Peter Karwacki: Traffic Circles? Vanier and St. Patrick

Why Is there No Traffic Circle at St. Patrick and Vanier Parkway?

Ottawa's Inconsistent Traffic Planning

If you've driven or walked through the intersection of St. Patrick and Vanier Parkway , you've probably noticed the ongoing frustration with that right-turn channel heading southbound onto Vanier Parkway. It's a poorly designed chokepoint that creates safety concerns for cyclists, pedestrians, and drivers alike.

So why doesn't Ottawa install a traffic circle there like the ones they've successfully built at St. Joseph and Jeanne d'Arc in Orléans?

Good question. I've been asking the same thing.

The Problem at St. Patrick and Vanier

The right-turn channel at this intersection has been a source of complaint for years.

During the recent public consultation on the St. Patrick Street Bridge renewal project, residents made it clear: they want this thing gone. Safety was the primary concern. And frankly, after watching how that channel functions, I understand why. It's a recipe for conflicts between turning vehicles and people crossing on foot or bike.

A traffic circle would solve this problem elegantly. Lower speeds, continuous flow, fewer conflict points, better sight lines. It works everywhere else the city has installed them.

Ottawa Says No—but we need the data!

The city's response? When I've tried getting a straight answer from city staff, I usually get the runaround. ( fill out a foia) form They're either (as I've come to feel) not helpful or they don't want to revisit a decision that's already been made.

Vanier Parkway is classified as a "principal arterial"—a major route carrying high volumes of traffic. City guidelines apparently prefer traffic circles on collector roads in residential areas, not on arterials. .

The St. Joseph Contradiction

St. Joseph Boulevard has a traffic circle. At Jeanne d'Arc. In Orléans. It's a two-lane roundabout that opened in 2010 and it works great. Residents in that area are happy with it.

If elected coucillor I would work to cure that choke point and others like it.

St. Joseph Boulevard has a traffic circle. At Jeanne d'Arc. In Orléans. It's a two-lane roundabout that opened in 2010 and it works great. Residents in that area are happy with it.

So what's the difference? St. Joseph is a residential/commercial boulevard. It's lower volume than Vanier Parkway. It's a different road classification. What are the data?

But if the city *can* build roundabouts, and they *have* built them successfully, why are they so resistant to even exploring the option at St. Patrick and Vanier? Why is this intersection different enough to warrant a permanent "no"?

I suspect the answer has less to do with traffic engineering and more to do with institutional inertia.

The signal system is already in place. The bridge reconstruction is focused on cycling and pedestrian improvements, not intersection redesign. Someone made a decision years ago, and now the city would rather not revisit it.

Meanwhile, pedestrians and cyclists navigate a dangerous right-turn channel. Drivers wait at signals that could be replaced with more efficient traffic flow. And the city continues to tout its roundabout program—just not here.

What Should Happen

Someone at city hall needs to take a fresh look at this intersection. I'm frustrated but because the engineering might actually support the traffic circle. Get a traffic engineer to model a roundabout design there. Look at the space available. Compare it to what works at St. Joseph.

If there's a real constraint—if the intersection is too narrow, if traffic volumes are genuinely incompatible with a circle, if bridge geometry makes it impossible—then say so clearly. Publish the study. Explain the decision in plain language.

But if it's just inertia and institutional resistance, then the city should reconsider.

Right now, St. Patrick and Vanier Parkway is a poster child for Ottawa's inconsistent, frustrating approach to traffic planning.

What other intersections in Rideau Rockcliffe are suitable for traffic circles?

There are quite a few others.

Lack of traffic circles creates frustration in drivers in Ottawa

If drivers are frustrated, it's likely a mix of factors:

Signal timing and coordination across corridors
Sprawling geography (lots of area to cover, longer commutes)
Peak-hour congestion on main routes
Whether transit alternatives exist

Roundabouts.

The real question is whether specific problem intersection left turns would benefit from them operationally. I think so, yes.

How about Vanier at St. Patrick, Hemlock and st Laurent,

At each intersection:

What causes the backups? (Peak hour queuing on one approach? Left-turn conflicts? Pedestrian crossing delays?)
What are the turning movement volumes? (Lots of U-turns? Heavy cross-traffic?)
Accident frequency and types
Whether signal timing is optimized or just dated

For roundabouts specifically:

St. Laurent is a major arterial—a roundabout might create different congestion patterns if traffic is heavy
Hemlock/St. Laurent especially: if you have high-speed through traffic mixed with local turning movements, that's trickier (roundabouts work better when speeds are moderate and relatively balanced)

Has anyone from the City looked at these intersections with an eye toward improvement? Sometimes the issue isn't the intersection design itself but signal coordination.

The real question is whether specific problem intersections would benefit from traffic circles.

Have you noticed particular intersections like Vanier at St. Patrick, Hemlock and st Laurent?

The City must look at these intersections with an eye toward improvement. The issue isn't the intersection design itself or signal coordination across a corridor, or peak-hour capacity limits on the roads feeding into them. It's volume, the lack of a sixth bridge crossing.

"left turns from Vanier backing up," "St. Laurent backed up trying to cross Hemlock"), actually tell us a roundabout would help.

Left turns are one of the clearer cases where roundabouts genuinely outperform signalized intersections.

Why left turns create bottlenecks at signals:

They require dedicated green-arrow time or waiting for opposing traffic to clear
That turn phase reduces green time for through traffic
Left-turners queue up and can block the through lanes behind them, creating backup even when the main corridor is nominally "green"

How roundabouts handle this differently:

Left turns (or U-turns) are just part of the normal circulating pattern—no special phase needed
Vehicles don't wait for a signal; they go when there's a gap in the circle
No queue backup onto the approach road (assuming the roundabout itself doesn't exceed capacity)

The constraint
Roundabouts work smoothly at moderate speeds and moderate volumes. On St. Laurent especially—if it's a high-speed arterial carrying significant through traffic—a roundabout could create its own bottleneck if the circulating traffic gets too heavy.

For Vanier/St. Patrick and Hemlock/St. Laurent, it depends on whether:

The through-traffic volume on the main roads can absorb merging into a circle
Left-turn volumes are high enough to justify the change (vs. just optimizing signal timing)

It's worth noting that Ottawa has been adding more roundabouts.

Just for fun I will add that the road infrastructure in Ottawa is...abominable.

Every available dollar has gone into LRT.

As Neil suggests, Soon this Will become a safety issue.