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.Congestion Is a Long-Standing ProblemCongestion is a by-product of concentrated activity and thus it shouldcome as no surprise that cities which exist to facilitate the concentra-tion of activity have wrestled with congestion, in one form or another,throughout modern history.At the height of ancient Rome, Caesarattempted to control congestion by banning transport carts from thestreets between sunrise and dusk (Carcopino, 1940).More recently,when delegates from around the world gathered in New York City forthe world s first international planning conference in 1898, attentioncentered not on questions of housing, land use, economic development,or infrastructure.Rather, attendees were most concerned with prob-lems stemming from the growing concentration of horses and carriagesin the city, including both traffic congestion and a contemporary formof pollution: manure (Morris, 2007).With the introduction and rapid growth of automotive travel inthe 20th century, the problem of urban congestion escalated rapidly.In Los Angeles, traffic congestion has been an ongoing concern formany decades.At various points in the city s history, frustrations abouttraffic congestion have fueled public debates, inspired innovative pro-posals, and ultimately resulted in public-policy actions.An initiativeA Primer on Congestion 13by business interests in the early 1920s led to the installation of thecity s first traffic signals, the regulation of on-street parking, dramaticimprovements in public transit, and a plan for extending the networkof major east-west boulevards and highways.As continued growth intravel overwhelmed these earlier improvements, Los Angeles began toplan and build new freeways in the 1940s and 1950s and, in the 1970s,launched efforts to add rail rapid transit back into the regional mix ofoptions.Advances in the 1980s and 1990s included extensive deploy-ment of freeway-ramp meters, reserved lanes for high-occupancy vehi-cles (HOVs), and computerized traffic-signal control to help improvetraffic flow.Most recently, the Metro Rapid and Orange Line bus rapidtransit (BRT) systems have offered important advances in the qualityof transportation options available in the region.In each of these cases, growth in congestion motivated the con-sideration and adoption of alternative approaches to reduce or controltraffic approaches that proved successful in the short term, until con-tinued growth in population and economy added even more travel-ers to the system.Today, Los Angeles finds itself in much the samepredicament.Absent Intervention, Congestion Will Likely WorsenIf congestion is already severe, the bad news is that it will likely growworse in the coming decades, given current trends in the underlyingfactors that contribute to congestion.Fundamentally, congestionresults from an imbalance between the supply of roadways and thedemand for automotive travel during peak hours (Downs, 2004).Thisimbalance, as illustrated in Figure 2.1, has been growing over the pastseveral decades across the country.Travel Demand Continues to RiseThe data in Figure 2.1 indicate that the total number of estimatedlane-miles throughout the United States has grown only slightly justover 7 percent since 1970, while the number of vehicle-miles trav-eled (VMT), has increased by about 170 percent.The population has14 Moving Los Angeles: Short-Term Policy Options for Improving TransportationFigure 2.1Growth in Lane-Miles, Population, Gross Domestic Product, and Vehicle-Miles Traveled in the United States Since 1970250Lane-miles200 PopulationGDPVMT150100501970 1975 1980 1985 1990 1995 2000 2005YearSOURCES: BEA (2008); BTS (2007a, 2008); U.S.Census Bureau (2007).NOTE: GDP = gross domestic product.RAND MG748-2.1grown as well, by almost 50 percent, but the increase in demand fortravel has far surpassed population growth.Indeed, growth in VMTappears to track most closely with growth in the economy as measuredby GDP.This is consistent with the logic that people with more moneycan afford to buy more cars and travel to more places (Downs, 2004).If future travel demand continues to track growth in GDP, oreven just growth in the population, and if new capacity is built at thesame sluggish pace as it has been in the past several decades, congestionwill almost certainly worsen, likely to a significant degree.Figure 2.2shows actual and forecasted growth for the population of L.A.Countyand national GDP between 2000 and 2017.Over this period, it isexpected that the population in L.A.County will increase by about 15percent, while GDP for the economy as a whole will rise by more than50 percent.If past trends hold, this will lead to a considerable rise inaggregate demand for automotive travel.Growth (%)A Primer on Congestion 15Figure 2.2Recent and Forecasted Growth in Population and Gross Domestic Product60L.A.population50U.S.real GDP403020102000 2005 2010 2015YearSOURCES: California Department of Finance (2007); CBO (2008).RAND MG748-2 [ Pobierz całość w formacie PDF ]