Special Report: Light Rail

Induced Demand, Transit Investment and Congestion

Improved transit doesn't necessarily permanently eliminate congestion on the roads, but it does enable a greater number of people to move around more efficiently at a given level of congestion.

By Nicholas Kevlahan
Published June 19, 2014

An article posted recently in Wired does a good job of explaining induced demand:

The concept is called induced demand, which is economist-speak for when increasing the supply of something (like roads) makes people want that thing even more. Though some traffic engineers made note of this phenomenon at least as early as the 1960s, it is only in recent years that social scientists have collected enough data to show how this happens pretty much every time we build new roads.

When a city makes it easier to drive by adding lanes, more people choose to drive and those lanes fill up with additional cars.

Induced demand does not just apply to automobile lanes, however. It also applies to other transportation modes, like pedestrian infrastructure or bike lanes or public transit.

It is important to be careful about the "reducing congestion" argument for investment in new public transit. Improved transit doesn't necessarily lead to less traffic congestion, due to the induced demand effect:

You might think that increasing investment in public transit could ease this mess. Many railway and bus projects are sold on this basis, with politicians promising that traffic will decrease once ridership grows. But the data showed that even in cities that expanded public transit, road congestion stayed exactly the same. Add a new subway line and some drivers will switch to transit. But new drivers replace them. It's the same effect as adding a new lane to the highway: congestion remains constant. (That's not to say that public transit doesn't do good, it also allows more people to move around. These projects just shouldn't be hyped up as traffic decongestants, say Turner and Duranton.)

Improved transit doesn't necessarily permanently eliminate congestion on the roads, but it does enable a greater number of people to move around more efficiently at a given level of congestion.

If there was no transit and everyone had to drive an automobile, there is no way the roads could handle the total demand. Cities with insufficient transit inevitably end up with essentially non-functioning road networks because there is no feasible alternative.

That is what has been happening on Greater Toronto and Hamilton Area (GTHA) roads, where travel times have been increasing dramatically as the region has fallen behind on transit improvements.

There are also many people, especially in Hamilton, who are unable to work at optimal jobs because of the lack of transit options. The opportunity cost of a transportation system that doesn't allow people to match themselves with the best jobs has been estimated to cost the GTHA between $1.5 and $5 billion a year in lost productivity.

A counter-example is Vancouver, which has demonstrated that congestion goes down if you improve transit, cycling and walking options and change land use to higher density mixed use so that more people can live in a way such that driving doesn't make sense.

But the article is probably right if all you do is improve transit but leave everything else the same - especially if the city is relatively low density - then traffic won't necessarily decrease.

This is the case in dense cities like New York and Paris, which have both heavy traffic and good transit, but where (as we see during strikes) the city would be entirely non-functional without transit since only a small portion of the population can drive at any given time.

Luckily, Hamilton has been developing a land use plan together with its LRT plan, which should maximize our advantage.

See also:

Nicholas Kevlahan was born and raised in Vancouver, and then spent eight years in England and France before returning to Canada in 1998. He has been a Hamiltonian since then, and is a strong believer in the potential of this city. Although he spends most of his time as a mathematician, he is also a passionate amateur urbanist and a fan of good design. You can often spot him strolling the streets of the downtown, shopping at the Market. Nicholas is the spokesperson for Hamilton Light Rail.


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By Cyclical (anonymous) | Posted June 19, 2014 at 12:23:24

Congestion results as not easy to reach destinations by other means. 'Smart centres' killed walkability. LRT definitely good for small business and vice versa.

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By H1 (anonymous) | Posted June 19, 2014 at 13:46:04

"estimated to cost the GTHA between $1.5 and $5 billion a year in lost productivity." I thought that was the cost of congestion on the GTA roads? If you use reality to look at this you would know that there are no empty workspaces not producing things because there are no workers. employers don't pay you if your not at work, that means employers aren't losing, there is no loss. The loss is personal time. time spent waiting in traffic. but according to the article if more busses and trains were added the roads would be as slow, just more people would be making the trip. I did not know there was such a worker shortage!

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By Pxtl (registered) - website | Posted June 19, 2014 at 15:11:34 in reply to Comment 102692

"It's okay, we're only wasting billions of dollars in unpaid time, not paid time!"

I am embarrassed on behalf of whatever causes you hope to represent.

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By Noted (anonymous) | Posted June 19, 2014 at 21:56:04

A few years old, but this Metrolinx report gives you a sense of the temporal and economic impact of congestion.



Table 1: Extent of Excess Travel delay in the GTHA, 2006

Minutes Per Day, Per Commuter

City of Hamilton: 4.8
Halton Region: 7.8
Peel Region: 11.1
City of Toronto: 15.6
Region of York: 12.9
Durham Region: 8.8
GTHA Avg: 11.5

Figure 6: Regional Distribution of the Total Annual Cost of Excess Congestion Experienced by Commuters, 2006 ($ million)

City of Hamilton: 94
Halton Region: 249
Peel Region: 845
City of Toronto: 1,389
Region of York: 623
Durham Region: 309

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By H1 (anonymous) | Posted June 20, 2014 at 10:11:55 in reply to Comment 102714

70% of Hamiltonians (ie. 139,470 commuters) work somewhere within Hamilton 23,400 of those (ie. 17% of intra-Hamilton commuters), worked downtown (ie. Downtown Community Improvement Project Area, or Queen/Victoria/Cannon/Hunter plus James from LIUNA Station to St. Joe's) as of the summer of 2010. The remaining 116,070 (ie. 83% of intra-Hamilton commuters) work somewhere other than the Downtown CIPA. StatsCan indicates that 23,445 Hamilton workers commute to Burlington and another 21,880 Hamilton workers commute west to Oakville, Mississauga, Brampton and Toronto.


94million loss / 27880 commuters @ 4.8 min per commuter that $895. per minute. wow ! that's some productive business we are missing out on!

I can use stats too. most are meaningless.

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By N1 (anonymous) | Posted June 20, 2014 at 15:30:27 in reply to Comment 102746

As of 2011: 200,865 commuters in the Hamilton Census Subdivision, 139,470 of whom are most directly impacted by Hamilton congestion. To that we can add the 38,340 workers commuting from other communities to work in Hamilton. To each of those 177,810 commuters you can assign varying congestion costs and time expenditure, since depending upon where they live they may encounter congestion outside of Hamilton during their commute. It's all relative.


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By Noted (anonymous) | Posted June 20, 2014 at 08:06:08 in reply to Comment 102714

As of 2006, Hamilton congestion represented 2.68% of total annual GTHA congestion costs.

2.68% of $15B = ~$402,000,000
2.68% of $34B = ~$911,000,000

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By jason (registered) | Posted June 19, 2014 at 22:59:19

Hamilton has tons of gridlock and congestion. I hit a red light once.

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By DowntownInHamilton (registered) | Posted June 20, 2014 at 18:00:45 in reply to Comment 102721

I hit a red light once.

Did it hurt?

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By CharlesBall (registered) | Posted June 20, 2014 at 08:48:59 in reply to Comment 102721

I posted about my first trip down King a few weeks ago. I had another on Wednesday at 12:36. Did it just to see if it was an anomaly the last time.

14.7 minutes between Wellington and Margaret on King. Less buses in the left lane between John and James but most of the delay was between the "International Village" and Bay St.

Once again bus lanes largely empty. Lots of taxi traffic stuck as well as me.

Maybe moving the taxis into the bus lanes would help a little.

Don't know why it is attractive to potential residents or businesses to have cars lined up and spewing exhaust all day in front of their homes and businesses. Can't see the current arrangement as a long term solution.

I like the idea of elimination passenger cars from Wellington to James. Just let Buses, Deliveries, and Taxis on King.

Comment edited by CharlesBall on 2014-06-20 08:55:56

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By Anon (anonymous) | Posted June 20, 2014 at 09:23:39 in reply to Comment 102728

Ever heard of Cannon Street? If you want to go Downtown, King makes perfect sense. If you want to go THROUGH Downtown; not so much. Nor should it.

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By John Neary (registered) | Posted June 20, 2014 at 11:23:14 in reply to Comment 102733

Cannon is also downtown, FYI.

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By Anon (anonymous) | Posted June 20, 2014 at 08:35:01 in reply to Comment 102721

You should try driving on the Mountain. You'll have to stop for lots of red lights. Funny thing though. No one ever complains about that.

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By DrAwesomesauce (registered) | Posted June 20, 2014 at 04:03:00

Yeah, once I had to drive from Dundas to the East End and I had to stop twice. I was so p*ssed off > I felt like my rights as a driver were under attack.

Twenty minute city, b*tches!

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By H1 (anonymous) | Posted June 20, 2014 at 10:20:21

I just love it when people move next to a factory and complain about the noise and smell and demand it gets shut down. I Love it when people move to the end of the runway at an airport and complain about the noise and smell and demand flights are restricted. I love when people move to a highway and complain about the traffic. Hwy 8 cut through the village of Hamilton to link Niagara with Gault.

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By Tell us More Granddad... (anonymous) | Posted June 20, 2014 at 11:02:14 in reply to Comment 102748

And the highway numbers for Bay, Cannon, Queen, Hunter, Bold, Duke, Herkimer, Charlton.........ahh, forget it.

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