3 Flashcards
2
Is expressed as the number of persons or vehicles per unit time that can be expected to travel on a given segment of a transportation system under a set of given land-use, socioeconomic, and environmental conditions.
Travel Demand
Are used to establish the vehicular volume on future or modified transportation system alternatives.
Forecasts of travel demand
two basic demand forecasting situations in transportation planning.
- Travel demand studies for urban areas
- Intercity travel demand
The information gathered provided useful insight concerning the characteristics of the trip maker, such as age, sex, income, auto ownership, and so forth; the land use at each end of the trip; and the mode of travel
Travel demand studies for urban areas
data are generally aggregated to a greater extent than for urban travel forecasting, such as city population, average city income, and travel time or travel cost between city pairs.
Intercity travel demand
Factors Influencing Travel Demand
- Land-use characteristics
- Socioeconomic characteristics
- Availability of transportation facilities and services
are a primary determinant of travel demand. The amount of traffic generated by a parcel of land depends on how the land is used. For example, shopping centers, residential complexes, and office buildings produce different traffic generation patterns.
- Land-use characteristics
characteristics of the people living within the city also influence the demand for transportation. Lifestyles and values affect how people decide to use their resources for transportation.
- Socioeconomic characteristics
referred to as the supply, also affects the demand for travel. Travelers are
sensitive to the level of service provided by alternative transportation modes.
When deciding whether
- Availability of transportation facilities and services
is the process used to predict travel behavior and resulting demand for a specific future time frame, based on assumptions dealing with land use, the number and character of trip makers, and the nature of the transportation system
- Travel Demand Forecasting
Five of characteristics of travel
- functional classification
- system extent
- system usage
- system performance/capacity
- system condition
Detailed information on existing travel is needed for two purposes
- analyzing existing problems, and
- developing mathematical models for forecasting travel.
A variety of surveys can be performed for gathering information related to existing travel demand
- Time Frame for Travel Surveys
- Origin-Destination (O-D) Surveys
- Traffic Volume and Passenger Counts
Since travel demand varies during a given year according to the season (or month of year) and day of week, a decision must be made carefully to select a specific time frame or reference for surveys
- Time Frame for Travel Surveys
The classification of trips into the three classes of internal, external-internal (and vice-versa), and through trips is useful for ‘meso’ scale and metropolitan level as well as small area studies.
- Origin-Destination (O-D) Surveys
To determine the use of various roadway facilities and assessing their level of service, vehicle counts are taken at selected locations along roadways.
- Traffic Volume and Passenger Counts
