Taking a model approach to improving transportation on the North Shore

By District Staff on Friday, Feb 8, 2019

We've been working closely with TransLink to finalize the new B-Line rapid bus service route that will run along Marine Drive and Main Street across the North Shore.

While we're making a few changes to the road to accommodate the new bus line — removing some left-hand turn bays, for instance — we're confident that impacts to traffic will be minimal.

How can we be sure? That's where DNV transportation engineer Ahmed Tageldin comes in.

Ahmed and his transportation colleagues have spent the past year interpreting data, modeling scenarios, and collaborating with TransLink, to identify the right combination of changes along Marine Drive and Main Street that will accommodate the new faster bus route, while ensuring vehicle traffic is not negatively impacted.

Here's a closer look at the process our transportation professionals follow when making changes to local roads.

Good decisions start with good data

Municipal decisions are typically driven by data, rather than by observation or 'intuition.' With accurate, up-to-date data, we're able to determine with a high degree of accuracy what the outcome of a change will be, whether it's modifications to a stream bed to reduce the risk of flooding, or in this case, changes to a busy thoroughfare.

For the B-Line project, the data we collected included:

  • Traffic count — How many cars travel through the area during various times of the day?
  • Turning data —  How many of the cars turn left or right, or go straight?
  • Travel time —  How long does it take to travel through the area?

And just as there were a number of data points collected, there were different ways we collected it.

A lot of the data was gathered electronically. The cameras attached to the signal lights at many intersections are typically used to control traffic flow, but they can also provide accurate counts of traffic, turning, and so on.

Some data was gathered through direct experience: transportation staff got in their cars and drove the route many times, over various days (and at various times of the day), recording the length of each trip.

Building a model from the data

Armed with data, our experts can then get to work generating a computer model of the area being studied.

Created using the most advanced modelling software on the North Shore, an animated base model provides a representation of how traffic flows, not just on the street being improved, but throughout the entire area: speed, travel time, where it becomes congested, how back-ups on some streets impact the flow on other streets, and so on. 

Better still, the model reflects the traffic at any time, so you can choose to view how it flows at, say, 9am on a Monday, or 5pm on a Friday.

It's as close as you can get to hovering over the area in a helicopter and observing how traffic moves through the District in real time, without having to leave the ground.

WATCH | Base model of the traffic flow along Marine Drive starting at Capilano Rd

Testing multiple scenarios to find the best solution

Now here's where it gets really interesting...

Using the base traffic model, engineers can start experimenting with modifications to a road, and see immediately what impacts those changes would have on traffic flow.

They can, for example, test the impact of converting a regular lane of traffic to a dedicated bus lane for six blocks, simply by making that change in the model. Or they can test diverting traffic to other streets. Or test removing a few left-turn bays. Or eliminating turns. Or any combination of changes.

The model reflects what happens to traffic on that street whenever a change is made, and also reflects what happens to the traffic in the surrounding streets and neighbourhoods as a result.

There is no guesswork, and no risk of inconveniencing drivers, cyclists, or pedestrians by conducting these experiments in the field. 

WATCH | Model of the final traffic pattern for the westbound Marine Drive portion of the new B-Line

WATCH | Model of the final traffic pattern for the eastbound Main Street portion of the new B-Line

Collaborating with other organizations

In cases such as the B-Line, where there are other considerations beyond local traffic, the next step is stakeholder collaboration.

While our goal with the B-Line was to make adjustments to the street with as little impact to traffic as possible, TransLink's goal was to ensure the express busses could move through the area at optimum service speed.

So, once planners had a scenario that delivered the results they wanted, they would then confer with TransLink, who would evaluate the scenario. If the scenario didn't deliver the desired outcome, it was back to us to try again.

Only once we had designed a scenario that worked for us and for TransLink were we ready to move forward.

Continuous monitoring after the fact

While we can roll out new transit service with a high degree of confidence due to the extensive data analysis (the new B-Line route should be operational later this year), we still monitor the changes to ensure that they're meeting expectations.

If the outcome is different than that which was predicted in the model, we can test further adjustments where necessary to keep traffic — and people — moving smoothly through the District.

Review the final plan for the new Marine-Main B-Line

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