Build highways and traffic will follow
Research shows new roadways do little to stop gridlock, with cars quickly filling up empty space
It’s a fantasy that anyone who’s spent an hour crawling along in traffic on Highway 401 has indulged in: if only an empty lane would appear alongside the roadway, the daydream goes, a frustrated driver could scoot to freedom and leave the gridlock behind.
Premier Doug Ford is promising to make a version of that dream a reality with plans for a major expansion of the GTA highway system his government says “will get Ontario drivers out of gridlock.”
But while the Ontario PC’s are betting the proposed Highway 413 and Bradford Bypass will win over discontented commuters in the run-up to the June 2022 election, the idea that future drivers will zip along empty new highways is likely too good to be true.
Decades worth of research and real-world experience indicates highway expansions have limited ability to reduce congestion, because traffic volumes quickly increase to fill up new road space and gridlock returns within a matter of years.
The phenomenon is called “induced demand” and experts say it doesn’t appear the province has adequately accounted for it in the highway vision it’s pitching to voters. Even the province’s own projections suggest the 413 would be afflicted by significant congestion soon after it’s built.
“When highway capacity has been expanded, there has been an increase in the amount of driving, and that’s what all the studies show,” said Susan Handy, a professor of environmental science and policy at University of California, Davis. While there’s debate over how fast gridlock returns, “over time you get back to where you were, congestion-wise,” she said. Induced demand may seem counterintuitive because it’s easy to think of traffic moving along highways as if it were water draining through a pipe; if the pipe were wider, the water would drain more quickly.
But transportation planners say it’s more accurate to look at road use in terms of supply and demand. For any product, higher costs lead to decreased demand. The time it takes to drive somewhere is a cost to the driver, so if highway travel times are long, some people will be less likely to drive, or will drive less often.
New highway lanes temporarily reduce the cost of driving by enabling quicker trips. That increases demand, and as people switch from other modes to driving, or opt to take longer or more frequent car trips, the new lanes soon become as crowded as the old ones.
Handy’s reviews of research into highway expansion suggest new lanes become congested within as little as five years.
There’s no shortage of real-world examples of induced demand, which researchers have observed as far back as the 1920s. But one notorious case is the Katy Freeway in Houston, Texas. An expansion of the chronically clogged highway was completed in 2011 at a cost of $2.5 billion (U.S.), creating a traffic corridor that is 26 lanes across at its broadest point and is among the widest on the continent.
Although drive times improved immediately after the expansion, by 2014 media reported that trips on the Katy were taking longer than in 2011.
The controversial Highway 413 project backed by the Ford government would be a 59-kilometre, four- to six-lane highway between Highway 400 in Vaughan and the Highway 401/407 interchange near Mississauga, Milton, and Halton Hills. The Bradford Bypass would run for about 16 kilometres between Highway 400 and Highway 404 in the County of Simcoe and York Region.
While the government hasn’t detailed costing, one estimate puts the two projects’ combined price tag at more than $10 billion.
Ford’s government predicts that by 2041, Highway 413 would save drivers 30 minutes each way on a 56-kilometre trip between Highway 401 at Trafalgar Road and Highway 400 at King Road, compared to how long the trip would take via Highways 400 and 401.
The government hasn’t released detailed modelling to support the 30-minute figure. But a spokesperson for Transportation Minister Caroline Mulroney said the numbers are based on calculations that show if the 413 isn’t built, peakhour operating speeds on the 400 and 401 will drop to 35 km/h by 2041, and a trip between King and Trafalgar will take 89 minutes.
The trip on Highway 413 would be faster, at 59 minutes. But even by the government’s estimates the new roadway would hardly be congestion-free. By 2041, at its busiest times the 413 would have an average travel speed of 55 km/h.
Asked whether the government’s estimates take into account induced demand, Jordanna Colwill, the minister’s spokesperson, said they capture “demand that would shift to the new highways from other modes or other adjacent roads.”
That’s different from factoring in induced demand.
“The reality is, people use cars and with major highways in York and Peel Region all forecasted to be operating over capacity by 2031, we can’t afford to delay building critical highway infrastructure,” Colwill said.