Evidence shows that Battery Electric Buses (BEBs) do cause additional wear to urban road infrastructure, and the city is examining what those impacts might be for Calgary when it rolls out upcoming electrified bus routes.

Ward 2 Coun. Jennifer Wyness quizzed city administration during Question Period at a Sept. 10 meeting on how they’ve contemplated safety and increased lifecycle costs with the future introduction of BEBs to the Calgary Transit fleet.

The City of Calgary has entered into agreements to buy 259 zero-emission BEBs, with $165 million in funding from the Canada Infrastructure Bank and $325 million from the Zero Emission Transit Fund, along with $100 million from the City of Calgary 2023-2026 budget.

According to the City of Calgary’s 40-foot electric buses webpage, they will purchase the vehicles in Q3 of 2024, with supporting infrastructure being bought in 2025. They expect infrastructure completed by 2027, with the buses in service by 2028.

Coun. Wyness told LWC that she’s concerned about the safety aspects, including exceeding the weight capacity limit on roads. The wear on roads is the other part of this equation, she said.  She notes an intersection near Royal Oak with heavy truck traffic that’s constantly rutted due to the heftier loads.

“It puts more pressure on admin to have to constantly go in and repave it because we have such heavy vehicles hitting this one intersection,” she said.

“We’re going to have roads and bus loops – what’s the plan? If how we design our roads is for different classifications of vehicles, will these EVs require us to do increased road work in suburban neighbourhoods where that bus route is because we’re putting the EV buses there?”

Coun. Wyness said she’s concerned about risk-layering that’s been ignored, along with cost-layering associated with deciding to pursue electric buses.

The impact of BEBs on road infrastructure

Poring over the different zero-emission City of Calgary webpages and the reports on implementing an EV transit fleet strategy, there was only one discoverable mention that EV buses could impact roads.

Several publicly-available reports commissioned by the City of Calgary either didn’t cover it, or it wasn’t included in the scope of those EV implementation reports.

On the 40-foot-electric-buses webpage, the FAQ does acknowledge that BEBs are roughly 20 per cent heavier than a traditional 40-foot diesel or compressed natural gas bus. A typical 40-foot diesel bus weighs 29,000 pounds, and, depending on the model, a BEB weighs between 30,000 and 35,000 pounds.

“Heavier vehicles including BEBs can negatively affect road infrastructure. To understand the impacts, we’re gathering knowledge from other Canadian municipalities that operate BEBs and have evaluated pavement quality impacts, such as Winnipeg Transit,” the website reads.

The City of Calgary did acknowledge that though the weight of buses was considered and determined that it could have an impact, this information was not presented to Calgary city council.

Winnipeg Transit’s 212-page technical evaluation report from 2021, provided at the bottom of this story, included reference to two University of Manitoba studies that reviewed an express route with high-density traffic to determine additional road wear.

“Even in a worst-case scenario where (zero-emission bus) is double that of (diesel bus), the incremental increase to road damage may only result in a 3.69% increase in road maintenance on shared roadways,” the report read.

The study suggested that Winnipeg Transit would need to work closely with the City of Winnipeg’s public works when designing and estimating lifecycle costs for new transit ways.  It also noted that when procuring the buses, cities can specify lightweight options for other parts of the buses to counteract the weight of the “propulsion system.”

Another study from the University of Edinburgh showed that a complete conversion of Scotland’s existing vehicle fleet to battery-operated would increase annual road wear by 20 to 40 per cent.

All of the studies acknowledged rapidly improving technology that could lighten the battery weight. It’s also noted in many studies and reports the overall cost savings of operating EV buses versus traditional diesel buses, potentially mitigating some of the added road maintenance costs, while saving on emissions.  

Determining the impact of EV buses

Stephen James, senior transportation engineer with Calgary Transit, said they don’t know yet what the dollar impact of EV buses on Calgary roads will be. They’re working with their colleagues at Calgary Roads to determine what additional funds might be needed for paving and maintenance.

However, he acknowledges that there will be some impact on Calgary roads. James said the extent to which they’re impacted relies on several factors. It depends on how much additional heavy traffic is on that road, the frequency of bus travel, the construction and condition of the road surface, and more.

“That’s what we’re going to be looking at with our study,” he said.

“We have developed a concept of operations… we have a good sense of where E-buses are going to go, what roads they’re going to travel down. So, that’s why we’re doing that analysis, to really kind of specifically answer that question of what the impact will be on those roads.”

On the safety front, James said that all buses must pass certification requirements and are rigorously tested for braking (specifically for weight), visibility, emergency exits, lighting and their tires. They have to meet Transport Canada requirements.

James also said that any new bus manufactured in North America goes through something called Altoona testing, done through Penn State University.  They test the structural integrity of buses, emissions, plus brake testing and lane changing with full loads.

“We will not accept a bus that hasn’t gone through any of these certification or testing processes,” he said.

Further, in terms of allowable axle weight on roads, James said already many Calgary Transit buses have overweight permits, allowing them to operate on city roads.

Still, Coun. Wyness said that city council – and Calgarians – should have the full life-cycle costs in front of them before making these decisions.

“They’re supposed to find a standardized way to present to council decisions that show the holistic connection, including road wear and tear and connect the department that will interact with these massive decisions council makes,” she said.

“If you look at administration’s presentation for some of these decisions, they’re still like, ‘trust us. We’ve got the start of an idea here. Just vote yes, so we can keep researching and keep spending money on this decision.’”

Meanwhile, there’s a continued delay beyond one announced in March for the City of Calgary’s EV Shuttle Bus pilot project, and they have to go back out to market to select another vendor.