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87 Cards in this Set
- Front
- Back
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What are four city characteristics that influence travel flows (Barber)?
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Size of the city
Principle functions of the city Geographical setting Transportation era during which most development occurred |
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What are the benefits of disaggregate analysis (Hanson)
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Can come up with theories to explain real travel
Can develop theories based on sub-groups Can aggregate to whatever groups you want |
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What is disaggregate analysis used most often for (Hanson)
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Corridor studies, localized studies
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What effect did immigration have on commuting in the 90s (pisarski)?
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Increase in working-age immigrant population increased commute patterns.
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At what income do households purchase cars?
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$25,000 for one car, $35,000 for second car
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What are some of Handy's key findings on immigrant travel behavior?
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Most immigrants travel by car, but higher proportion use transit than natives
Iran, Korea, Vietnam, Taiwan have highest auto use 22% of immigrants carpool vs 12% of natives Immigrants tend to move to suburbs as they assimilate Carpooling is highest in areas with poor transit |
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What are some of Crane's key findings on gender and travel behavior?
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Gender gap in commuting is not closing
Influences on female travel behavior include: household/child rearing responsibilities, race, income, occupation/labor market issues Gender gap is more pronounced for commute distance than commute time Women's commute time is lengthening faster than men's Gender most significant variable in predicting trip length and distance |
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How much have commute distances increased in the last 25 years? (Crane)
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25%
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Which modes of transportation are the "peakiest"?
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suburban rail, 80% in peak, subway 70% of trips in peak, bus most evenly disbursed (55% peak).
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What are some seasonal transit variations?
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Highest in winter, lowest in summer
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What are some aggregate spatial characteristics of travel?
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Travel varies significantly by urban form, and is closely linked to land use
•Transit tripmaking tends to be most dense around the city center, with morning trips headed in, and afternoon trips out •Automobile use is more evenly spread throughout urban areas |
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How have central/suburban commute patterns changed over time?
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Originally central city to central city was highest, now suburb to suburb is highest
central city to central city second highest Suburb to suburb has highest growth, central city to central city lowest growth |
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How does temporal distribution of travel vary?
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Day of week, season, time of day
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How has work trip purpose changed over time?
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Decreased as a percentage of travel
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What are some aggregate characteristics of trip length?
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Varies widely by trip purpose, city size, and travel mode
•Large cities host longer trips, small cities shorter •Work trips tend to be a bit longer than most others (vacations and certain types of goods movements are the longest), while shopping and school trips tend to be shorter •Transit trips tend to be shorter than auto trips, though longer in duration |
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What size cities have longest and shortest commutes?
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Overall, small cities have shorter commutes and big cities have longer ones. However, Pisarski's data shows
Small cities have higher percentage with long commutes, lower with short, opposite true for large cities |
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What are some aggregate characteristics of mode split?
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Patterns vary by size and spatial structure of cities, available modes, and local public policies
•Travel in U.S. cities is dominated by the private automobile •Transit use is strongly related to city size •Walking comprises a surprisingly large share of travel, but is often overlooked by planners |
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What variable tracks vehicle travel best?
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Vehicle travel tracks changes in income better than any other measure
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How are vehicles, drivers, workers, population and number of households changing over time?
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Vehicles: highest growth, highest trend
Drivers and workers:second highest growth, about same for each, workers growth more in recent years population: lowest of all, lower growth Households: was the same as workets, then slowed |
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How do the length (distance) of bus, rail, and subway trips compare?
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Bus is shortest, then subway, then rail
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What are some characteristics of transit riders that Black identifies?
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Less likely to own a car
55% women Minorities more likely to ride transit Lower income |
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Which is more valuable to transit riders, out of vehicle or in vehicle time?
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Out of vehicle
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What are the two types of transit models Black identifies?
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trip end model: happens earlier in model process, destination depends on mode you choose, can account for improvements to transit system, uses variables that describe traveler characteristics
Trip interchange model:allocate trips according to attractiveness of transit vs auto for each trip, doesn't assume always choose mode with least friction, no focus on socioeconomic characteristics of traveler (best choice:use both) |
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Identify some travel trends
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VMT is growing faster than population (tracks with income)
population growth has evened out HH size down, but flattening Female labor force participation up, but flattening drivers licensing rates up (not for younger people though), esp for females Percent of HH with no car down Daily trips for personal/fam business up most, social up second most Trip length and time up carpooling down vehicle occupancy down transit mode share down internet up income up cost of driving down |
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Who has shorter commutes, married or unmarried women?
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Married
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What did crane find to be the most significant predictor of trip length?
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Gender
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What did Rosenblom find about the mobility needs of older americans?
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Transit isn't working for them. May not continue to self-regulate. Seniors are going to be more dependent on the car (because more of them have driven, lived in suburbs)
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What factors did Doyle and Taylor find that influence number of trips taken?
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Having a license, Employment,kids
Ethnicity more important than gender |
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What is an important Doyle/Taylor finding about race and gender?
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Race more significant influence on work trips than gender, gender more significant on non-work trips
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What are some reasons women have shorter commutes?
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1. Lower-skill jobs with lower wages – people are not willing to commute long distances
2. Women have constraints due to household responsibilities a. Need to save time b. But also it is possible they would have longer commutes since housing choice is constrained. This may explain women of color with children, whose commutes tend to be longer, though transit use is a major factor) 3. Women’s jobs are more spatially ubiquitous (e.g. retail, not finance jobs downtown) 4. employers who need women locate near them 5. Spatial mismatch 6. mode differences |
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Which commute times are longer, urban or suburban?
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Urban
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What is the effect of having children on women's and men's commute times in the suburbs
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Shorten's womens commutes, lengthens men's
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Which groups did Doyle/Taylor find to have the longest commute times?
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Married fathers, single mothers
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Which did taylor/doyle find is better at predicting licensing and auto availability
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ethnicity better than gender
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What did pisarkski find about carpooling vs driving alone?
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Carpooling down to 12%, driving alone increasing
Carpooling (for commutes) starts earlier than other commute trips |
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What happens to peaks as travel times increase?
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They spread
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Which are higher, central city or suburban travel times?
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Suburban, except for biggest cities
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When do alternative modes (walking and transit) play biggest role?
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8am-12pm
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What did blumenburg identify as some strategies to help poor with work transportation?
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increase proximity of jobs to low income people, move people to jobs, improve overall mobility, transportation major barrier to good jobs.
Enhancing fixed route transit in dense urban areas, add demand responsive service, brokering resources like churches, nonprofits to help with this, taxi subsidization, have programs that give low-income people access to cars (important because most travel not for work) |
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What did blumenburg find about transportation spending in lowest quintile?
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Expenditure data from the Bureau of Labor Statistics shows that the households in the lowest-income quintile actually spend slightly less than all other households on transportation. Specifically, transportation comprises 17 percent of expenditures in the lowest-income quintile, compared to 18-21 percent of expenditures for other income groups.
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Did Handy find that immigrants have become more or less reliant on transit over time?
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Less (8% in 2000)
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What did Handy identify as some disadvantages to transit?
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1. the transit fare costs of traveling with children
2. difficulty traveling with packages 3. lack of safe and comfortable shelters 4. lack of safety on buses 5. long waits 6. and limited schedules and routes 7. Unreliability and limited service hours are of particular concern for immigrants using transit to get to work 8. Women in particular are concerned with safety at stations, treatment by bus drivers and passengers, and inability to communicate in English. |
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What did Handy identify as some barriers to car ownership for immigrants?
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costs of buying and maintaining a car, inability to get a driver’s license, risk of vehicle confiscation, inability to get insurance, and having no way to learn how to drive.
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What did Handy identify as ways to improve transit for immigrants?
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d. In areas with concentrations of newly arrived immigrants, increase number of routes, destinations served, frequency of service, and reliability of arrival times; and improve coordination of transfers between routes;
e. Provide ride-home shuttle services at grocery stores and round-trip rides to healthcare facilities; and Extend hours of service earlier and later to accommodate work schedules, b. Increase frequency of service during commute hours specific to immigrant communities and reliability of arrival times, and i. Require cultural sensitivity training and basic language skills for bus drivers;q. Identify residential and workplace clusters of immigrant communities and increase transit linkages, |
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What is Downs' "triple convergence"?
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With increased road capacity, mode split changes, routes change, travel times change
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What is induced demand?
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see fast flowing traffic, move to new route, but also employment growth, new development
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What percent of transit trips are bus trips according to Downs?
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60%
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What does Downs identify as some changes that might encourage transit use?
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increase density, change nature of transit to work in low density environments (challenge from transit unions not wanting things like jitneys), increase cost of car (easier).
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What does Cevero identify as two problems with induced travel studies?
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Causality (did new capacity cause congestion, or was it lurking there before?) and attribution (sometimes fail to mention new development that happens as capacity decreases
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What did Cevero find happened to new capacity in 6-8 years?
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20% of capacity preserved, 40% used by external factors (new development), 30% induced demand (behavioral shifts—triple convergence), 10% induced demand through land-use shifts.
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What did shoup identify as some problems with ITE trip gen and parking data?
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data, self-fulfilling prophecy, maximum becomes the minimum, low R2.
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What are the six circular steps Shoup identifies as problematic with ITE parking/trip gen?
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count parking and publish misleading data, planners use data to set minimums, developers build parking, transpo engineers survey sites for trip gen, planners look at transpo system, density limited, increases travel.
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What does Johnston identify as the pre-analysis steps of travel modeling?
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• Consists of problem identification, formulation of objectives, data collection, generation of alternatives, and definition of evaluation.
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What does Johnston identify as post-analysis?
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looking at implementing different models to account for income classification, environmental measures such as non-point run off and habitat damage
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What does Johnston identify as some future improvements to modeling?
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including land use, alternative non-motorized transportation options, micro-simulation of goods movement, using a disaggregate tour based model that takes into account joint mode destination, household activity based on GIS parcel information for relationships between space and time.
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What do Meyer and Miller identify as the three major components of the transportation planning database?
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data collected on the transportation system itself (inventory), data associated with developing a community vision and goal (attitudes, trends), monitoring of system performance (feedback).
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What do Meyer and Miller identify as the three classification schemes for data collection?
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TAZs (homogeneous socioeconomic characteristics, minimize intrazonal trips, roughly equivalent to each other), corridors/subareas (fine level of detail, focused), functional classification (eg arterial roads, high ridership transit lines).
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What are four sampling methods in data collection?
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Four sampling procedures include simple random sampling (each unit has an equal chance of being selected), sequential sampling (every nth unit is selected), stratified random sampling (random samples taken within each stratum), cluster sampling (units grouped into clusters, random clusters selected).
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What are the major types of transportation counts?
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• Continuous counts (taken 365 days/year)
• Control/seasonal counts (taken during short periods to estimate AADT) • Coverage counts (6-8 hrs at specific locations) • Cordon counts (estimate total movements within a study area) • Screenline counts (count volumes that cross imaginary lines/boundaries in transpo network) • Vehicle classification (type of vehicles in traffic at a specific location) • Truck weight data (generally collected at weigh-in-motion sites) • Spot-speed data or moving vehicle method (estimates travel speeds at specific location) • Parking counts |
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What are some transit data collection techniques?
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• Ride check (recording passengers on-off at stop and arrival times)
• Point check (estimating passengers and recording arrival times) • Boarding count • Fare box reading • Revenue count • Transfer count |
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What are some key elements of asset management?
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• Inventory data (permanent aspects)
• Attribute data (mutable aspects) • Performance prediction models (predict future asset conditions) • Alternative selection methods (select improvements by identifying deficiencies) • Priority assessment methods (prioritize projects in context of budget) • Validation procedures (fine-tune decision support system) |
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What are some methods of collecting user characteristic passenger data?
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• Households surveys-most expensive, provide the most detail. Three basic techniques to collect data include personal home interview, telephone interview, and mail-back survey.
• Workplace or special trip generator sites, visitor or tourist centers surveys -similar to household surveys, used to obtain info from employees at their places of employment and from shoppers and users of recreational facilities. • Vehicle intercept and external station surveys-obtain data on pattern of movements of persons and goods in a study area. Roadside handout or postcard survey, license-plate survey, DMV data to send out survey • Panel surveys-longitudinal surveys of same group over time • Stated Preference surveys-Ask questions about how people might respond to transpo programs/changes • transit onboard surveys—used to collect data on transit riders, trip characteristics, and route performance from the customer perspective |
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What are some ways of collecting goods movement user characteristic data?
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• Congestion management info (truck hours of travel, truck speed, added congestion cost, etc)
• Intermodal access (truck volumes on/off facility, accident rates on access roads, etc) • Truck route designation and maintenance • Safety mitigation (steep grades, low-clearance bridges, accident rates) • Economic development (commodity movements, shipping costs) |
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What do Meyer and Miller say ranks high/low according to market research on transit?
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Travel time, reliability, personal comfort, and convenience have consistently ranked high. Out of pocket costs usually ranked low.
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What elements make up the community planning process according to Meyer and Miller?
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• Values (basic social drives that govern human behavior)
• Goals (generalized statements that broadly relate to the physical environment to values) • Objectives (specific and measurable statements that relate to the attainment of goals) • Measures of effectiveness (tests that reflect the degree of attainment of particular objectives) • Standards (minimum acceptable level for the criterion measure) |
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What does Shepard call the three main tasks of transportation planning?
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• Describe trips based on number of trips of each type, places where trips start and end, and route followed by each trip.
• Discover how traffic flows are related to the internal geographical structure of a city. • Determine inequities associated with any pattern of transportation. |
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What does Shepard identify as the four main types of trips?
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• Home-based work
• Home-based nonwork • Non-home-based • Goods movement |
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What is Welfare economics?
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Welfare economics is based on two concepts:
• A welfare-maximizing pattern of provision maximizes the sum of consumer and producer surplus • A welfare maximizing pattern of provision will be Pareto optimal. Not always good for transpo decisions |
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What does Shepard identfy as explanatory variables for trip generation?
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a. number of people in a zone
i. land uses, residents b. characteristics that make people travel i. auto ownership ii. family size iii. income c. Accessibility of destinations == better access = more trips |
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What does Shepard identify as two methods for determining trip generation?
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Linear regression, categorical analysis
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What are three basic elements that each trip distribution model includes?
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number of trips generated by a place (determined in trip generation step), the degree to which the in situ attributes of a particular destination attract trip makers (“site characteristic” varies by type of trip, eg home-based work is attracted by employment more than other factors), the inhibiting effect of distance (“situation” characteristics).
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Describe a gravity model
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In gravity models the number of trips made between an origin and a destination is positively related to the number of trips leaving the origin and to the “pull” of the attributes of a destination, but is inversely related to the distance between the origin and the destination.
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What are two ways the intervening opportunity model differs from the gravity model?
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First, the in situ characteristics of a destination are measured simply as the number of opportunities available there. Second, the effect of distance between places on number of trips s measured differently than in gravity models.
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What does Shepard say the critical factor in IO model is?
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In intervening opportunity models, the critical factor with regard to distance is not the amount of distance between two zones itself, but rather the number of other opportunities closer to an origin than any particular destination being considered by a traveler.
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Describe an entropy model
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Entropy models estimate trip distribution based on unconstrained choices—just as we would estimated that the probability of a coin coming up “heads” in a single toss would be 50%. It assumes trip distribution patterns are as evenly scattered as possible given any information we have on trip patterns.
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What are two methods of trip assignment that Shepard identifies?
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Incremental: allocate trips according to cheapest route available at each time, update each time to reflect congestion (as route becomes more congested, people take different route). Iterations. Most use this. Multi-path: some people don’t know what cheapest route is, so split up routes. More effective but more time consuming.
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What is McFadden's discrete choice model?
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Set of choices, try to predict what choice they will make among them given a set of data about the individual. Shift analysis from zone to person.
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What changes to modeling process do Michelson and Wheeler recommend based on the Atlanta case?
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better goal definitions, better link between forecasting methods and policy sensitivity.
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What are some common and differing practices in how MPOs do modeling according to TRB report?
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• Common practice: Forecasts of population, households, and employment are required as input to the travel forecasting process.
• Differing practice: About half of MPOs also forecast one or more of the following: household size, automobile ownership, and income. • Common practice: The modeled region is divided into TAZs. The zone system is mapped in a GIS database. • Differing practice: The number of TAZs in a region varies from several hundred to several thousand, depending on the region’s size. between each pair of zones—is accomplished primarily with a gravity model. • Differing practice: Destination-choice models are used by 11 MPOs for trip distribution. Such a model can take into account differences in circumstances that influence travelers’ destination choices, which are poorly accounted for in a gravity model. • Common practice: Mode choice is the allocation of trips between automobiles and public transit. Within automobile travel, there is allocation between drivers and passengers; within public transit, there may be allocation among local bus, express bus, and various rail options. • Differing practice: Some MPOs include bicycle and walking trips in their mode-choice model. More than 90 percent of large MPOs reported using a mode-choice model, while 25 percent of small MPOs reported using such a model. • Common practice: Assignment is used to allocate trips to actual routes in the transportation network. • Differing practice: Many smaller MPO regions have little traffic congestion and minimal transit service, and MPOs may assign average daily (24-hour) travel. |
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What areas of improvement does TRB identify for modeling?
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Extensive use of K-factors is not recommended because they interfere with a model’s ability to predict future travel.
• Most travel forecasting models are in need of substantial improvement to address commercial and freight travel Better ValidationValidation is often hampered by a lack of independent data sources, and many MPOs validate against much of the same data used to develop the models. • Sensitivity testing checks the reasonableness of travel forecasts. Such testing is currently done by only a small number of agencies. • The most commonly cited improvement was a tour- or activity-based model. About |
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What does Koppelmann identify of some advantages of new modeling techniques?
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New models can account for interactions among household members concerning travel purposes, modes, and destinations, as well as temporal effects such as peak-period traffic, and can provide better understanding of the complexity of human travel behavior. They can also take changes in land use into account.
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What does Koppelmann say still needs to be done to improve modeling in the future?
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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 a non-technical audience |
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What are four improvements in the four-step modeling process that TRB identifies?
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Improved measures of arterial congestion
Improved sensitivity testing Modeling alternative modes Inclusion of transit and autos in trip distribution |
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What are some advanced modeling techniques TRB identifies?
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Improved land use modeling
Activity-based modeling Tour based models Discrete choice modeling Supply side models |
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What is an activity based model?
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these models emphasize participation in activities and focus on sequences or patterns of activity. The differences between activity-based models and the current four-step approach include a consistent and continuous representation of time, a detailed representation of persons and households, time-dependent routing, and microsimulation of person travel and traffic. Require detailed info about population.
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What does TRB identify as four obstacles to model improvement?
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No money
No staff institutions don't want change no software technical issues |
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What does TRB say are some opportunities for MPOs to improve modeling?
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Jointly fund research
Create best-practices handbook |
