Moving People: Traffic Congestion, Road Building, and Sustainable Transportation Solutions in Urban Areas, страница 4

•  the capacity and management of the road system is in balance with the demand for highway capacity with full social cost pricing” (Bayliss, 2000).

Noticeably, construction of new roadways does not fit into this sustainability definition, at least not without full social and environmental pricing.  Yet a common and enduring response to alleviating urban transportation congestion is to build new highways without integrating full ecological costs.  

2.2  Road Building as a Response to Congestion

It appears that finding solutions to congestion is an ongoing, adaptable process.  Road building has been a common response, but sustainable responses should be applied to avoid high environmental costs.  First, a question must be asked.  What strategies are available?  In this section, the question of road building as a useful response to the congestion problem is considered.

Recent research has shown that road building is not a suitable response to reducing traffic congestion; for example, one study showed how cities that built new roads had the same traffic congestion levels as those that did not (Surface Transportation Policy Project, 1998).  Other empirical studies, such as those performed by the Texas Transportation Institute (2005) and Southern Environmental Law Center (1999), also indicate that the problem of lengthened commutes on clogged roads has not been resolved in the long term by road building initiatives.  There is even evidence of reduced traffic congestion when road capacity is reduced (Cairns et al., 1998).  

Occasionally road building offers short term relief of traffic congestion, but only a few urban areas have added roadways at the same rate that traffic congestion grows (TTI, 2005).  Even if these areas keep up with congestion growth rates, only congestion, and not sustainability, is addressed.  Diminishing returns are observed in most road building scenarios and, occasionally, road building worsens regional traffic congestion (TTI, 2005).  

There are studies that quantify this worsening of traffic congestion.  As transportation networks expand, so do commute times.  Regarding lengthening commutes, it is estimated that the average annual delay per capita for motorized travel in peak traffic periods has increased from 16 hours in 1982 to 47 hours in 2003 (TTI, 2005).  Measures in various urban areas, such as the Washington, DC area, show more severe congestion that lasts longer and affects more of the transportation network (TTI, 2005).

The increase in traffic congestion from 1982 to 2003 is clear (Figure 1).  More notably, this chart shows that a flip in congestion level proportions has occurred over the last twenty years.  In 1982, travel was predominantly uncongested (i.e., 70%).  By 2003, only 33% of travel is uncongested while 67% of travel is at extreme, severe, heavy, or moderate congestion levels (TTI, 2005).  During a short amount of time, we managed to worsen the congestion problem tremendously.

Figure 1. Congestion delay increases in billion hours (TTI, 2005).

An increasing disconnect between the traveling public stuck in this roadway congestion and those charged with managing transportation systems has also reverberated in recent years; this disconnect may be from a degraded living environment and a degraded quality of life partially due to traffic congestion.  As an example, the Southern Environmental Law Center (1999) observes that focusing on road building is “out of step with public opinion”.  The Center describes a Virginia Commonwealth University’s findings that 70% of Virginia residents want their congestion problems resolved via roadway maintenance and mass transit; maintenance implies keeping existing roadways at or above a baseline condition, while avoiding new construction.  The majority of Virginia residents interviewed wanted alternatives to road building.