Drawbacks of Typical Transportation Planning/Analysis in the U.S.
Inaccurate assumptions in transportation planning practices and policies hinder the effectiveness of many transportation projects and many potential business ventures. If a transportation engineer tells you “We’ve performed a detailed analysis, and determined exactly what is needed.”, you might consider asking whether that analysis was based on any of the questionable assumptions described below.
The primary goal of conventional transportation planning is to ensure that there will be no traffic jams for motorized vehicles during the busiest fifteen minutes of the year, twenty years from now, assuming that the Vehicle Miles Traveled (VMT) grow every year by 3%, regardless of rising fuel costs, global warming, public transit development, telecommuting, or anything else. This goal is usually accomplished by widening roads, adding left turn lanes, increasing speed limits, removing pedestrian crossings at one side of a busy intersection, etc. These ‘amenities’ are often financed with System Development Charges, a tax on developers. There is usually NO consideration of pedestrians or cyclists, except as impediments to the smooth flow of motorized vehicles. The overall effect is to overbuild automobile roadways now, expecting them to become comfortably full (but not overcrowded) in twenty years. The motorized traffic projections are based on data collected 1950-1980, in the manual of the Institute of Transportation Engineers (ITE). The well-documented effects of “induced traffic” are rarely considered, in which a wide, new, free road attracts more users than expected.
In the USA, transportation projects are not evaluated for cost-effectiveness in relation to other priorities, or for functionality after completion. It is generally assumed that projects will function as predicted, and that all available Transportation money should be spent.
“There is not enough data” to account for present conditions. For instance, the fact that freight companies at the airport in Portland, OR schedule their trucks to avoid the local peak rush hour is irrelevant. 50-year-old field-based data, that was poorly sampled at the time from a random portion of the country, is considered superior to anecdotal local data based on experience today.
There are no generally accepted practices or data to describe pedestrian and bicycle facilities, safety, and trips. For example, many transportation engineers do not consider themselves qualified to distinguish between the service level provided by an 8-foot wide grade-separated bike path, versus a 2-foot wide bikelane on the shoulder of a 6-lane arterial with a 45 mph speed limit. This is not usually part of the planning process. Neither do they feel qualified to distinguish professionally between the pedestrian experience of running across a 6-lane arterial at a short signal light, versus strolling across a 2-lane connector at a long signal light. It’s usually not part of the job description.
Besides roads and bikeways, there’s parking. In most municipalities in the US, retailers are required by law to provide 3 or 4 parking spaces per 1000 sf of retail space. With access lanes, each parking space requires a total of 300 sf. In other words, the total parking space must be roughly as large as the building itself (900 to 1200 sf of parking, for every 1000 sf of building). Some large retailers believe this is wasteful, and that less parking is actually needed. This simple policy has created countless dead zones across America, at the outer corners of the parking lots of suburban malls, where shoppers only park during the week before Christmas.
Urban businesses that want to re-use an existing building must provide ample parking. If the owner of a potential neighborhood business such as a restaurant believes that many potential customers will walk and bike, the business owner must pay for extensive research and analysis to prove that fewer parking spaces are needed. Without spending tens of thousands of dollars for research and/or System Development Charges, the new business use will not be permitted. This dooms many small commercial locations in historic buildings. The property owner must either acquire adjacent properties to demolish the adjacent (often historic) buildings for parking, or else find a race-to-the-bottom use such as a used tire store or battery store, for which the zoning code requires minimal parking. This policy prevents large residential zones from being renovated into walkable mixed-use areas with multiple neighborhood commercial centers. Each potential business would need to overcome huge regulatory impediments, in order to provide residents with the nearby amenities that are essential for a walkable neighborhood. Portland, Oregon is one of the few places in the US where some of the retail parking requirements are relaxed, if a public transit route is nearby.
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