The Carbon Efficient City: Building Blocks to Cool Our Planet

9. Regional Transportation

117 T ransportation is a response to the need people have for access to places and things that they can’t get to on foot. Because transportation creates value by providing access, by definition transportation networks are useful to the extent that they effectively connect people with the things they need. Assuming people have many needs that can’t be met within walking distance of their homes, they require roads, vehicles, and transit to get to and between places. The notion of transportation networks is an important one, because if a means of transportation doesn’t meet most of the mobility needs of individuals, it won’t get used. A light rail line in a vacuum that connects only two points is practically useless unless everybody lives at one end and only needs to go to the other end. The light rail line creates more value if it has park-and-rides at both ends. It can then get people from many points to one point, but it still can’t get people from many points to many points. If we add plentiful connections to bus routes at both ends of the light rail line, it begins to have a substantial network effect that can provide value to many people with many different access needs. Over the past century or so, most of our lives have become regional; we CHAPTEr 9 rEgIonAl TrAnsPorTATIon If you listened to Americans talk about their governments’ responsibility to provide roads for their cars, you might think they were all socialists. —Al Hurd CHAPTEr 9 118 spend the bulk of our time in the vicinity of our home city (often referred to as a metropolitan area). Almost 80 percent of U.S. residents and 50 percent of the world’s population now live in urban areas where they work within the surrounding region, join regional clubs or teams, watch the games of a regional sports team, and recreate and shop at amenities and stores within the region.1 Because of this, a high percentage of access needs can be satisfied at a regional level. Unfortunately, access solutions that interconnect only parts of the region tend to satisfy only some of the people only some of the time. Chapter 6 looked at ways to support the development of self-sufficient neighborhoods that would have the effect of shortening some individual daily trips or eliminating them entirely. Naturally, designing the built environment to simultaneously reduce the need for vehicles, infrastructure, fuel, and trips in the first place is the most helpful action we can take. This chapter examines how development patterns and transportation networks can reduce the carbon intensity of the trips that must continue to exist. A 2009 Urban Land Institute report concludes that transportation greenhouse gas (GHG) emissions are the result of the interaction of four factors: vehicle fuel efficiency, the carbon content of the fuel burned, the number of miles that vehicles travel, and the operational efficiency experienced during travel. The report summarizes the four basic strategies that can be used to reduce GHGs as follows:» Vehicle Technology—Improving the energy efficiency of the vehicle fleet by implementing more advanced technologies» Fuel Technology—Reducing the carbon content of fuels through the use of alternative fuels (for instance, natural gas, biofuels, and hydrogen)» Travel Activity—Reducing the number of miles traveled by transportation vehicles, or shifting those miles to more efficient modes of transportation » Vehicle and System Operations—Improving the efficiency of the transportation network so that a larger share of vehicle operations occur in favorable conditions, with respect to speed and smoothness of traffic flow, resulting in more fuel efficient vehicle operations.2 What would a less carbon-intensive transportation map look like? First, it would account for more people per motorized vehicle. Larger vehicles operating at capacity have a much lower carbon impact and a lower economic cost per passenger-mile traveled than vehicles driven by a single occupant. To put a group of people into one vehicle, however, those people must live or work REGIONAL TRANSPORTATION 119 close to a common starting point and be able to meet many of their needs at a common end point. Clearly, then, encouraging compact, mixed-use neighborhood development concentrated in urban centers is a strong enabler of a more carbon-efficient transportation system. But the reality is that that the majority of existing development patterns are relatively low density. We must therefore focus...