National Academies Press: OpenBook

Effective Methods for Environmental Justice Assessment (2004)

Chapter: Chapter 9 - Economic Development

« Previous: Chapter 8 - Community Cohesion
Page 212
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 212
Page 213
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 213
Page 214
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 214
Page 215
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 215
Page 216
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 216
Page 217
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 217
Page 218
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 218
Page 219
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 219
Page 220
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 220
Page 221
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 221
Page 222
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 222
Page 223
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 223
Page 224
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 224
Page 225
Suggested Citation:"Chapter 9 - Economic Development." National Academies of Sciences, Engineering, and Medicine. 2004. Effective Methods for Environmental Justice Assessment. Washington, DC: The National Academies Press. doi: 10.17226/13694.
×
Page 225

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

217 CHAPTER 9. ECONOMIC DEVELOPMENT OVERVIEW Transportation projects have long been identified with economic development. By changing the pattern of accessibility, highway projects can facilitate trade between locations, allow consumers to more easily shop or sell wares at particular places, and even change commuting patterns in ways that might facilitate the growth of employment centers. These economic impacts often are distributive in nature. The shopping malls locating along a beltway might represent commercial activity that to some extent comes at the expense of stores in a downtown area. Similarly, a highway bypass can facilitate the growth of employment centers, but at the expense of other employment locations. Inner city mayors and downtown business interests have often expressed concern that outlying highway projects can draw jobs and economic development away from central areas, but the distributive effects of highway projects are much more general. Many highway and road projects can generate differential economic impacts across places, and if those differential impacts correlate with the spatial pattern of low- income or minority populations, this can require an environmental justice analysis. STATE OF THE PRACTICE The idea that the economic impacts of highways are distributed across the landscape has a long basis in theory. Mohring and Harwitz (1962) argued that many of the economic development impacts observed near highways come at the expense of slower growth in other areas. Forkenbrock and Foster (1990) suggested that a proposed new highway from St. Louis to St. Paul would provide employment growth near the corridor in large part by shifting jobs and economic activity from areas more distant from it. Boarnet (1998a) analyzed data for highway capital stock, employment, private capital, and economic output in California counties from 1969 through 1988. The results suggested that increases in highway capital stock were associated both with higher levels of economic output in the county receiving the additional capital and with lower levels of economic output in other counties. Boarnet concluded that this evidence confirmed the idea that highways redistribute economic activity across the landscape. While some theory suggests that such redistributions need not be zero sum, Boarnet interpreted the magnitudes of the statistical associations as suggesting that the redistributive impacts of highway infrastructure can be at least as important as any aggregate increase in economic growth associated with highways. Many authors have argued that transportation planners should avoid double counting highway project benefits. Economic benefits flow from changes in accessibility; and, partly for that reason, counting both economic benefits and the underlying changes in accessibility will double- count (and hence inflate) true project benefits. An example of double counting is as follows: suppose a highway improvement reduces the cost of shipping tomatoes to market. Also suppose that, because of these savings, tomatoes are sold at a lower price that exactly reflects the lower shipping costs. The lower market price simply reflects the reduced shipping cost and thus is not a

218 unique benefit. Transportation analysts could count either the reduced shipping costs or the lower market price of tomatoes as a benefit, but not both, because the one flows directly from the other. For this reason, highway project benefit-cost analysis has often focused strictly on user benefits—reduced travel times, lower vehicle operating costs, and a reduction in the number of accidents—and broader economic impacts have at times been ignored (see AASHTO 2003 for a discussion of this approach). The matter is even more complicated for economic impacts that are in part shifts in activity. Here analysts often argued that ignoring economic impacts altogether was more practical than having to evaluate the gains in one location and the losses in another. The old maxims do not apply when examining environmental justice concerns. To continue with the tomato analogy, lower shipping costs that result in lower market prices benefit consumers. Lower shipping prices that do not result in lower market prices benefit shippers or tomato growers. Understanding the distributive impacts of the various economic benefits illuminates who gains from a transportation project. The same holds true for business development and economic growth. Environmental justice requires a shift in focus from aggregate benefit-cost comparisons to an understanding of which groups benefit and which groups do not. While traditional highway project analysis has not focused on the distributive impacts of economic benefits, there are many methods and techniques that can be easily adapted to the task. Because local officials often understand and care about the spatial distribution of economic impacts of highway projects, there is research and practice to provide a foundation for environmental justice analysis in this area. The techniques range from plotting businesses in a corridor, to survey and focus group techniques, to more complex analytical methods. Most have their roots in existing transportation analysis and so will be familiar to transportation planners. In evaluating the environmental justice implications of highway economic impacts, the primary task will be to adapt existing tools to a spatial and distributive framework. This can often be done easily and without substantial additional commitments of agency resources. SELECTING AN APPROPRIATE METHOD OF ANALYSIS There are generally two types of economic effects: direct and indirect. The nature and extent of these effects can be quite different during and after construction. Each of these aspects is discussed below. Be sure to adequately address each of these issues as part of an economic assessment. Steps in the assessment. In general, an environmental justice assessment for the economic development impacts of highways involves two steps—assessing the spatial extent of the positive and negative effects and then overlaying this information on data (often in the form of maps) about minority and low-income communities to assess whether the distributional impact raises environmental justice concerns. In this chapter, we discuss methods for assessing the spatial extent of positive or negative economic impacts from highway projects. Methods for analyzing the locations of low-income or minority populations and for overlaying spatial impacts with demographic characteristics are described in Chapter 2.

219 Direct and indirect effects. In the rest of this chapter, we refer to direct and indirect economic impacts of highway projects. Direct effects impact businesses immediately within the project area, while indirect effects are experienced by businesses outside of the project area. For example, if a store is adjacent to a widened highway, a direct effect of the project could be increased business due to greater vehicle traffic past the store location. If that increased business represents a shift of business from a competitor a few miles away, the loss in business at the competing store would be an indirect effect. During and after construction. The distributive impacts of highway projects can be divided into two phases—the construction disruption and the postconstruction period. During construction, access to businesses in the vicinity of the project can be disrupted. Sometimes businesses fear that they will lose customers because of poor access, loss of parking spaces, noise, or other disamenities associated with nearby road or highway construction. The disruption to business activity can be temporary, if the lost customers return after construction is complete, or permanent, if customers form loyalties with substitute stores or suppliers during the construction period. Importantly, there is some disagreement about how much businesses are harmed during a road construction project. Often, transportation agencies take measures to minimize or mitigate the effects of the loss of access, parking, or noise. Also, the negative effects on nearby firms will be influenced by the loyalty of their customers and the nature of their competition. Hence different firms in a construction zone could be affected differently by the project. After construction, a completed road or highway project can change the pattern of accessibility and thus influence the competitiveness of different businesses. One might imagine that the spatial influence of a road project after construction will be roughly the reverse of the impact during construction. The businesses near the road improvement will benefit from improved access, and might be able to lure customers from more distant competitors. Yet while this example helps illustrate the different distributive impacts of the construction and post- construction time periods, there are many reasons why the impacts during and after construction will not be mirror images. Environmental justice analysis should consider the spatial pattern of the positive and negative impacts of highway projects before and after construction, and how those patterns affect minority and low-income communities. METHODS Table 9-1 summarizes the methods we present in this chapter. Method 1. Map and GIS assessment The simplest method for assessing the environmental justice impacts of highways related to economic development is to map businesses around the project. This could be as straightforward as walking or driving the corridor (i.e., a so-called “windshield survey”) to assess which businesses might be affected by a construction project. More involved analyses can be carried out by looking at business locations that are depicted on a map. Typically, such a map would be developed using geographic information systems (GIS). A similar technique could be used for

220 the after-construction period to identify which firms might benefit from improved access and which might be negatively affected by the loss of business to those firms. Table 9-1. Summary of methods for analyzing economic development Method Assessment level Appropriate uses Use when Data needs Expertise required 1. Map and GIS assessment Screening Project/corridor Effects are expected to be low and more resource-intensive techniques are not available Low Geographic information system (GIS) 2. Surveys or focus groups Screening/ detailed Project/corridor/ system Project or policy is controversial and high level of interaction with affected individuals is required Medium Group interaction and facilitation 3. Gravity models Detailed Project Changes are expected in accessibility in many directions and over a wide area High Accessibility modeling When to use. This technique is among the least resource intensive and simplest to apply. It is appropriate either where more resource-intensive techniques are not available to an agency or for projects with relatively small impacts for which more rigorous (and hence expensive) analyses would not be commensurate with the scope of the project. Analysis. For each business identified in the project, you can assess whether the impact of construction will result in a loss of customers using rules of thumb (e.g., reasonable walking or driving distances) or expert judgment (see the description of focus groups in Method 2). This direct effect cannot be cleanly separated from indirect effects because to some extent the loss of customers will depend on available substitute business locations in the same market area. Hence, for each business in the construction zone, you may also want to use data in a GIS format to assess possible competing businesses. This could be a simple listing of such firms, or one could assess the relative characteristics of the competing businesses and the businesses in the construction zone to assess the likelihood of shifts in a customer base. Data needs, assumptions, and limitations. The key element of this method is to document firms that are likely to be affected either during or after construction because of their proximity to the project. These firms will experience the direct effects of the project. For indirect effects, one could catalogue firms in surrounding market areas. The area of interest might be established based on rules of thumb, as noted earlier, or on more detailed assessments of market areas and the locations for nearby competitors of particular firms near the project.

221 Results and their presentation. One example of this technique would be to walk or drive the project corridor and catalogue each business by location, type of business, and assessment of the expected impact during and after construction. A hypothetical example of the survey results is shown in Table 9-2. Table 9-2. Example of local access assessment Location Business Expected impact during construction Expected impact after project completion 22 Main Gas station One entrance lane obstructed No change in access 26 Main Grocery Loss of 20 parking spaces New right turn lane into parking lot 30 Main Hair salon Entrance lane narrowed Five new parking spaces 34 Main Drugstore Increase in traffic in opposing lane at parking lot entrance New dedicated left turn lane into parking lot The same type of analysis could be used to understand impacts after construction. For each business in an area of improved accessibility, you can assess whether that business will likely draw business away from competitors. This can again be based on rules of thumb or expert judgment. Assessment. This method is the simplest and least resource intensive of those described. As such, it is appropriate in several circumstances. Agencies with limited capabilities can conduct a GIS-based analysis quite easily. This method is also suited to small projects and particularly to those where the agency expects few or no environmental justice issues. Agencies can use this technique as a screening method to verify hunches that projects will have limited environmental justice implications or to illuminate possible issues that will require further analysis. The disadvantage of a GIS-based assessment is that the results can be subjective if, for example, agencies do not carefully articulate the criteria that led to particular conclusions regarding choosing competing businesses or project impact areas. Agencies should take care to apply systematic criteria when making such judgments so that the outcome of the assessment can be clearly linked to the assumptions and methods used. Method 2. Surveys or focus groups Understanding attitudes and reactions of parties affected by transportation projects is important in assessing environmental justice. Surveys or focus groups are a useful tool to acquire information about the characteristics of the affected parties, as well as their expectations regarding the project. These can include expected business losses due to construction disruption, expected benefits due to improved accessibility after the project is complete, and perceived changes in competitiveness due to the altered pattern of accessibility. The quality and appropriateness of surveys and focus groups can vary in different contexts. Occasionally, analysts have been suspicious of these methods, fearing that they allow users to overstate negative impacts. Yet agencies have sometimes under-appreciated the value of surveys or focus

222 groups both as a means of outreach and as an analytical tool. In some instances, the perceptions of persons and businesses affected by a project might be more accurate than analytical methods, and surveys and focus groups are an excellent way to get information that otherwise might not be available. When to use. Survey or focus groups are especially useful (1) when input from affected parties is vital for understanding the distributive character of economic impacts, (2) when impacts are confined to small geographic areas and analytical techniques based on data for larger geographic regions will not capture the spatial character of the impacts, (3) when data on impacts are not readily available from other means, and (4) when agencies will benefit from direct interaction with the public, as in the case of controversial projects where perceptions are important or when an agency wishes to facilitate communication with parties affected by the project. Analysis. Surveys can be used to capture the general attitudes of a wide range of parties. The results can be analyzed to match groups that benefit from, or are disadvantaged by, transportation projects to geographic locations. Survey sample sizes should be large enough that summaries by geographic areas, income, or race will have sufficient within-category sample sizes. That will often require over-sampling within specific geographic areas, income groups, or minority or ethnic groups. Data needs, assumptions, and limitations. Surveys can be designed to elicit two kinds of information. The first includes general characteristics of the parties in question, such as type of business, number of employees, logistical and other inventory arrangements, and mode of travel of a firm’s suppliers, clientele, and employees. The second includes the expectations of the affected parties regarding losses and gains during and after construction of the project. Firms can be asked to estimate how much business will be lost due to construction disruptions, such as closed lanes, noise, and lack of parking space. The gains are mainly in the form of expected increases in business volume once the project is completed. After completion the project may also adversely affect some firms because of shifts in economic activity to locations better served by the new transportation infrastructure. Hence, some firms might be asked to estimate these negative impacts. Surveys are typically conducted either by mail or phone. Various books give detailed advice on how to conduct a survey using either method. One popular reference book is Mail and Internet Surveys: The Tailored Design Method (Dillman 1999). These books offer suggestions on matters such as phrasing questions in a neutral manner, techniques to increase response rates, and follow- up methods for subjects who do not initially respond to the survey. This literature is useful whether an agency develops its own survey or contracts with an outside firm to create it. There are many firms that provide survey research services. Some have a national client base, while others specialize in particular regions or metropolitan areas. Internet-based surveys have recently been used in some settings and are also described in Dillman (1999). A common risk in Internet-based surveys, however, is that the sample of respondents will not be representative of an underlying population of interest. This can occur both because persons or firms with Internet access do not represent a random sample of all persons or firms and because those parties who are particularly interested in a topic are the most

223 likely to respond to a survey. While response bias is a potential issue in any survey, it is often regarded as more problematic in settings, like some crude Internet-based surveys, where nonrespondents are not contacted to prompt a response. For environmental justice studies, the fact that low-income populations might not have good Internet access could limit the scope for Internet-based surveys. For this reason, we cannot recommend them. Note that, when assessing the economic impacts of transportation projects, the survey population is likely to be firms. This raises additional complications beyond those in household surveys. Before the survey is sent, the appropriate officer within the firm must be identified. This should be an individual who has the needed data readily available. For surveys about economic impacts, this individual will likely be someone high in the management structure of the firm. Thus a pre- survey contact to explain the importance of the study is important. Response rates will increase if firms clearly understand how the survey study will benefit them. Even with the best efforts, response rates for surveys of firms are often lower than response rates for surveys of households. For firms, response rates of 20 to 30 percent are not unusual. See, for example, the discussion in Boarnet (1998b) or Kalafatis and Tsogas (1994). Focus groups provide opportunities for open-ended responses and discussions that are typically not possible in surveys. The groups are usually small—often not more than six or eight persons. They are thus typically used when the need for detailed information outweighs the need for statistical analysis. Focus groups are desirable when agencies are in the exploratory phase; often the information gathered can be used in later research. For example, it is common to use focus groups in the preliminary phase when designing a survey. Results and their presentation. The central purpose of surveys and focus groups is to acquire a clear understanding of the general attitudes, concerns, and preferences of minority populations and low-income populations regarding a proposed transportation project. Results of these methods of interacting with protected populations can be used to help assess whether the project would have a generally positive or negative effect on the economic well-being of these populations. The results also can be used to identify changes in the project or measures that could be taken to mitigate undesirable effects. Often, the analysis of survey data involves summarizing responses for the population. For environmental justice analyses, survey responses will typically be summarized by geographic area, income, or race. This requires that data be collected on locations of survey respondents (firms or households) and on income or race for individuals or for firm owners, employees, and clientele. Assessment. Surveys and focus groups provide detailed information due to the first-hand knowledge of the persons surveyed or interviewed. Hence, these techniques can improve the understanding of the distributive impacts of transportation projects, and the results can be used to design mitigative measures. One must be careful when using survey data, however. Survey respondents who oppose a project, for example, may exaggerate its negative impacts. In addition, the gains and losses predicted by respondents will be based on their perceptions, which may be inaccurate. Care should thus be taken when interpreting the results. Surveys are most reliable

224 when respondents are better able to judge impacts than any other group and when they have little incentive to exaggerate or misstate impacts. Method 3. Gravity models In addition to being used as a trip distribution model in the traditional four-step transportation planning process, gravity models are also widely used for market analysis. These models can be used to determine such things as the spatial extent of retail market areas, optimal store or public facility sizes, and optimal store or facility locations. The ability of gravity models to give estimates of the size of market areas is of particular interest when assessing the economic impacts of highway projects. Gravity models can be used to understand how changes in accessibility will change market areas, and hence sales, at particular store locations or in particular geographic areas. They can give both qualitative assessments of locations that will likely experience changes in business activity after a transportation improvement and quantitative estimates of those changes. Good references on gravity models for this sort of application include Hayes and Fotheringham (1984), Bendavid-Val (1991), and Filipovitch (1996). Gravity models have two basic elements, scale and distance, which are the determinants of the interaction between any pair of geographical areas. For example, densely populated cities (large scale) tend to generate and attract more trips than sparsely populated cities. Moreover, trips are more likely to occur between cities that are located closer together (short distance) than between distant cities. Gravity models can be adapted to assess environmental justice impacts of highways by analyzing how changes in accessibility (distance impacts) affect the relative attractiveness of communities or neighborhoods. When to use. Gravity models are most appropriate for a highway project that creates significant changes of accessibility in many directions and over a wide area. They can help answer questions about how a proposed transportation project would affect the ability of businesses operated by or serving minority populations to be competitive. Agencies with an operational transportation planning model can make some adjustments to the model to analyze environmental justice impacts. Also, gravity models can be used as a stand-alone tool. Some technical skills are required, however, and so this method may not be suitable for agencies with limited resources. Analysis. With traffic analysis zones (TAZs), census tracts, or census block groups as the units of observation, gravity models can predict how a highway project will affect the attractiveness of an area through changes in its relative accessibility. Consider the hypothetical example in Table 9-3. In the table, origin TAZs are shown in each column, and destination TAZs in the rows. For example, initially, average time for trips that start and end in TAZ A is 5 minutes. Average time for trips that start in TAZ A and end in TAZ B is 15 minutes. The impact of the project is depicted in Figures 9-1 and 9-2. Before a new highway is built, traffic from TAZ A to C must go through B. The construction of the highway causes disruption in TAZs A and C, thereby increasing travel time both within the TAZs and between them. However, after the highway is opened, travel time between A and C (bypassing B) is reduced by more than half. Because less traffic needs to go through TAZ B, the travel time between A and B

225 also decreases. However, the travel time between A and C becomes less than between A and B. The question is then, how does the new highway affect the relative attractiveness of each zone? The production-constrained gravity model can be written as: T O w d w dij i j a ij b j a ij b j = ∑ where Tij = the shopping spending of zone i residents in zone j Oi = total shopping spending of zone i residents wj = the number of retail stores (or total retail square footage) in zone j dij = the distance between zone i and j The total amount of retail sales in zone j, Rj is given by R Tj ij i = ∑ Table 9-3. Travel times between TAZs Initial travel times (minutes) Origin TAZ Destination TAZ A B C A 5 15 25 B 15 5 10 C 25 10 5 Travel times during the construction (minutes) Origin TAZ Destination TAZ A B C A 10 15 30 B 15 5 10 C 30 10 10 Travel times after the opening of the highway (minutes) Origin TAZ Destination TAZ A B C A 5 12 10 B 12 5 8 C 10 8 5 The parameter a is expected to be positive, as the larger the number of stores in a zone, the more attractive it will be to shoppers. In contrast, b is expected to be negative because the more distant

226 the zone, the less likely shoppers will travel to shop there. The above model can be estimated with survey data on shopping travel patterns. In past studies, the ranges of a and b were found to be between 0.5 and 2.0, and -0.5 and -2.0, respectively. Although how the values of the parameters are determined is beyond the scope of this guidebook, some insights into their relative values may be provided here. For example, the values of the parameters may reflect characteristics of trip makers and road networks. Inaccessible locations, such as those within congested areas, may be associated with larger dij because even short distances can provide disincentives for making a trip. Also, destination characteristics and trip purpose can be reflected by the parameter wj. For instance, grocery stores attract trips with higher frequency than furniture stores. In this case, zones with stores that attract trips with lower frequency may be associated with a smaller wj. A B 15 10 C Figure 9-1. Initial network travel times between TAZs A B 12 8 10 C Figure 9-2. Network travel times between TAZs after the opening of the highway

227 The forecasted link travel times during and after construction can be input into the gravity model. The results will be a new pattern of trip distribution between zones. If we assume that each zone generates the same amount of traffic, the travel time between zones will determine the amount of traffic between them. The initial distribution will therefore be such that TAZ B will be the most attractive because it is most accessible to both A and C. During the construction, the distribution pattern will not change much because even though travel times in TAZs A and C increase, the relative travel times do not change overall. However, after the highway is opened, travel times from both TAZs A and B to C will decrease, thereby improving the overall attractiveness of TAZ C. TAZ B, on the other hand, will become less attractive relative to C. With this pattern of changes in trip distribution, we can assume that businesses in TAZ C will benefit from the highway opening, but those in TAZ B will likely suffer. According to these results, we can create a map that reflects the distribution of benefits as shown in Figure 9-3. A Negative Neutral Positive B C Figure 9-3. Distribution of economic impacts after construction This map can then be overlaid on a map that represents ethnic and income groups to analyze the environmental justice impacts of the new highway. It is also possible to quantify the gain and loss at different locations in monetary terms. A gravity model can be used to allocate retail- shopping spending to various neighborhoods based on existing residential locations and accessibility changes due to the new highway project. For example, if the population and average income in the three TAZs above are known, they can be used to estimate retail-shopping spending by residents of each TAZ using the gravity model described below. To quantify the impact of a highway project on retail sales, you can compute the retail sales in each TAZ based on current network travel times. This is used as a basis for comparison. The new network travel times can then be used to predict retail sales after the project is completed. The change in retail sales reflects gains and losses in each TAZ. This information can be used to construct a map of distributive impacts. The overlaying technique, as discussed earlier, can then be used for further analysis to determine how distribution impacts may differentially affect protected populations. Data needs, assumptions, and limitations. The key information for this method is how a highway project affects accessibility. This information will be used to determine changes in link

228 travel times in the network, which will in turn become inputs for the gravity model. For the construction phase, changes in accessibility can include delays that can be estimated by the number of lanes lost. The construction delay can also be estimated through expert judgment based on past experience with similar projects. For the postconstruction period, changes in accessibility will likely be available from other elements of the project analysis. The information on changes in accessibility can then be used to forecast the change in link travel times in the overall network. Forecasted link travel time changes, for both the construction and post- construction time periods, can be used to obtain a gravity model assessment of the spatial distribution of the economic impacts of a highway project. Results and their presentation. The primary results obtained from applying gravity models is an assessment of how businesses in a particular area of the community would fare if a major transportation project were undertaken. The analysis can be carried out to estimate competitive effects during the construction phase, as well as when the project is completed. As indicated in Figure 9-3, it is possible to superimpose a spatial depiction of changes in competitiveness on socioeconomic data. This facilitates an assessment of the economic development effects on low- income or minority activity spaces of the community. Assessment. In agencies with readily available transportation planning models, the method for assessing environmental justice impacts using the gravity model is quite simple and straightforward to implement. Agencies with limited resources, however, may not be able to utilize this method. The method works well with large transportation projects to identify which areas of a community would experience gains or losses but is sometimes not sensitive enough for smaller ones. This is due to the aggregate nature of the analysis, with data typically aggregated to TAZs or similarly sized geographic observations. Of course, if small-scale geographic impacts are important, one could collect data for smaller areas. In assessing distributive impacts, the unit of analysis should be internally homogenous in racial, ethnic, or income distribution. If this is not the case, variations within a geographic area will possibly have environmental justice implications that would not be illuminated by the analysis. If the geographic observations are not internally homogenous, additional studies on microlevel distributive effects within areas of special concern can be used as a supplement to further clarify environmental justice issues. Another important problem that cannot be addressed explicitly by the gravity model is the impact of new development. New highways can attract new development, which could in turn affect the distribution of sales. The gravity model, however, treats retail businesses as exogenous and therefore cannot capture this aspect of the distributive impacts of transportation projects. The problem can be alleviated if new development can be forecast. The forecast future retail floor space can then be input into a gravity model. This will yield results whose reliability will depend on the quality of the forecast of changes in the location of business activity. RESOURCES 1) Burkhardt, Jon E., James L. Hedrick, and Adam T. McGavock (Ecosometrics, Inc.). 1998. TCRP Report 34: Assessment of the Economic Impacts of Rural Public Transportation. Washington, DC: Transportation Research Board, National Research Council.

229 This report examines the economic effects of selected rural public transportation services at the local level through case studies. It provides practical examples of how to assess effects associated with the introduction or expansion of public transportation services in rural areas. 2) Cambridge Systematics, Inc., Robert Cervero, and David Aschauer. 1998. TCRP Report 35: Economic Impact Analysis of Transit Investments: Guidebook for Practitioners. Washington, DC: Transportation Research Board, National Research Council. This report provides guidance on selecting methods to conduct analysis of the economic and land development effects of transit investments. It reviews the major methods and shows their application through case studies. 3) Forkenbrock, David J., Thomas F. Pogue, Norman S. J. Foster, and David J. Finnegan. 1990. Road Investment to Foster Local Economic Development. Iowa City: University of Iowa, Public Policy Center. A detailed presentation of the conceptual relationship between transportation investment and economic development is contained in this monograph. The relationship is explored in an analysis of postinvestment effects of businesses that benefited by specific road projects. 4) Hagler Bailly Services, Inc. 2000. “Guidance on Using Economic Analysis Tools for Evaluating Transport Investments.” National Cooperative Highway Research Program, Project 2-19(2) Contractor Final Report. Washington, DC: Transportation Research Board, National Research Council. This NCHRP report discusses research and application of existing techniques for measuring economic development and productivity effects of transportation projects. It discusses the appropriate use of existing tools, including their usefulness, reliability, and data requirements. It is designed to help analysts select appropriate techniques given their unique needs, data constraints, and staffing expertise. Case study examples are provided. 4) Weisbrod, Glen, and Burton Weisbrod. 1997. “Assessing the Economic Impacts of Transportation Projects: How To Choose the Appropriate Technique for Your Project.” Transportation Research Circular 477. Washington, DC: Transportation Research Board, National Research Council. This circular, sponsored by the Transportation Research Board Committee on Transportation Economics, is a concise primer on how to best assess economic effects of transportation projects. It is designed to provide the reader with guidelines for (1) identifying the types of economic effects most relevant for decision-making, (2) defining the appropriate evaluation perspective, and (3) selecting techniques to be used for analysis and presentation of findings. 5) Wilbur Smith Associates, Benjamin J. Allen, C. Phillip Baumel, David J. Forkenbrock, and Daniel Otto. 1993. Guide to the Economic Evaluation of Highway Projects. Ames, IA: Iowa Department of Transportation. This guidebook identifies methods by which economic analysis can be used to help decision- makers select highway projects and project types that would produce net economic benefits. It explains how the included methodologies work and discusses how to ensure that they are applied so as to produce results that are consistent and fair.

230 REFERENCES American Association of State Highway and Transportation Officials (AASHTO). 2003. User Benefit Analysis for Highways. Washington, DC: AASHTO. Bendavid-Val, Avrom. 1991. Regional and Local Economic Analysis for Practitioners. Westport, CT: Praeger Publishers. Boarnet, Marlon G. 1998a. “Spillovers and the Locational Effects of Public Infrastructure.” Journal of Regional Science, Vol. 38, pp. 381-400. Boarnet, Marlon G. 1998b. “Business Losses, Transportation Damage, and the Northridge Earthquake.” Journal of Transportation and Statistics, Vol. 1, No. 2, pp. 49-63. Dillman, Don A. 1999. Mail and Internet Surveys: The Tailored Design Method. New York: John Wiley and Sons. Filipovitch, A.J. 1996. Spatial Distribution Analysis. Mankato, MN: University of Minnesota, Mankato, Urban and Regional Studies Institute. Available at http://krypton.mankato.msus.edu/~tony/courses/604/gravity.html. Forkenbrock, David J., and Foster, Norman J. 1990. “Economic Benefits of a Corridor Highway Investment.” Transportation Research, Vol. 24A, No.4 (July), pp. 303-312. Haynes, K. E., and Fotheringham, A. S. 1984. Gravity and Spatial Interaction Models. Beverly Hills, CA: Sage Publications. Kalafatis, S.P., and M.H. Tsogas. 1994. “Impact of the Inclusion of an Article as an Incentive in Industrial Mail Surveys.” Industrial Marketing Management, Vol. 23, pp. 137–143. Mohring, Herbert, and Harwitz, Mitchell. 1962. Highway Benefits: An Analytical Framework. Evanston, IL: Northwestern University Press.

Next: Chapter 10 - Noise »
Effective Methods for Environmental Justice Assessment Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB’s National Cooperative Highway Research Program (NCHRP) Report 532: Effective Methods for Environmental Justice Assessment is designed to enhance understanding and to facilitate consideration and incorporation of environmental justice into all elements of the transportation planning process, from long-range transportation systems planning through priority programming, project development, and policy decisions. The report offers practitioners an analytical framework to facilitate comprehensive assessments of a proposed transportation project’s impacts on affected populations and communities.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!