Lec 8, TD: part 1, ch.5-1&2; C2 H/O: pp.455-460: Urban Transportation Planning, Intro.

Urban transportation planning process and demand forecasting

Short- and long-range elements of TP Simplification of the system by links and

nodes Level of travel demand forecasting Get a general view of the travel-demand

forecasting process Urban activity forecasts and TAZ

TD Part 1: Topics

Urban Transportation Planning Process

Responsible for urban transportation planning

State gov.

DOT, UTA, local agencies

Travel-demand forecasting is necessary for these activities.

Short- and long-rang elements of transportation planning

Transportation systems management (TSM) Try to make existing systems as efficient as possible and make provisions for an area’s short-range transportation needs.

Long-range planning Identifies facilities to be constructed, major changes to be made to existing facilities, and long-range policy actions.

Actions: for (1) efficient use of existing road space, (2) reduction of vehicle use in congested areas, (3) improvement of public transit service, (4) efficient internal management

Potentially implementable plans will be further analyzed (refined) to be included in State’s transportation improvement program.

Level of travel-demand forecasting

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Use of travel-demand forecasting:

TSM (short-range)

Long-range planning

Refinement (after a set of plans have been chosen as finalists)

Updating the analysis

Level of travel-demand forecasting (cont)

Sketch planning tools: Preliminary screening of possible configurations or concepts. Rough estimates but can analyze many alternatives. Used for both long-term and short-term planning. Until the need arises for detail analyses, sketch planning suffices.

Traditional tools: A small number of alternatives but detailed analysis.

Microanalysis tools: More details for immediate applications. Effective in near-term planning (data must be very accurately observed (or collected) or estimated). Data collection costs a lot for each alternative plan Hence we can evaluate only a small number of plans.

Overview of the forecasting process

We will go through these 4 steps.

Must have data of activity (land use) and transportation systems

Defining the study area

3. Check zonal activities (characterized by, say, residential population, average income, employment (by type), car ownership, residential density, vacant land, non-usable land, etc. These are used as independent variables of trip generation formulas.

Depending on the needs, data may be aggregated for analysis unit: zones ring or sector.

The results of an activity analysis provide the planner with present levels of activities in zones to help in predicting future levels.

Sector

Ring

1. Define the boundary first.

2. Subdivide the area

Example: WFRC’s transportation planning study area and TAZs

Notice that not all part of the Weber, Davis, and SL County are included in this TAZ map. Some part of the counties are ignored, like wet land, steep hills, etc.

Urban activity forecasts:

Place PROVO here

Urban activity forecasts provide the estimates of where people will live and where businesses will be located in the future.These activity forecasts are direct inputs to the next stage of the process, trip-generation analysis.

Network geometry in nodes and links The network description

is an abstraction of what is actually on the ground, and as such does not include every local street or collector street in the area.

Zone Centroid

Centroid connectors

Node

Link Computer-based

modeling tools require a link-node representation of the network.