Edge City, by Joel Garreau

Capt'n Midnight

http://members.cox.net/kdrum/Edgecity.htm

Here are a few of the laws that Garreau offers up:

* The farthest distance an American will willingly walk before getting into a car: Six hundred feet.
* The function of glass elevators: To make women feel safe. Not to offer a view out. Rapes rarely occur in glass elevators.
* Why elected officials feel they must encourage commercial development or die: For every $1 of tax revenue that comes in from a residential subdivision, as much as $1.22 goes out to provide services, especially schools. By contrast, for every $1 of tax revenue that comes in from commercial development, at most 32 cents is required in expenditures, usually for roads.
* The maximum desirable commute, throughout human history, regardless of transportation technology: 45 minutes.
* The prime location consideration when a company moves: The commute of the chief executive officer must always become shorter. [This is not a joke; Garreau cites a genuine study that strongly suggests it's true.]
* What people who hire commercial real estate salesmen look for in a resume: Background as a jet-fighter pilot. It is an article of faith that the best commercial salesmen are former sky jockeys, although it is the sheerest speculation exactly why that correlation may exist.

And finally, a series of laws that helps explain the lack of mass transit in edge cities and why this will never change:

* The level of density at which automobile congestion starts becoming noticeable in edge city: 0.25 FAR.
* The level of density at which it is necessary to construct parking garages instead of parking lots because you have run out of land: 0.4 FAR.
* The level of density at which traffic jams become a major political issue in edge city: 1.0 FAR.
* The level of density beyond which few edge cities ever get: 1.5 FAR.
* The level of density at which light rail transit starts making economic sense: 2.0 FAR.
* The level of density of a typical old downtown: 5.0 FAR.
* The density-gap corollary to the laws of density: Edge cities always develop to the point where they become dense enough to make people crazy with the traffic, but rarely, if ever, do they get dense enough to support the rail alternative to automobile traffic.

does this mean that Dublin will get worse traffic but never get to rail density

Metrobest

I think traffic in Dublin will get worse before it gets better. The fact is that the existing road network cannot handle the volume of traffic. Metro and luas will take cars off the road along their corridors, particularly in peak time, however the car will continue to dominate especially outside the M50 ring. A two-pronged strategy will have to focus on improving the road network in outer zones (improving capacity on access routes to the M50, elimination of traffic lights, another tunnel under the city centre to take traffic to/from the Port Tunnel), with a strong incentive for high density corridors into the denser areas by a good high frequency line like Metro North.

Density levels in a lot of the Dublin area are quite respectable by American standards, so a lot of the city is at a level where it can support trams and metro. The success of Luas has stunned the "experts" who claimed Dublin did not need a high volume tram line.

What we are seeing evidence of with luas is that where there is a medium/high capacity transport system in place, the corridors along it densify. The people of Dublin don´t have any spiritual attachment to their cars or to low density suburbia. They simply don´t have a decent alternative in most cases.

Dexterm99

As Garreau points out, jobs created edge cities.
Dublin and Ireland for that matter will always have poor public transportation systems if we lack big edge cities. Density levels in Dublin are high but everywhere else in Ireland is low because we have a small population and low levels of industrialisation.

There must be a spatial strategy to grow employment in other centers around Ireland for public transport to work.

L1011

Do we have any 'edge cities' in Ireland, though? Tallaght isn't quite at that level yet, neither is Swords.

Dexterm99

Agreed, but I'd say Tallaght is close due to the size of the population and the amount of high density buildings built in recent years. There are others which have the pottential such as Blanchardstown, Bray and Lucan.

spacetweek

Capt'n Midnight wrote: »

does this mean that Dublin will get worse traffic but never get to rail density

Most parts of Dublin are already at rail density, or light rail density at least, as the Luas's overcrowding (even on Sundays!) shows.

The car dependency mindset in Ireland can be dismantled, as unlike America, where people talk about having the "right to drive", Irish people drive because public transport is non existant or rubbish. As the luas and DART show, when you provide good PT here, people flock to it.