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(6) In making the forecasts of future economic activity, the study area's economic advantage in holding and attracting industries and workers should be analyzed and evaluated. Industry location decisions are influenced by such factors as costs of production, access to resources, characteristics of the labor force (i. e., its occupational skills, productivity, educational level, age, sex, etc.), the quality of the area's nonhuman resources, including the geography of the region (i. e., the future supply of these resources, climate, terrain, water, transportation, recreational facilities, etc.), and the fiscal and financial policies guiding the area's governing unit (i. e., its tax structure, borrowing powers, etc.).
(7) Moreover, analyses of data forecasts should take account of the effect on the local economy of variations (recent or otherwise) in the national economy; the effect of economic fluctuations on different industries, and the probable effect of technological developments on local industries over time.
(8) Forecasts which are merely extrapolations of recent trends may give misleading estimates of the future. An analysis of relationships between factors found within
part of any forecast and provide a basis for forecasts that diverge from these trends.
(9) Regardless of the method used to make future estimates, the results obtained should be tested for reasonableness and consistency. For example, an important check is to prepare a population forecast based on the employment forecast and compare this with the independent population forecast based on demographic techniques.
b. Population studies
(1) A population forecast is required to provide an estimate of the total potential tripmakers at some future time. The population and economic forecasts together form the basis for estimating future land use and travel demands, since the number of people and jobs are the major determinants of tripmaking.
(2) The first step in a population study should be a survey of all available historical data on total population, its distribution by small areas, and its characteristics. Using these data, analyses can be made of changes in rates of growth and in composition of the population. Such analyses will aid in determining the appropriate forecasting technique to be used. (3) All available pertinent population studies previously conducted by others should be fully utilized to the extent they are applicable and acceptable. These may include estimates of current population as well as forecasts, and may relate to the study area, parts of the area, or to larger regions containing the study area.
(4) Several forecasting methods are in common use today. The technique used to forecast population will depend upon the input requirements of other phases of the study, the detail of the available data, and the special characteristics of the study area (size, composition, and growth rate). The most important information that should be provided by the forecast is an estimate of future total population and average household size (or number of households).
(5) All assumptions and the reasons for making them should be documented. The population forecast should be checked for consistency with other forecasts independently prepared, especially those relating to employment.
C. Land use
(1) The land use study incorporates a wide variety of undertakings, all of which are aimed at providing an accounting of the current land use activity structure of the study area and the most probable or desirable future structure.
(2) The land use study should include the following items for the entire study
(a) An inventory of the location and intensity of existing land use activities, including vacant land. The inventory of vacant land should take account of land subject to flood, to the extent such information is available. Requests for flood hazard information may be addressed to the appropriate district office of the Corps of Engineers, U.S. Army. Inventory should also be made of authorized public and private capital improvement plans and programs, and existing pertinent zoning and subdivision regulations.
(b) An analysis of past trends to aid in determining land consumption rates and the most likely location patterns of households and business firms.
(c) The distribution of an areawide forecast of population and economic activity to small areas (zones). The forecast should give full consideration to officially approved plans or programs and community goals and objectives.
(3) The land use data needed as a base for developing the forecast may be obtained from field surveys, local planning agencies, other secondary sources, or a combination of these. All existing land use data, such as those available in local planning departments, should be fully utilized, provided they are adequate for the needs of the transportation study. Where a new field survey is necessary, it should be jointly undertaken by local and regional planning agencies working with the transportation study group.
(4) The land use data should be collected in a form that will allow their use for a variety of public and private planning purposes, including study of the area's land use characteristics and growth trends. To accomplish these objectives, it is desirable to list land use by specific activity rather than to classify land use into general categories. The Standard Land Use Coding Manual is a valuable guide for identifying and coding detailed land use activities. Adherence to the system recommended in the manual will maintain detailed data in a form that will permit its application to specific needs of various users as they arise.
(5) A forecast of land uses within an area - their type, intensity, and geographic distribution - is based on the long range goals and objectives of the individual communities, the broad planning concepts for the entire urban region, and the market forces inherent in private and public capital expenditures. The land use forecast is essential for determining
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future travel movements and transportation needs for the entire urban area.
(6) Land use forecasts provide the information needed for the travel forecasts. Normally these will be required for both a short-range period of about five years, as well as for a long-range period of about 20 years, to correspond to capital improvement program periods. In some cases, the forecasting process itself, as well as the requirements of the other phases of the study, may warrant forecasts for each five-year increment of the 20-year forecast period. The estimates of the future distribution of land use activities should permit periodic comparison of forecasts to actual development.
(7) The specific information to be provided by the forecast will vary considerably with the size of the study area. As a minimum, however, the following estimates should be provided for each zone, for each forecast period:
(1) The inventory of the existing transportation system should provide complete information on the physical features and operational characteristics of each link of the major street system (freeways, expressways, arterials, and collectors). Among the physical features of roads and streets that should be inventoried are rightof-way width, roadway width, roadway type and condition, parking regulations, and traffic control regulations and devices. Other items that may be included are listed in the National Committee on Urban Transportation (NCUT) Procedure Manual 5A, Inventory of the Physical Street System. The items to be included should fit the specific needs of each urban area study.
(2) Operational characteristics needed include the capacities of the roadways and the Imajor street intersections; the volume of traffic
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on each segment of the system; the speed of traffic movement at different volumes; and the frequency and location of accidents. NCUT Procedure Manual 3E, Maintaining Accident Records, may be used as a guide for making accident studies.
(3) The street capacity study should utilize the techniques described in the Highway Capacity Manual. Data from the physical street inventory will be required for the capacity study.
(4) Procedures for measuring traffic volumes are provided in the Bureau of Public Roads Guide for Traffic Volume Counting Manual. Traffic volumes should be measured at a sufficient number of points to describe the traffic being carried by the major street system. Both the annual average daily traffic (ADT) and the morning and evening peak-hour volumes are needed. The total traffic counting program should also include manual and machine counts at selected cordons and screenlines, turning movement counts at important intersections, and vehicle classification counts at points representative of conditions on different types of roads and streets.
(5) A functional classification should be made of the existing street system using the procedures given in the National Committee on Urban Transportation Procedure Manual 1A, Determining Street Use, and 7A, Standards for Street Facilities and Services, and in Highway Planning Technical Report, Number 3.2
(6) The inventory of the transportation system should also provide information on public transportation. Transit studies should provide data which will be useful in estimating the choice of mode of travel in the forecast year. The following data should be collected for each transit line by period of the day for an average weekday for the survey year:
(a) Transit route map by type of service and transit vehicle
1/ Highway Capacity Manual, 1965. Special Report 87 by the Highway Research Board, Washington, D. C.
2/ "Developing and Analyzing Functionally Classified Networks Utilizing Traffic Simulation-Phase 1," Highway Planning Technical Report, Number 3, Bureau of Public Roads, February 1966.
(b) Passenger counts at the CBD cordon or maximum load points
(c) Passenger fare distribution by single or combination fares (d) Operating data, consisting of:
1 Revenue vehicle-miles
by type of service and standard regulations
nal-to-terminal running time
5 Regularity of service as measured by ability to maintain schedules (7) Often additional information is needed on the character of trips within the central business district. To collect this information, "on and off" counts may be necessary.
e. Travel patterns
(1) Urban transportation planning requires specific knowledge of the current travel patterns of the area being studied. Information is needed on the location and amount of travel by the various modes, and on such trip characteristics as purpose, length, and time of day. Although similarities in certain trip characteristics are found in urban areas, there is enough evidence of differences to require these data be obtained in each area.
(2) For urban areas of over 50,000 population, it is considered essential that the base year travel for all types of trips (zone-to-zone, zone-to-external station, and external station-to-external station) by automobile, transit, truck, and taxi be established by purpose and time of day. This is usually done by conducting a comprehensive origin-destination survey.
(3) The zones into which the planning area is subdivided for analysis purposes should be sufficiently small to permit the transportation planning process to develop traffic assignments meaningful at the arterial street level. Normally there should not be more than 10,000 future trip ends (origins and destinations) in any zone.
(4) The zones should not be so large that the assigned volumes would be unrealistic,
for representation by a point. Preferably zones should be square and of homogenious land uses. Consideration should also be given to the compatibility of the selected zones with census tracts.
(5) It is recommended that the travel information be obtained by an external cordon and a home interview survey using methods described in the Bureau of Public Roads Home Interview Procedure Manual. Sample rates suggested in the manual are recommended. Other survey techniques are acceptable, provided adequate sampling procedures are used and adequate controls are established for expansion purposes.
(6) In preparing estimates of travel patterns for the forecast year, it is recommended that mathematical models be used. The models must be calibrated against the current travel patterns and, if results are to be acceptable, procedures used should meet the following tests:
(a) The total number of person trips, auto driver trips, transit trips, truck trips, taxi trips, and work trips are in reasonable agreement with controls independently established.
(b) Trip generation relationships used for estimating travel should be in reasonable agreement with actual relationships in the area being studied, and the trip length (time) frequency distribution and mean trip length values of estimated and actual travel should be similar.
(c) The number of work trips estimated to be destined for selected employment areas within the city should compare with actual employment data within reasonable limits.
(d) The distribution of trips crossing preselected screenlines should compare within acceptable limits with actual volumes measured on facilities crossing these lines. These screenlines should be placed so as to measure different portions of the travel pattern. The check should be made for vehicle trips and for transit person trips where the latter are significant.
(e) Weighting factors used to calibrate the travel distribution formula must be correlated logically with characteristics of the area where applied. The use of factors merely to provide a "match" between estimated and actual travel patterns will not be considered acceptable.
(f) The assignment of the synthesized vehicular travel to the current
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comparison with actual ground counts and vehicle-miles of travel.
(7) Estimates must be made of the future travel by all modes. Zone-to-zone, zone-to-external station, and external station. to-external station traffic should be forecast, and it is recommended that estimates be made of the peak period travel as well as of the total 24-hour travel. Estimates of the future travel that will be generated from and attracted to each zone should be based on relationships betwe en travel, land use, and socio-economic characteristics found significant in the base year analysis.
f. Terminal and transfer facilities (1) The effectiveness and efficiency of the urban transportation system is dependent to a large measure upon the availability of adequate terminal and transfer facilities at trip origins and destinations.
(2) An inventory of the present supply of parking space should be made as outlined in Procedure Manuals 3C, Conducting a Limited Parking Study, or 3D, Conducting a Comprehensive Parking Study, of the National Committee on Urban Transportation. The inventory should cover parking facilities, both at the curb and in offstreet garages and lots. Also, information on the location and use of truck loading and unloading facilities is needed. In addition, information on parking rates and on the average time, by hour of the day, required to park and unpark vehicles in offstreet facilities will be useful in estimating choice of mode of future trips.
(3) Special studies should be made of selected major terminal facilities serving substantial volumes of commercial traffic whether located inside or outside of critical areas. The study of these facilities will provide information useful for determining future parking, loading, and unloading requirements for similar terminals which may be required in the future.
(4) Estimates should be made of the future requirements for both parking and commercial loading and unloading facilities in critical areas. These estimates should be developed, utilizing the travel forecasts (as discussed under "Travel patterns") by trip purpose and time of day. Parking estimates should be consistent with forecasts of vehicle trip ends in a given area. The feasibility of satisfying future parking demands should be determined considering their compatibility with existing and future land uses, ordinances, codes, other regulations, and their effects upon the operational characteristics of freeways, expressways, arterial streets, and transit networks.
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g. Traffic control features
(1) Many engineering techniques for increasing the traffic capability of facilities are known. Some involve, for the most part, relatively minor expenditures and little or no construction. The traffic control features analysis in the transportation planning process should include studies leading to recommendations for the fullest utilization of the capacity of existing expressways and arterial streets. Traffic engineering techniques include improved signal operations, turning movement controls, parking restrictions, unbalanced lane operations, oneway street operations, through street systems, uniformity of signs, signals, and markings, simple channelization, street lighting, and pedestrian controls.
(2) These techniques are more fully defined in the report Increasing the Traffic-Carrying Capability of Urban Arterial Streets, by the Bureau of Public Roads, and available from the U. S. Government Printing Office.
h. Zoning ordinances. subdivision regulations, building codes, etc.
(1) Zoning ordinances, setback requirements, subdivision controls, building codes, tax policies, and the official map, together with licensing powers, are basic techniques used to control community development. The forecasting of future land uses is subject to considerable error at best, but lacking adequate controls, "planned" development will in most instances have little chance of becoming reality. Further, land
use controls are important to protect the traffic-carrying capability of, and public investment in, transportation facilities.
(2) Existing State, regional, and local laws and ordinances should be analyzed in the light of the objectives for future development and deficiencies carefully documented. The review of such laws and ordinances should be made as they are initiated or approved.
i. Financial resources
(1) One of the more critical factors influencing programs devised to implement an urban transportation system plan is the availability of adequate financial resources. In addition to determining the transportation system needs for a study area and the estimated costs to fulfill these needs, the transportation planning process should also survey and analyze the ability of the affected governmental units in the study area to
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(2) A financial resources study should begin with an inventory of the sources and amounts of revenue available for the construction, maintenance, and operation of transportation facilities in the study area over the past 5 to 10 years. In addition, a historical record of the disbursements actually made for transportation purposes over the same period of time should be obtained.
(3) It is also well to determine the mental units involved by analyzing the trend overall financial condition of the local governof their funded debt. This trend, along with any laws specifying debt limitations or taxing restrictions may help indicate to what extent the governmental units within the study area will be able to contribute to the financing of the area's transportation system.
(4) The next step in the analysis is to be available for transportation improvements to prepare estimates of the revenues expected estimates are usually available for short-time within the study area. For many urban areas, periods.
j. Social and community value factors
(1) In the development of transportation plans, it is important that full consideration be given to the possibility of utilizing these facilities to raise the standards of the urban area. Open space, parks, and recreational facilities are important environmental factors. It is becoming more and more important in our transgiven not only to the preservation and enhanceportation planning that additional attention be ment of existing open space, but also to the providing of additional open space in anticipation of future development. Similarly, conscientious attention should be given to the preservation of historical sites and buildings.
(2) In planning the location of transportation facilities, every effort should be made to avoid areas subject to flooding. If an encroachment of flood plain appears necessary, an evaluation should be made of the flood potential on the highway and the effect of the highway construction on the flood hazard.
(3) Care also should be exercised in selecting locations for new transportation facilities so that neighborhoods are not disrupted. To the maximum extent possible, cutting through school districts, fire station districts, etc., should be avoided and the appearance of the facility from the viewpoint of the motorist, the pedestrian and the nearby residents should be considered.