One-Way Streets Found To Be More Dangerous For Children

By Adrian Duyzer
Published May 23, 2012

Controversy has erupted in a New York City neighbourhood over a plan to turn two streets that are currently two-way into one-way streets.

Department of Transportation (DOT) Deputy Commissioner Michael Primeggia claims this move is to improve pedestrian safety, but a copy of the report acquired by shows that the plan "is almost entirely concerned with the movement and flow of motor vehicles and the calculation of 'vehicular level of service'". (Sound familiar?) reports that at a community presentation, Primeggia failed to back up his claims of increased safety with any specific examples, simply saying that, "I know two-way streets are less safe."

But one Park Slope resident, who is a professional transportation planner and traffic engineer and a member of the federal Transportation Research Board, came prepared to refute Primeggia's claims. Unfortunately, he was unable to deliver his presentation because the meeting was cut short, but was able to provide it to Here is a copy of his planned testimony.

The proposal under consideration here this evening may have merit in terms of moving traffic through Brooklyn as a whole. However, in terms of serving Park Slope, this project is ill-conceived and you would be ill-advised to endorse such a plan.

I'll focus on just one aspect of the plan -- the significant negative impact it can have on some of Park Slope's most precious but vulnerable citizens, that is, our small children. With PS 321, the magnet school that was PS 10, PS 39, PS 282 and various middle schools, private and parochial schools, more than 3,000 children use Sixth and Seventh Avenues daily to walk to and from school.

One-way street networks can result in more pedestrian accidents, particularly among children. This effect has been noted in a number of transportation studies published in respected academic journals. I'll cite and quote certain relevant reports and articles for your consideration:

First, from a 2003 study published in the American Journal of Public Health:

"Children 5-9 have the highest population-based injury rate in pedestrian-motor vehicle accidents." Why? As the report goes on, "because in many pedestrian crashes the driver reportedly does not see the pedestrian before the accident. Higher vehicle speeds are strongly associated with a greater likelihood of crashes involving pedestrians as well as more serious pedestrian injuries... In residential settings with large numbers of children, speed management appears to offer the greatest potential for injury prevention."

By way of explaining this effect, I'll refer to two other reports. First from a 2004 report published in the Journal of the Institute of Engineers regarding one-way streets:

"Superficially, it would seem that crossing traffic on a one-way street is preferable to crossing a two-way street. As is often the case, the conventional wisdom is wrong. In fact, crossing a one-way street presents greater difficulties to the pedestrian than crossing two-way streets... One of the inherent disadvantages with one-way streets is that they force additional turning movements at the intersections...[and] increase the occurrences of vehicle-pedestrian conflicts at any given intersection."

Second, from a paper presented at the federal Transportation Research Board's 1999 Urban Streets Symposium:

"In traffic engineering circles, the operational disadvantages associated with one-way streets are becoming increasingly recognized. The system...[causes] an increase in the number of turning movements and total miles of travel. One-way streets present challenges to the pedestrian due to speed and pedestrian expectations at intersections... there are simply more (typically 30-40 percent) more vehicle/pedestrian conflicts within a one-way street network than in a comparable two-way system."

Conversion to one-way avenues may well result in more traffic volume, higher speeds, more turning movements on Sixth and Seventh avenues. Where does this all lead?

Well, from the Canadian Journal of Public Health, a 2000 study conducted in Hamilton, Ontario, found that:

"Children's injury rate was 2.5 times higher on one-way streets than on two-way streets" in Hamilton. Conclusion: "One-way streets have higher rates of child pedestrian injuries than two-way streets in this community."

Given this evidence, it's clear that two-way streets are better for kids, with a decreased rate of injury and death. They're also better for business. They're more useful and usable than one-way streets. We proved they worked when we converted James and John. All the experts keep telling us to drop our one-way system.

So what are we waiting for?

Adrian Duyzer is an entrepreneur, business owner, and Associate Editor of Raise the Hammer. He lives in downtown Hamilton with his family. On Twitter: adriandz


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By Grendel (anonymous) | Posted May 23, 2012 at 08:14:32

I find these delays exasperating as well but having seen decades of Hamilton urban development unfolding, we're actually moving at a pretty good clip.

How does Hamilton's infrastructure budget look? Could that be a factor in all of this? I'm familiar with the "how much does a yellow line cost" argument, but I think that most would agree that execution has a great deal to do with success, etc.

It's not hard to imagine two-way street conversions that worked out to the detriment of pedestrians and cyclists. Certainly not in a city with a track record of patronizing but ultimately marginalizing those constituencies. As you point out, speed can be fatal.

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By jonathan (registered) | Posted May 23, 2012 at 23:25:35

The first article doesn't specifically address safety as it relates to one-way streets; merely reiterates the well known fact that the safer the road, the better. No arguments there. So...which is safer?

I had to dig for the second article, since the linked url is bad, and the specific article wasn't noted, but found it here: The Journal of the Institution of Engineers Singapore - A Microscopic Simulation Study of Two-Way Street Network VS One-Way Street Network. (Click on the 'Cached' link to the right--the download link goes to the same bad url as the one above). Yep, it's the results of a computer model that indicate pedestrians and cars meet up more often. Not that they're more dangerous, just that there are more of them, because cars have to loop around. It's not even the point of the study--merely a side note on a study showing that one-way streets are faster and more environmentally friendly than two-way.

The third is not an article from a journal, but an opinion paper presented to a symposium, noting no studies, no data analysis, no empirical evidence to support themselves. It also stops short of claiming that two-ways are safer than one-ways, choosing rather to limit itself to the increase in 'potential conflicts' within an interesection. Except that its analysis directly conflicts with one published in 1998 in the Journal of the Institute of Transportation Engineers, which found the number of conflicts of two-way to be at least six times more than one-way. While perhaps not relevant, it is worth noting that the article is written by a private engineering firm with a vested interest in converting one-way streets into two-way streets.

Which brings us to the final article, which has been refuted multiple times by both myself and SpaceMonkey (and, oddly, referenced in the article noted above).

I did, however, find this article interesting: No Two Ways About It: One-Way Streets Are Better than Two-Way.

Now, to be clear, I'm all for converting to two-way, despite the fact that it will make my commute...less than pleasant. But to claim that it's somehow safer than one-way, or that the above article somehow puts the entire issue to bed, is completely false.

Comment edited by jonathan on 2012-05-23 23:28:24

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By jonathan (registered) | Posted May 24, 2012 at 00:02:03 in reply to Comment 77223

...I'm going to add to this by saying that, if one were to tell me that intersections were safer in two-way street configurations, and jaywalking was safer in one-way configurations, I wouldn't argue that. As a driver, I've had the, 'Look for the hole, look for the hole...there it is, take i---OH CRAP, PEDESTRIAN FROM THE OTHER WAY, WHERE THE HELL DID HE COME FROM?!?!' moment, and as a jaywalking pedestrian, I'd much rather jaywalk across Main St. than risk getting creamed while stuck in the turning-lane-only-centre-lane crap you find on other roads.

I should also took me over two hours to get from a jobsite in downtown Toronto to downtown Hamilton today, most of that time spent trying to get to the Gardiner from University/Queen. So my tolerance for highly-congested two-way streets is pretty thin today.

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By Brian C (anonymous) | Posted May 23, 2012 at 23:56:44

Thank you Jonathan for highlighting the article: "No Two Ways About It" It's nice to read an objective study, not just somebody's preference. It was interesting to see that Hamilton is mentioned on page 9

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By BeulahAve (registered) | Posted May 24, 2012 at 12:13:13 in reply to Comment 77224

I would definitely not call the "No Two Ways about It" article posted by jonathan (but link down as I write this) an "objective study". If memory serves me right, it was released by the Independence Institute, formerly called (I am not joking) the Center for the American Dream of Mobility and Home Ownership. It doesn't seem to be accessible today, maybe due to all the hits from RTH readers!

I believe that paper actually cites an article by Andrew Dreschel against conversion of James and John to two-way, and I think he has since changed his mind on that one.

Here is a link to a blurb about the paper:

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By highwater (registered) | Posted May 24, 2012 at 13:08:19 in reply to Comment 77245

The link still works for me. The CADMHO appears to have been a former policy centre under the Colorado-based, libertarian Independence Institute that is no longer active.

However the Institute is still active, hosting fun family events like their annual Alcohol, Tobacco and Firearms Party. Money quote: “We’re witnessing, folks, a world of sacrifice to others run amok.”

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By jonathan (registered) | Posted May 24, 2012 at 01:17:24 in reply to Comment 77224

...I wouldn't exactly call it 'objective'. More a counter-point to the article above, except that it references actual, real world statistics, vs 'potential points of conflict'. The problem with the latter is that it in no way factors in a person's ability to take note of the world around them, and adjust accordingly. Perhaps the Symposium paper is correct, and the peer-reviewed** Journal paper is not. Perhaps there are indeed more potential points of conflict in a one-way intersection than in a two-way. But perhaps people's ability to recognize these is sufficient in both, and the end result is, the accident rates are the same.

**I gag on those words every time I read them. Does peer-reviewed mean anything when you've never heard of the Journal before? And does it mean anything more than that the math was correct? There have certainly been incidents where peer-reviewed articles have been later proven to be completely and utterly wrong (a certain Korean? Japanese? geneticist comes to mind).

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By Grendel (anonymous) | Posted May 24, 2012 at 06:40:42

Agreed that it's helpful if people not dumb down the calculus around traffic engineering and weigh studies critically on their merits. Citing studies that, superficially at least, bolster one's existing world view -- confirmation bias -- is of course a one-way street of the mind. Hindsight bias arguably does a similar disservice to the complexity of history.

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By George (registered) | Posted May 24, 2012 at 18:40:50

"The best place to raise a child" - Two way now!

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By DowntownInHamilton (registered) | Posted May 26, 2012 at 09:53:40

Are there any studies regarding safety of adults on 1 way streets as compared to 2 way streets?

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By IRC22 (registered) | Posted June 04, 2014 at 20:09:24 in reply to Comment 77342

Listed are some before/after safety studies indicating one-way streets are safer for pedestrians than two-way streets.

PORTLAND, OR (1949): Portland converted most of their downtown two-way streets to one-way streets in the late 1940’s. After conversion, vehicle accidents decreased from 6,127 to 3,361 (-45.1%). The number of pedestrian accidents decreased from 237 to 126 (-46.8%). Volume of traffic in downtown increased from 12,734 to 16,708 vehicles (+31.2%) and average speeds increased from 7.9 mph to 14.2 mph (+79.7%).

CINCINNATI, OH (1975): Cincinatti converted Vine Street between Central Parkway and Mc Micken Ave. from two-way operation to one-way in 1975. After conversion, vehicle accidents decreased from 212 to 128 (-39.6%). The number of pedestrian accidents decreased from 16.6 to 13 (-21.7%). Volume of traffic increased from 24,520 to 28,025 (+14.3%).

NEW YORK CITY, NY (2008): The Park Avenue Tunnel at 33rd Street was one of the top pedestrian crash locations in the city from 1996-2007, averaging 12 pedestrian crashes per year. The city converted the tunnel to one-way operation in 2008 and the intersection saw a dramatic drop in both pedestrian injury crashes (100%) and all injury crashes (74%).

Cities that have converted one-way streets to two-way streets have seen a dramatic rise in pedestrian related crashes:

DENVER, CO (1986): Denver converted several one-way couplets to two-way streets in 1986. After conversion, the vehicle accident rates at intersections increased 37.6% while the mid-block accident rate increased 80.5%.

LUBBOCK, TX (1995): Lubbock converted a couple of downtown one-way streets to two-way in 1995. After conversion, total accidents increased by 41.6%

CINCINNATI, OH (1999): Cincinatti converted Vine Street to two-way operation in 1999. After conversion, vehicle accidents increased from 75.9 to 164 (+116%). Pedestrian accidents increased from 5.9 to 12 (+103%). Volume of traffic increased from 30,900 to 35,600 (+15.2%) and the average speed decreased from 18.0 to 12.4 (-31.1%).

ALBEQUERQUE, NM (1999-2003): Albequerque converted most of their downtown one-way streets to two-way streets between 1999-2003 (62 blocks total). After conversion, vehicle accidents increased from 778 to 824 (+5.9%). Pedestrian accidents increased from 14 to 26 (+85.7%). Bicycle accidents increased from 5 to 12 (+148%). Volume of traffic decreased from 359,430 to 284,180 (-20.9%).

Sources: City of Denver, One-Way Street Monitoring Study, Phase 1 Conversion Report, January 1990.

City of Lubbock, Main and 10th Street Accident Analysis, Before/After Study, 1998

City of Cincinnati, Over-the-Rhine/Vine Street Circulation Study, February 2003.

NYC DOT, The New York City Pedestrian Safety Study and Action Plan, August 2010.

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By big picture (anonymous) | Posted June 16, 2014 at 09:48:10 in reply to Comment 102050

What's missing from these numbers is the actual numbers of users before and after conversions, as well as the actual injury rates.

If pedestrian accidents rose 50% but number of pedestrians rose by 200% then it's actually safer per pedestrian km.

# of collisions means very little if we don't discuss the severity of the incidents or the number of safe usages. A street closed to everyone has a collision rate of zero. And 100%. at the same time.

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By IRC22 (registered) | Posted June 18, 2014 at 00:53:19 in reply to Comment 102486

The pedestrians risk exposure is an important factor to consider. That said, i don't think there would be a dramatic shift in pedestrian volumes after a two-way street conversion, especially since these studies compare the near immediate impacts of conversion (I.E. if a two-way street conversion is to add vitality to the area, it's not going to happen overnight)

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By big picture (anonymous) | Posted June 19, 2014 at 00:39:46 in reply to Comment 102595

Did these collision numbers change overnight? that seems like an assumption as well If the numbers came from a full year before and a full year after, that leaves lots of time for commute patterns to change.

Actual risk is much more important then number of interactions regardless. Did they not bother to study that at all in any of these cities?

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By Fred Street (anonymous) | Posted August 29, 2012 at 10:31:39

Reader's Digest's September 2012 issue ranks Hamilton as the 9th best city population 80,000+ in Canada to raise a family.

01. Sherbrooke, QC
02. Ottawa-Gatineau, ON
03. Guelph, ON
04. Calgary, AB
05. Windsor, ON
06. Montreal, QC
07. Vancouver, BC
08. Toronto, ON
09. Hamilton, ON
10. Peterborough, ON
11. Kitchener, ON
12. Moncton, NB
13. Kingston, ON
14. Halifax, NS
15. Oshawa, ON
16. Trois-Rivières, QC
17. London, ON
18. Québec, QC
19. Abbotsford, BC
20. Edmonton, AB

#21-42 here:

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By highwater (registered) | Posted June 20, 2014 at 07:49:40 in reply to Comment 80131

Beaten by Windsor! Well, that's embarrassing.

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