A Health Impact Assessment of a Proposed Bill to Decrease Traffic Speed Limits on Local Roads in Massachusetts (U.S.A.)

Decreasing traffic speeds increases the amount of time drivers have to react to road hazards, potentially averting collisions, and makes crashes that do happen less severe. Boston’s regional planning agency, the Metropolitan Area Planning Council (MAPC), in partnership with the Massachusetts Department of Public Health (MDPH), conducted a Health Impact Assessment (HIA) that examined the potential health impacts of a proposed bill in the state legislature to lower the default speed limits on local roads from 30 miles per hour (mph) to 25 mph. The aim was to reduce vehicle speeds on local roads to a limit that is safer for pedestrians, cyclists, and children. The passage of this proposed legislation could have had far-reaching and potentially important public health impacts. Lower default speed limits may prevent around 18 fatalities and 1200 serious injuries to motorists, cyclists and pedestrians each year, as well as promote active transportation by making local roads feel more hospitable to cyclists and pedestrians. While a lower speed limit would increase congestion and slightly worsen air quality, the benefits outweigh the costs from both a health and economic perspective and would save the state approximately $62 million annually from prevented fatalities and injuries.


Keywords: health impact assessment, speed limits, crashes, injury prevention, air pollution, physical activity, monetization


Slowing Down Will Get You Through a Traffic Jam Faster

Slowing Down Will Get You Through a Traffic Jam Faster

Measures to Minimize Bottlenecks Emphasize the Importance of Cutting Your Speed

 Article borrowed from The Wall Street Journal
Written by

When traffic thickens on freeways, drivers often make decisions that worsen conditions. They speed up when they should slow down. They change lanes when they should stay put. They squeeze together when they should spread out.

Jo Craven McGinty
Jo Craven McGinty

In effect, they leave no room to react. When something unexpected occurs, it leads to sudden braking, and what might have been a manageable slowdown becomes a miserable crawl or, worse, traffic grinds to a standstill.

Once the flow of traffic is disrupted, the shock wave ripples backward, with driver after driver braking. Instead of progressing smoothly, traffic rapidly queues.

“Everyone is selfish and wants maximal travel time versus optimal time for everyone,” said Hesham Rakha, a professor of civil and environmental engineering at Virginia Tech. “By being selfish, you make the system worse.”

The Federal Highway Administration estimates that 40% of all congestion nationwide can be attributed to recurring bottlenecks. The problem cost the country $78 billion last year in wasted time and fuel, according to INRIX, a company that studies the economic and environmental costs of congestion.

Bottlenecks can’t be entirely eliminated, but they can be minimized. Solutions include variable speed limits that change in response to congestion, metered on-ramps that use traffic signals to gradually feed drivers onto freeways, and zipper merges which, when a lane is about to end, instruct drivers to use all lanes until a designated point then take turns merging.

Essentially, the approaches direct drivers to go slower in order to go faster.

“The intuition is if you are more aggressive, you will get to your destination faster,” Mr. Rakha said. “Studies have shown that if you are less aggressive, you’ll get there faster.”

Traffic engineers measure the capacity of a freeway by the number of vehicles per lane per hour. Under normal conditions, with traffic flowing freely, capacity is about 2,000 vehicles per lane per hour, according to Bernard J. Arseneau, director of traffic management systems for Omaha, Neb.-based HDR Inc.

When traffic begins to slow, capacity initially increases because the density makes up for the reduced speed, and more of the tightly packed vehicles pass through. The benefit peaks at around 45 mph with about 2,200 vehicles per lane per hour. But at maximum volume, the system is vulnerable.

“When you get to that level, it doesn’t take much to mess things up,” Mr. Arseneau said. “Any disruption is likely to break down traffic.”


Ideally, drivers should maintain a steady slower speed, avoid unnecessary lane changes, which induce braking, and lengthen the gaps between vehicles to allow for adjustments. But left to their own devices, drivers are more likely to jockey for position. Some change lanes or race forward to cut in line. Others counter by tailgating or straddling lanes.

Mr. Rakha compares it to pouring sand through a funnel. “If you pour sand suddenly, not as much goes through as if you pour exactly the amount the funnel needs,” Mr. Rakha said. “There is more throughput by pouring less into the funnel.”

Once freeway traffic drops below 45 mph, vehicles begin to queue, and capacity drops to about 1,600 vehicles per lane per hour. The reduction of 400 to 600 cars per lane per hour is significant.

“You end up with stop-and-go congestion,” Mr. Arseneau said.

To help drivers make better choices, state departments of transportation employ various techniques.

Minnesota uses the zipper merge, often in work zones when a lane is dropped, and the technique is taught in the state’s drivers education manual. Zippering doesn’t hasten traffic, but it makes merging more orderly, and it significantly reduces queue lengths.

“The length of the backup gets reduced by up to 40%,” said Ken E. Johnson, a traffic engineer with the Minnesota Transportation Department.

Variable speed limits slow vehicles before they begin to queue. Georgia, for example, recently implemented variable speeds on I-285 in Atlanta to reduce congestion. There, depending on road conditions, the speed, posted on electronic signs, may vary from 35 mph to 65 mph.

Ramp meters keep freeway traffic moving by controlling the volume of merging traffic. In 2001, Minnesota turned off 430 ramp meters for six weeks and studied the effect. Among other things, the researchers found that freeway volume decreased by 9% and travel times increased by 22%.

“We know if we can delay congestion from occurring and slow traffic down, that will prolong the free flow and get more vehicles through,” Mr. Arseneau said. “You want to make sure you keep that traffic flowing as long you as can.”

It is a tall order that the engineers acknowledge is counterintuitive.

“We’re telling them to slow down to reach their destination faster,” Mr. Rakha said. “It’ll be hard for the driver to recognize that.”

Write to Jo Craven McGinty at Jo.McGinty@wsj.com

Slow Down – Ontario moves to cut speed limits in residential streets

Link to article click here

Published by the Toronto Star – Friday, September 5, 2014

Slow down: Ontario moves to cut speed limits on residential streets

Government expects to introduce an amendment in the fall to drop the limit to 40 km/h from 50 to save lives, minister says

Community Safety Minister Yasir Naqvi says the Ontario government is ready to move on reducing speed limits on residential streets to 40 kilometres an hour.


Community Safety Minister Yasir Naqvi says the Ontario government is ready to move on reducing speed limits on residential streets to 40 kilometres an hour.

The Ontario government is putting the brakes on speed limits along residential streets across the province.

Community Safety Minister Yasir Naqvi told Ottawa CBC radio on Friday the Liberal government is expected to table an amendment to the Highway Traffic Act this fall lowering the default speed limit to 40 kilometres per hour from 50.

“Fifty kilometres an hour is too fast,” the Ottawa-Centre MPP told CBC, adding he supports the move to lower the speed limit.

“If you look at some other jurisdictions, like New York City and Paris, you’ll see they’re taking the same initiatives,” Naqvi said. “And I think it will put Ontario in a leadership place in North America by reducing the speed by these 10 kilometres an hour,” he said.

Neither Naqvi nor his office could be reached by the Star for further comment.

Naqvi said in the CBC interview that when he goes door to door “this is an issue that comes up often.”

“You’ve got a lot of young children who play on the street, especially in the summer months.”

“New Democrats are open to ways to improve road safety. As always, we will look closely at any legislation brought forward and consult with police, municipalities, and other stakeholders,” NDP transportation critic Joe Cimino said.

OPP Commissioner Vince Hawkes said the OPP we would support any initiative “that will continue to ensure that Ontario highways and roadways remain amongst the safest in North America.”

In Toronto, there has been pressure on city council to lower the default speed even lower to 30 km/h on residential streets in some cases.

Toronto’s chief medical officer Dr. David McKeown in 2012 advocated a 30 km/h speed limit on residential streets and “a citywide speed limit of 40 km/h on all other streets” to reduce the severity of injuries to pedestrians and cyclists.

McKeown made the proposals upon the release of a $45,000 report, “Road to Health: Improving Walking and Cycling in Toronto,” which cited evidence that pedestrians are far less likely to be killed for every 10 km/h reduction below 60 km/h.

“Small increases in traffic speeds results in a disproportionately large increase in pedestrian fatalities,” McKeown wrote.

According to the World Health Organization, almost 50 per cent of pedestrian deaths occur when the car is travelling at 50 km/h. At 80 km/h, the odds of survival are close to nil. But at 30 km/h or slower, more than 90 per cent of those struck make it out alive.

The Star previously reported that reducing deaths is one reason cities such as Paris have put in place, or are pushing for, nearly citywide 30-km/h speed limits. And not only that, say advocates: a 30-km/h limit reduces congestion and energy costs, is environmentally friendly and strengthens a sense of community.

Tory critic MPP Michael Harris said he first wants to see the studies that clearly prove that lowing the speed limit by 10 km/h will saves lives.

“It is important that any changes to the speed limits are based on research and data,” Harris told the Star.

Pat Vinini, executive director for the Association of Municipalities of Ontario (AMO) said talk of reducing speed limits is news to here.

“I don’t understand what is behind this proposal. Certainly it is not coming from our members,” she said.

More cities are lowering traffic speed limits, but does it actually make roads safer?

More cities are lowering traffic speed limits, but does it actually make roads safer?


More from Tom Babin, Calgary Herald – 


Published on: July 10, 2014 – Last Updated: November 26, 2014 11:08 AM MST

child biking traffic safety

After the 12-year-old boy in her neighbourhood was killed by a sport-utility vehicle, Jodi Morel started to do the math.

And tragic mathematics it was. As a member of the traffic committee in her Calgary neighbourhood of Mount Royal, Morel was called to the scene of the collision. She learned the driver was not speeding, but the vehicle was on a street with a 50 km/h speed limit and still had enough force to kill.

“A witness walked me through the scene,” she recalls about that tragic case. “My response was that ‘(The driver) must have been speeding.’ But it was completely legal. In this case, nobody did anything wrong.”

Later, Morel found research showing how deadly a vehicle becomes the faster it is moving, like in the chart below.

Being hit by a slower moving vehicle increases the chance of survival. 

While as many as nine out of 10 pedestrians hit at 20 km/h will survive, for example, at 60 km/h — a speed Morel figures is close enough to the speed limit that few speeding tickets would be issued — as many as 90 per cent will die.

To Morel, this added up to a no-brainer conclusion. One that many jurisdictions around the world are also arriving at: If we want to save lives on city streets, lower speed limits. She subsequently started a campaign to do just that, called Slow Down YYC (on Twitter here)

Dale Calkins, a cycling advocate in Calgary, has similar ideas. He works with 30 For Sunnyside, a group urging 30 km/h speed limits in that community rather than the current default limit of 50 km/h because he think lower speeds is one way to make neighbourhood life safer for pedestrians and cyclists

“We are lacking a conversation on road safety,” he says. “There are a lot of things we should be talking about, and this is one of them.”

Many communities in Calgary struggle to control traffic speed

There are plenty of other people talking about the idea too. Many jurisdictions around the world are reducing speed limits in a bid to reduce the number of automobile deaths. New York City is in the midst of lowering its speed limit to 25 mph (40 km/h) from 30 mph. London drops to 20 mph (32 km/h) on July 20. San Francisco is looking at the same. Even Airdrie has a default speed limit of 30 km/h on residential roads. (Notwithstanding the B.C. government’s recent decision to raise speed limits on a few highways).

While the idea makes intuitive sense — slower-moving vehicles equate to less carnage on the human body — there’s the bigger question: Does it actually work? Do lower speeds make roads safer?

The answer seems to be a resounding yes, albeit with a few caveats. Dr. Don Voaklander, a professor in the school of public policy at the University of Alberta, says there are plenty of studies that show slower moving vehicles not only reduce fatalities, but result in fewer accidents as well. He cited one study that found every one per cent reduction in speed resulted in a two per cent reduction in traffic incidents.

“Reduced speeds not only reduce the severity of (collisions), slower speeds also mean drivers can brake and stop in shorter distances,” Voaklander said. “Speed does kill.”

Those caveats, however, are big ones. There’s no guarantee drivers will blindly obey reduced speed limits. Speeding is a problem today, even with a 50 km/h limit. So Voaklander says enforcement of those limits is key, especially on those wide suburban residential roads in which drivers feel safe going fast.

So if lower speed limits are such a no-brainer for safety (and a host of other reasons, from improved street life to reduced pollution), why isn’t it being done? In Calgary, there are jurisdictional  considerations — a blanket change to default limits in Calgary would require a change by the provincial government — but reducing speed limits is rarely supported by drivers. Despite speed being cited as a problem in some polls by 70 to 80 per cent of community members, there’s a lack of both political and societal will to change them. Nobody, it seems, wants their commute slowed, and such debates tend to pit commuting voters against voters living in those communities being driven through.

A study in 2006 by the OECD into speed management suggested a reason for this is psychology of drivers. Basically, it said drivers rarely think of themselves as doing something risky, even when we’re aware of the dangers of driving. Here’s an excerpt from that report:

The benefits and disadvantages of lower speeds are not perceived in the same manner by individuals and by the community as a whole. The societal consequences of road accidents are well known, and excessive speed is a major contributing factor. However, for an individual driver, the risk of being involved in an accident is relatively small and the driver therefore rarely experiences the worst safety consequences of excessive speed. The more journeys a driver completes successfully at a higher speed, the more the notion that high speeds are safe is reinforced….This contradiction between societal and individual consequences makes it a challenge to create sound speed management.

Voaklander had a more simple reason for the rejection of the idea: “Everybody thinks they’re a great driver,” he says. “We have a sense that we’re in this contained, safe (state). That we’re omnipotent”

So how is that sentiment combated? Voaklander says just as important as enforcement is education about the dangers of speeding and the benefits of the reductions. It can be a slow process, but it may be the only solution.

Few people think reduced speed limits are a panacea. But paired with education, traffic calming initiatives and enforcement, they can help make roads safer. Public sentiment seems to be swinging in that direction. Voaklander pointed to a recent plebiscite in Morinville, north of Edmonton, in which residents voted to keep photo radar because of concerns about safety, a result he wouldn’t have expected in the past, when we were more blase about traffic injuries.

Jodi Morel, for one, vows to keep raising the issue in memory of the boy killed in her neighbourhood.

“I find it surprising that people don’t understand this idea. The amount of time (a driver would save with a higher speed limit) isn’t worth the safety of somebody else,” she says. “I think if they understand that people could get killed, they might change their mind.”

 Leave a comment below or follow me on Twitter, Google Plus,or Facebook, or drop me a line via email me at tbabin@calgaryherald.com.

Calgary’s traffic fatalities nearly doubled Edmonton’s total in 2013

Calgary traffic fatalities nearly doubled Edmonton’s total in 2013

By Robson Fletcher – Metro http://metronews.ca/news/calgary/1082026/calgarys-traffic-fatalities-nearly-doubled-edmontons-total-in-2013/

calgary traffic fatalities

A total of 40 people were killed on city streets in 2013, up 39 per cent from the previous five-year average.

A growing number of community leaders are calling for lower speed limits as newly published data shows Calgary streets were nearly twice as deadly as Edmonton’s last year.

Calgary police recorded 40 traffic fatalities in 2013, marking a 39-per-cent increase from the annual average over the previous five years, according to a report to be presented to members of city council this week. Edmonton, by contrast, saw 23 people killed, representing a 16-per-cent decrease from the previous five-year average in that city, according to a report published earlier this month.

The spike in Calgary fatalities comes despite no significant change in the total number of collisions in 2013 compared to the five-year average. Impaired driving offences were also down more than 15 per cent during the same timeframe. For Mount Royal resident Jodi Morel, the numbers add up to one thing. “I think speed is obviously a factor,” she said Sunday. “When you’re looking at the same number of accidents, the only real variable is how fast these people were going when the collision occurred.” Morel has been campaigning to reduce the standard speed limit in Calgary’s residential areas from 50 km/h to 40 km/h, citing international evidence she says clearly shows a “huge” difference in fatality rates.

Tony Norman of the Marda Loop Community Association (MLCA) said reducing speed limits is “one of those ideas that makes a lot of sense.” In light of residents’ concerns over dangerous driving, he’s organizing a “neighbourhood pace car program” for Marda Loop that he plans to launch on July 12. The pace-car movement – now active in numerous Calgary neighourhoods – sees volunteers affix magnets to their vehicles and erect lawn signs aimed at encouraging “driving by example.” Norman said it’s one small thing communities can do but he’d like to see action from higher municipal levels. “Grassroots stuff is all good and fine but we need the city to come in with their hammer and do something about it,” he said. Coun. Peter Demong, who introduced a successful motion at council last month calling on the province to boost fines for speeding in residential areas, said Sunday he’s not in favour of adjusting the default speed limit across the city. “I’m one that likes to go step by step,” he said. “I’m not in favour of a blanket lowering of speed limits to 40 km/h, simply because I think that would raise the aggravation level of a lot of drivers in trying to get from point A to point B.” Demong said he’s prefer to see targeted enforcement in areas where speeding is a particular problem. “I would say, anecdotally, even in the last four years since I’ve been elected, that I am noticing a huge increase on residential roads in the amount of speeding,” he said. “It’s gone, I would say, ballistic.”

NYC Allowed to Cut Speed Limit to 25 MPH to Lower Traffic Deaths

Bloomberg Post – link here

A bill that would allow New York City to lower its speed limit to 25 miles per hour was approved by the state legislature.

The measure, backed by Mayor Bill de Blasio, would reduce the limit in most areas from 30 miles (48 kilometers) per hour and was passed yesterday. More than 250 people are killed and almost 4,000 seriously injured in city traffic crashes each year, according to a memo by the bill’s sponsor, Senator Jeffrey Klein, a Bronx Democrat.

“Slowing down by even five miles per hour is going to save lives that otherwise could have been lost in senseless traffic accidents,” Klein said in an e-mailed statement.

Rich Azzopardi, a spokeswoman for Governor Andrew Cuomo, declined to comment on the measure.

De Blasio, 53, took office in January as the first Democrat to lead the metropolis in two decades. Lowering the limit is a key component of his Vision Zero plan to end pedestrian traffic deaths, which also includes public outreach and enhanced police enforcement. In April, the legislature approved his plan to add 120 speed cameras in school zones.

Lowering the limit to 25 mph would reduce the chance of fatalities in accidents involving pedestrians to 10 percent from 20 percent, the memo said.

Vision Zero is modeled on a program in Sweden, where a law adopted by the parliament in 1997 sets the goal for traffic fatalities at zero. Since its adoption, traffic engineers have reworked roadways to limit the danger of human error and traffic fatalities have been cut in half, the New York Times reported last month.

To contact the reporter on this story: Freeman Klopott in Albany at fklopott@bloomberg.net

To contact the editors responsible for this story: Stephen Merelman atsmerelman@bloomberg.net Stacie Sherman

Calgary dog recovering after being hit by car that didn’t stop

Calgary dog recovering after being hit by car that didn’t stop

Calgary dog in hit and run

Calgary dog in hit and run

A Calgary family is feeling lucky after their family pet was hit by a vehicle and dragged down the street Tuesday.

Bugsey, a two-year-old Doberman cross, was struck while being loaded into her dog walker’s vehicle.

“She was loading Bugsey into the back and a little bit of her tail end was sticking out,” explains owner, Stefani MacKichan.

“A car came ripping around a corner and she got caught under the front left wheel.”

Bugsey’s dog walker, Brenda Mulyk, is still shaken up.

“It clipped her back end and dragged her down,” Mulyk explains. “I saw her laying there under the tire and I thought, ‘Oh my God she’s dead.’”

According to Dimitri Tsoumpas, who witnessed the incident, the driver of the vehicle got out but then drove away without helping Bugsey.

“He stopped and got out to kind of see what had happened,” says Tsoumpas. “I think he might have gotten a clue and popped back in and took off.”

Bugsey suffered deep road rash wounds, a broken leg and needs surgery.

“The basic thing to do is stop and see if you can help,” says MacKichan.

The Calgary Police Service says it tracked down the driver who says he stopped and didn’t see the dog.

According to police the driver also says there was nobody around and that’s why he drove away.

Police also say that there are conflicting reports over whether the dog darted out into traffic.

Tsoumpas is appalled.

“It was unbelievable;you want to see someone take ownership for what happened, I think the negligence is a little bit shocking.”

Meanwhile, the Mackichan family estimates that Bugsey will require thousands of dollars worth of veterinary care to fully recover.

The driver of the vehicle is not being charged.

Hit and Run

Screen Shot 2014-06-10 at 9.02.47 PM


The Case For A 19 MPH Speed Limit


Cars in Paris will soon be going très slow. The city’s new mayor, Anne Hidalgo, recently introduced a plan to lower the default speed limit throughout the city from 50 kph (31 mph) to 30 kph (a little slower than 19 mph). Though billed as an anti-pollution plan, it will make streets safer for pedestrians, Le Parisien reports.


Since the first “Tempo-30” zone was introduced in Buxtehude, Germany, in 1983, the traffic-calming measure has been adopted by other European cities, including Stockholm, Munich, Dublin, and Barcelona. The policy has largely been implemented by smaller cities and only in residential areas, though, making the Parisian plan, which will affect the city’s 2.2 million* residents, notable for its scale. Studies have shown that reducing speeds to 30 kph or less both reduces the total number of accidents and how fatal accidents are for pedestrians. London‘s 20 mph zones, mostly in residential areas, have reduced the frequency of fatal and serious injury accidents by 53%. The creation of 78 slow zones in the city lowered the annual injury accident rate from 1,660 total accidents to 590, and 282 fatal accidents to 77. And according to experts, the slower speed limit doesn’t necessarily cause more traffic jams.

In Paris, the 30 kph limit will apply to most streets, excluding some major thoroughfares like the Champs-Elysées. The initiative, which does not have a roll-out date yet, represents larger efforts by Parisian administrators to slow traffic to protect pedestrians and reduce CO2 emissions (though the effects of slowing down to 30 kph on emissionsaren’t entirely clear). Earlier this year, the city reduced the speed limit on its busy ring road, Boulevard Périphérique, by 10 kph, down to 70 kph or 43 mph. (Critics noted that the change made no difference, since congestion kept traffic at a crawl anyway. Under the new plan, its speed limit will remain 70 kph.) A little more than a third of the city’s streets already had 30 kph speed limits, as per a September 2013 initiative, and certain sections of the city where cyclists, pedestrians, and cars are likely to mingle, called “meeting zones,” are limited even further, to speeds of 20 kph or less.

You might assume that lower speed limits slow drivers’ travel time, but that’s not usually the case. On urban streets, “a lower speed limit may actually reduce overall travel time by allowing a more harmonic traffic rhythm,” according to a study from the Accident Research Center at Monash University in Melbourne, Australia.

Congestion in cities is “all about competing demand at intersections,” as Tom Vanderbilt, author of the book Traffic: Why We Drive the Way We Do, explained to me in an email. “Drivers speeding toward a red light, stopping, and restarting can actually cause more congestion than if everyone just drove more slowly and timed their approach to their light.”

And ensuring that urban drivers keep speeds down under light traffic conditions could save a significant number of lives. Research has shown that the risk of pedestrian fatality rises sharply at speeds higher than 30 kph. A U.S. National Highway Traffic Safety Administration report found that only 5% of pedestrians hit by a car going 20 mph or less died, compared to 40% struck by a vehicle going 30 mph and almost 100% of pedestrians struck by vehicles going 50 mph or faster.

Paris is not the first city to test out 30 kph zones as a pedestrian-protecting measure, though it may be one of the largest cities so far to make 30 kph the default speed limit. In 1992, Graz, Austria (population: 265,778), made 30 kph the default speed limit citywide.


These 30 kph zones are also a vital component of Sweden’s Vision Zero policy, which aims to reduce pedestrian traffic fatalities to zero. There, as well as in cities in the Netherlands, Ireland, and the U.K., speeds have been reduced to 30 kph in most residential zones and some city centers. The Greens/European Free Alliance, a political group within European Parliament, wants to make it an even broader policy: it recently proposed making 30 kph the default speed limit throughout the European Union.

The U.S. is still playing catch up. New York City has been experimenting with 20 mph zones since 2010, but recent plans to reduce the default speed limit to 25 mph (as part of New York’s Vision Zero) have beenstalled by state lawmakers.

[H/T: Raise The HammerWorld Streets]

*The original version of this post listed the population of Paris as 2.2 billion, rather than 2.2 million. Thanks to commenter Kenny Landes for pointing out the error.

[Image: Paris via vvoe / Shutterstock]