Cut To The Chase

September 27, 2002

October 11, 2002

October 18, 2002


Reinvent planning

How did they plan great cities before we had fancy computers to draw colorful maps?

Are cities planned better since?

These questions were brought into focus recently when I attended a meeting where developers were presenting their ground-truthing for the county's General Plan 2020 update. For months developers and environmentalists have attended marathon meetings attempting to map out their ideas for future development patterns for the unincorporated areas. Environmentalists had gone in separately to make requests for better connectivity and reduced sprawl. The developers are checking to see that they can attain a reasonable yield and how property rights can be best addressed.

The developers' approach to ground-truthing caught my attention. They had given up on using the county's cartoon-colored computer maps and gone to a local map store where you can buy laminated aerial photographs. They had then overlaid the property lines and voila! You could see the landscape, geography and most importantly -- what was actually built and not built. An excellent example of necessity being the mother of invention, the developers had combined the best of both worlds for a reasonable price. Shouldn't this rightfully be the goal of planning? To best connect plans with the real world?

They had hit upon the best combination of technology to serve people attempting to make reconcile future plans with the on-the-ground realities of today. I saw clearly that regional planning practice has allowed the addition of glossy technology to get in the way of what's most important to planning: the landscape, the sense of place, any real sense of scale and what's already there.

Colorful computer maps are artificial representations of "data" -- they can distort and hide as much as they can illuminate. Much of the data itself becomes quickly outdated and expensive to update. It can also give false prominence to what they choose to put on the maps. You lose your sense of scale. There is no sense of human or natural scale. There are no landmarks. Maps are dominated by artificial boundaries. Roads take prominence for orientation and therefore how you think and relate to the process. The ease with which you can draw a road on a blank flat map entirely ignores the geography and communities over which you can draw it.

Aerial photographs on the other hand allow you to connect with what's really there. Aerial photographs are available commercially for a reasonable price. They are regularly updated.

Aerial photographs are being used more and more in planning but not consistently. It really is a mixing of the best of the past with the best of the current. Inexpensive desktop supercomputers and color printers allow quick reproduction. I suggest that all jurisdictions should shift to the dominant use of aerial photographs with parcel overlays in all planning processes. Overlays of other useful data should be considered, but should not dominate the practice.

Another example of where the use of technology is outstripping our planning common sense is Sandag's traffic modeling. Regional modelers have declined to update their public documentation and release their models for public review. They have not been independently technically reviewed, at least not in the last seven years -- which is a very long time indeed when it comes to software. These models are used to justify many billions of dollars of transportation projects and infrastructure choices as well as future tax increases. They are the basis for all traffic projections throughout the region. They define the parameters that purport to tell us how projects are going to perform.

Yet requests to release key modeling information have gone ignored for more than a year. They admit to making major changes, but have refused to update the documentation last published in 1995. National modeling experts, while praising some features of Sandag's model, have also warned that too many important elements will lead to distorted results, telling us in effect to build the wrong transportation projects and not to build the right ones. And yet Sandag resolutely declines to compare real system performance with forecast system performance in addition to not updating their public documentation. It is as if they wish to say: "Pay no attention to that man behind the screen!" But we must have access behind that screen -- in this case -- to the software programming being used to define the forecasts. This is not only common sense, it's professionalism and in science, it's called technical peer review.

It's also fundamental to the public being able to buy in to the system. Project lists and dollar estimates are notoriously rising and unaccountable in the transportation infrastructure game. Traffic is also notoriously rising. These models are at the heart of technical side of the decision-making process, how impacts are measured and how projects are being ranked for performance. The problem sounds technical but the results aren't: when the models fail us, so too will our multi-billion dollar transportation plans.

Since they are asking the public to pick up the tab based upon the output of these models the technical information must be made available to the public and it must undergo regular independent analysis to validate both the methods and assumptions -- and to also compare forecast results with actual system performance.

Then and only then do we have a chance of determining whether what we are being asked to pay for is actually going to perform and have a chance at being the best transportation network system design.

We have the right to know whether plans we are being asked to pay for are based on solid and credible technical work. Too many of the transportation experts I have spoken with have warned me of the mismatch between our modeling and the problems we are trying to solve. Based on rising traffic and rising costs, it's past time we opened up the black box to see whether our transportation kings are in fact wearing any clothes.


Chase is editor of the San Diego Earth Times and chair of the mayor's Environmental Advisory Board. She can be reached at carolyn.chase@sddt.com.


September 27, 2002

October 11, 2002

October 18, 2002