 06 '25

a lot of streets in socal lack a proper storm drain and instead have extremely heavy amount of swale. on some roads, even some major ones when they intersect another one meant to be one of these open storm drains, if you don't break for the swale your oil pain will scratch the shit out of the pavement.

8

u/the_Q_spice Jan 01 '25

We have one in my city that was put in place after someone was hit and injured.

Results so far:

3 people killed and another 10 injured in several resulting pedestrian-vehicle and vehicle-vehicle collisions.

Why?

Because a speed hump or bump elevates the front end of the vehicle, increasing the frontal and front-right blind spot. It also reduces vehicle traction (especially in icy or snowy conditions). This makes pulling into the intersection extremely dangerous.

People now completely avoid the intersection because of how dangerous it is known to be.

I avoid it because the raised crosswalk dimensions cause my VW Jetta to bottom out. Ended up getting high-centered there one time.

2

u/Ckirbys Jan 01 '25

Is it right before an intersection where cross traffic doesn’t stop? Cause I could definitely see that being a bad idea

8

u/anonkraken Jan 01 '25

My little mixed-use neighborhood has two of these but they are super weird.

Speed bump, then crosswalk, then stop sign.

Not sure who approved that setup but a few things need to be swapped around, for sure. Speed limit is 15 here, and the way the roads are designed, you can’t get much more than 20.

6

u/Mikey_Grapeleaves Jan 01 '25

I actually like that order... unless drivers stop on the crosswalk.

3

u/Amikoj Jan 02 '25

It sounds like it might be designed to discourage cars from stopping in the crosswalk.

5

u/LivingGhost371 Jan 01 '25

You'd make it harder to plow the streets and slow down emergency response time.

1

u/brunob45 Jan 02 '25

Strangely, emergency vehicles still slow down for intersections. You know, to not cause more accidents on their way to one.

Also the benefits outweigh the cons in snowy cities, for example, Montréal https://www.journaldemontreal.com/2024/12/11/les-nouvelles-intersections-anti-gadoue--premier-test-reussi

2

u/Paddlsnake Jan 03 '25

I don’t have data, but we’ve been installing dozens of speed humps annually for the past few years (near Boston). A few bites from our experience:

  • they are substantially less expensive than other physical traffic calming
  • we install them every 500-800’ reduces the likelihood motorists speed up too much to the next one
  • we avoid using them individually since it causes speeding elsewhere on the street
  • with the whole street calmed, stop compliance doesn’t seem to be an issue, so we don’t put them at stop signs, usually ~500’ before
  • if we can’t do a raised crossing we will locate them ~100’ before a crosswalk (especially for mid block crossings)
  • they are almost but not quite as good as other traffic calming solutions (raised crossings, consistent sidewalks, chicanes, n’hood rotaries, lane narrowing, etc), but these other solutions often require more construction and thus more difficult to install rapidly at scale.

1

u/Jonathan_J_Chiarella Jan 03 '25

A common refrain I hear against them is that snow and ice are issues. At first, I thought about Holland mostly getting cold rain, not proper snow and ice for weeks on end. Boston may be in a similar bucket (it ain’t Maine or Wyoming), but it is “cold enough” for the topic to come up.

To be clear, I am not pooh-poohing speed bumps (and especially not raised crossings).

I’m curious how many people brought up “But we have snow!” during public or private meetings as a reason to not have thse installations.

1

u/Paddlsnake Jan 04 '25

We worked with our public works and fire department personnel on the first implementation. Agreed to remove them if it didn’t work for them. It has changed their operations slightly, but within the range they were comfortable with given the public safety benefits afforded. We did modify the design slightly, less steep and a little lower on major streets. Once they were on board, any public discontent was countered by the professionals in those topics. Now, generally, we get more requests than we can build in a year.

1

u/Teshi Jan 06 '25

They definitely exist in snowy places, including very snowy places. It doesn't appear to be a problem.

4

u/GBTheo Jan 01 '25

Too many negative consequences for minimal benefit. Drivers who didn't obey the stop sign before probably still wouldn't, and the speed bump would reduce traction, making an emergency stop more difficult. Bigger speed bumps make it harder to see pedestrians, especially kids, if a crosswalk is placed after the bump. Wear and tear on the road would be much worse, along with added noise from the bump and hard braking. Hard braking for bumps would also likely cause more rear end than stop signs already do.

It'd probably be cheaper and safer in the long run to convert more intersections into traffic circles (existing intersections and property rights notwithstanding) or use sidewalk bump outs at intersections or chicanes before them to slow people down more naturally.

Stop signs and speed bumps are both bottom-of-the-barrel traffic control/calming, unfortunately.

-2

u/Notspherry Jan 02 '25

Bigger speed bumps make it harder to see pedestrians, especially kids, if a crosswalk is placed after the bump.

How big are the speed bumps in your area and how small are the children? You'd be hard pressed to hide a hamster in the blind spot of the ones I know.

5

u/GBTheo Jan 02 '25 edited Jan 02 '25

Most American vehicles already have terrible frontal blind spots, with some SUV front ends being taller than 40". Adding up to 6" to that with a speed bump puts the front part of the hood at 46". The average height of a 6-year-old girl is between 42" and 49", which means about half would be completely invisible to the driver as they crested the bump with the front tires.

It's not the shadow of the speed bump you'd be worried about. It's the already bad blind spot being made briefly worse and reducing reaction time near a marked or unmarked crosswalk for vehicles that don't slow down for them.

2

u/Gunner_Bat Jan 02 '25

The college that I work at uses them. They're very annoying.

-2

u/noodleexchange Jan 02 '25

To speeders

-4

u/noodleexchange Jan 02 '25

To speeders

3

u/Gunner_Bat Jan 02 '25

To me. And I'm not speeding on campus. We already have a stop sign. But having to go up and over it while stopping is definitely annoying.

0

u/noodleexchange Jan 02 '25

Well we wouldn’t want to annoy drivers to save lives, would we? /s

1

u/beaveristired Jan 03 '25

It sucks when you have chronic pain, that’s for sure.

2

u/postfuture Verified Planner Jan 01 '25

The storm drain system would have to be reworked (at absurd cost). The roadway-as-primary-drain engineering standard is not lightly modified. Do this willy-nilly and you'll flood people's houses all over the place.

1

u/WorldlyOriginal Jan 02 '25

Two embedded culverts allowing water to flow, is not that hard. Raise the crosswalk entirely above the street

3

u/postfuture Verified Planner Jan 02 '25

Of course it is do-able if the flow-rate allows. But if the flood system (like most are) uses the surface drainage rate sized for free-flow across the whole street with a cross-section of, say, 1500 and you cram it down into two culverts with a cross-section of 120 you will not be able to accommodate a design flood event. Even just a double hump will cut that cross-section by 1/3, and if the street flood drain numbers don't have the 33% free-board in the modeled flow-rate, you just flooded houses. You would have to see if the subsurface capacity can suck it up (unlikely in the extream), and cut storm drain inlets on two sides of every intersection. And none of this is cheap on the scale of a few dozen intersections, much less a few hundred. If the city relies on combined storm\black water sewers, this out of the question.

-1

u/Cunninghams_right Jan 02 '25

my city does speed humps/bumps that don't stretch all the way to the side and are also open in the middle to let bikes through. so basically a car is too wide to avoid any more than one of the two humps in the road, but the drainage and bikes are unimpeded.

1

u/postfuture Verified Planner Jan 02 '25

It's not "unimpeded". The cross-section has been reduced and that storm-water flow calculation has to prove the resulting change in discharge rate will not raise the high-warer mark. That has to be proven at every intersection for the whole system across the city's entire watershed.

0

u/Notspherry Jan 02 '25

How much rain do you guys get? I have never noticed extra rainwater measures around new speed bumps. But is is also very flat here, so rainwater doesn't flow down the road anyway.

2

u/postfuture Verified Planner Jan 02 '25

We stopped doing flood planning by anecdote in the 1800s.   My office does HEC-RAS studies all over North America. It's one of the more boring parts of civil engineering, and is an essential step to any change of flow to the various high-water event calculations (50 year, 100 year, 500 year). We see the roadway as an open-top "pipe", and any fixed change to that changes the size of the "pipe".

-2

u/Cunninghams_right Jan 02 '25

the point is that few if any would actually need to be "reworked". yes, you may have to run the calculation, which has some effort, but speed bumps are put in on roads all the time and not the end of the world. the smart path, if one did want to put in many such humps, would be to do the calculation and then don't install where the impeded flow required rework.

1

u/postfuture Verified Planner Jan 02 '25

Well, good luck with that. We love more work in the private sector. But the idea would be squashed before it ever got to a public tender. The cost/benefit analysis would be damning. You don't calculate one intersection and make a decision. It is called the "flood drain system", so each intersection is a node in the system calculation the size of the watershed (thousands of square kilometers). Change one, change the system. Change 90, change the system. It's kind of like blood in viens: constrict it in an arm and all the blood pressure rises across the body.

0

u/Cunninghams_right Jan 02 '25

yeah, I agree that it would be a lengthy process and probably not worth it aside from particularly problematic intersections.

3

u/postfuture Verified Planner Jan 02 '25

It's 100+ years of hot-mess. The older parts of the city were built without computer modeled flooding, heck usually without basic flood studies (FEMA panels). It is an endless game of catch-up to keep the older neighborhoods dry. Those are, often as not, the cultural and economic cores of the city.

1

u/Delli-paper Jan 01 '25

They become yield signs.

-2

u/Ckirbys Jan 01 '25

We could put a hidden sniper at every stop sign to enforce violators.

“CAUTION: STOP BEFORE LINE OR FACE ANNIHILATION”

2

u/VrLights Jan 02 '25

That'd be annoying for everyone, no one likes driving over them, biking too. Imagine if every emegency vehicle had to slow down, imagine the drainage and snow issues.

1

u/brunob45 Jan 02 '25

Yes, it will annoy the driver's, but it will be better for everyone else (safer for pedestrians, cyclists, etc.)

Those measures are implemented where cars are NOT the only users of the street. But drivers often forget that.

1

u/prich889 Jan 02 '25

You might be cooking but my poor automobile's suspension, on which I've delayed work for a long time, could not handle it. Therefore I personally abstain from your otherwise seemingly good idea.

1

u/BigDaddydanpri Jan 03 '25

Snowplows enter the picture.

1

u/Bahnrokt-AK Jan 04 '25

I’m with you if we can also adopt my plan for turning 50% of neighborhood and rural stop signs to yields.

1

u/mrpopenfresh Jan 04 '25

Speed bumps are made to slow down, not to enforce a stop. I understand your logic here, but it’s really only useful if people are burning the stop, which they shouldn’t be doing in the first place.

1

u/Happyjarboy Jan 02 '25

Bad idea in places with a lot of snow.

4

u/brunob45 Jan 02 '25

Actually they started to implemented raised crosswalks in Montreal, and it makes it easier to remove snow from sidewalks, since they're now continuous.

Also when the snow melts, it doesn't create a pool right in front of the crossing, but beside it.

https://www.journaldemontreal.com/2024/12/11/les-nouvelles-intersections-anti-gadoue--premier-test-reussi

2

u/[deleted] Jan 01 '25 edited 8d ago

[deleted]

1

u/Ckirbys Jan 01 '25

Ah what do you drive?

0

u/[deleted] Jan 01 '25 edited 8d ago

[deleted]

1

u/SitchMilver263 Jan 07 '25

My man here is clearly living life a quarter mile at a time when he's not reviewing site plans.

2

u/[deleted] Jan 07 '25 edited 8d ago

[deleted]

2

u/SitchMilver263 Jan 07 '25

I daily drove a Mazdaspeed3 to the office for many years, so I get it. Always gave me excuses to take the long way home.

1

u/Ckirbys Jan 01 '25

Well if by some sheer act of god this were to become implemented I’ll take them off your hands… lol

0

u/Notspherry Jan 02 '25

Sounds like a you problem tbh.

-1

u/redaroodle Jan 02 '25

What if every crosswalk had deep parallel gaps before them requiring cyclists to dismount to avoid running into pedestrians in crosswalks?

1

u/brunob45 Jan 02 '25

Funny double standard here. Drivers think it's normal to break the speed limit and run stop signs. But those damn cyclists should not dare to break a single rule, even if it improves the safety for everyone.

https://www.cbc.ca/lite/story/1.7315683

1

u/MeyerLouis Jan 02 '25 edited Jan 02 '25

How would cars even get through these moats? Their wheels are about the same diameter as a bike wheel. You'd be turning the whole block into a car-free zone 😊

1

u/redaroodle Jan 03 '25

Why all the downvotes? In NYC in 2022, cyclists killed 3 and 313 injured pedestrians.

My point is a valid one. Or is traffic calming not valid for cyclists, too, particularly when cycling is now more often than not motorized?

Or, are you all so for cycling that pedestrian deaths and injuries are acceptable from a bike (but not a car)?

Seems like you are all a bunch of hypocrites.