1、Brief 15. Commuting Flow Patterns January 2015 Commuting in a merica 2013 The National Report on Commuting Patterns and TrendsAbout the AASHTO Census Transportation Planning Products Program Established by the American Association of State Highway and Transportation Officials (AASHTO) and the U.S. D
2、epartment of Transportation (U.S. DOT), the AASHTO Census Transportation Planning Products Program (CTPP) compiles census data on demographic characteristics, home and work locations, and journey- to-work travel flows to assist with a variety of state, regional, and local transportation policy and p
3、lanning efforts. CTPP also supports corridor and project studies, environmental analyses, and emergency operations management. In 1990, 2000, and again in 2006, AASHTO partnered with all of the states on pooled-fund projects to sup- port the development of special census products and data tabulation
4、s for transportation. These census transpor- tation data packages have proved invaluable in understanding characteristics about where people live and work, their journey-to-work commuting patterns, and the modes they use for getting to work. In 2012, the CTPP was established as an ongoing technical
5、service program of AASHTO. CTPP provides a number of primary services: Special Data Tabulation from the U.S. Census BureauCTPP oversees the specification, purchase, and delivery of this special tabulation designed by and for transportation planners. Outreach and TrainingThe CTPP team provides traini
6、ng on data and data issues in many formats, from live briefings and presentations to hands-on, full-day courses. The team has also created a number of electronic sources of training, from e-learning to recorded webinars to downloadable presentations. Technical SupportCTPP provides limited direct tec
7、hnical support for solving data issues; the pro- gram also maintains a robust listserv where many issues are discussed, dissected, and resolved by the CTPP community. ResearchCTPP staff and board members routinely generate problem statements to solicit research on data issues; additionally, CTPP has
8、 funded its own research efforts. Total research generated or funded by the current CTPP since 2006 is in excess of $1 million. Staff Penelope Weinberger, CTPP Program Manager Matt Hardy, Program Director, Policy and Planning Jim Tymon, Chief Operating Officer/Director of Policy and Management Proje
9、ct Team Steven E. Polzin, Co-Author, Center for Urban Transportation Research, University of South Florida Alan E. Pisarski, Co-Author, Consultant, Falls Church, Virginia Bruce Spear, Data Expert, Cambridge Systematics, Inc. Liang Long, Data Expert, Cambridge Systematics, Inc. Nancy McGuckin, Data E
10、xpert, Travel Behavior Analyst Contact Penelope Weinberger, e-mail: pweinbergeraashto.org, phone: 202-624-3556; or CTPPinfoaashto.org 2015 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. Pub Code: CA15-4 IS
11、BN: 978-1-56051-586-9 2014 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.Commuting in America 2013: The National Report on Commuting Patterns and Trends Brief 15. Commuting Flow Patterns This brief is the
12、fifteenth in a series describing commuting in America. This body of work, sponsored by American Association of State Highway and Transportation Officials (AASHTO) and carried out in conjunction with a National Cooperative Highway Research Program (NCHRP) project that provided supporting data, builds
13、 on three prior Commut- ing in America documents that were issued over the past three decades. Unlike the prior reports that were single volumes, this effort consists of a series of briefs, each of which addresses a critical aspect of commuting in America. These briefs, taken together, comprise a co
14、mprehensive summary of American commuting. The briefs are disseminated through the AASHTO website (traveltrends.transportation.org). Accompanying data tables and an Executive Summary complete the body of information known as Commuting in America 2013 (CIA 2013). Brief 15 describes the pattern of com
15、muting travel. Specifically, the home-to-work trip is analyzed to understand the flow of travel that has to be accommodated by transportation infrastructure and services. The discussion covers two distinct elements: first, information about the length of commute trips; and second, information about
16、the spatial orientation of trip flows. Commuting Trip Lengths Assessing patterns of commuting flows at the national level requires the use of broader, more abstract information than can occur at the metropolitan level where more detail is possible. At the national scale, reliance on aggregate units
17、of geography is necessary, which may mask some of the detail needed for local project-level planning but provides an understanding of aggregate needs and trends. The nature of the categorization used to classify urban areas as, for example, cities or suburbs, is often bound by historically-deter- mi
18、ned jurisdictional boundaries that may not always provide a precise understanding of the physical characteristics of the area or commute trip length or orientation. What may be seen very clearly as a suburb in one area may be very unclear to others unfamiliar with the area. The Census Bureaus use of
19、 multiple principal cities, rather than a single central city per metropolitan area, exacerbates the difficulty. Thus, the flow measures presented here are necessarily relatively blunt instruments to characterize what is happening at the broad national or regional scale. A fundamental element of all
20、 flows is simply the typical lengths of work trips. Data are limited in this area, available only intermittently via the National Household Travel Survey (NHTS). Figure 15-1 presents the average trip lengths for more recent periods in which NHTS data are available. By and large, the pattern for work
21、 trips, and for trips of all 2014 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.4 Commuting in America 2013: The National Report on Commuting Patterns and Trends purposes, has been slowly increasing in len
22、gth over time, with a small dip in 2009, pre- sumed to be attributable to the slow economy, but which is not statistically significant at the 95 percent confidence level. The next NHTS, scheduled for 2015, will help resolve whether this is a pattern change or a cyclical phenomenon. Figure 15-1. Trip
23、 Length T rends for All Modes Source: NHTS Examination of trip lengths by metropolitan area size, shown in Figure 15-2, as ob- served in the 2009 NHTS, shows an almost 30 percent increase in trip lengths as metro size increases. Not surprisingly, non-metro workers are shown to have the longest trip
24、lengths of all. Work-trip lengths have shown only slight variation, with no significant trends, from the 2001 survey. Note that discussions of NHTS work trip length do not include work-at-home trips in the calculation. 8.5 10.7 11.6 12.1 11.8 8.7 9.5 9.2 10 9.7 0 2 4 6 8 10 12 14 1983 1990 1995 2001
25、 2009 Trip Length in Miles Work All Purposes 2014 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.5 Brief 15. Commuting Flow Patterns Figure 15-2. Average Work Trip Length by Metro SizeSource: NHTS A broader
26、 measure is that shown in Figure 15-3, which breaks trips into 10-mile catego- ries. It shows that, over time, the trend among both men and women is toward longer trip lengths. One might expect work trip lengths to rise during recession periods, as workers become more willing to travel greater dista
27、nces to obtain employment. However, while that may be a valid hypothesis, the statistical trends are more about job losses than increases; as noted in other briefs, job losses in the recent past were high in factory work and construc- tion, which are typically longer-distance trips. High fuel prices
28、 also dampen the enthusiasm of individuals to take jobs more distant from home. The dramatic decline in home values also locked many households into their existing home location due to “underwater” mort- gages and an inability to relocate to find work or move closer to a new or existing job in their
29、 current location. Data are not available to diagnose and fully disentangle the magni- tude of the impact of these events. 0 2 4 6 8 10 12 14 Less than 250,000 250,000 500,000 500,000 1,000,0001M3M 3M+ Not in MSA ALL Miles Metro Size Category (Population) 2014 by the American Association of State Hi
30、ghway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.6 Commuting in America 2013: The National Report on Commuting Patterns and Trends Figure 15-3. Work Trip Length Trends by GenderSource: 2009 NHTS Workers Working beyond Their County of Residence Ano
31、ther indicator of commuting flows is the Census long-term data regarding workers leaving their home county to travel to work. The Census asks whether workers work in their residence county or in another county in-state or out-of-state. Commuting in America has tracked these patterns since the 1960 C
32、ensus. It can be argued that counties are a weak source of such basic information given the substantial variations in county sizes, especially comparing East Coast to West Coast counties. Ever-larger metropolitan areas are encom- passing multiple counties as well. The trends over time are very clear
33、 and are a strong indi- cator of increasing cross-county flows. As the nations workers roughly doubled from 1960 to 2010, workers leaving for jobs in counties outside their residence county quadrupled, from 9.4 to 37.5 million. As a result, the share of all workers leaving their home county rose fro
34、m 14.5 to 27.4 percent of workers, as shown in Figure 15-4. Note that the lower level of increase from 2000 to 2010 is not a sign of a diminishing trend, but, rather, of the relatively smaller percentage change in workers in the period compared to previous decades. Table 15-1 provides more detail on
35、 the 2010 pattern, differentiating between male and female worker travel. The data reveal a strong distinction in malefemale patterns. Men are more likely to work outside the county of residence but inside the state (25.5 percent vs. 21.6 percent) and to work outside the state (4.5 percent vs. 3.0 p
36、ercent), a total difference 0 10 20 30 40 50 60 70 Less Than 10 Miles 1020 Miles More Than 20 miles Less Than 10 Miles 1020 Miles More Than 20 Miles Less Than 10 Miles 1020 Miles More Than 20 Miles Men Women All Workers Percent of Work Trips Trip Length 1995 2001 2009 2014 by the American Associatio
37、n of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.7 Brief 15. Commuting Flow Patterns Figure 15-4. Workers Commuting Outside Their County of Residence Source: CIA3 and ACS of 30 vs. 24.6 percent. Historically, this pattern had been tru
38、e because of the greater ten- dency of women to often take jobs that are closer to home and part-time, to be available for household-serving activities. The pattern persists even as gender-based household roles and responsibilities continue to evolve. Table 15-1 Commuting Behavior by Jurisdiction an
39、d Gender All Male Female Total workers 136,941,010 100.0% 71,948,651 100.0% 64,992,359 100.0% Worked in state of residence 131,726,663 96.2% 68,712,557 95.5% 63,014,106 97.0% Worked in county of residence 99,361,852 72.6% 50,380,850 70.0% 48,981,002 75.4% Worked outside county of residence 32,364,81
40、1 23.6% 18,331,707 25.5% 14,033,104 21.6% Worked outside state of residence 5,214,347 3.8% 3,236,094 4.5% 1,978,253 3.0% T otal working outside county of residence 37,579,158 27.4% 21,567,801 30.0% 16,011,357 24.6% Source: ACS 2010 9.4 14.8 20.1 27.5 34.2 37.5 14.5% 19.2% 20.8% 23.9% 26.7% 27.4% 0%
41、5% 10% 15% 20% 25% 30% 0 5 10 15 20 25 30 35 40 45 50 1960 1970 1980 1990 2000 2010 Percent of Workers Millions of Workers 2014 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.8 Commuting in America 2013: Th
42、e National Report on Commuting Patterns and Trends Another significant distinction in workers staying or leaving their county of residence has to do with their choice of mode depending upon their travel circumstances. One would certainly expect that walking would be a close-to-home mode; yet, four p
43、ercent of walk- ers indicate that they cross a county line and another two percent cross state lines in their walk-to-work travel, indicating they live near jurisdictional boundaries. While the percent of inter-county commute trips by walking is certainly a lower percentage than other modes, it is s
44、till significant. Another somewhat surprising observation is that transit has more significant shares in worked outside the residence county and state. Only 59 percent of transit travel is within the residence county, with about 32 percent working outside the county and more than 9 percent working i
45、n another state. This raises transits share of work travel from its over- all average of 5 percent to 6.7 percent in inter-county travel and 12.2 percentmore than double the overall averagefor interstate work travel. Carpooling also increases share for trips leaving the home county, but only slightl
46、y compared to transit. Figure 15-5 identifies the geographic distribution for each mode. Figure 15-5. Commute Mode by Jurisdiction of Destination Source: ACS 2010 The high share of “Work outside state of residence” for the “Other” mode could be reflecting individuals who fly or take intercity rail t
47、o out-of-state jobs. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Drive Alone Carpool Transit Walk Other Mode Share Commute Mode Worked in county of residence Worked outside county of residence Worked outside state of residence 2014 by the American Association of State Highway and Transportation Officials
48、. All rights reserved. Duplication is a violation of applicable law.9 Brief 15. Commuting Flow Patterns Geographic Variations in Flows outside the County of Residence Figure 15-6 lists the states in order of the percentage of commuters leaving their home county to work. In reality, the data illustra
49、tes the attractive power of major metropolitan areas; perhaps a better term is “megalopolitan” areas. Figure 15-6. Percent of Workers Leaving Their Residence County for Work Note: Includes work outside residence county, both within and outside the state. Red bars indicate states in which 40% of residents leave their home county to work. Y ellow bars indicate national average. Source: ACS 2010 0% 10% 20% 30% 40% 50% 60% HI AZ NV AK WY MT ND NM CA UT WA FL SD ID NE VT TX DE ME OR KS IA DC AR OK CT IL AL NC WI TN SC PA LA OH MI KY IN WV CO
