Are Roadside Memorials a Hazard?

This is an evergreen issue in highway safety, one that the New York Times has recently opened for debate. I brought up the issue recently after a trip to Montana, which permits a standardized memorial for road safety purposes (but does not look kindly upon additional embellishments).

And the issue has come up again in Australia, in a suburb of Melbourne, where, if this account from The Age is to be believed, a roadside memorial to the death of four young drivers has, in a moment of supremely tragic irony, led to the death of another young driver, a mere two weeks later. The memorial has since been removed, to some controversy.

But the first thing to note is that this is one of those enduring gray areas in traffic safety; as far as I know, there’s been no peer-reviewed study of the crash risk posed by roadside traffic memorials. This doesn’t stop people from offering firm opinions, but as far as I can tell, the science is nil. We don’t even really know the distraction effects of memorials, or if they are are any greater than that posed by billboards, signs, people walking their dogs, etc. (none of which carry, as memorials do, at least the potential to actually encourage safer driving). That said, one can also make the argument that intersections are places where drivers have to make often complicated decisions, and to have a large memorial engaging their attention at that location may not be a good idea. And what their attention is being engaged by is a question to consider as well. One reason is related to a theory proposed by psychologist Steven Most (who is quoted in Traffic): “Emotion-induced blindness.” As The Economist described his study:

Dr Most made this discovery while studying the rubbernecking effect (when people slow down to stare at a car accident). Rubbernecking represents a serious lapse of attention to the road, but he wondered if the initial reaction to such gory scenes could cause smaller lapses. The answer is, it does. What he found was that when people look at gory images—and also erotic ones—they fail to process what they see immediately afterwards. This period of blindness lasts between two-tenths and eight-tenths of a second. That is long enough for a driver transfixed by an erotic advert on a billboard to cause an accident.

It is entirely possible that something like this could have occurred in the Australia case, the memorial inducing a moment of emotion that triggered some kind of attentional blindness, though there is really no way to know for sure what was going on in the mind of the driver, or what she saw or didn’t see, as she made the turn. Reading a bit deeper into the article, a couple of other things stand out. One is that the speed limit of the road was 80 KPH — it is now going to be lowered to 70 KPH. The previous speed limit is roughly 50 MPH, which, judging by the Google Earth photograph below, seems incredibly high for a road bordering a quite residential area.

I don’t know the area in question, but given the article’s description, it seems a sort of once-rural area that is being increasingly developed.

A worker at the Foodies Service Station, at the intersection, said there was an accident every two weeks and traffic lights were desperately needed. Hermiz Toma, who has worked at the station for eight years, said in the past three to four years the accident rate had spiked as the neighbourhood had expanded. “The area is becoming busy with new buildings and more cars and it is too hard for people to get from Ormond to Hallam Road,” Mr Toma said.

It seems, in other words, like one of those “in-between areas,” as Hans Monderman put it, in Traffic: Neither limited-access highway nor low-speed residential area. Instead, you have a high-speed road going through an increasingly dense environment — the “traffic world,” as Hans put it, plunging like a knife into the social world. The authorities in question now plan to install a traffic light at that particular intersection, a typical standard response to a serious crash. Will they do so at every intersection along that road, or only the intersection where the crash occurred? Is a traffic light an appropriate response? Would a road diet on that very wide-looking road, and a series of roundabouts, have created an entirely safer situation — i.e., the truck would have had to slow to navigate the intersection — that might have prevented the first deadly crash that inspired the memorial, as well as the following fatal crash that is now being blamed on the memorial?

I’d be curious if anyone can shed any further local knowledge — or has thoughts about memorials in general.

(Thanks to Gerry)

This entry was posted on Tuesday, July 14th, 2009 at 4:21 pm and is filed under Traffic Culture, Traffic Engineering, Traffic safety, Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

6 Responses to “Are Roadside Memorials a Hazard?”

  1. Nancy Says:

    70 kph is actually more like 43.4 mph, which is still high for a residential area. I don’t see the need for speed limits above 35 mph in residential areas, and prefer 30 or 25. [What I really wish is that drivers would treat the speed limit as the UPPER limit, not the lower limit.]

  2. Anon Says:

    The math behind this question is incredibly simple. Select any of the many stretches of road around the world that are sites of frequent accidents. If descansos are not a hazard, then the time distribution of accidents will look like a Poisson process. If they are a hazard, they will be bunched around the presence of a descanso.

    It’s of course an issue too fraught to be examined objectively. In New Mexico, the birthplace of this custom, the memorials literally are part of the indigenous religion.

  3. Fritz Says:

    Some good observations and questions, but I take issue with the idea that “people walking their dogs” don’t encourage safer driving. If there are more people on the side of the road on a regular basis, people drive more slowly and more carefully.

  4. Mark Young Says:

    I’m not sure about memorials specifically, but there are wider concerns on external-to-vehicle driver distractions – the most obvious one being billboard advertising. We published a paper recently in Transportation Research Part F indicating a detrimental effect on driver attention and lane-keeping performance. But the argument is always, “well, what about things like memorials, monuments, or even just attractive scenery?”

    I don’t really have an answer to that, except that billboards are specifically designed to distract, and are a ‘voluntary’ distraction we can cut down on. Coming back to memorials, I can well believe the emotion-induced blindness theory – being made to think about a fatality risk can ironically lead to an internal distraction as the driver muses on the tragedy. And distractors inside our own head are just as bad as those in the real world.

  5. mikey2gorgeous Says:

    We have an interesting dilemma in the UK – “Ghost Bikes” have started appearing at sites where a cyclists was killed (they are painted white & chained up at the accident site). While bringing the deaths to the attention of drivers is undoubtedly a good thing, it re-inforces the ‘culture of fear’ that we are suffering from here.

    The single most effective thing we can do to increase cyclist safety in the UK at the moment is to get more people cycling to increase the ‘safety in numbers’ effect (until proper funding & action comes from government). These ghost memorials surely work against this?

  6. Laurens de Jong Says:

    Did you read the article in the July 2009 issue of Accident Analysis & Prevention? “Drivers’ perceptions and reactions to roadside memorials”


    Despite their growing popularity in North America, little research has been conducted on understanding the effects of roadside memorials on drivers’ behaviour. In this study, an online survey of 810 drivers found that public opinions on the policy options as well as drivers’ self-reported reactions to the presence of roadside memorials were fairly divided. In addition, an on-road experiment was conducted to examine the short term effects of roadside memorials at two intersections. Our results showed that the number of red light violations was reduced by 16.7% in the 6 weeks after the installation of the mock memorials compared to the 6 weeks before whereas the number of violations at two comparison sites experienced an increase of 16.8%.

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