Reason #2. There are more effective ways to fight traffic congestion. This method is like using a chain saw to do heart surgery.

One of the things I learned in high school art class was that skilled craftsman know what tools to use for a particular task. The more tools in one's tool-box and the more skillful one is in using those tools, the more likely it is that one would consider a variety of ways to craft an object. By the same rule, "if the only tool in your box was a hammer, every problem would look like a nail."

It is pretty clear to me that if the well intentioned folks who crafted Proposition T had spent the time constructing a truly effective traffic reduction methodology, they would not have chosen such a blunt instrument. Their tool is the product of a methodology born in the 1960's and refined slightly, over the next several decades, until its ossification in publications put out by the Institute of Transportation Engineers (ITE), that have been, dare I say it, fundamentally discredited by contemporary practitioners of the art and practice of City and Town Planning.

The ITE's methodology, based on empirical data from the suburbs, required every 250 square feet of office space and every 200 square feet of retail space to require at least one parking space and to generate two or more car trips. As I've stated in previous posts, no mitigating factors were assumed (such as the fact that someone might walk between stores, or from home to work, etc). As a result, statistics like those displayed below, which are national averages were also assumed to apply to all areas equally. It also assumed that all parking would be free to the driver (at least seemingly free. See, The High Cost of Free Parking, by Donald Shoup, for a complete disputation of that assumption).
Given the ITE's logic, it stands to reason that reducing the amount of commercial space would reduce car trips, no? Well, no, actually. It's not that simple. It wasn't then and it isn't now. Yet, so mindless was this characterization that it became a self-fulfilling prophecy that was codified nearly identically in zoning manuals from Portland Maine, to Portland, Oregon. You'd think there would be regional differences, but no, there is a surprisingly similarity. The reality is that the amount of "internal capture" (a planner's term for those within a study area who stay in the area) within cities varies widely. For example, Annapolis, MD enjoys upwards of a 50% capture rate between jobs and housing. Having lived there one summer, I can tell you I saw lots of folks walking from home to work. (And you thought I was going to use New York as the example, didn't you?). To achieve that kind capture, you must have a very robust mix of uses within close proximity.

This obvious little fact is one of many tidbits of reality that transportation planners have learned (well I should say, relearned) over the last couple of decades. There are indeed a lot of things that affect "trip generation rates," not the least of which is density and land-use mix, among others. I would call such urban form-making strategies, "naturally occurring Transportation Demand Management Techniques." However, urban form (which not only includes such considerations as land use and density, but also walkability, block size, roadway width, and at least a couple of dozen other considerations), constitutes only one set of tools within the Transportation Demand Management (TDM) toolbox (an important set, to be sure, but not the only one). What are some of these other techniques? Simply put, TDM includes a variety of strategies that change travel behavior, for example by encouraging more efficient travel patterns, such as shifts from peak to off-peak periods and parking "cash-out" offers which encourage shifts from automobile to alternative modes (e.g., shifting from riding alone, to car-pooling, bicycling and/or walking). The Victoria Transport Policy Institute in Victoria, BC has an extraordinary website called the TDM encyclopedia that has more than you'll ever want to know about this subject http://www.vtpi.org/tdm/tdm12.htm. From the website:

Many factors affect people’s transport decisions including the relative convenience and safety of travel modes (such as whether streets have sidewalks and bikepaths, and the quality of transit services available), prices (transit fares and the price of parking at destinations); and land use factors (such as whether or not schools, parks and shops are located close to residential neighborhoods).

There are numerous TDM strategies using various approaches to influence travel decisions. Some improve the transport options available; some provide incentives to change travel mode, time or destination [i.e. parking "cash-outs where employees are paid not to bring their car]; others improve land use accessibility; some involve transport policy reforms and new programs that provide a foundation for TDM.

Municipalities that have successfully utilized TDMs have done so by negotiating with developers prior to a project's approval. In such cases, the developer commits to a percentage of employees that will arrive in something other than a single-occupancy vehicle, and posts bonds to guarantee compliance, which is checked annually by the municipality. Jurisdictions have been able to achieve a reduction of 50 to 60% or more, of ride-alone commuters.

So now I hear you say, "Gee, utilizing TDM sounds like a good idea. Why not pass Prop-T and use TDMs," as many have written to me, privately? The simple answer is because RIFT's arbitrary and capricious cap on commercial development makes the the use of TDMs much more difficult. While LUCE does include a fairly strong set of recommendations for TDMs, it also assumes a certain amount of traffic reduction through that "naturally occurring Transportation Demand Management" that occurs as a result of land-use mix and density. RIFT represents a strategic and tactical blunder of the highest order by disregarding that careful balance. Put another way, if one utilizes a chain saw to perform heart surgery, regardless of how skillful the heart surgeon is, it will be very difficult to sew the patient back up again.