April 17


Virtual Speed Humps: Effective or Ineffective Traffic Calming Tool?

By Mike Spack

April 17, 2018

cross walk, crossing, crosswalk, crosswalk design, crosswalk safety, virtual crosswalk

Mike Spack, PE, PTOE

Recently, I was contacted by the New York Times Upfront magazine, to comment on a 3D speed hump being used in Iceland. (Click to view the article). The question was, are painted virtual speed humps effective?

The goal of speed humps is to help calm traffic, making it safer for pedestrians. I have written extensively on the topic of traffic calming in its various forms. However, in a majority of accidents involving pedestrians, the cause of the accident is the pedestrian themselves because they are distracted.

Virtual speed humps are not a new concept as can be seen in the images below. Many countries have tested them and some, including China, have implemented them. But the question still remains: are they effective in slowing traffic and reducing pedestrian accidents?

What do you think? I’m throwing this question to my readers. I’m not aware of any specific studies with proof that 3D crosswalks help. In some situations, the optical illusion can create motorist confusion, which has the potential to create an accident. Leave your thoughts in the comments below.

Want more information on speed calming? Check out these articles:

This 3D art of a girl playing in the road was used in Canada in an attempt to increase driver safety. (Click to view the article)

This crosswalk in Venezuela was pained by artist Carlos Cruz-Diez to increase driver awareness of pedestrian crosswalks.  (Click to view the article)


  • I’m sure there’s more nuance in your opinion than in the one-sentence blurb that was published, but I’d take issue with the sentiment expressed in the NYT article and say that a good deal of the responsibility should remain with drivers.

    Pedestrians are overwhelmingly likely to bear most of the impact of an auto-ped crash (upsetting pun fully intended) and therefore have a vested interest in avoiding crashes, but it’s not always possible to minimize the risk entirely given the way we as transportation engineers have been constructing the built environment for the last 70 years. While it’s true that pedestrian-involved crashes are on the rise, calling out distracted walking starts getting a bit too close to victim blaming to me. There’s got to be some effort on our part to bring awareness back to drivers, whether through HAWKs or RRFBs or even passive treatments like virtual speed humps as stopgap measures while we work on more permanent street design solutions. (My apologies for getting on my soapbox for a bit; I’ll come back down now.)

    But the question posed by this post is about research on virtual speed humps. I can’t speak to that directly, but there’s plenty out there on the general concept of high-visibility sidewalks. And if we take treatments that push the boundaries of what’s MUTCD-approved to their logical conclusion, that’s pretty much what a woonerf/shared street is trying to do. (And I saw plenty of those articles at TRB this year.)

    Like a virtual speed hump, woonerfs (at least as they’re implemented in the US) tend to subvert driver expectation and cause them to back off and examine their surroundings more closely. That’s not a good idea on a high-speed, high-volume street, but on a local-serving street like the one in the photo, traffic calming treatments should always be welcome – especially ones that don’t contribute to noise or vehicle wear like a speed hump would. As long as the context is appropriate, count me in.

  • Hey Mike,

    Have you contacted Oklahoma DOT about their experiment with a “Three dimensional alternative crosswalk pattern”. They are listed on the MUTCD Official Rulings database as having an open experiment 3(09)-33 since September 2013. I would hope they have some results after five years of testing.

    Just a thought.


    Sidenote – Too few traffic engineers use the official MUTCD/FHWA approved process for experimentation and thus it becomes hard to quickly research who is actually ‘studying’ a new treatment versus political-based implementation w/o any study.

  • Hi Mike,

    I have done some research (in my MSc a couple of years ago) on Pedestrian Safety and prediction of their accidents. Currently, I’m working on the application of Autonomous Vehicles focusing on (human/vehicle) driving behaviours.

    According to my experience of working with human (specifically, drivers) behaviours, such fake 3D humps might help traffic calming in a specific area (I’m not sure), but they will reduce drivers’ trust on the legitimacy of the road signs in the long-term. After a couple of encountering with such virtual humps, Drivers might get careless about the REAL hump sings. More importantly, they might lose their trust on any pavement sign, specifically the (vital) safety signs such as the ones used for schools, hospitals, etc., and this behaviour dramatically impacts upon the safety of the road and pedestrians in the long-term. However, this claim needs more research – a case study focusing on safety might reveal the outcomes of such virtual humps.
    But, I (as an ordinary driver) don’t like to see such signs when I’m driving, as it WILL impact upon my trust on road signs.


  • I agree with Mike’s comment within the article. My experience is that traffic calming often involves finding a solution to a problem that doesn’t exist, which is a difficult exercise. Having said that, residents who request traffic calming measures typically put a lot of effort into describing their issue and rallying community support, and want to see that effort rewarded by some physical change to the roadway or at a minimum additional signs (including the beloved all-way stop). If adding painted images to the roadway is perceived by those with concerns as being a safety improvement, and if there is no liability to the municipality and their staff (particularly engineers) for authorizing the implementation, and if there are no limitations on the municipal budget for pavement markings and their maintenance (or if a local community group picks up any added costs and somehow accepts liability), then does it matter if it is actually effective in slowing traffic and reducing pedestrian accidents?

  • Thanks for all of the comments! I’d categorize myself as a minimalist traffic engineer – try to install the least infrastructure to achieve the desired result. For that reason, I like Wonnerf’s in urban areas that mix all modes of transportation. Then the responsibility is on all users to stay alert and safe, which is the message that is clearly conveyed by the environment. Of course, the trade-off is lower vehicle throughput. Brighter signs and 3-d images are an arms race that I believe creates a false sense of security. Mike

  • I have to admit, I don’t like speed bumps/humps to begin with. But, I must say I REALLY do not like ‘virtual’ installations. As previously mentioned, this just creates distrust of traffic controls by the motorist.

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    Mike Spack

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