Debunking the Induced demand argument

@SeanW Don't try frame me, please. What I said there does not fit your summary of it. I'm happy to say I am very much in favour of road construction... we have a lot to catch up on in this country. That doesn't mean I'm blind to what happens when you try to apply road-building to transport problems that have much better solutions,though.

Once you go beyond two lanes each way with limited access, you're in the land of diminishing returns in roads... and if you're getting traffic jams on wide roads at morning and evening commutes, then adding capacity to that road will never get you out of that hole, because the problem is one of throughput, and private car travel has lousy throughput.. encouraging more of it will just set you up for the same problem again in a couple of years (and yes, I did consider other factors when I cited N7 and M50.. all that those other factors did was accelerate the return of congestion: they did not create it).

With an average 1.2 people per car, and each car needing eight to ten lane-metres of road, cars are basically the worst possible way of getting lots of people in and out of a place.

So, my position is we should build more roads, but for connectivity and safety, not commuting: commuting is best done on public transportation. Induced demand works both ways: make public transport reliable and convenient and people won't feel they need to drive everywhere; keep spending the transport budget on adding road lanes, and they will.

"Induced Demand" should have capital letters in your comment because it is a theory, a very specific theory, which has been proven time and time again across the world.

"Induced Demand" is not some fluffy way to say "if you build roads, people will use them".

The proven theory shows that building new roads or widening existing roads with the specific aim of reducing private car congestion does not work in the medium to long term.

The theory only applies to roads. You simply can't build enough roads to facilitate private car use.

High capacity, high speed public transport is the only way to keep up with increasing demand.

Look at LA for proof of the theory. 6 lane motorways all over the place and the city is gridlocked every single day.

This is simplistic. It depends on where the use is. Plenty of roads throughout the country were improved 50 years ago and perform their job to this day. The motorways will do their job except perhaps for the 30km around Dublin and perhaps Cork.

And while what you is true of cities, LA has less road capacity than most US cities.

The problem with public transport is that people are expected to suit the transport, rather than the transport serving the people.

Wow. Clearly my logical comment hit a nerve.

When this thread first started and I saw its title I was intrigued to see how 'Induced Demand' would be debunked. That hasn't happened, but I have a better understanding of why it appears to be a controversial phrase.

Induced demand is a long known and accepted theory, in the same way as latent demand in economics. However, acknowledging induced demand in terms of building roads to ease congestion will not make you anti roads, or have the Green Party police come and take away your SUV and replace them with a pair of sandals, or insist you live in a tree.

I used to live in Munich a long time ago, and yes, it is an example of how things should be done, but it has many advantages that Dublin doesn't have in terms of building out public transport: it's flat, it has very little suburban sprawl, and the surrounding towns are very compact with high density housing. Munich also had a very tunnel-friendly geology, and the dubious "advantage" of being part flattened in WW2, allowing a lot of the U-bahn to be built as cut-and-cover.

And Munich might be officially only the size of Dublin (1.5 million vs 1.2), but its hinterland has over 5 million inhabitants. It is also has a strong local government with real powers, as well as being the state capital of Bavaria, Germany's wealthiest state, so works in Munich have three budgets to dip into: the Federal transport budget, the Bavarian State one, and its own city budget.

The big success of Munich's transport (and German transport generally) isn't so much the infrastructure as the simple, unified ticketing: your S-Bahn, U-Bahn, Tram and Bus travel has all been usable with the same ticket for about fifty years, even though these are operated by different companies (the City of Munich owns the trams and the Underground; Deutsche Bahn owns the S-bahn commuter railway, and the city and various private companies run the buses).

With Leap, we now have the same idea here, but we still don't have the simple pricing system they use in cities like Munich, where a ticket is for any journey on any means within a period of time.

But no public transport is perfect, and Munich still has holes: there is a bizarre desert of transportation around Perlach in the south-east, and the geography of Munich itself means the U-bahn hugs the Isar valley and doesn't stretch very far to the east or west. But the long term vision is what we should be aiming for with Dublin (Munich's first U-bahn line only opened in 1971, and it was just 13 stops along what is now U6... over the decades it has steadily grown to nearly 100 stations).

This was all done as a reaction to horrible car traffic in the late 1950s and early 1960s. Munich could have widened its streets (and it did do this where blocks were flattened by bombing), but extensive road widening would have cost even more of the city's buildings, and there just wasn't the apetite for it, so the city looked for an alternative to just making more room for cars, and that was to build a real alternative to roads for mass transport.

But one thing you also notice about Munich is there's a different attitude to public transport, which you really see when it comes to buses. When I worked in Munich, I would occasionally see the head of my company (a branch of a multinational, employing 200+ people) on the same bus as me. I cannot imagine an Irish executive doing the same, and until that prejudice against bus transport changes, we won't make the kind of progress that other countries can.

Did I say I'm anti roads?

I'm anti widening motorways or building additional ones to "relieve" congestion.

I'm fully supportive of a bypass of towns including Galway city (assuming it's actually a bypass, not a distributor road with lots of entries and exits).

I'm fully supportive of improved roadways to the regional cities (from Dublin) and between the regional cities.

Lord save us from economical public transport.

I'd imagine the tens of thousands of people who use the Luas every day are saying WTF to you right now.

To be honest what we need is better regional development so that Dublin doesn't continue to grow. It is already way too big given the size of the country. But that is a different argument. Just to stress thought that trying to limit growth in Dublin doesn't preclude improving the current public transport offering by the way. We need both things to happen.

I was happy they cancelled the Magnetbahn - it was a one-trick-pony that didn’t do anything except dump passengers into the main train station, which is really only of use to tourists. Munich does get a lot of tourists, but tourists aren’t so time-pressed that a 40 minute train trip rather than a 10 minute one will make or break their trip. And the cost of this was eye-watering: €2 billion in 2005 - about the same cost as the second S-bahn tunnel, which will benefit the entire commuter rail network.

Ah, I didn’t know about that new fare, a really good idea - especially when the daily fare-capping kicks in. Dublin also lifted one of Munich’s best ideas: the family card, at €10 for two adults and up to four children, anyhwere in the city - for tourists it’s a great idea. (The Munich ticket allowed you to swap a dog for one of the four children -- somehting I reckon many a parent has been tempted to do at times...). I think Leap is a fantastic idea overall, especially as it works nationwide (for once, we’re thinking bigger than other countries). If they could manage to get all of the country’s local bus operators on board with it, it would be a great way of encouraging public transport use.