By: Jan R. Prusinski, PE
The lead article in the 11/8/11 Wall Street Journal’s Personal Journal section highlights “The Hidden Toll of Traffic Jams.” The article states that there is mounting evidence that exposure to traffic exhaust causes damage to the human brain. This does not seem to be surprising, but it is very concerning, especially when you consider that traffic congestion exacerbates and concentrates pollution in urban areas....
The converse–i.e., relieving congestion–would seemingly be the answer. In one interesting study (Currie & Walker, Columbia University), the installation of E-ZPass toll plazas in New Jersey, significantly reduced traffic congestion on toll roads and eased exhaust fumes; premature births dropped 10.8%.
The Texas Transportation Institute provides an annual survey of the most congested cities in America (Urban Mobility Study, 2011). DFW and Houston rank 5 and 6 in TTI’s list of most congested “very large” urban areas. Austin and San Antonio are both in the top 15 of the most congested “large” urban areas. The excess fuel consumed due to congestion, according to TTI, of these four areas combined is nearly 175,000,000 gallons of gas. If you consider that each excess gallon of gas adds to the base load of pollution emitted in these cities, you begin to understand the scale of the problem. Both DFW and Houston are currently non-attainment areas for ozone pollution, and Austin and San Antonio are borderline. Traffic congestion would seem to be a key player in worsening air pollution.
What is the solution to increasing urban congestion? Well, many would have you believe that decreasing urban sprawl through increased urban density would help relieve pollution. This can be accomplished through zoning, developmental restrictions, increased mass transit, and fewer highways and “loops” around cities. However, increased urban density and lack of new and expanded highways may be having just the opposite effect. A 2000 study by the Goldwater Institute, entitled “How Urban Density Intensifies Traffic Congestion and Air Pollution” notes that “the problem of traffic congestion is very simple — it has to do with too many cars in too small a space. It would seem that the best approach to solving the problem would be to take actions to disperse traffic and to make it move faster.” Ask Austin residents, who must contend with the I-35 and MoPac corridors, about the benefits of urban densification. Is mass transit the answer? The Goldwater Institute report thinks not. It concludes that, after comparing European cities’ higher densities and greater per- capita use of mass transit with the U.S., “higher transit service levels do not result in lower levels of traffic congestion.”
Clearly, with Texas poised to increase in population to well over 30 million by 2030, we need to continue developing a road network that not only keeps pace with the growth, but that relieves current congestion so that pollution, and its increasingly apparent negative health impacts, are reduced. A combination of increased road funding through gas tax or other methods, continued expansion of toll roads, managed lanes, and public private partnerships, will be necessary to accomplish this goal.
"This blog was previously posted in the Cement Council of Texas' "Texas Cement and Concrete Blog" (now inactive) and was carried forward to the current blog ("Cementx Pavement Blog") as it contains content that may be of interest to the reader".
The Cementx Pavement Blog seeks to make pavement owners, engineers and contractors smarter about selecting, designing, constructing and maintaining pavements. New blog postings began February 1, 2017; however, we carried over pavement-related blog postings from our older blog, the "Texas Cement and Concrete Blog," which ran until December 2016.