Sequential demand forecasting models
1 / 31

Sequential Demand Forecasting Models - PowerPoint PPT Presentation

  • Updated On :

Sequential Demand Forecasting Models CTC-340 Travel Behavior 1. Decision to travel for a given purpose People don’t travel without reason 2. The choice of destination 3. The choice of mode 4. The choice of route or path Trip generation

Related searches for Sequential Demand Forecasting Models

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Sequential Demand Forecasting Models' - Ava

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Travel behavior l.jpg
Travel Behavior

  • 1. Decision to travel for a given purpose

    • People don’t travel without reason

  • 2. The choice of destination

  • 3. The choice of mode

  • 4. The choice of route or path

Trip generation l.jpg
Trip generation

  • Forecast the number of trips which begin or end in a Traffic Analysis Zone

    • Must be calibrated

    • Dependent upon

      • land use

      • socioeconomic factors

      • at both ends

Trip generation4 l.jpg
Trip Generation

  • Trip ends (Q)

    • How many trips are being made due to a land use

  • Production (P)

    • origin of residential based trip

      • Home - based trip -- begins or ends at home

      • non-home based trip -- trip does not begin or end at home

  • Attraction (A)

    • destination of residential based trip

Trip purpose l.jpg
Trip purpose

  • work, school, shopping, social, recreational

  • Can be single purpose or multi purpose

Zonal model l.jpg
Zonal model

  • look at trips between zones

  • A zone is a homogeneous area of

    • land use

    • population

    • income

    • vehicle ownership

    • same access paths

Trip rate analysis l.jpg
Trip Rate Analysis

  • Determine the average productions and attractions of a trip generator

  • ITE Trip Generation Handbook

    • rates by land use

    • based on 1000 sf, employees, students, dwelling units, etc

  • Need to determine whether the generator or the adjacent street controls volumes generated

    • Why?

Pass by trips l.jpg
Pass-by trips

  • Trips not generated by land use

    • Vehicle deviates from its course to use land use and then continues on its path

    • What are major land uses where this type of trip is important

    • can be 25 - 60% of trips

    • Subtract trips from through traffic, add to turning traffic (in and out)

Linked trips l.jpg
Linked Trips

  • Trips with multiple destinations all within one area and not requiring road access between destinations

  • 10 - 20 % of trips for certain land uses

    • Used in Malls and shopping centers

Example l.jpg

  • Drive in Bank 5,000 sf w/drive thru

  • 60,000 sf office building

  • AM & PM trips

  • What other times might be important?

Grand vista l.jpg

131 Single Family Homes

370 Townhouse units

400 Garden Apartments

640K Office Park

257K Shopping center

3 banks & Restaurants

365K Industrial Park

90K Medical Office

180 Room Hotel

Grand Vista

Grand vista12 l.jpg
Grand Vista

  • Spreadsheet

Trip distribution l.jpg
Trip Distribution

  • Where do the trips come from?

  • Gravity Model provides answers

    • force of attraction between two bodies is proportional to the product of their masses and inversely proportional to the product of the distance between them

Trip distribution14 l.jpg
Trip Distribution

  • F is the friction factor

  • proportional to W

    • F = 1/W^2

  • P is productions in i

  • A is attractions in j

  • Q is the trips from i to j

  • K is the difference in socio-economic factors from i to j

Trip distribution15 l.jpg
Trip Distribution

  • Gravity model works for large and small developments

    • may need to calibrate large developments

  • usually use census tracts as zones

  • can use information developed by developer

  • Retail stores use zip codes

Trip distribution16 l.jpg
Trip Distribution

  • Attraction depends on

    • uniqueness

    • distance

    • closeness to other services

    • urban or rural

  • Shopping Centers usually have a 5 mile radius of influence

Grand vista17 l.jpg
Grand Vista

  • 6 access roads

  • Need to distribute traffic to each site driveway

    • Based on destination/start point

    • This is where judgment comes in

  • Spreadsheet

Modal choice l.jpg
Modal Choice

  • Trip makers choose mode

    • trip type is a factor

    • socio-economic status is a factor

    • transit captives

  • 2 types of models

    • pre-distribution - attraction has no impact on mode

    • Post-distribution – attraction does impact mode

Models l.jpg

  • Diversion curves

    • based on auto costs, transit travel time, auto travel time, transit LOS, auto LOS, income

Models20 l.jpg

  • Utility and Disutility

  • measures satisfaction or impedance of choice

  • All provide a percentage of trips per mode

    • As inputs change, outputs also change

Network assignment l.jpg
Network Assignment

  • Determine path

  • Number of paths depends on network

  • person trips vs vehicle trips

  • Transit Assignment

    • depends on capacity, facilities, connectivity

Network assignment22 l.jpg
Network Assignment

  • 3 major times - Peak Hours

  • Trip direction is important

  • Diversion Curves

    • good when only two paths to choose from

    • arterial vs freeway

    • many iterations

      • based on travel time of each facility

Link flow l.jpg
Link Flow

  • Flow that occurs on a link in a network

  • Route Choice Behavior

    • user equilibrium

      • goes on shortest path

    • system equilibrium

      • cost of system is minimized

    • stochastic equilibrium

      • user assigns self to “shortest path”

Minimum path algorithms l.jpg
Minimum Path Algorithms

  • Minimizes most important user criteria

    • cost, time, distance

    • can also develop trade-offs between criteria to determine “best route”

    • can determine the traffic on a link

Minimum path algorithms25 l.jpg
Minimum Path Algorithms

  • All or Nothing

  • Multipath Traffic Assignment

  • Capacity Restrained

  • Transit Assignment

All or nothing l.jpg
All or Nothing

  • Need to find minimum path tree for network

  • place traffic on links

  • gives info on most heavily used links

  • not accurate for high volumes

Grand vista27 l.jpg
Grand Vista

  • Add traffic to links to get build volumes

  • Spreadsheet