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environment, our health, and our eco-nomic vitality.

As our anxiety about these problemsgrows, however, so does our creativity.We are in a time of fundamental changethat portends both danger and oppor-tunity.

and regional planners and decision-mak-ers to redesign existing and new placesso that people can choose to walk, bike,or use transit for daily trips.

Studies show that improving theproximity and connectivity of activitiescan reduce the overall number of vehicle

trips generated within agiven area by as much as 25percent.2 This, along withoperational improvementsto improve free-flow move-ment on local roadways, canmake an important contri-bution toward reducing theamount of CO2 generated.

Stormwater runoff isanother important environ-mental problem exacer-bated by our automobile-oriented development pat-tern. That’s because road-ways, surface parking lots,and driveways result in

large amounts of paved, impervious sur-face which, in turn, can lead to excessiverunoff.

As the EPA’s Lynn Richards noted lastyear in an article in the Planning Commis-sioners Journal, it is important to askwhether street and road widths in ourcommunities are sized appropriatelysince “over[ly] wide streets will createexcess impervious cover.”3 Richards alsotouched on the importance of downsiz-ing our parking requirements, pointingout that “parking lots designed for peakdemand periods [create] acres of unusedpavement during the rest of the year.”

F O R WA R D M O T I O N

21st Century Transportation Planning Challengesby Hannah Twaddell

American settlement patternshave always been strongly in-fluenced by our transportation technology. In 18th century America, thebest locations for cities and commercewere accessible to major rivers and ports.Few people lived in “backwater” com-munities. Once you got off theboat, however, you had to relyon the power of feet – humanor horse. Within cities, allactivities had to be locatedwithin walking distance ofeach other. Suburban growthextended about as far as onecould go within a day’s ridefrom town.

With the advent of steam-and diesel-powered trains inthe 19th century, peoplebegan venturing away fromthe rivers and built new citiesacross the landscape. Howev-er, since foot-power was still the domi-nant form of local travel, rail townsretained the compact form of older com-munities.

The automobile allowed us to spendthe 20th century spreading out in alldirections. Networks of highways andlocal roads created opportunities to buildcities virtually anywhere. With the powerof hundreds of horses under the hood,cars made it possible for people to livemiles away from daily activities such aswork, school, and shopping. No longerconfined to the walkable dimensions ofone-horse towns, we shaped new com-munities around large street networksand parking lots.

As the 21st century dawns, the Amer-ican dream made possible by the remark-ably fast, flexible mobility of theautomobile has begun to take on night-marish qualities. It is becoming clear that our collective dependence upon the automobile is threatening our natural

“Giant Steamboats at New Orleans,” by Hippolyte Sebron (1853).

1 Inventory of U.S. Greenhouse Gas Emissions andSinks: 1990-2007 (U.S. EPA, 2009).

2 Land Use and Site Design, Traveler Response toTransportation System Changes – TCRP-95 (Trans-portation Research Board, 2003).

3 “Managing Stormwater Runoff: A Green Infrastruc-ture Approach,” PCJ#73 (Winter 2009); available toorder & download at: www.plannersweb.com/wfiles/w284.html.

Our Natural Environment

A 2009 report by the U.S. Environ-mental Protection Agency indicates thatfossil fuel combustion for transportationis responsible for a third of America’s CO2

emissions, which are an important ingre-dient of the “greenhouse gases” associat-ed with global climate change.1

The three most prominent factorsaffecting the transportation sector’s emis-sions are the fuel economy of vehicles onthe road, the types of fuels used, and theoverall amount of driving by all vehicles,expressed as vehicle miles traveled(VMT).

Federal agencies, state governments,and private sector entrepreneurs areworking on the tasks of making vehiclesmore energy-efficient and finding newsources of fuel. But our success at reduc-ing VMT depends largely upon our abili-ty to plan and locate communities inways that reduce our need to drive. Toachieve this goal, it is essential for local

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Our Health

Between 2010 and 2050, the numberof Americans aged 65 and older isexpected to grow from about 40 to 88million.4 According to Census Bureauprojections, 20 percent of Americans willfall in this age range by 2050, up from 13percent today.

The problems that these increasingnumbers of older people will face whenthey lose the ability to drive will be muchmore than an inconvenience. Withoutother travel options available, theiraccess to everyday activities and essentialservices will be sharply curtailed – justwhen their needs for social connectionsand medical attention increase.

By creating communities where peo-ple can get around without cars, we canmake a significant difference in thehealth and happiness of older adults. A 2006 study by the Northern VirginiaTransportation Commission found that“seniors from walkable, mixed-use urbanand town areas are more mobile, taking20 percent more trips each week thanthose from suburban and exurban areas.They are also less likely to be socially isolated.”5

Meanwhile, the health of tomorrow’sworking-age adults is already being com-promised by obesity linked to sedentaryliving. According to the Centers for Dis-ease Control and Prevention (CDC), 17percent of children aged 6-19 (more thannine million young people) are obese.That percentage has tripled since 1980.6

A third of our children in this age rangeare overweight, a far cry from the CDC’sgoal to reduce this figure to five percent.

The Alliance of Biking & Walking,with funding from the CDC, has releaseda remarkably useful, data-filled report,Bicycling and Walking in the United

States 2010 Benchmarking.7 The report,authored by Kristen Steele and MonicaAltmaier, points out that “states wherebicycling and walking levels are lowesthave the highest levels of obesity.” Simi-lar correlations were also found with twoother major public health concerns, diabetes and high blood pressure.

Steele and Altmaier note that: “Walk-ing and bicycling have great potential toimprove public health. In 2001, 41 per-cent of trips in the U.S. were shorter thantwo miles and 28 percent were shorterthan one mile. Since bicycling canaccommodate trips of up to two milesand most people can walk at least onemile, there is a lot of hope to use thisform of travel in our communities.”

Forward-thinking communities suchas King County, Washington, are incor-porating walkability goals and perfor-mance measures into their comprehen-sive plans, while other places, like AlbertLea, Minnesota, are adopting programsto promote active living. Meanwhile,more and more communities are adopt-ing Complete Streets policies, aimed atdesigning streets that accommodate notjust cars, but bicyclists and pedestrians.

Our Economy

Our traditional source of revenue fortransportation – the gas tax – cannotkeep pace with the escalating costs ofmaintaining the system we have, let

alone paying for new infrastructure. Theresponsibility for transportation fundinghas been shifting toward states, localities,and the private sector.

That said, every local official is keenlyaware that raising a city or county salesor property tax is even more politicallychallenging than raising a state or federalgas tax. It’s no wonder jurisdictions allover the country are searching for betterways to negotiate infrastructure invest-ments from developers, and that tollroads are making a comeback.

Nineteenth century transportationinvestments, from turnpikes to railways,were largely private, for-profit ventures,while the 20th century was the age oftax-supported “freeways” and transit sys-tems. The 21st century is likely to bringabout an interesting marriage of the two.Just as we pay transit fares now, we willprobably pay more roadway tolls anduser fees in the years to come.

SUMMING UP

We’ve entered a dynamic time in theworld of transportation and land useplanning. For many years, engineers andpolicy makers have focused on the goalof increasing the speed with which peo-ple can move between places. Upon real-izing that we’re literally driving ourselvestoo far apart, we can right the balance byboosting the importance of two othergoals:

• Bringing people and places closertogether,

• Providing people with more choicesof travel routes and modes betweenplaces.

By working together on designingcommunities that offer more flexibletravel choices, we can sustain our com-munities through the 21st century – andbeyond! ◆

Hannah Twaddell is a Princi-pal Planner in the Char-lottesville, Virginia, office ofRenaissance Planning Group.Her articles on transporta-tion planning topics appearregularly in the PlanningCommissioners Journal.

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4 Projections of the Population by Selected Age Groupsand Sex for the United States: 2010 (U.S. CensusBureau, 2008).

5 Jana Lynott, et al., Meeting the Transportation Needsof Northern Virginia’s Seniors: Recommendations forPublic Transit Systems and Other Mobility Providers(Northern Virginia Transportation Commission,2006).

6 Preventing Obesity and Chronic Diseases ThroughGood Nutrition and Physical Activity (Centers for Dis-ease Control and Prevention, 2008).

7 The report is available to download at:www.peoplepoweredmovement.org.