Setting the limit
Transportation manager Dean Schick explains the science and sensitivities behind St. Albert's speed limits
Saturday, Jun 28, 2014 06:00 am
We asked you: How do you feel about speed limits in St. Albert? Are there certain streets/areas that you find particularly frustrating?
Amanda Babey, @smandaleeb:
Despite what drivers seem to think, Bishop Street is not a freeway.
Woodlands Road seems to be extremely problematic. I live right on it and people speed up and down it every day like it's a race track. I have resorted to standing outside and watching my child walk to and from school because too many drive carelessly and don't pay enough attention to the fact that it's a residential area with many children!
Personally I think all residential roads should be decreased to 40 km/h and the other collector type roads should all be 60 km/h. There are some that are 50 right now and there are no homes, or schools facing onto them. It makes no sense. I guess they are just a cash cow for photo radar. Also why is that little piece of 137 Avenue from Ray Gibbon Drive to 170 Street 60 km/h? The rest is 70.
North Ridge Drive really needs a posted speed decrease.
The only reason most roads are 50 is for the purpose of photo radar, most roads are made to handle 60 km/h speed limit!
I agree that the section of Ray Gibbon that is 60 should be 70. In fact, Ray Gibbon could be increased to 75.
There's a weird section by Sir George Simpson that's like a grey area. If you go one way it's 30 but the signage in the other direction says 50.
The 30 km/h section on Mission by the grain elevators and on Hebert make me crazy. It's posted 30 on Grenfell – around the corner by Wildrose no one pays attention to that. People need to respect the speed limits on all the collector loops in residential areas too.
Cruising on a four-lane road like Sir Winston Churchill Avenue on a sunny day, one might stop to ask why the speed limit – 50 kilometres an hour for much of the road – is set so low.
Driving down Dawson Road with the speedometer locked at 50 when it’s ideal road conditions can be a challenge for some as well.
But speed limits in St. Albert aren’t set arbitrarily. A limit that might seem too slow on an ideal day has a variety of other factors taken into account, explains St. Albert’s transportation manager Dean Schick.
“On a nice sunny day there’s minimal volume, minimal perceived conflict from other vehicles or road users, and so that would be a perception of what the ideal speed should be, because I may not recognize as a driver that I’ve passed five different access points to condos, commercial lots, and I’m driving across a 60-degree curve, but all my brain takes in is I’ve got two lanes of travel, and it’s a nice road condition, I should be driving faster,” Schick says.
City engineers use guidelines from the Transportation Association of Canada to help them determine speed limits for St. Albert’s roadways, Schick says.
The guidelines help provide an assessment tool for the engineers and use a scoring system.
“It takes subjectivity out of the equation,” Schick says.
Factors considered include the roadway classification (i.e., arterial, collector or local road); the land use surrounding the road (this can impact who is on the road and how it’s used); as well as the number of travel lanes, median separation and the length of the road corridor.
Engineers consider the speed at which the road is deemed safe under ideal conditions then lower the limit based on the presence of various risk factors.
These factors can include “horizontal” and “vertical alignment” (usually meaning hills and curves), lane width, roadside hazards, pedestrian and cyclist exposure, the pavement surface, intersections, private access points and on-street parking.
Each road in St. Albert has its own profile and hazards, Schick says.
The speeds aren’t set only with drivers in mind, but also take into account other road users like pedestrians and cyclists.
“You need to equate the most vulnerable road user when you’re looking at the most potential danger,” he says.
As a pedestrian hit by a car, your chance of survival diminishes significantly as speeds increase. At 30 km/h your chance of survival is high but drops to only 10 per cent at 60 km/h.
“We need to design speeds and roadways for all road users,” Schick says. “We are a very heavy vehicle-reliant community but on the same token we want to enhance mobility and ensure the quality of life is high for all residents using our network systems.”
While there are many complaints that speeds are too low – Sir Winston Churchill Avenue and Bellerose Avenue are two that Schick hears about often – there are also complaints that speeds are too high.
The latter complaint is often about local roads.
Schick says all drivers have their own perspectives on their routes and needs from a roadway. For instance, while driving to work a driver might want the limit to be higher, but on the local roads close to home think the speed limit is too high.
And drivers aren’t the only people complaining. The city also gets complaints from frustrated pedestrians who think traffic is travelling too fast or not stopping at crosswalks.
“You don’t often hear a pedestrian complain the speed is too low on any roadway,” Schick says.
Engineers might crunch the numbers, but education and enforcement also play a role in addressing the city’s speed limits.
“The majority of drivers out there are in general very reasonable and travel at a speed which will allow them to avoid crashes. However, complacency created from driving under ideal scenarios may create a false sense of security in both the drivers’ capability and the vehicle capability. That’s just a reality,” Schick says.
Stu Fraser, supervisor of the peace officer program for the city, says an average driver doesn’t see the work the engineering department does or necessarily understand what hazards may lie ahead on a road.
A good example is coming into the downtown area from the west via Sir Winston Churchill, Fraser says.
“The average motorist doesn’t realize that Dean and his section have gone out and played with the crosswalk lights because we have pre-school and out-of-school care down there, we have seniors going back and forth from the support services (to the mall),” he says.
“We’ve created an expectation by signage and by enforcement that this is the speed from one end of Sir Winston to the other, yet the average driver just knows that it’s a four-lane divided collector route and they’re frustrated because they can’t get quickly where they want to go.”
It’s not always clear to a driver why the speed limit is what it is, Fraser says.
“We’ve artificially by perception depressed the speed limit, but it’s because of a number of various factors that have been identified,” he says.
Schick says his department tries to be evidence-based when it comes to decisions.
Martin Parker Jr., a traffic engineering principal for the U.S.-based firm Wade Trim, echoed Schick’s desire for evidence.
“You need to have this factual information and then you can make good decisions that are realistic,” Parker says.
When it comes to setting speed limits, Parker says, one size does not fit all.
He says setting speed limits should be like shoe shopping for municipalities.
“You go out and look for your size, look for your style and so on and purchase the shoes, see how they fit and then you’re happy,” Parker says.
However, that’s not how it always works.
“The problem with speed limits, everyone has an opinion, and instead of selecting a speed limit that fits the conditions, we go with general limits.”
To determine a limit that’s realistic, Parker says doing some measurements is required. He says speed samples should be first on the list to determine the 85th percentile speed – the speed at which or below 85 per cent of the people are travelling.
“It gives you a good idea of what the general driver perceives on that section of road,” Parker says.
After that you need to collect crash data. The presence of pedestrians and other road users also needs to be considered.
In urban situations in particular, the needs of non-motorists often should have an impact on the speed limit, he says.
But it depends on the conditions of each individual road and its uses.
Updates to speed limits should absolutely be on the table, Parker says.
“Conditions change. We should always be open to a review,” he says.
Bellerose Drive/McKenney Avenue – 50/60 km/h
Bellerose changes from a two-lane undivided road, with no curbing or other urban features, to a four-lane divided road that travels through a major commercial area.
Schick says some speed-limiting factors on this road include a hill on the east end that impacts visibility coming up to intersections, as well as road curvature.
On McKenney there is a hill as well, along with a private access point on the north side, west of Liberton Drive, along with an “S” curve with multiple private access points.
There are multiple roadway intersections along the road.
Pedestrian use, including children attending school in Lacombe Park, needs to be considered as well, Schick says.
Dawson Road – 50 km/h
Many feel the 50 km/h speed limit is too low for this undivided four-lane road. However, Schick says speed-limiting factors include the fact that it’s undivided, is used by pedestrians (many of whom are children) and there are multiple intersections that provide neighbourhood access.
Giroux Road – 60 km/h
A four-lane divided arterial road, Giroux Road has some less severe “S” curves to consider. There are minimal private access points but there are some. There are also intersections and pedestrian movements, including high school students, to consider.
Grandin Road – 50 km/h
A four-lane undivided road, Grandin Road has potential pedestrian conflicts, roadway intersection points, a hill and the entrance to the downtown area – all of which serve as speed-mitigating factors, Schick notes.
Poirier Avenue – 50 km/h
While it is a four-lane roadway, Poirier Avenue is undivided and there is some curvature that limits the visibility of major intersections.
Schick notes there are private access points on the east end as well as pedestrian movements to accommodate.
Residents complain about drivers’ speeds in the area, particularly at the Parkwood Drive and Pinewood Drive points, he says.
Sir Winston Churchill Avenue – 50/60 km/h
Schick notes there are multiple school zones and private access points along this road.
The limit is 60 km/h at the west end but 50 km/h near commercial and residential access points. Near some of those spots there is an “S” curve that limits visibility.
The road also shifts from a two-lane undivided road to a four-lane divided road, he notes.
Villeneuve Road – 60/80 km/h
The road is an undivided two-lane roadway that transitions from a rural setting to an urban one. Coming in from a highway speed, there are segments of 80 km/h and 60 km/h to reduce speeds to urban-appropriate levels, Schick says.
Factors considered in the limit include intersections with neighbourhood sites and city works sites.
Villeneuve also approaches a major commercial area near St. Albert Trail, he notes.