1、Brief 11. Commuting Departure Time and Trip Time OCTOber 2013 Commuting in America 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)
2、and the U.S. Department 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 transportatio
3、n policy and planning 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 d
4、ata tabulations 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 ongo
5、ing technical 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 p
6、rovides training 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 limi
7、ted direct technical 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; addition
8、ally, CTPP has 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 Janet Oakley, Director of Policy and Government Relations Pr
9、oject 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. Contact Penelope We
10、inberger, e-mail: pweinbergeraashto.org, phone: 202-624-3556; or CTPPinfoaashto.org 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. Pub Code: CA11-4 ISBN: 978-1-56051-582-1 2013 by the American Associa
11、tion 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 11. Commuting Departure Time and Trip Time This brief is the eleventh in a series describing com
12、muting in America. This body of work, sponsored by the 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 on three prior Commuting in Ame
13、rica 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 comprehen- sive summary of American
14、commuting. The briefs are disseminated through the AASHTO website (www.transportation.org). Accompanying data tables and an Executive Summary complete the body of information known as Commuting in America 2013 (CIA 2013). One of the important characteristics of commuting is the fact that it is a rel
15、atively high-frequency trip taken by travelers at similar times. Transportation professionals and others often refer to this resulting pattern as rush-hour or peak-period travel. Historically, commuting to and from work has defined these peak travel periods, which traditionally take place during wee
16、kday mornings and evenings as the workforce travels to and from their places of employment. These peak periods for travel define the transportation infra- structure and service needs for roads and transit systems. Understanding these peak peri- ods and the distribution of commuting over time is impo
17、rtant to transportation planning and forecasting. The length of time spent traveling to work is another important measure of commut- ing. The commute trip length in time is impacted by the trip length in distance and the trip speed. Thus, this measure reflects workers decisions related to residentia
18、l and workplace location, as well as their travel mode choice and the congestion levels they encounter in their travels. With work being such an important trip, measures of commute travel time are a significant indicator of the publics value of time for commuting to work. This brief provides quantit
19、ative data regarding work-trip departure times and trip travel times. Commuting Departure Time As a general rule, one would expect the distribution of travel by time of departure for work to be a substantially stable attribute of work travel. Most places of employment have hours of operation that sh
20、ape work start and end times for employees. The occupational and industrial structure of the nations economy determines work schedules for large shares of the population; individual workers then shape their individual travel around such factors as trip distance, anticipated congestion/travel speed,
21、their risk tolerance for on-time arrival, the availability of travel modes (auto availability or transit schedules), and coordination of 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.4 Commuting in Am
22、erica 2013: The National Report on Commuting Patterns and Trends household travel activities (dropping off spouse, taking kids to school, running errands, etc.). The composite impact of these factors is the resultant distribution of travel departure times for the trip from home to work. Figure 11-1
23、shows the travel departure time distribution based on data collected in the 2011 American Community Survey (ACS). Note that respondents were asked what time they departed for work at their primary job (for multi-job holders). This distribution will be sim- ilar, but not identical, to a distribution
24、of time spent commuting to work. Recognizing that the mean trip length is approximately 25 minutes, the peak roadway volumes of commuters will occur approximately one half hour later than the distribution in Figure 11-1. In the re- cession period that dominates recent empirical data, the sharp losse
25、s in home construction and manufacturing may have affected that departure time distribution to some extent. The distribution in Figure 11-1 is very similar to one derived from 2000 census long- form data, with some slight increases in early morning shares. 1The major exception is the 7:008:00 a.m. p
26、eriod, which is the major travel period. Surprisingly, the amount of travel in that period declined by a substantial amount, approxi- mately 1.7 million commuters over the 12-year period; it was the only period showing fewer com- muters than in 2000. Overall, commuter counts increased by approximate
27、ly 7 million, or nearly 6 percent. Figure 11-2 shows the change in work trip departures by time period. It is not clear what the basis is for the 7:00 a.m.8:00 a.m. drop of roughly 5 percent is. It may reflect changes in the nature of employment types, which can influence start times, or it may be a
28、 reflection of higher congestion levels forcing earlier start times or other non-work traffic absorbing the peak capacity and, in effect, forcing commuters into earlier or later departure times to have tolerable travel times. There may be important regional differences that affect the scale of the s
29、hift. Such a shift in the peak-period commute, absent offsetting changes in non-work travel, could have substantial effect on peak-period congestion. Long and Short Commutes To gain insight into the impact of commuting on individuals, analysis frequently uses thresholds of 20, 60, and 90 minutes as
30、useful for descriptive analysis. Looking at time of departure by those reaching work in under 20 minutes and over 60 minutes, one sees the expected patternlower percentages for those traveling under 20 minutes in the early morning hours and higher percentages for those traveling over 60 minutes. Fig
31、ure 11-3 dis- plays the pattern. It is in the later morning hours that the percentage with commutes under 20 minutes becomes substantial. 1The census long-form survey was conducted in April each decade whereas American Community Surveys are conducted throughout the year. It is not expected that this
32、 would impact the trip departure times, but that hypothesis has not been tested. Work trip departure times continue to be the most concentrated in the 7:008:00 a.m. hour. 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation o
33、f applicable law.5 Brief 11. Commuting Departure Time and Trip Time Figure 11-1. Distribution of Workers by Trip Departure Times Source: ACS 2011 Figure 11-2. Distribution of Numbers of Workers by T rip Departure Times, 2000, 2011 Source: 2000 Census, ACS 2011 Figure 11-3. Long and Short T rips by T
34、ime of Departure, 2011 Source: ACS 2011 4.3% 3.6% 4.8% 8.7% 9.9% 14.8% 12.8% 11.2% 5.5% 6.3% 2.9% 1.4% 7.1% 6.8% 0% 2% 4% 6% 8% 10% 12% 14% 16% 18% Percent of Workers Work Trip Departure Time Midnight4:59 a.m. 5:005:29 a.m. 4:0011:59 p.m. 5:305:59 a.m. 6:006:29 a.m. 6:306:59 a.m. 7:007:29 a.m. 7:307
35、:59 a.m. 8:008:29 a.m. 8:308:59 a.m. 11:0011:59 a.m. 10:0010:59 a.m. 9:009:59 a.m. Noon3:59 p.m. Midnight 4:59 a.m. 5:00 5:59 a.m. 6:00 6:59 a.m. 7:00 7:59 a.m. 8:00 8:59 a.m. 9:00 9:59 a.m. 10:00 a.m. Noon Noon Midnight 2000 4.36 9.47 24.32 38.33 20.21 6.98 5.19 16.31 2011 5.71 11.14 24.65 36.58 21
36、.98 8.34 5.58 18.35 0 5 10 15 20 25 30 35 40 45 Work Trip Departures (Millions) 36% Midnight4:59 a.m. 5:005:59 a.m. 6:006:59 a.m. 7:007:59 a.m. 8:008:59 a.m. 9:009:59 a.m. 10:00Noon NoonMidnight All Times 34% 36% 42% 47% 52% 54% 51% 43% 17% 14% 11% 7% 6% 5% 6% 6% 8% 0% 10% 20% 30% 40% 50% 60% 70% Pe
37、rrcent of Work Trip Departures Percent under 20 Minutes Percent over 60 Minutes 2013 by the American Association of State Highway 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
38、 Trends This follows the same pattern seen in the year 2000 statistics, as shown in Figure 11-4. The patterns exhibit remarkable stability, with some small declines in shares of workers reaching work in under 20 minutes. Figure 11-4. Shares of Long and Short T rips by Time of Departure, 2000 and 201
39、1 Source: 2000 Census, ACS 2011 Work Trip Departure and Gender Rather similar stability is manifested in the data when differentiated by the gender of work- ers. Figure 11-5 depicts the pattern of time of departure for males and females. Figure 11-5. Work Trip Time of Departure by Gender Source: ACS
40、 2011 The noteworthy factor is that males predominate in the early hours. A crossover point is reached between 7:00 and 7:30 a.m., after which females are in the majority until the eve- ning hours. Differences may be the result of different trip lengths, involvement in different industry classes (th
41、at have different start times), different impacts on trip timing related Midnight4:59 a.m. 5:005:59 a.m. 6:006:59 a.m. 7:007:59 a.m. 8:008:59 a.m. 9:009:59 a.m. 10:00 a.m.Noon NoonMidnight 0% 10% 20% 30% 40% 50% 60% Percent of Work Trip Departures 2000 Percent under 20 minutes 2000 Percent over 60 m
42、inutes 2011 Percent under 20 minutes 2011 Percent over 60 minutes Midnight4:59 a.m. 5:005:29 a.m. 4:0011:59 p.m. 5:305:59 a.m. 6:006:29 a.m. 6:306:59 a.m. 7:007:29 a.m. 7:307:59 a.m. 8:008:29 a.m. 8:308:59 a.m. 11:0011:59 a.m. 10:0010:59 a.m. 9:009:59 a.m. Noon3:59 p.m. 0 2 4 6 8 10 12 Work Trip Dep
43、artures (Millions) Male Female 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.7 Brief 11. Commuting Departure Time and Trip Time to parenting responsibilities (getting children off to school), and/or d
44、ifferences in travel location relative to congestion levels. If one uses the percentage leaving for work before 6:30 a.m. as the metric for Time Left Home, a surprising difference arises: almost 27 percent of all male workers leave before 6:30 a.m. but only 15 percent of females do. In absolute term
45、s, there are 19 million males out before that time, exactly double the 9.5 million females who are early commuters. Different participation in various industries with different traditional start times may explain part of this difference. Figure 11-6. Modal Shares by Work Trip Departure Time Source:
46、ACS 2011 Work Trip Departure and Mode The overall question of commute mode used is more related to when the traveler left home than might be expected. Figure 11-6 displays this relationship. It is clear that the private vehicle is dominant in the early morning hours and tapers off in the later parts
47、 of the early morning commuting period, starting around 8:00 a.m. This is the period that shows a sharp 75% 80% 85% 90% 95% 100% Midnight4:59 a.m. 5:005:29 a.m. 5:305:59 a.m. 6:006:29 a.m. 6:306:59 a.m. 7:007:29 a.m. 7:307:59 a.m. 8:008:29 a.m. 8:308:59 a.m. 9:009:59 a.m. 10:0010.59 a.m. 11:0011:59
48、a.m. Noon3:59 p.m. 4:0011:59 p.m. All Percent By Mode Other method Walk Bicycle Motorcycle Taxicab Transit Car, Truck, or Van 2013 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:
49、 The National Report on Commuting Patterns and Trends drop-off in commuters starting their travel, roughly half as compared to the 7:008:00 a.m. period, and then volumes drop even more sharply to a third or quarter of that before noon. The figure can mislead in this way. For example, the 11:00 a.m.Noon travel period, in which walking to work and transit are so strong, represents about 5 million travelers in total, compared to 35 million in the peak 7:008:00 a.m. hour. From the
