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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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Page 4
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
×
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Suggested Citation:"Chapter 1 - Summary." National Academies of Sciences, Engineering, and Medicine. 2012. Improving ADA Paratransit Demand Estimation: Regional Modeling. Washington, DC: The National Academies Press. doi: 10.17226/22720.
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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.

1 C h a p t e r 1 The Americans with Disabilities Act of 1990 (ADA) created a requirement for ADA- complementary paratransit service for all public transit agencies that provide fixed-route transit service. ADA-complementary paratransit service is intended to complement the fixed- route service and serve individuals who, because of their disabilities, cannot use the fixed- route transit system. In fulfilling their ADA obligations, transit operators have a responsibility to consider current and probable future demand for ADA-complementary paratransit service and to plan and budget to meet all of the expected demand. The models described in this report are intended to improve the ability of metropolitan planning organizations (MPOs) and transit operators to estimate the probable future demand for ADA-complementary paratransit service. At the same time, the models predict travel by ADA-paratransit-eligible individuals on all modes, not just ADA paratransit. Previous Work—Phase I The research project on which this report is based is the second phase of a project that already produced an earlier set of demand estimation tools, described in TCRP Report 119: Improving ADA Paratransit Demand Estimation. The tools described in TCRP Report 119 estimate total ADA paratransit demand for entire transit service areas based on six variables: 1. ADA paratransit service area population 2. Base fare for ADA paratransit 3. Percent of applicants for ADA paratransit eligibility found conditionally eligible 4. Whether or not trip-by-trip eligibility determination based on conditions of eligibility is used 5. Percent of service area population with household incomes below the poverty line 6. The effective window used to determine on-time performance (i.e., the window from the passenger’s point of view, including requirements to be ready early and adjustments made in the scheduling process that may not be communicated to passengers) The TCRP Report 119 tools were based on statistical analysis of demand at 28 transit sys- tems believed to offer high-quality ADA paratransit service complying with ADA require- ments, although the Report 119 tools might not necessarily meet the expectations of all users. To apply the TCRP Report 119 tools, a planner needed only six data items, which could be entered into a ready-made spreadsheet that produced total expected ADA paratransit demand for a service area. Summary

2 Improving aDa paratransit Demand estimation: regional Modeling Phase II Research Compared to the TCRP Report 119 tools, the models developed in this research are intended to permit more detailed forecasts and to deepen understanding of the travel behavior of ADA paratransit-eligible people. Two models were produced: • A sketch planning model, which allows a planner to enter a small number of variables by means of a spreadsheet interface and explore how these variables affect predicted trip-making on ADA paratransit and other modes in the Dallas-Fort Worth area. Although these forecasts are limited to the Dallas-Fort Worth area where data was collected to estimate the models, they allow exploration of hypothetical changes in age profile, income, household size, travel times, on-time performance, and fares within the Dallas-Fort Worth area. The sketch plan- ning model is limited to predictions of travel by people already registered as eligible to use ADA paratransit. • A regional planning model (actually a system of multiple models) that can be adapted to provide forecasts tailored to conditions in other metropolitan areas. This model system also includes the effects of changes in demographic and travel variables on registration (applica- tion and determination of eligibility) to use ADA paratransit. Used in conjunction with an existing regional travel demand model, the new model system produces forecasts of travel by ADA paratransit-eligible people, with detail about numbers of trips by mode (ADA paratransit, other specialized service, car passenger, car driver, scheduled transit, and walk/wheelchair), by trip purpose, and by destination. To apply the regional planning model system to another area, planners will need census- tract-level socioeconomic data, employment data by census tract or travel analysis zone (TAZ), and matrices of zone-to-zone travel times and distances for whatever year a forecast is desired. It would also be necessary to incorporate differences in the characteristics of the ADA paratransit-eligible population. This could be done by collecting new survey data on the local ADA paratransit-eligible population or by adjusting “expansion weights” in the Dallas- Fort Worth sample to match the local ADA-eligible population. The latter could be done with any data that the local operator has on the riders (probably just age distribution), as well as census comparisons of regional demographic distributions with those in Dallas-Fort Worth, such as adjusting the percentage below poverty rate. Without such data, the regional planning model can still be used for exploratory analysis, but is limited to the Dallas-Fort Worth region. These models advance the state of the art in understanding travel by people with disabilities, in particular by ADA paratransit. The research demonstrates how the travel of people with dis- abilities can be explicitly treated in regional travel demand models. However, due to data limita- tions, the models were only calibrated on the basis of total ADA paratransit trip-making. It was not possible to calibrate on the basis of geographic distribution, travel by other modes, or trip purpose distribution. These are significant limitations, but of less practical concern than might be imagined. ADA paratransit services are planned on the basis of total demand within a service area. Because the service is purely demand responsive within the established service area, origins and destinations (and routes of travel) vary from day to day and are not usually a major factor in planning. By law, trip purpose cannot be a factor in service delivery. Both models are based on analysis of a survey of 800 users of ADA paratransit service operated by Dallas Area Rapid Transit (DART) and the Fort Worth Transportation Authority (FWTA), combined with the regional travel demand model of the North Central Texas Council of Gov- ernments (NCTCOG) and census-tract data for the same area. The survey obtained detailed information about actual trips made by ADA paratransit riders not just on ADA paratransit but also on other specialized services, by private car as a passenger or driver, on scheduled transit,

Summary 3 and walking or going by wheelchair. For each trip, respondents provided trip purpose, mode of travel, trip duration, and exact point of origin and destination. The NCTCOG model provided data about travel times between zones in the region, as well as the number of jobs of various types in each zone, which serve as an indicator of the activities available in each zone that would attract trips. The resulting models explain observed ADA paratransit trip-making on the basis of socioeco- nomic data for each census tract (e.g., income, age distribution, and household size), travel times between analysis zones, and jobs of various types in each zone. In keeping with the intent of the ADA law and regulations, the forecasts of ADA para- transit ridership correspond to service that complies with requirements for level of service. The methods are also designed to exclude demand for services that exceed requirements for ADA- complementary paratransit. Of particular importance, demand is predicted only for service by ADA-eligible individuals, for trips within 3/4 of a mile of fixed-route service, based on reserva- tions taken at least 1 day in advance. Demand is predicted for service that is not capacity con- strained by significant numbers of denials, unreliable service, or excessive telephone wait times to reach a reservationist. Evidence about Planning and Policy Issues The models and the survey data provide limited evidence about planning and policy issues connected with ADA paratransit, including several questions about demand for ADA paratransit raised by TCRP Report 119. Aging of the Population It is widely anticipated that increasing numbers of older people will lead to growing demand for ADA paratransit. A recent report for the American Public Transportation Association esti- mated that, compared to levels in 2010, the demand for ADA paratransit by people age 65 and older will grow by 32% in the next 10 years and by 76% in the next 20 years. By comparison, the census population projections used in the report indicate that total population in urbanized areas will grow by just 17% in 10 years and 39% in 20 years. That analysis implied that the ADA paratransit demand would grow much faster than the population because of increasing numbers of older people. However, TCRP Report 119 did not find any connection between ADA paratransit demand and the size of the older population in a transit area. Several measures of the size of the older population were tested in the analyses for TCRP Report 119 and none of them were found to be statistically significant. Instead, ADA paratransit demand was found to be proportional to the total population of an area after adjusting for differences in fares, poverty rates, and eligibility screening processes. The model of registration rate and the models of tour generation and mode choice include age variables. To test what effect the models predict for an older population, the model system was run with a 10% increase in the fraction of the population over age 60. Also the proportion of ADA paratransit registrants age 60 and older was assumed to increase by 10%. The results of this test were ADA paratransit trips per registered person: -3.9% Number of registered persons: +1.8% Total ADA paratransit trips: -2.2%

4 Improving aDa paratransit Demand estimation: regional Modeling Trips per person registered for ADA paratransit would decline, which corresponds with the experience of ADA paratransit operators that older people travel less than younger people, while the number of registered people would increase, which corresponds to the fact that older people are more likely to have disabilities than younger people. The drop in trips per registered person is much larger than the increase in registered persons, so a 10% increase in the senior population would create a 2.2% reduction in total ADA paratransit trips. Effect of Incomes and Poverty TCRP Report 119 found that transit systems serving areas with higher poverty rates had much lower demand per capita than transit system service areas with lower poverty rates, all else being equal. This finding surprised some observers, given that people with lower incomes have fewer travel options and so would tend to be more dependent on ADA paratransit. The report theo- rized that the apparent effect of poverty rate on ADA paratransit reflects differences among communities rather than differences among individuals. For example, if communities with high poverty rates have fewer activities available, fewer shopping opportunities, and fewer services in general than other communities, then high poverty rates would be expected to depress demand for all types of travel, including ADA paratransit. The model of registration rate and the models of tour generation and mode choice include income variables. To test what effect the models predict for a population with a reduced poverty rate, the model system was run with a 10% decrease in the fraction of the households below the poverty rate and with a 10% increase in median income in each census tract. Also the propor- tion of poverty-level ADA paratransit registrants was assumed to decrease by 10%. The results of this test were ADA paratransit trips per registered person: +4.1% Number of registered persons: -5.8% Total ADA paratransit trips: -1.8% Trips per registered person would increase, which reflects the fact that the models predict more trips overall with higher incomes as well as more trips by ADA paratransit. However, the number of registered persons would decline more, since the registration rate model found that poverty rate and registration rate are correlated, while higher median incomes go with lower registration rates. Overall, the models predict that higher incomes would reduce ADA paratransit travel slightly. Most of the predicted effect comes from a decreased registration rate, which is consistent with the well-established two-way connection between lower incomes and higher rates of disability.1 This finding of more ADA paratransit travel with reduced poverty rate is based on an assump- tion that incomes would rise within the Dallas-Fort Worth area, so it is not directly comparable to the finding of TCRP Report 119 about differences among communities. Also, it does not take into account the possibility that a general community-wide rise in incomes would result in changes in available activities and services in the community. Household Size The effect of household size has not previously been a topic of discussion in connection with ADA paratransit demand, but household size is commonly included in regional travel models. Household size might be expected to decline in the future with a higher percentage 1 Elwan, Ann, 1999. “Poverty and Disability: A Survey of the Literature, SP Discussion Paper No.9932,” World Bank.

Summary 5 of older people, including many women who have outlived their spouses and more women raising children alone. People who live alone may make more trips because they cannot delegate activities to others. On the other hand, people with disabilities who live with others may make more trips because they have someone to assist them, accompany them, or provide rides for them. But while they might make more trips overall, they might make fewer trips using ADA paratransit. In general, the smaller the household, the fewer the opportunities for getting rides. The model of registration rate and the models of tour generation and mode choice include variables related to household size. For convenience, the effect of larger rather than smaller households was tested. The model system was run with a 10% decrease in the fraction of sin- gle-person households and with a 10% increase in average household size in each census tract. Also the proportion of ADA paratransit registrants in single-person households was assumed to decrease by 10%. The results of this test were ADA paratransit trips per registered person: +1.0% Number of registered persons: -5.3% Total ADA paratransit trips: -4.4% The results are opposite in direction from the result for an aging population, but with a much larger drop in registered persons and a much smaller increase in trips per registered person, leading to a significant drop in ADA paratransit trips. Sensitivity to Fares TCRP Report 119 found a fare elasticity of demand for ADA paratransit of –0.77, meaning that a 10% difference in fares corresponds to a 7.7% difference in demand in the opposite direction. In other words, if one system has 10% higher fares than a second system, it will have 7.7% lower demand on average, all else being equal. Given that the analysis was based on comparison of ADA paratransit in different areas, that is all the results imply. They do not say whether such a strong effect applies to fare changes within one ADA paratransit system. In fact, other analysis of fares and ridership in ADA paratransit systems has produced evidence that the actual fare elasticity of ADA paratransit demand is much lower. An analysis of ADA paratransit in Los Angeles, cited in TCRP Report 119,2 found a fare elasticity of 0.43, which is close to values seen in general public bus service.3 Also, since ADA paratransit riders tend to have low incomes, it is possible that lower income riders are more sensitive to fares than higher income riders. Evidence from the model development supports a fare elasticity for ADA paratransit in the neighborhood of –0.41 for riders with household incomes under $15,000 per year and in the neighborhood of –0.23 for riders with household incomes of $15,000 per year or more. (Note, however, that even the higher income group still has few members with incomes over $35,000 per year.) Each of these groups constituted about half of the sample in the survey of ADA para- transit riders. This finding is based on analysis of a “Stated Preference” survey, in which ADA paratransit riders were presented with various service scenarios requiring tradeoffs between ADA paratransit fares and travel times, combined with the results of the travel model showing how travel times affect demand. 2 HLB Decision Economics, 2004. “Demand Forecasting Model for LA Access ADA paratransit,” Access Services Inc. 3 “The Demand for Public Transit: A Practical Guide,” Transport Research Laboratory, Report TRL 593, 2004, quoted at http:// www.vtpi.org/tdm/tdm11.htm.

6 Improving aDa paratransit Demand estimation: regional Modeling Sensitivity to Travel Time Travel times on ADA paratransit are typically much longer than times for similar trips by private car. ADA regulations4 prohibit “substantial numbers of trips with excessive trip lengths” but do not specify what is excessive. The FTA has interpreted the regulations to require that ADA paratransit travel times should be comparable to travel times by fixed-route transit. Common sense suggests that ADA paratransit users, like anyone else, will be influenced in their choices by travel times. To investigate this issue, the model system was run with modified ADA paratransit travel times. These tests indicated that elasticity with respect to ADA paratransit travel is –0.5 for ADA paratransit trips, –1.1 for ADA paratransit passenger-miles, and –0.1 for total trip-making by ADA-eligible people. In other words, a 10% increase in ADA paratransit travel times would result in • A 5% reduction in ADA paratransit trips • An 11% reduction in ADA paratransit passenger-miles • A 1% reduction in trips by all modes by ADA-eligible people Most of the decrease in ADA paratransit trips would be made up by a corresponding increase in trips by other modes (mode shift), but not all of them—there would be a 1% decrease in total trips made by ADA-eligible persons. The elasticity for total trip-making is quite small, but still quite a bit higher than trip “suppression” elasticities estimated for the general population, which are typically much smaller than –0.1. Conversely, the mode-specific elasticity of –0.5 is toward the low end of values typically estimated for the general population, based on the experience of the research team. These results are consistent with the fact that ADA paratransit users tend to have fewer travel options than the general population. Because they have few options, ADA paratransit riders would reduce their use of ADA paratransit in response to an increase in ADA paratransit travel time by less than the general population reduces its automobile or transit use in response to a similar increase in travel times on those modes. But the same lack of options means that fewer foregone ADA paratransit trips can be made up by trips on other modes than would be the case for transit riders or drivers. To some extent, relatively low sensitivity to ADA paratransit travel time could also reflect the fact that travel on ADA paratransit is less predictable than automobile or transit travel time, because the operator may group any given trip with a different set of other trips from one occasion to the next. The research also provided some evidence on the value that ADA paratransit users place on travel time. Based on the Stated Preference tradeoff analysis, a change in ADA paratransit travel by one multiple of car travel time (e.g., from twice automobile travel time to 3 times automobile travel time or vice versa) is valued the same as a fare change of $1.73 by people making less than $15,000 per year, and the same as a fare change of $2.96 by people making $15,000 or more. If a car trip takes an average of 30 minutes, these results imply a “value of time” of about $3.50 per hour for the lower income group and about $5.50 per hour for the higher income group. Importance of Pick-up and Drop-off Time ADA paratransit systems typically take reservations based on the rider’s desired pick-up time or desired appointment time. The ADA regulations note only a prohibition on “substantial 4 49 CFR 37.131, “Service criteria for complementary ADA paratransit.”

Summary 7 numbers of significantly untimely pick-ups,” but in later interpretations FTA has been clear that timely drop-offs are also an important part of on-time performance.5 In the Stated Prefer- ence analysis that was part of the ADA paratransit user survey, half of respondents were asked to make tradeoffs involving late pick-ups and half were asked to make similar tradeoffs involv- ing late drop-offs. The analysis found that a change of 5% in the frequency of late pick-ups was valued the same as a $1.06 fare change, but a change of 5% in the frequency of late drop-offs was valued the same as a $1.41 fare change. In other words punctuality for drop-offs was considered 35% more important than punctuality for the pick-up. In practice, of course, both pick-up and drop-off punctuality are important for each trip. Telephone Hold Time TCRP Report 119 attempted to measure the effect on ADA paratransit demand of telephone hold times when making reservations. A survey of practitioners conducted for that research ranked “ability to get through on the phone to reserve a ride” very highly as a factor that influ- enced demand. However, 9 of 28 systems studied did not have a measure of average hold time available. Analysis using the 19 systems with a measure of average hold time found that longer hold times appear to depress demand, but the result was not statistically significant. In the ADA paratransit user survey for this research, the Stated Preference analysis asked respondents to make tradeoffs between the time “you may have to wait on hold for when you call to reserve a trip” and other service variables. The analysis found no significant impact for choices involving hold times of “up to 1 minute,” “up to 3 minutes,” and “up to 5 minutes.” If correct, this result would imply that variations in hold time within this range are relatively unimportant compared to other variables in the analysis, namely fare, travel time, and late- ness for pick-up or drop-off. Alternatively, the result could indicate problems with the way the question was stated, or it could mean that these statements of measured hold time are very different from customers’ subjective sense of hold time. In other words, the difference between hold times of up to 3 minutes and hold times of up to 5 minutes may feel much greater than it sounds in a survey question. Pedestrian Access to Activities A reasonable speculation is that people with disabilities who live close enough to shops and services that they can walk or go to them by wheelchair will be less dependent on ADA para- transit. Ideally, this would be tested by taking into account the quality of pedestrian access in the form of safe sidewalks accessible to people with disabilities, crosswalks, clear pedestrian signals, sufficient crossing time at intersections, benches for resting, reduced traffic speed, and traffic islands. Aspects of accessibility for people with disabilities include accessible bus stops, curb ramps at intersection corners, audible pedestrian signals at street crossings, sidewalks that are clear of constructed obstacles such as telephone poles in the path of travel, and sidewalks that are in good repair. Comprehensive data about the quality of pedestrian infrastructure by zone was not available, but it was possible to test the effect on ADA paratransit registration rates of a high density of service and retail activities in a census tract. A very significant result was found: a 10% increase in access to activities reduces ADA paratransit registration rate by approximately 9%. 5 Disability Rights Education and Defense Fund, June 2010. “On-Time Performance in ADA Paratransit,” Topic Guides on ADA Transportation, available at http://www.dredf.org/ADAtg/index.shtml.

8 Improving aDa paratransit Demand estimation: regional Modeling Further Research and Development This is the first attempt to develop a disaggregate regional model of travel by ADA paratransit- eligible individuals, so numerous unanswered questions and opportunities for further develop- ment remain. Disaggregate model of registration. In this research, the rate at which people apply for and obtain ADA paratransit eligibility was modeled using aggregate data for census tracts. The alter- native would be to construct a disaggregate model using data from a large sample of individuals like the ones gathered in a regional household travel survey. It would be necessary to reliably determine which individuals in the overall sample have actually been certified as eligible for ADA paratransit. In a disaggregate model it would be possible to include the increase in mobility and accessibility that ADA paratransit would provide for the individual. This could be measured by the difference in the overall expected utility from the trip generation, distribution, and mode choice models with, versus without, ADA paratransit as an alternative. People expected to achieve the greatest benefit from ADA paratransit would be expected to be more likely to apply for it. The effect of automobile ownership on registration. Automobile ownership and availability were not included in the tract-level registration rate model, because this variable is endogenous to many travel demand model systems. That is, it is predicted rather than used as an input, because, for many households, ownership decisions depend on relative accessibility by various modes. In further research along this line, it may be worthwhile to include automobile owner- ship as an exogenous factor, because it is unlikely that the level of ADA paratransit service would significantly affect automobile availability levels among the eligible population. Differences among regions that affect registration. A comparison among regions might be able to determine the effects of • The process used by the provider in determining eligibility (e.g., whether a simple paper appli- cation is used or all applicants are subject to functional testing); and • The level of awareness of the service (the degree of activity/sophistication of social service agencies/advocacy groups in the region may be an indicator). The effect of ADA paratransit service variables. The effects of ADA paratransit travel time, fares, service reliability, and telephone hold times could be further explored using additional Stated Preference research, time series modeling, or disaggregate modeling in a region where there is significant variation in these variables. The effect of alternatives to ADA paratransit. Good alternatives to ADA paratransit would be expected to reduce demand or increase overall mobility. Two alternatives of vital importance whose effect could not be modeled in this research were • Specialized services provided by Medicaid, adult day health care, programs for people with developmental disabilities, and so forth. Availability of these services varies among regions. In principle they vary among ADA paratransit riders within a region due to differences in eligibility (especially for Medicaid) and in some cases location. However, it was not practical to measure these differences. • Fixed-route transit service. The attractiveness of fixed-route transit service for those ADA paratransit riders capable of using it for some trips depends on proximity to service, fare, frequency of service, transfers required, and accessibility features. Modeling the attractiveness of fixed-route transit service for such riders would require having zone-to-zone travel data for these variables and such data were not available in the data maintained by NCTCOG for

Summary 9 the study area. This information is available in many large regional travel models. In regions whose models have this information, it would be possible to test how the availability of con- venient fixed-route service affects ADA paratransit demand. Regarding accessibility features, both transit operators, DART and FWTA, operate 100% wheelchair-accessible fleets, so there was no opportunity to test differences. Ideally, the availability of accessible pathways to transit stops would also be measured. Weekend trips and time of day. Currently, the model only predicts weekday ADA paratransit trips, and not weekend trips. Modeling weekend trips would require collection of additional survey data. Also, trip departure time choice for ADA paratransit users was not modeled. Model estimation in another region. It would be desirable to estimate a similar or more re- fined model in another region. Aside from the possibility of modeling the effect of transit level of service, weekend trips, and departure time choice, this would help test the transferability of the results found in Dallas-Fort Worth. Estimating a similar model in another region would require a travel survey of ADA paratransit customers. There may be opportunities to conduct such a sur- vey by extending the sample used in a regional household travel survey of the general population. Model testing in another region. Short of estimating a new model, the model developed in this research can be applied using census data and travel network data in another region. This process would test whether the model makes reasonable predictions beyond the region in which it was estimated. Calibration using geographic and trip purpose distribution and travel by all modes. In a new model for another region, it would be desirable to calibrate results on the basis of observed geographic and trip purpose patterns and on the basis of observed use of modes other than ADA paratransit. From a policy perspective, it would be especially useful to confirm the validity of forecasts of travel by fixed-route transit. A premise of the ADA and of much work in ADA paratransit planning is that many ADA paratransit customers could use fixed-route transit for many of their trips. It would also be important to confirm the validity of forecasts of travel as a passenger in a private car, given that such travel is by far the most common mode of travel by ADA paratransit-eligible people. Refinement of travel survey methods. In most respects, the research determined that ADA paratransit riders can be surveyed with methods similar to those used for traditional household travel surveys. However, respondents to this travel survey appear to have over-reported their use of ADA paratransit. It appears that respondents who travel infrequently may have made it a point to schedule the trips they needed to make on their assigned survey days. This effect oc- curred despite use of standard travel survey methods, including controlled choice of assigned survey days. The resulting over-reporting was adjusted for by using a calibration procedure, but there was no way to test or adjust for the possibility that travel by other modes could have been correspondingly under-reported. Respondents in a typical general population travel survey have much less opportunity or incentive to make such adjustments to their usual travel patterns. However, the respondents in this survey travel much less frequently and non-discretionary travel such as for work or school makes up a much smaller part of their overall travel. Testing ways to control for or prevent over-reporting of ADA paratransit trips would be useful.

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TRB’s Transit Cooperative Research Program (TCRP) Report 158: Improving ADA Paratransit Demand Estimation: Regional Modeling presents a sketch planning model and regional models designed to help metropolitan planning organizations and transit operators better estimate the probable future demand for Americans with Disability Act (ADA) complementary paratransit service, as well as predict travel by ADA paratransit-eligible individuals on all public transportation modes.

Both models permit more detailed forecasts and deeper understanding of the travel behavior of ADA paratransit-eligible people. All model parameters and coefficients are contained in the report and a fully implemented version is available on a CD-ROM that is included with the print version of the report.

The CD-ROM is also available for download from TRB’s website as an ISO image. Links to the ISO image and instructions for burning a CD-ROM from an ISO image are provided below.

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