Transportation Planning and Travel Demand Forecasting CEE 320 Anne Goodchild

Outline Transportation Planning Travel Demand Forecasting Defined Transportation Planning Organizations Long term plan example Short term plan example Travel Demand Forecasting 4 step process

Transportation Planning The process to provide the information needed for decision makers to choose among alternative strategies for improving transportation system performance. Transportation planning is future-oriented Uncertainty in predictions Balance short-term and long-term benefits The problem is not isolated and independent Hierarchical structure Broad impact and involvements

Transportation Planning Organizations Federal transportation legislation requires that a Metropolitan Planning Organization (MPO) be designated for each urbanized area with a population of more than 50,000 people in order to carry out the metropolitan transportation planning process, as a condition of Federal aid. In 1990, the Washington State Legislature passed the Growth Management Act (ESHB 2929) authorizing the Regional Transporaton Planning Program. This program allows for the formation of Regional Transportation Planning Organizations (RTPOs). The primary functions of RTPOs are to develop regional plans and policies for transportation, growth management, environmental quality, and other topics determined by the RTPO; provide data and analysis to support local and regional decision making; build community consensus on regional issues through information and citizen involvement; build intergovernmental consensus on regional plans, policies and issues, and advocate local implementation; and provide planning and technical services on a contractual basis. --source: http://www.wsdot.wa.gov/ppsc/planning/WhatRTPO.htm

Transportation Planning Long term (strategic) planning Very complex Based on long-term predictions Involves multiple levels of government and administration Short to medium term planning Less complex Reduced uncertainty More specific Short term plan tends to place no great demands on construction activities and therefore has no large capital requirements. The scale of the problem usually is quite limited and the analysis and evaluation, while being detailed, are usually simple in structure. This type of problem comes under the generic term Transportation systems management (TSM).

A Long-Term Transportation Plan PSRC’s long-term plan: Destination 2030 The Puget Sound Regional Council is an association of cities, towns, counties, ports, and state agencies that serves as a forum for developing policies and making decisions about regional growth and transportation issues in the four-county (Pierce, King, Snohomish and Kitsap) central Puget Sound region What is a Highway of Statewide Significance? The Revised Code of Washington (RCW) sets minimal criteria for HSS designation:  “This statewide system shall include at a minimum interstate highways and other statewide principal arterials that are needed to connect major communities across the state and support the state’s economy.” The Washington State Transportation Commission expanded the criteria, an HSS roadway must also be: A State Highway; A Principal Arterial that is part of the National Highway System (NHS); Rural routes serving statewide travel; and/or Urban routes that are: Statewide travel links to Rural HSS, Connections to Principal Arterial Ferry Routes, Long haul freight links - FGTS Class T1 and T2, and Connections to ports - FGTS Class T1 and T2.   Designation of a route as HSS means: Higher priority for improvement funding; State has authority for setting level-of-service (LOS); Highway segment is exempt from local transportation concurrency requirements; Identified as an essential public facility; Consideration for primary funding by a the RTID. Source: PSRC Website: http://www.psrc.org/projects/mtp/index.htm

Key Messages from Destination 2030 Snohomish Key Messages from Destination 2030 Puget Sound is a Growing Region We Have a Balanced Plan Linking Land Use and Transportation Investment and Finance Principles Monitoring Performance Kitsap King Our region’s growth is constrained by water on one side, mountains on the other, and things like wetlands and earthquake fault lines in between. Transportation answers aren’t simple or cheap. Custom fit: The beauty of Destination 2030 is it’s custom fit to our region – not just our topography but our cities, towns and neighborhoods. So in the end we can grow but still maintain our natural environment and quality of life. Pierce

A Long-Term Transportation Plan Destination 2030 is comprehensive: Identifies over 2,200 specific projects that have been designed to result in improved roads, transit, and ferry service. Over 2000 miles of new and improved regional state roadways. More than 2000 miles of new walkways and bikeways to connect communities with transit, shopping, and services. Incentives to better transit service, carpools, etc.

A Long-Term Transportation Plan Programs: State Ferry and Highway Programs Local Transit Seattle Monorail Regional Transit Non-motorized Freight Aviation More information at:http://www.psrc.org/projects/mtp/d2030plan.htm

A Short-Term Transportation Plan SR 520 Freeway bottleneck Old and at end of useful life

A Short-Term Transportation Plan 4-lane alternative ($1.7-2.0 billion) The WSDOT team studied potential I-5 improvements to accommodate SR 520 traffic from the 8-Lane Alternative through downtown Seattle. Project investigations found that I-5, already over capacity, would be unable to handle traffic from the 8-Lane Alternative without considerable improvements. The 8-Lane Alternative will be in the SR 520 Bridge Replacement and HOV Project Draft EIS as a traffic/engineering appendix. Further environmental analysis of the 8-Lane Alternative will not be included in the Draft EIS. The 8-Lane Alternative may be further evaluated if the I-5 study identifies operational improvements on I-5 that would accommodate the SR 520 8-Lane Alternative. 6-lane alternative ($2.6-2.9 billion)

A Short-Term Transportation Plan Electronic Toll Collection WSDOT is assuming tolls to be a future means of funding the project. The Regional Transportation Investment District (RTID) - made up of King, Pierce and Snohomish counties - is also developing a potential long-term funding package for approval by the voters.

Basic Elements Transportation System DB Socioeconomic and land use DB Goals and Objectives Identify Deficiencies and Opportunities Develop and Analyze Alternatives Evaluate Alternatives Implement Plan

Planning Realities Uncertainty in predicting the future Economy, fuel, population growth Analytical limitations Inventory, forecasting, performance measures Influence of politics MPO is an explicitly political forum In a democracy, elected officials should make key decisions

Travel Demand Forecasting

Need for Travel Demand Forecasting Impacts of facilities or modes of travel Lines on existing roads Roads Light rail Bus service Geometric design Pavement design

Traveler Decisions Types of decisions Influences Time (when do you go?) Destination (where do you go?) Mode (how do you get there?) Route choice (what route do you choose?) Influences Economic Social

Predicting Travel Decisions Collect data on travel behavior Observation (number of buses, cars, bikes, etc.) Surveys Collect data on what travelers have done Collect data on their values and choices (utility) Inexact nature of prediction Incomplete data Reporting problems

Travel Demand Forecasting Divide process into 4 steps: Trip Generation Trip Distribution Mode Split Trip Assignment We will explore further: Trip generation Poisson models Mode choice logit models Trip assignment route choice models

Trip Generation Relates the number of trips being produced from a zone or site by time period to the land use and demographic characteristics found at that location. Assumptions: Trip-making is a function of land use Trips are made for specific purposes Different trip types are made at different times of the day Travelers have options available to them Trips are made to minimize inconvenience System modeling is based on Traffic Analysis Zones and networks Poisson model often used

Trip Generation An example trip generation map: TAZ (4) P=26,268 A=17,740 Suburbs TAZ (5) P=33,255 A=18,190 TAZ (2) P=14,498 A=16,799 City TAZ (3) P=13,461 A=19,774 P=8,980 A=23,696 CBD Trip productions and attractions are computed for each zone by land use Trip Purposes HBW – Home based work trip HBNW – Home based nonwork trip NHB – Non-home based trip Usually computed using trip generation rates P = trips produced, A = trips attracted

Trip Distribution Connect trip origins and destinations estimated by the trip generation models Different trip distribution models are developed for each of the trip purposes for which trip generation has been estimated Most common model in practice is the "gravity model"

Gravity Models Distribution of trips is: Proportional to the number of trips produced and attracted by each zone Inversely proportional to the separation between the origin and destination zones Widespread use because of its simplicity, its reasonable accuracy and support from the USDOT

Gravity Models Development Trail and error process TAZ (4) 1730 Suburbs TAZ (5) 1850 TAZ (2) 1600 City TAZ (3) 2100 1700 P=8,980 CBD

Trip Distribution Tij = Number of trips produced in zone i and attracted to zone j Pi Number of trips produced by zone i Aj number of trips attracted by zone j Fij friction factor (the gravity part) c is often 1 and n is often 2 t travel time Kij socio economic adjustment (fudge) factor

Mode Split Based on utility (level of attractiveness) of modes Logit model most commonly used TAZ (4) 577 bus 1153 car Suburbs TAZ (5) 462 bus 1388 car TAZ (2) 640 bus 960 car City TAZ (3) 1050 bus 1050 car 1000 bus 700 car P=8,980 CBD

Trip Assignment Assigns trips to paths through the network Two most common methods All or nothing (shortest path) assignment Capacity restraint (incremental) assignment TAZ (4) Suburbs TAZ (5) TAZ (2) City TAZ (3) CBD 8980

Example: Bellevue 1999-2010 Forecasted Population Growth The legend is not recognizable, but the numbers are not important here. Basically the darker the color, the bigger the growth. Decrease 0-99 100-499 500-999 1000-2999 3000+ Forecasted Population Growth Source: Bellevue Transit Plan 2001-2007

Example: Bellevue 1999-2010 Forecasted Employment Growth The legends are not recognizable, but the numbers are not important here. Basically the darker the color, the bigger the growth. Decrease 0-99 100-499 500-999 1000-2999 3000+ Forecasted Employment Growth Source: Bellevue Transit Plan 2001-2007

2010 Total Bellevue Trips to Downtown and Overlake The legends are not recognizable, but the numbers are not important here. Basically the darker the color, the bigger the growth. 5,000 trips 10,000 trips 15,000 trips 20,000 trips 25,000 trips 2010 Total Bellevue Trips to Downtown and Overlake Source: Bellevue Transit Plan 2001-2007

2010 Total Eastside Trips to Downtown and Overlake Source: Bellevue Transit Plan 2001-2007

Primary References Mannering, F.L.; Kilareski, W.P. and Washburn, S.S. (2003). Principles of Highway Engineering and Traffic Analysis, Third Editio. Chapter 8 Transportation Engineering Online Lab Manual (2000). Oregon State University, Portland State University, Idaho University. http://www.webs1.uidaho.edu/niatt_labmanual/index.htm