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113 Cards in this Set

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  • Back
What percentage of trips in the United States are work-based trips?
15%. (source?)
What are some differences in travel behavior patterns among racial groups (holding other factors constant)?
1) African-Americans use public transit more frequently.

2) Latinos use carpools more frequently, at twice the percentage rate of non-Latinos. (Pisarksi 2006)
What are the four steps of the four-step travel forecasting model?
1) Trip generation 2) Trip distribution 3) Mode choice 4) Trip assignment (source?)
How have carpooling rates changed?
They have declined from 20% in 1980 to about 12% in 2000. (Pisarski 2006)
How have average national travel times changed?
They have grown from 21.7 minutes in 1980 to 22.4 minutes in 1990. (Pisarski 2006)
In "The Pedigree of a Statistic," what did Shoup say about statistics for the percent of land in US cities that is paved for cars?
Shoup said that the statistics appear to have been made up.
What recommendations does Koppelmann make for traffic modelers in "Innovations in Traffic Modeling?"
- Develop an integrated system of models that builds on advances in knowledge about human decision-making, development patterns, and transportation system operations
- Validate models by checking the performance of past models against current conditions
- Gather more data about land use, populations, and transport facilities
- Get more government funding for research
- Find ways to present model results to non-technical audiences
What transportation challenges for low-income families do Blumenberg and Waller identify in "The Long Journey to Work?"
- Jobs are in suburbs, but many families are in the central city
- Fixed-route public transit is poorly suited to dispersed travel patterns
- Low-income families have high car access rates (86%) but they own older, less reliable cars
- Transit is burdensome: time cost is high and trip chaining is difficult
According to Sheppard's "Modeling and Predicting Aggregate Flows," what are some trip categories used in trip generation models?
- Home-based work
- Home-based non-work
- Non-home based
- Goods (industry oriented)
- Goods (consumer oriented)
In "Reflections on the Planning Process," Wachs lists three factors transportation policy must consider. What are they?
Effectiveness, efficiency, and equity.
The Papacostas and Prevedouros reading on "Traffic Impact and Parking Studies" lists four major measurements for parking. What are they?
- Occupancy (percent spaces occupied of available spaces)
- Accumulation (number of vehicles parked at a given time)
- Turnover (number of vehicles utilizing the same stall over given period of time)
- Average duration of occupancy (total vehicle hours/total number vehicles parked)
According to Blumenberg, what are three strategies to improve transportation to connect low-income workers with jobs?
- Enhance existing fixed-route transit in dense urban areas
- Create demand-responsive service in areas with densities too low for fixed route serivce
- Give low-income workers access to cars
In Doyle and Taylor's "Variation in Metropolitan Travel Behavior by Sex and Ethnicity," what are their four findings on travel mode?
- Women hold driver's licenses at nearly the same rate
- Ethnicity and income predict licensing, auto availability, and mode choice better than gender
- Men are more likely to drive alone and women are more likely to carpool and ride transit
- Women make more daily trips on average
In Black's "The People Who Ride Transit," what are the two types of modal split models?
- Trip end models
- Trip interchange models allocate trips according to attractiveness of transit versus automobile
In Johnston's "The Urban Transportation Planning Process," what is the typical margin of error for travel forecasts?
1% margin of error for each year.
What variables does Johnston find influence mode choice in "The Urban Transportation Planning Process?"
Trip costs, household income, household car ownership, and car accessibility.
In "The Urban Transportation Planning Process," what improvements to future models does Johnston mention?
- Including land use
- Incorporating alternative (non-motorized) transportation
- Using micro-simulation of goods movement
- Using disaggregate models
What share of U.S. households own at least one car?
91.7% in 2001. (Source?)
In Pucher and Renne's "Socioeconomics of Urban Travel: Evidence from the 2001 NHTS," what are the common reasons for walking and biking?
Social and recreational trips (and much less common for work and shopping).
What effect does income have on travel, according to Pucher and Renne's "Socioeconomics of Urban Travel: Evidence from the 2001 NHTS?"
- Higher-income workers make more frequent and longer trips.
- Low-income workers have lower mobility because of lower employment rates and their location in congested central cities.
According to Pisarski's "Commuting in the Nineties," what is happening to the peak travel periods?
The peaks are spreading because people are traveling earlier and later around those times.
How many motor vehicles are there for each licensed driver?
1.1 in 2001 -- the highest in the world. (Pucher and Renne, "Socioeconomics of Urban Travel: Evidence from the 2001 NHTS?")
According to Pucher and Renne's "Socioeconomics of Urban Travel: Evidence from the 2001 NHTS," what is the main determinant of auto ownership?
In Pucher and Renne's "Socioeconomics of Urban Travel: Evidence from the 2001 NHTS," how does income affect transit mode?
- The poor are eight times more likely to use buses.
- The affluent are three times more likely to use rail.
- Subway use is consistent across incomes.
- Walking declines with income.
On what mode of travel do the elderly depend, according to Pucher and Renne's "Socioeconomics of Urban Travel: Evidence from the 2001 NHTS?"
Automobile. (They also make over half of their automobile trips as drivers.)
What four reasons do Blumenberg and Waller identify for the geographical isolation of the poor in "The Long Journey to Work: A Federal Transportation Policy for Working Families?"
- Years of urban disinvestment
- Lack of affordable housing
- Residential segregation
- Lack of transportation options
What four challenges do Blumenberg and Waller identify for working families in "The Long Journey to Work: A Federal Transportation Policy for Working Families?"
- The spatial mismatch between suburban jobs and families living in the central city
- Fixed-route public transit is poorly suited to dispersed travel patterns
- The families tend to own older and less reliable cars
- Transit is burdensome due to time costs and lack of suitability to trip chaining
According to Blumenberg and Waller in "The Long Journey to Work: A Federal Transportation Policy for Working Families?", what three strategies will link low-income workers with jobs?
- Urban reinvestment
- Increasing housing mobility to let workers move closer to jobs
- Improving transportation mobility strategies
According to Pisarski's "Commuting in the Nineties," what share of transit trips to work are made in New York City?
What three elements of modal distribution does Sheppard identify in "Modeling and Predicting Aggregate Flows?"
- Number of trips generated by a place
- Attractiveness of a place (dependent on type of trip)
- Inhibiting factors from distance
What are the three types of parking studies in Papacostas and Prevedouros' "Traffic Impact and Parking Studies?"
- Comprehensive
- Limited
- Site-specific
Name the three types of trip distribution models in Sheppard's "Modeling and Predicting Aggregate Flows."
- Gravity
- Intervening opportunities
- Entropy
According to Doyle and Taylor's "Variation in Metropolitan Travel Behavior by Sex and Ethnicity," where are single mothers most likely to live?
In the central city (where trips are shorter).
What are the three ways to collect data for parking studies in Papacostas and Prevedouros' "Traffic Impact and Parking Studies?"
- Ins and outs (count all vehicles in the beginning, then count entering and exiting vehicles)
- Fixed period (count all vehicles in an area and repeat the count every 15-60 minutes)
- License plate surveys (get the license plate number for vehicles in every stall every 30 minutes)
What percentage of adults have drivers' licenses?
86% (89% men and 84% women).
According to Pisarski's "Commuting int he Nineties," how do transit times compare with driving alone?
The average transit travel time roughly doubles that of driving alone, with commuter rail having the longest travel times.
What does Downs describe as the most powerful predictor of transit use in _Still Stuck in Traffic_?
Area density.
How do Meyer and Miller define spot speed data in _Urban Transportation Planning_?
The amount of time is takes for a group of cars to travel a measured distance.
What percentage of people drive alone to work according to Pisarski's "Commuting in the Nineties?"
- 80% for metropolitan areas over 5 million
- 90% for metropolitan areas under 5 million

(Note that New York City, as always, skews the data.)
What does Downs say in _Still Stuck in Traffic_ about how transit can contribute to congestion?
- Buses (on which people make 60% of their transit trips) get stuck in traffic
- Buses impede traffic because of frequent stops and their size
Why does Downs say in _Still Stuck in Traffic_ that reducing traffic congestion is not a valid reason for expanding transit capacity?
Induced demand: increased transit capacity lowers congestion in the short run, but less congested freeways draws other drivers
What is the incremental assignment approach in Sheppard's "Modeling and Predicting Aggregate Flows?"
It allocates a limited number of trips at a time along the cheapest available route and updates data after each allocation so that the cheapest route available changes to reflect congestion.
What is triple convergence (found in Downs' _Still Stuck in Traffic_)?
People shifting from different times, different routes, and different modes of transportation to take advantage of expanded roadway capacity.
What barriers prevent agencies from adopting advanced modeling practices?
- Lack of evidence that the new practices would yield notably better forecasts
- Unavailability of software
- Resource and staff limitations
- Belief that current models do an adequate job

(Transportation Research Board, "Metropolitan Travel Forecasting")
According to Cervero's "Are Induced Travel Studies Inducing Bad Investments?", what are two methodological problems with induced-demand studies?
- Causality (does expanded road capacity cause higher traffic or vice versa?)
- Attribution (have studies specified events that have taken place between expanded road capacity and rising traffic?)
What are some issues that Johnston identifies with transportation modeling in "The Urban Transportation Planning Process?"
- Problem identification
- Formulation of objectives
- Data collection
- Generation of alternatives
- Definition of evaluation
- Alternatives are usually analyzed in terms of differences from the preferred plan
- Rarely considers equity or economic welfare
- Garbage in, garbage out
According to the TRB "Metropolitan Travel Forecasting" report, what four improvements have agencies have made to four-step trip-based models?
- Improved measures of arterial congestion
- Inclusion of highway and transit travel in trip distribution
- Improved modeling of non-motorized travel
- Improved sensitivity testing and testing of reasonableness of models based on what they currently observe
In Sheppard's "Modeling and Predicting Aggregate Flows," what are the two most important factors in determining modal split?
Differences in travel times and differences in costs.
What are the four different types of sampling in Meyer and Miller's "Data Management and Use in Decision Making?"
- Simple random sampling
- Sequential sampling
- Stratified random sample
- Cluster (area) random sampling
What are the three basic tasks of transportation planning according to Sheppard's "Modeling and Predicting Aggregate Flows?"
- Describing trips
- Discovering how traffic flows are related to geography
- Determine inequities associated
What are some modeling innovations Koppelman describes in "Innovations in Traffic Modeling?"
- Account for interactions among household members concerning travel purposes, modes, and destinations
- Account for temporal effects such as peak-period traffic
- Can provide better understanding of the complexity of human travel behavior
- Can take changes in land use into account
How do intervening opportunity models differ from gravity models?
- The in situ characteristics of a destination are simply measured as the number of opportunities available there.
- Distance is measured differently.

What is Wardrop’s first principle of network equilibrium (mentioned in Sheppard's "Modeling and Predicting Aggregate Flows")?
The perceived costs of travel between each origin and each destination are the same no matter which route travelers use. Travelers have no unused, cheaper alternative available.

("The journey times on all routes actually used are equal and less than those which would be experienced by a single vehicle on any unused route.")
Since 1950, what percent of the labor force growth is due to women joining the labor force?
50%. (Pisarski, "Commuting in the Nineties")
What percentage of the U.S. labor force is foreign-born?
16% for men and 12% for women. (Source?)
According to Lave's "Love, Lies, and Transportation in LA," how do the average commutes for Los Angeles and New York compare?
Los Angeles commutes are 29 minutes long, and New York's are 34 minutes long (on average).
According to Downs in _Still Stuck in Traffic_, has expanding capacity reduced traffic congestion in the past?
No -- the TTI reports high travel times for cities with a high percentage of transit riders.
What does Down suggest to encourage greater use of current public transit in _Still Stuck in Traffic_?
- Increasing density
- Increasing the cost of owning and operating private vehicles
When in the day do most recreation trips take place?
7-11 PM. (Barber, "Aggregate Characteristics of Urban Travel")
According to Barber's "Aggregate Characteristics of Urban Travel," what issue does peaking play in congestion and capacity?
- If existing capacity can only handle the average traffic, there will be tremendous delays at peak hours
- If enough capacity is provided for peak periods, there will be excess capacity for most of the day, leading to increased demand and eventually congestion.
What examples of TDM (transportation demand management) does Barber provide in "Aggregate Characteristics of Urban Travel?"
- Staggering work hours
- Ridesharing
- One-way streets
- Enforcing parking violations
- User parking costs
Who is most likely to use transit at off-peak hours?
Low-income people.

(Barber, "Aggregate Characteristics of Urban Travel.")
What percentage of travel takes place on transit, according to Barber's "Aggregate Characteristics of Urban Travel?"
Less than 10%.
According to Barber's "Aggregate Characteristics of Urban Travel," what percentage of trips are by automobile?
About 75%.
At what time during the day do traffic peaks take place?
7-9 AM and 4-6 PM (Barber, "Aggregate Characteristics of Urban Travel")
In "Describing Disaggregate Flows," what reasons do Hanson and Schwab offer for using disaggregate data?
- Constructing theories
- Analyzing policies and their effects
What variables have the greatest effect on individual travel in Hanson and Schwab's "Describing Disaggregate Flows?"
- Gender and employment status that describe individual roles within the household

(These have a greater effect than social status variables like income and occupation.)
According to Pisarski's "Commuting in the Nineties," what explained the unexpected population growth in 2000?
Immigration (concentrated in the 25-45 age group).
What share of workers will be 65 or older in 2020 and 2030, according to Pisarski's "Commuting in the Nineties?"
16% in 2020 and 20% in 2030. (The percentage is 13% in 2000.)
What percentage of trips are working, shopping, and social?
10-15% each. (Barber, "Aggregate Characteristics of Urban Travel")
What is the most important travel destination according to Barber's "Aggregate Characteristics of Urban Travel"?
The home, with 40% of trips.
Five characteristics of urban travel… (Barber)
1) Trip purpose, 2) Temporal distribution, 3) Modal split, 4) Distribution trip lengths, 5) Spatial pattern of trip making
What share of immigrants live in central cities?
Around 30% live in central cities; over time, they move to suburbs. (Handy, "Key Findings on Immigrant Travel")
Who has the longest commute time? (Doyle, Taylor)
Married fathers (longer commute by choice), urban single mothers (transit-dependent, spatial mismatch)
How is trip utility measured? (Barber)
Trip’s desirability à depends on activity, purpose, traveler, time, cost and distance
Changing household roles (Rosenbloom)
Women more likely to make stops on way home from work; women still do majority of housework; since 1980s, men participate in more traditionally female chores; 71% of married women + 82% of single mothers with children under 18 are employed full-time
Do single fathers and mothers have similar travel patterns? (Rosenbloom)
NO. Single fathers and mothers have different family sizes; more men are full-time; men earn more; different activity, travel decisions; even w/ lower incomes, female single parents make more trips and are more constrained by children’s needs
What share of trips are for shopping, personal, and HH-serving purposes? (Doyle and Taylor)
50% trips for men; 70% trips for women… leads to more trip-chaining among women
Why is transit so insignificant in U.S.?
Most Americans live in low density areas (need 7 units/acre of 4200+/sq. mile to support most transit); traveling in POVs offers advantages
According to Handy's "Key Findings on Immigrant Travel," what fraction of transit riders in Los Angeles are immigrants?
Two thirds.
What immigrant groups carpool the most/least?
Most: Mexicans, 29%; least: Iranians = 11%
What share of daily local travel in 2001 was by car?
86%. (Pucher and Renne, "Socioeconomics of Urban Travel")
What are weaknesses with primary methodology for analyzing aggregate flows and forecasting (Mitchelson)
1) Goals are unstated or not specific enough—better goals would be “goo” level of accessibility, energy conservation, service to elderly, etc. 2) Gravity model’s impedance factors for trip duration are based on car travel; 3) Impedance mechanism based on fixed trip duration à factors are descriptive instead of causal
What do all MPOs require as input to travel forecasting process?
Population, households, and employment. (TRB, "Metropolitan Travel Forecasting.")
How many trip purposes used in large MPOs?
9 purposes in large MPOs, fewer in smaller
Interest in time/cost/distance of urban trips and twofold
1) Data on time/cost used to forecast travel, 2) principal motivation behind new investments is savings in travel times
What federal requirements mandate regional transportation planning?
Clear Air Act of 1970s: required states to adopt State Implementation Plans (STP)

1977 amendment to Clean Air Act: required all regional transportation plans to show attainment of emissions reductions in STP through modeling of travel and vehicle emissions

Clear Air Act of 1990: tied funding to actual attainment

Surface Transportation Act 1991: reinforced Clean Air Act, emphasized multi-modal planning, public participation, interagency consultation
What is transportation asset management?
Decision-making process for making cost-effective decisions for managing assets; inventory data, attribute data, performance prediction models, alternative selection models, priority assessment methods, validation procedures
Why do women have shorter commutes?
1) Lower skill jobs w/ lower wages; 2) Constraints due to HH responsibilities; 3) women’s jobs more spatially ubiquitous; 4) employers who need women locate near them; 5) spatial mismatch: minority women commute just as long as men; 6) mode differences
What is most effective method of serving disadvantaged populations?
Invest in improving safety, convenience, feasibility of walking in cities, poor concentrated in inner cities; transit trips necessitate walking
What share of CA’s population is composed of immigrants?
About 25%
What are the most important service characteristics (Barber)?
Average speed of mode and ability to offer accessibility throughout city
Which immigrants use car more than natives?
Korean, Vietnamese, Iranian, and Taiwanese
What percentage of Americans live in HH with at least one other worker?
About 70%; foreign-born constitute about 5% of workers living in HH with 3+ workers
5 Gender trends?
1) Women make more trips but fewer miles; 2) Women less likely to be licensed; 3) More likely to make trip for purpose of serving passenger; 4) More likely to link or chain trips together; 5) Less likely to have car crashes, but more likely to be injured
What are personal vehicle use rates in cities vs. suburbs?
81% vs. 91% largely attributable to transit
Which groups retain higher rates of transit?
Hispanics; although assimilate into auto use quickly b/c of demands of employment
What are Rosenbloom's three major findings on gender and travel behavior in "Understanding Women's and Men’s Travel Patterns: The Research Challenge"?
- Although men and women's behavior is converging, they are still far from equal and trends toward convergence are slowing
- Disaggregate data suggest that, when other variables are controlled, major differences appear
- Most underlying variables (household role, income) are closely linked to gender
What states had more than 10% of workers commuting over an hour?
NY, NJ, MD, IL, almost CA
What is the state of commercial and freight models?
NEEDS IMPROVEMENT; lack data within beyond metro area; only modeled by ½ small MPS; 80% of large MPOS model some trips
What are some suggestions for travel forecasting improvement?
- Less k factors
- Address freight and commercial travel
- More validation including historic data and backcasting - More sensitivity assumptions independent of model
What are some weaknesses of current transportation modeling practice?
- Weakness of models
- Errors introduced by modeling practice
- Lack of or questionable reliability of data
- Biases arising from institutional climate in which models are used
What percentage of women are in the labor force?
(2002) 62% of women 16 or older
(2002) 75% of women 25-34
(2001) 70% of women 45-54
What are some weaknesses of the four-step model process?
- Inability to represent individual decisions
- Effects of value of time and reliability
- Continuous time of day variations in travel
- Goods movement
- Other issues: pricing, time policies, hourly speeds, improvements in traffic operations, non-motorized travel, peak spreading
What about older women?
1) Older women self-regulate more; 2) older women (65+) constitute 80% of all elderly who live alone, don’t have driver’s license, exist below poverty, have no access to HH driver; 65+ take at least 88% trips in private auto; Most of these HH in low-density by suburbs or rural where transit not available
What is systematic optimism bias?
Overestimating performance (transit, full roads)
What is the ecological fallacy in disaggregate flows?
Assuming that relationships that exist at the aggregate level exist at the disaggregate level
According to "The People who use transit," what is the order of
"peaked modes?"
burban RR (78% of trips taken in peak period), Subway/elevated (67%), and bus (56%)
How does occupation affect transit use?
White collar workers more likely to use transit b/c clerical & sales jobs tend to be concentrated in central cities while blue collar jobs are located in suburbs (plus factory jobs unionized, which leads to higher incomes & car ownership)
Is the gender gap more pronounced in commute distance or time?
Distance (20% vs. 11%)
What percentage of workers work a “normal” working schedule (33-40 hrs/week)?
What is the geographical distribution of urban population growth?
50% of pop growth in suburbs, 30% in central city, and 20% in nonmetro areas
Put the following in order in terms of growth (1969-2001) from low to high: drivers, households, vehicles, population, workers
Population, households, drivers, workers, vehicles