4. Data and Assumptions

A large number of data and assumptions are required to estimate costs and benefits of the Final Rules. Some of these data, such as the number of facilities (by type) are drawn directly from Census data. Other data, such as the number of uses of an element during a facility visit must be determined from discussions with experts. Other data values are estimated from closely related data using reasonable proportions or proxies.

Assumptions and professional judgment are applied when data is not available. Assumptions play an important role in determining outcomes. Arguably, they are as important as data since they generally multiply with the same numbers. Uncertainty is higher with assumptions and accordingly, they are assumed to also have a larger parameter range around a most likely value.

4.1 Cost Estimation Data and Discussion

4.1.1 Number of Facilities

Baseline data on existing facilities are drawn from several sources (Appendix 3A). The 2007 Economic Census is a primary source for the number of employer-based commercial establishments.[1] In these cases, facilities and facility groups are classified using appropriate North American Industry Classification System (NAICS) codes. The number of facilities in 2010 is estimated by applying sector-specific construction growth rates to 2007 data.[2] Data on public facilities, which are not included in the Economic Census,  have come mostly from the Quarterly Census of Employment and Wages, supplemented by data from trade groups, industry studies, and other government sources.

Table 3 shows that the total estimated number of facilities is more than 7 million, with nearly half of those facilities (3.9 million) falling into the broad Indoor Service Establishment facility group. Single-level stores are also estimated to have a large number of facilities (0.8 million), followed by Restaurants and Offices of Health Care Providers (approximately 0.5 million each). Together, these four facilities account for slightly less that 80 percent of all facilities in the analysis. Such facilities, that are large in number, magnify any imbalances in costs and benefits.

The number of new facilities constructed each year after the rule passes (and up to year 15) is estimated on a facility-specific basis (Appendix 3B). Industry reports provide data on annual growth rates from 0.3% to 1.2% depending on the facility.[3] In several cases, recent industry growth rates of 3% or more were reported. It was assumed that no industry would maintain a growth rate of more than 1.2% for the 15 years of construction in this analysis. Examples of facilities that grow at slower rates include restaurants, hospitals, and nursing homes and those that grew faster include schools (all types) and museums.

Table 3 : Number of Establishments in 2010 by Facility Group














Motion picture house



Theatre / Concert Hall









Convention Centers



Single Level Stores



Shopping Malls



Indoor Service Establishments



Offices of Health Care Providers






Nursing Homes



Terminal (private airports)






Museums, Historical Sites & Libraries



Parks or zoos



Amusement Parks



Nursery schools - Daycare



Elementary Private Schools



Secondary private schools



Undergraduate and Postgraduate Private Schools



Ski Facilities



Homeless shelter



Food Banks



Social Service Establishments



Exercise Facilities



Aquatic Centers / Swimming pools



Bowling Alleys



Golf Courses (private with public access)



Golf Courses (private only)



Miniature golf courses



Recreational Boating Facilities



Fishing Piers and Platforms



Shooting Facilities



Office Buildings



Elementary Public Schools



Secondary Public Schools



Undergraduate, postgraduate public schools



Public Housing



State and Local Judicial Facilities (courthouses)



State and Local Detention Facilities (jails)



State and Local Correctional Facilities (prisons)



Parking Garages



Self Service Storage Facilities



Theatre / Concert halls (public)



Stadiums (public)



Auditoriums (public)



Convention Centers (public)



Hospitals (public)



Nursing Homes (public)



Museums, Historical Sites & Libraries (public)



Parks or zoos (public)



Homeless shelter (public)



Exercise Facilities (public)



Social Service Establishments (public)



Aquatic Centers / Swimming pools (public)



Miniature golf courses (public)



Recreational Boating Facilities (public)



Fishing Piers and Platforms (public)



Office Buildings (public)



Parking Garages (public)



Golf Courses (public)



Restaurants (public)



Amusement Parks (public)


4.1.2 Number of Elements per facility

As mentioned in Section 3.1, the number of elements per facility requires assumptions about the average facility and the element before the number of elements can be counted. These assumptions were developed initially by Department architects and HDR and then discussed, changed or verified by a panel of architects with broad experience and facility specialties. Data tables on the assumptions of the element specifications, the typical facility size and the number of elements are contained in Appendix 3C, 3D and 3E. Examples of assumptions include total square feet of space at the facility, number of stories, or seating capacity. In all cases, the same number of elements was assumed per facility, whether undergoing barrier removal, alterations or new construction.

The numbers of elements per facility are defined as uncertain with parameter values defining the most likely low and high values (following the basic risk-analysis framework). A standard low and high range is defined as +/- 20% of the most likely value is applied to all facilities.

Assumptions and values for the likelihoods that average facilities actually contain the element are presented in Appendix 3F and 3G. Most requirements have most likely likelihood values between 3% and 90% (see Appendix 3F). Some facility-requirements are assumed to have likelihood values that differ among facilities (see Appendix 3G). Conditions that support the assumption likelihood that an element is actually in the average facility are contained in these Appendices.

Likelihood values are treated as uncertain in the model because data have not been found to verify assumptions or provide experts something to comment upon. The uncertainty range for these values is assumed to be a three-fold increase or decrease in the most likely value up to the ultimate percentage boundaries of 0 and 100%. For example, a most likely value of 3% ranges from 0% to 10%. A 90% most likely value would range from 30% to 100%.

The distribution of elements across facilities and the total number of facilities reveals important implications for the analysis, especially for requirements that have imbalanced costs and benefits. The top five elements with the largest numbers in all facilities are shown in Figure 4. Side reach requirements comprise the single largest category with 34% of all elements. Together these five elements represent about 60% of all elements subject to the requirements in the Final Rules. Although these elements are the most frequently occurring, they are not necessarily those with the largest costs or largest benefits. However, for side reach, as discussed in more detail below, costs for this requirement are estimated to be much larger than benefits.

Figure 4 : Total Number of Elements: Top Five Most Frequently Occurring and All Others

Figure 4: Total Number of Elements: Top Five Most Frequently Occurring and All Others

Analytical scenarios determine the number of elements that contribute to the total cost. The number of applicable elements per facility depends on the baseline. In practical terms, as discussed in Section 2.4, if the IBC standards comply with the Final Rules then the number of elements that would be included is zero. In addition, readily achievable and SH scenarios track through Figure 1 to determine the proportion of elements that are costed under each type of construction.

Finally, some requirements are not allocated to a facility and thus not included in the analysis. Table 4 lists the requirements that are not included in the analysis and the reason for exclusion.

Table 4 : Requirements not included in Baseline Scenario

Requirement Reason

Location of Accessible Routes

Not applied in any typical facility


Common Use Circulation Paths in Employee Work Areas

No appreciable costs


Accessible Means of Egress

No appreciable costs


Handrails Along Walkways

Not applied in any typical facility


Platform Lifts in Hotel Guest Rooms and Dwelling Units

Not applied in any typical facility


“LULA” and Private Residence Elevators

Not applied in any typical facility



Not applied in any typical facility


Limited Access Spaces and Machinery Spaces

No appreciable costs


Operable Parts

No appreciable costs


Lawn Seating in Assembly Areas

Not applied in any typical facility


Visible Alarms in Alterations to Existing Facilities

No appreciable costs


Detectable Warnings (technical)

No appreciable costs


Accessible Courtroom Stations

Only affects employees


Raised Courtroom Stations Not for Members of the Public

Only affects employees


Accessible Route in Court Sport Facilities

Not applied in any typical facility


Accessible Boarding Piers (Alt/BR)

No appreciable costs


Accessible Boat Slips (Alt/BR)

No appreciable costs


Accessible Teeing Grounds, Putting Greens, and Weather Shelters (NC)

No appreciable costs

4.1.3 Construction Costs

An independent certified professional cost estimator was hired to provide detailed cost estimates for each of the 117 requirements. [4](See Appendix 7B identifying members of Cost RAP Panel). Unit cost estimates were derived using standard industry practices and published sources for construction costs such as reference materials published by RS Means. Separate low, middle, and high estimates are developed for each element and separately for new construction, alterations and barrier removal. Costs for new construction reflect the costs of meeting the specified standard that would be incurred above the costs of construction and design already planned. Some elements are expected to have zero cost in new construction because the cost of the element or design is negligible or, in some cases, because at the design phase architects would be expected to be able to “design around” the element’s requirement with no appreciable design or construction costs. Under barrier removal, costs are higher than new construction because they include the full cost of retrofitting to bring an element into compliance. Costs under alterations are more complicated, as they must reflect only the incremental costs necessary to bring an element into compliance, and not other costs that would have already been planned under the alterations.

Less stringent requirements have a negative cost, i.e. a savings for facilities. It is assumed that no entity would undertake construction under alterations or barrier removal scenarios to change to a less stringent requirement. (See Appendix 3H for a full listing of costs as well as notations on unit cost assumptions and descriptions.)

At the expected level, the most expensive barrier removal costs include those listed in Figure 5. These costs per element do not reflect the likelihood nor the frequency of occurrence of the element at any facility. By far the most expensive requirement is that for sloped entry into wading pools, since slope grade and related regulations (such as no more than one turn) would result in extremely long ramps. (It is understood that this is unlikely to be technically feasible in many circumstances and the likelihood of facilities building such ramps has been adjusted accordingly.) Many other elements with high construction costs are related to recreational facilities such as accessible holes at mini golf, location of accessible routes to stages, and primary accessible means of entry to pools (see Figure 5).

Figure 5 : Top 5 Average Barrier Removal Construction Costs Per Unit

Figure 5: Top 5 Average Barrier Removal Construction Costs Per Unit

4.1.4 Operations and Maintenance Costs

The level of incremental O&M costs and type of O&M costs incurred vary among elements. O&M costs are developed by a firm specializing in facility management. O&M costs are captured as an annual percentage of capital costs. Elements are grouped into four categories depending on maintenance needs: standard maintenance, high use maintenance, extraordinary wear and tear, and equipment. Low, most likely, and high estimates of the percentage of capital costs are defined in each case. O&M estimates range from a low of 2%-4% for standard maintenance items to a high of 4%-6% for equipment (see Appendix 3I).

For a large portion of facilities, the maintenance of many elements is likely to be part of service agreements, which can last for extended periods. Unless compliance results in a significant increase in the number of elements being serviced, or a significantly higher cost or complexity for particular element, significantly changes in service agreements are assumed to be unlikely. Many other elements, such as lower side reach, would not have measurably different O&M costs. Thus, for a large number of the requirements, incremental O&M costs are zero.

4.1.5 Loss of Productive Space

The value of lost productive space is composed of two parts: (a) an estimate of the lost space; and (b) an estimate of the value of that space. Data on lost space (in square foot terms) have been developed by the Department’s architects and an independent certified professional cost estimator using standard industry practices.[5] Changes in productive space for each element are included only if meeting the requirement would result in a loss (or addition) of space would have a direct impact on business income. A significant number of elements (nearly four fifths) would result in no change in productive space, those that do would have impacts of 5 to 40 square feet. Accessible self-service units can also have significant impacts on productive space at the high end of estimates, as some facilities may need to decrease the number of non-accessible units. The productive space impact of galley kitchen clearances under barrier removal can also be significant at the high end. Several elements would result in ‘savings of productive space; the largest being the less stringent requirements for accessible route to press boxes and accessible routes to tiered dining in sports facilities, both resulting in reductions of several hundred square feet. (See Appendix 3J.)

The annual value of building space per square foot has been derived from facility-specific data. Variability in space impacts and monetized space are included in the analysis. Based on a lack of facility specific data on income per square foot, data were estimated using building costs per square foot, adjusted by the ratio of income per square foot for office buildings to construction costs per square foot for office buildings. (See Appendix 3K.)

This analysis determined which facilities and requirements would actually incur a loss if there was a space impact. Not all facilities have productive spaces (e.g. schools). Also, not all requirements cause losses of value, even if there is a space impact (e.g. requirements impacting parking lots). In some cases, losses in productive space are excluded for specific facility-requirement combinations (e.g. space impacts from changes in single-user toilets are not valued for hotels because they impact lobbies only). Otherwise, costs are incurred for facilities based on the same scenario assumptions (e.g. readily achievable and alternative baselines).

4.1.6 Replacement Costs

Most elements should last for the life of the building if properly maintained. An independent professional cost estimator provided estimates of the rate at which elements would need to be replaced during the 20- or 40-year time frame for the nearly 20 elements considered here that would expect replacement. Examples include platform lifts and playground equipment. Costs that might stem from a desire to remodel and not from the fact that an element is at the end of its useful life are not included. For those elements likely to need replacement, the replacement cost is equal to the full cost of construction under alterations. Replacement rates range from once every four years to once every ten years. (See Appendix 3L.)

4.1.7 Expert Cost Review

A panel of experts was convened by the Department to review key assumptions associated with facility and element profiles, likelihoods of occurrence, and differences between barrier removal, alterations and new construction. The panel reviewed initial estimates of facility size and the frequency of occurrence by element developed by the Department’s architects. Decisions during the working group were consensus-driven for most likely, low, and high parameter values. A sample from the workbook used in the session is shown below in Figure 6.

Figure 6 : Example of Cost RAP Question

13. Accessible Routes from Site Arrival

Key Element Features:

  • routes accessible by vehicle only
  • Horizontal surface construction materials and accessible path of travel, range - 100', 200', & 500'+ travel distance





Range(s) to use in estimating range of unit costs to account for variations in facility sizes and configurations (if applicable):




Likelihood that a typical individual facility (in any facility group)
will have the element and will be affected by the incremental change to the requirement:

50%        Other: ________

4.2 Benefits Data and Assumptions

4.2.1 Number of Facility Visits of U.S. Adults

The computation of user benefits relies on estimating the number of annual visits per facility group by persons with disabilities. Industry specific data on the average number of annual visits for adults are assembled for each commercial facility to calculate a figure for the number of persons with disabilities. Data on the average (or total) number of visits have been collected for many types of facilities (see Appendix 4A).[6] Some of the figures on total or average visits included both adults and children. In those cases, the data were scaled down by the percentage of the U.S. population 18 years of age and older. All the data are estimated for 2010 using population growth rates. (See Appendix 4B for population data from U.S. Census Bureau.)

When such data for a facility type cannot be found, the following methodology is used. The number of visits for each private facility type, a baseline Q0, is derived from the total sales of a facility group divided by the estimated market price of a facility visit. The total sales per facility group are based on the total sales per industry sector, determined by the U.S. Economic Census, representative of the facility groups. For example, the indoor service establishment facility group (Group I) includes total sales revenue from the personal and laundry service (to capture laundromats and beauty parlors) and at least five other service industry sub sectors including banks and offices of lawyers and accountants (see Appendix 4C). Sales data from 2007 are scaled to 2010 dollars using the Consumer Price Index (see Appendix 4D).

The following facilities are not specifically listed in the Economic Census: fishing piers and platforms, and shooting facilities. The total sales at these facilities are each assumed to be one-third of the total sales revenue of the category, “All Other Amusement and Recreation Industries” (NAICS code 7139908). The remaining third of sales is unknown. It is not known to what extent this assumption over or under estimates sales at these facilities.

Sales are divided by market price per visit to estimate the total number of facility visits. However, data on revenue from sales receipts are not available for some facilities that are counted by the Economic Census or for the public facilities. For these facilities, the numbers of facility visits are directly assumed as such:

  • 25% of the U.S. population 18 years and older visit an office building once a year.
  • For public facilities with a private counterpart for which information on the total number of visits was available (such as amusement parks), visits were allocated proportionally based on the number of facilities.
  • Facility visits for public housing are estimated from data on the number of people living in public housing. A visit consists of a day spent at the facility. Long-term residents spend every day there and thus visit it every day of the year.[7]
  • Visit to judicial facilities vary. It is assumed that 1% of the total adult population of the United States (18 years and older) needs to visit a judicial facility annually.
  • Visits to detention facilities are derived from data on monthly estimates of felony cases.[8] An annual number of detainees is estimated, assuming that all alleged felons are detained. Further, each alleged felon is assumed to be detained for an average 10 days. Therefore, the number of visits per year is equal to the number of annual detainees multiplied by the average number of days detained, divided by 365 days.
  • Visits to state and local correctional facilities are derived in a similar way as public housing for the number of prisoners in state and local correctional facilities.
  • The remaining public facilities (such as Public Recreational Boating Facilities) are assumed to have the same proportion of visits per facility as their private counterpart.

The baseline Q0 divided by the U.S. population 18 years and older illustrates the number of visits per facility type made by the typical U.S. consumer, shown below in Table 5. For example, this estimate shows that the typical U.S. consumer visits a restaurant about 200 times annually. (Restaurant facilities are defined by the Economic Census to include full-service restaurants; limited-service eating places; special food services, such as food service contractors, caterers, and mobile food services; and drinking places.) This also shows that the average U.S. consumer most frequently visits single-level sales establishments (including grocery stores, bakeries, clothing stores, and hardware stores), at a rate of about 1.2 times a week. Since it is assumed that the users of school facilities are the enrolled students, the visits made to these facilities reflect the population of the age groups that attend each school facility.

Table 5 : Total Number of Annual Visits per Facility Group by Adults

Facility Visits
Inns 434,136,553
Hotels 639,668,490
Motels 573,375,553
Restaurants 48,756,051,381
Motion Picture House 1,102,872,542
Theatre / Concert Hall 324,797,197
Stadiums 175,461,750
Auditoriums 158,913,682
Convention Centers 47,522,304
Single Level Stores 19,414,266,163
Shopping Malls 2,601,181,776
Indoor Service Establishments 25,520,961,000
Offices of Health Care Providers 858,282,176
Hospitals 73,773,974
Nursing Homes 539,414,177
Terminal (private airports) 969,217
Depots 24,274,734
Museums, Historical Sites & Libraries 1,766,284,371
Parks or zoos 89,624,967
Amusement Parks 267,791,915
Nursery schools - Daycare 3,368,899,276
Elementary Private Schools 534,547,173
Secondary Private Schools 167,651,785
Undergraduate and Postgraduate Private Schools 898,786,369
Ski Facilities 45,609,249
Homeless Shelter 103,765,718
Food Banks 210,183,703
Social Service Establishments 1,012,206,708
Exercise Facilities 1,487,367,687
Swimming pools / Aquatic Centers 401,547,700
Bowling Alleys 237,021,233
Golf Courses (private with public access) 274,110,039
Golf Courses (private only) 64,624,920
Miniature golf courses 512,937,275
Recreational Boating Facilities 42,088,779
Fishing Piers and Platforms 6,004,045
Shooting Facilities 29,690,431
Office Buildings (new) 78,132,713
Office Buildings 78,132,713
Elementary Public Schools 3,481,539,779
Secondary Public Schools 4,580,973,393
Undergraduate and Postgraduate Public Schools 12,215,929
Public Housing 79,278,000
State and Local Judicial Facilities (courthouses) 3,070,066
State and Local Detention Facilities (jails) 12,215,929
State and Local Correctional Facilities (prisons) 928,919,605
Parking Garages 1,576,883,489
Self Service Storage Facilities 41,943,610
Theatre / Concert Halls (public) 200,939
Stadiums (public) 517,080,852
Auditoriums (public) 8,186,098
Convention Centers (public) 70,023,447
Offices of Health Care Providers (public) 0
Hospitals (public) 18,087,152
Nursing Homes (public) 49,752,934
Museums, Historical Sites & Libraries (public) 3,421,306,405
Parks or zoos (public) 1,375,642,128
Homeless Shelter (public) 15,205,650
Exercise Facilities (public) 48,272,115
Social Service Establishments (public) 362,522,271
Swimming pools / Aquatic Centers (public) 51,136,050
Miniature golf courses (public) 24,517,450
Recreational Boating Facilities (public) 57,378,698
Fishing Piers and Platforms (public) 6,004,045
Office Buildings (public) 196,782,624
Parking Garages (public) 14,125,413
Golf Courses (public) 46,733,865
Restaurants (public) 1,746,595
Amusement Parks (public) 5,578,917

By far, the largest number of visits are made to Restaurants (49 billion visits), Indoor Service Establishments (25.5 billion visits), and Single-Level Stores (19 billion visits). The large number of visits to Indoor Service Establishments and Single-Level Stores is partly due to the broad nature of those two facility categories. The Restaurant facility type is also fairly broad and includes fast-food establishments as well as luxury restaurants. Other facilities, especially many of the specialized recreational facilities, have significantly fewer visits – close to 50 million or less. These estimates can also be presented as the average number of visits by a typical adult: 159 average visits a year to restaurants, 83 average visits a year to indoor service establishments, and 63 average visits a year to single-level stores (see Appendix 4A for estimates for all facilities).

4.2.2 Number of Facility Visits of Persons with Disabilities

Estimating visits for persons with disabilities begins with the estimate of U.S. facility visits noted above and then adjusts this level in several ways. Each requirement targets a specific type of disability. The target population of persons with disabilities consists of five groups as defined by the U.S. Census Bureau: ambulatory, wheelchair only, seeing, hearing, and upper body limitation (see Appendix 4E).[9] An ambulatory disability includes persons using a wheelchair. The percent of this targeted population is applied to the baseline Q0 to establish a Q0 for each requirement at each facility by requirement. The assumptions of each requirement’s target population are shown in Appendix 4K. These percentages of persons with disabilities are assumed to be invariant over time, but actual numbers of persons with disabilities grow with population. This requirement specific Q0 expresses the number of visits made by each target population.

The baseline Q0 of each facility is adjusted for persons with lower income to account for the portion of the population with disabilities, who tend to have a lower average income. The income adjustment is a ratio of total household income expenditures per facility for low income persons and average income persons. This adjustment indicates whether low income persons are more or less representative at a facility compared to those with average income. In other words, persons with a lower average income would be underrepresented at some facilities, such as typical luxury facility visits (sports stadiums, opera houses, museums) and overrepresented at other facilities (government housing, laundromats). The assumptions made for each facility are shown in Appendix 4F.

4.2.3 Lifecycle Assumptions

Several assumptions are made for the lifecycle portion of the analysis. New construction and alterations are assumed to require three years for completion, while barrier removal is expected to take one year. Benefits can be assumed to lag in the first five years as facility users become familiar with changes in the facilities. It is assumed that in the first year, 50% of steady state benefits are realized. Each year, this percentage increases linearly until after five years, when the full benefits related to this portion of construction are reached. Steady state benefits are reached five years after all construction has been finished; from this point, steady state benefits increase at the same pace that population does. By the end of the period when construction start to age, the benefits also start to decrease at the same rate, until they have reached zero when all construction has aged.

4.2.4 Generalized Use and Access Cost

The generalized use and access cost is the sum of the value of time spent traveling to, accessing, and using the facility and the market price of a facility visit. Two of the components of the generalized use and access cost, P0, are facility use and travel time, both based on data from the 2005 American Time Use Survey, published by the Bureau of Labor Statistics, U.S. Department of Labor. The average of the responses that concern this analysis range from 4.87 hours spent participating in fishing to about 10 minutes spent purchasing gas (see Appendix 4G).

It can be noted that the estimates for use time of residential facilities includes the total time spent at the facility during the entire year, as one visit is defined as one year.

Another component of the generalized use and access cost, access time, is an estimated variable developed by HDR and the Department, and verified by the RAP panel (see Appendix 4H). As described above, access time includes the time spent accessing a facility, not the time spent using the facility. The most likely estimates of access time range from 7 minutes spent accessing gas stations to 58 minutes spent accessing an amusement park.

As mentioned above, the market prices, C0, of some facilities only affects the generalized use and access cost since the number of visits is assumed directly. The market price for visiting an office building, although not paid directly at the entrance, like at a movie theater, is instead estimated to be the value of the person in the office building providing the visitor service, assumed to be $20.

The market price per visit of a school facility is estimated based on assuming a private elementary or secondary school has an annual tuition of $10,000, and a private undergraduate and postgraduate school has an annual tuition of $30,000. The market price for public schools is assumed to be equal to private schools. However, taxpayers pay this price instead of the visitor directly. This annual tuition is divided by the number of days in a school year of elementary and secondary schools, 180 (or 160 for undergraduate and postgraduate schools) to determine the price per visit.

While the market price per visit of government housing (which, being a residential facility is assumed to be a year) could be estimated from the average monthly rent paid (reported by HUD in January 2008 to be $293), this figure does not affect the calculation the number of visits, which is based upon the number of residents, as described in section 4.2.1 above. The market price of state and local judicial, detention, and correctional facilities is assumed be zero. Appendix 4I lists the market prices per facility.

4.2.5 Value of Time

As described above, the generalized use and access cost includes the cost of time of a facility visit. The total time, including travel time, access time, and use time, are monetized by the value of a visitor’s time. The value of time varies by the usual primary function of a facility: non recreational (work), recreational, or residential (see Appendix 4J). The value of time is estimated according to the Bureau of Labor Statistics, U.S. Department of Labor, estimates of the average wage for the average production worker in 2006, approximately $20 per hour, as a standard estimate what could be earned for an alternate use of that time (i.e. working). It is assumed that the average for the low income population is half of the average wage rate or, $10 per hour. Due to a high proportion of persons with disabilities being low income, the $10 wage rate is used as a conservative estimate for their baseline value of time. This baseline value of time is used for many facilities for which work or housework/errands are performed. Using common economic assumptions, the value of time for recreational facility visits is one half that of the baseline value of time, or $5 per hour.

The value of time spent at a residential facility, which is the state and local government housing facility group, is determined to be half the average wage rate, also $10 per hour. Persons in state and local detention and correctional facilities are assumed to have a value of time of $0.10 per hour.

The value of time for persons enrolled in school facilities is estimated by using the value of time of the adult supervisor of the child. In other words, value the time as if the child was an adult - which assumes 1 hour of supervision for each hour saved. This will also take the normal adjustment factor for non-work time. Therefore, for each child in a classroom (the visitors of the school facilities), the teacher’s supervision time is valued at $1.30 ($20 per hour divided by an estimated 25 children per classroom).

Premiums on the value of time are developed for two parts of the user experience at a facility. Changes in access time due to requirements are valued at the most likely level of twice the value of time. Some requirements also directly affect the primary purpose of the facility visit. The value of use time at these facilities is enhanced and the associated premium on the value of time is 35% of the value of time and applies for the entire use time. Both of these assumptions are most likely values and are consistent with published sources on the economics of the value of time. Appropriate ranges have been applied to the distributions around these parameters. (See Appendix 4J.)

The premium for use time at a facility that is enhanced by a particular element is assumed to be the difference between the premium value of sitting down and standing up. The premium for access time at a facility is the difference between the premium value of walking and sitting down in a segregated vehicle.

4.2.6 Access Time Change

Data from an expert panel provide a basis for understanding total access time per requirement during a facility visit. As mentioned in Section 3.2.2, the total access time is computed from the product of (a) the access time change per requirement use; (b) number of uses per visit; and (c) the likelihood that benefits are realized. The realization of time change and number of uses per requirement are described in Appendix 4K. An example of the data requested from the panel is shown in Figure 4. Data from the panel data  are summarized for the access time per facility by creating a range of possible access times per facility by the given high, low, and most likely estimates provided by the panelists (see Appendix 4L). The average of the responses determines the low and high limits of the range.

Likelihood of Experiencing Benefits
Users may not always experience the full benefit of increased access, as indicated by the RAP Benefits Panel. The RAP Benefits Panel provided estimates of the time savings that would be experienced by users of the facility because of the new access requirements. The panelists’ responses provide a range of likely benefits per use of a facility amenity. However, questions did not require panelists to account for all expected time savings associated with the use of each requirement during a facility visit. Accordingly, it is possible that panelists focused on the time savings per use but not the uses per visit. In some cases, the use of an accessibility element, and thus the realization of benefits, is quite remote (e.g. needing to use the visible alarms). Because results of the panel indicate a high total access time savings, panelists exhibited cognitive biases towards higher impact time or uses, potentially because of the associated discomfort in overcoming accessibility obstacles. To be conservative in the estimation of benefits, a likelihood for experiencing benefits due to each element is incorporated into the model. The likelihoods of experiencing benefits vary from 0.0001% (visible alarms in alterations to existing facilities) to 100% for raised courtroom stations not for members of the public. In consultation with the Department, HDR/HLB determined the likelihood of experiencing benefits from individual requirements grouped into one of several categories based upon the type of time savings resulting from each requirement and the likelihood that benefits would occur. The categories were then ranked from least likely to most likely and assigned conservative estimates of the likelihood of experiencing benefits to ensure that incremental benefits occur only when the element is actually used (such as, for example, a power outage necessitating an alternate means of opening automatic doors or the likelihood of needing to use the rest room during a visit to a shopping mall). Likelihood estimates for each requirement, and descriptions of the groupings (general categories) used can be found in Appendix 4M.

These final parameters for the range of possible time changes and expected number of uses per requirement result in a reasonable, conservative estimate of total time change per facility given the applicable requirements. The total change in access time at the expected level is compared for consistency and validation with the access time provided by the expert panel. The average change and total access time savings in access time should normally not exceed the current access time. The total change in access time per facility group is shown in Appendix 4N.

Figure 7: Example of Benefits RAP Question

13. Accessible routes from site arrival points within sites: Vehicle-only routes would not have to provide an accessible pedestrian route.

  • Time increase in moving around a facility in a car (including waiting for a car) or traveling independently more cautiously or less conveniently compared to having accessible buildings or elements connected through accessible routes
  • Expected number of trips made to and from sites within a facility visit
  • Target population: Ambulatory

Time increase (minutes):                                             Expected number of uses per 100 visits:

o Range: 10 – 60       o Other:                                 o Range: 20 – 60       o Other:        

o Most Likely: 20      o Other:                                 o Most Likely: 30      o Other:        

Lost Access:

% of target population whose independent access is now not possible: ____


4.2.7 Price Elasticity of Demand for a Facility Visit

Elasticities for some facility groups are derived directly from literature sources (see Appendix 4O). Facilities of the same type are assumed to have the same elasticities. Elasticities range from 1.8 for golf courses to 0.16 for auditoriums (based on price elasticity of small market orchestras), reflecting the fact that visits to golf courses are fairly sensitive to price, while visits to auditoriums are much less so. State and Local Judicial Facilities, detention and correctional facilities are assumed to have an elasticity of zero; it is assumed there is no market demand for these facility visits and that visits to these facilities are determined by other factors instead of price.

4.2.8 Ease of Access Adjustment

Each facility is assumed to have an ease of access factor according to the current and future conditions, assuming adoption of the Final Rules. These factors range from 60 percent to 100 percent. At 100 percent, facilities are generally accessible (except for the Final Rules), and vice versa for 0. As discussed in Section 3.2.3, the ratio of current to future EOA provides a scaling factor for the price (or visit) responsiveness by users. Assumptions on the EOA factors are in Appendix 4P.

4.3 Risk Analysis

Uncertainty in the estimation of costs and benefits is addressed through risk analysis. Risk analysis principally involves quantifying the uncertainties in factors for estimating cost and benefit. Quantification involves defining probability distributions of possible values for each factor. Data used to quantify uncertainty come in part from research and discussions with experts. The distributions of cost and benefit factors are inputs to the model, which is then solved using simulation. The simulation process varies all factors simultaneously so that interrelationships between variables are more realistically handled and the impacts of factors on final results are considered jointly. The results include all possible estimates according to their probability of occurrence. In addition, the analysis identifies which parameters are the key influences on results. Risk analysis addresses and in fact, encompasses the approach to sensitivity analysis called for in OMB guidelines.

Uncertainty is quantified for most parameters in the model. Expert RAP panels provided many of the critical inputs with respect to the range of values. These include access time change, uses per visit, and unit costs. Some uncertain variables, such as the number of elements per facility, have a range determined as + and – 20% of the most likely value (the value provided by the panel and HDR architects). This range represents upper and lower boundaries for the distribution. Other parameters, such as (a) the likelihood that an element is in an average facility and (b) the likelihood that benefits are realized during a facility use, have ranges that are determined by consistent application. No data is available to verify these values so ranges wider than +/- 20% are used. In all cases, PERT distributions are used with the low, most likely and high parameter values to define the distribution.[10]

4.4 Definition of Baselines

The ADA Standards are the primary baseline for this assessment because they are the only uniform set of accessibility standards that apply to every place of public accommodation, commercial facility, and State or local government facility in the country. Alternate IBC baselines potentially have a different incremental cost and benefit for each requirement and facility combination.

The Department did not attempt to calculate the incremental benefits and costs in each case (e.g., separately for IBC 2000, IBC 2003, and IBC 2006). With the 1991 Standards as the primary baseline, this would have amounted to conducting four separate regulatory assessments rather than one. Instead, the Department has identified which of the revised requirements should logically be subject to an IBC baseline (because the IBC provision is more stringent than the current requirement in the ADA Standards) and then, with respect to those requirements, where the IBC provision is also equivalent to the new or revised requirement in the Final Rules, assessed zero benefits and zero costs. Where the IBC provision is not equivalent to the provision in the Final Rules, even if it is more similar to the provision in the Final Rules than it is to the provision in the 1991 Standards, the full incremental benefits and costs of the Final Rules against the ADA baseline have been applied. At worst, this approach will have overstated the benefits and costs for facilities under the IBC baseline. It could not have understated the benefits and costs because whenever the IBC provides a less stringent (less costly) provision than the 1991 Standards (so that the incremental cost difference between compliance with the IBC provision and compliance with the revised requirement would be greater than that between the IBC and the current requirement), the IBC provision is trumped by the current requirement, which must then serve as the baseline.

Appendix 9 shows a table of each requirement’s assumption for its application to each IBC baseline. Overall, there are 16 requirements that are in compliance with IBC 2000, 27 that are in compliance with IBC 2003, and 35 that are in compliance with IBC 2006.

Analyses of these baselines are conducted separately for each edition year of the IBC. For each baseline, requirement-level comparisons are made with 1991 Standards and 2004 ADAAG. If the alternative baseline is equivalent to the 2004 ADAAG, the element is assumed to be compliant. Otherwise, compliance is required and at a cost that would be similar to that which would be required if the element complied with only the 1991 Standards.

[1] Employer-based establishments are more likely to require compliance than non-employer establishments (which may be self-employed firms).

[2] The business cycle (i.e. ups and downs of the economy) has not been considered in the lifecycle of the regulation. It is assumed that any business cycle impacts will average out over the planning horizon.

[3]   McGraw-Hill Dodge Construction Potentials Bulletin (February 2010).

[4] Paulette R. Rutlen, CPE, Chief Estimator, The Austin Company worked with the Department to develop unit cost estimates in May 2007. In April 2010, the unit costs were increased 3.6%, the January 2007 to January 2008 year-over-year increase in RSMeans 30-city national average construction cost index (CCI).

[5] BCC Building Cost Consultants of Plattsmouth, Nebraska provided estimates of changes in productive space which were reviewed by the Department’s architects.

[6] These facilities include: inns, hotels, motels, restaurants, motion picture houses, multi-level stores, offices of health care providers, both public and private hospitals, both public and private nursing homes, terminals, depots, both public and private parks or zoos, both public and private amusement parks, nursery schools/day care, elementary private schools, secondary private schools, undergraduate and postgraduate private schools, homeless shelter, food banks.

[7] Data are collected by the US Department of Housing and Urban Development (HUD).

[8] Data are collected from Bureau of Justice Statistics.

[9] Mobility is also a term used to describe the type of disability that persons have with an ambulatory disability.

[10] A PERT distribution is a triangular distribution determined by a minimum, maximum and most likely value.  The descriptor “PERT” comes from the fact the same assumptions regarding the mean (that it is four times more likely that the minimum and/or maximum value) are made as in PERT (Program Evaluation and Review Technique) network project planning.  (See Vose, David, Risk Analysis: A Quantitative Guide - Third Edition, Chapter 14).


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March 9, 2011

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