Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction...

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Transportation Planning, Transportation Demand Analysis • Land Use-Transportation Interaction • Transportation Planning Framework • Transportation Demand Analysis

Transcript of Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction...

Page 1: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Transportation Planning, Transportation Demand Analysis

• Land Use-Transportation Interaction

• Transportation Planning Framework

• Transportation Demand Analysis

Page 2: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Land Use-Transportation Interaction

Change in

Land use

Change in

Trip

generation

Change in travel needs

Change in

transportation

supply (added services

& facilities)

Accessibility

Land Values

Transportation

serves land uses

Transportation shapes land uses

Page 3: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Land Use-Transportation-Environment Interaction

Land use

Transport

Environment

..

ZonesUrban Area

Change in land use over time (i.e. change in residential units, commercial land use, industrial land use, retail land use, etc.

Page 4: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Land Use Patterns, Bid RentPressure for growth

Demand for land Bid rent

Land use pattern Location of

activities

CBD

Bid rent $/sq.km

PopulationJobs

Distance from CBD

CBD Distance

Page 5: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Purpose of Land Use Models

• To explain/predict:

Change in land use as a function of:

- accessibility to employment

- land value

- percent of urban level available vacant land in a zone

- public transit accessibility

- quality of water & sewer services

- etc..

Page 6: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Modelling Travel DecisionsUser Decisions

1. To travel (for a given trip purpose at a given time)? (Trip generation)

2. Destination? (Trip distribution)

3. Mode? (Modal Choice)

4. Route? (Assignment of trip to network)

Modelling Approaches

•Four-stage urban transportation modelling system (UTMS)

•Unified approaches

Page 7: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Urban Transportation Demand Modelling: Four- Stage Modeling System

Population & Employment Forecasts

Trip Generation

Trip Distribution

Modal Split

Trip Assignment

Link & O-D Flows, Times, Costs, Etc.

TransportationNetwork & Service

Attributes

Page 8: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Four Stages of Urban Travel Demand Modelling

I JTrip GenerationOi

Dj

I JTrip Distribution Tij

J

I JMode Split

Tij,auto

Tij, transit

I

J

Traffic assignment

Path of flow Tij,auto through the auto network

Page 9: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Multiple Trip Purposes

HW HS NWS

Generation Generation Generation

Distribution Distribution Distribution

Modal Split Modal Split Modal Split

Road Assignment Transit Assignment

Population Employment

Trip Rates, etc.

Transport

Network

Link & O-D volumes, times, costs, v/c ratios, etc.

Page 10: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

The Traffic Prediction Process

Trip generation P & A

Transit network Road network

Trip distribution

Modal split

Transit person trips Auto person trips

Occupancy Occupancy

Transit vehicle trips Auto vehicle trips

Freight & other vehicles

Transit traffic assignment Road traffic assignment

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Trip Generation

Modelling Methods

•Linear regression method

•Cross-classification (category analysis) method/trip rate method

_______________________________________________________

Trip generation

•Productions & Attractions

•Home-based & non-home based

trips

J

I

Zones

Page 12: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Productions & Attractions

Pi = Trip productions of zone i = f(land use, socio-economic characteristics of zone i)

Aj = Attractions of zone j = f(land use, socio-economic characteristics of zone j)

Regression Model Examples: (P.M. Peak Period Work Trips)

Pi = 0.4572 emp - 138 (R2 = 0.87)

Aj = 0.1848 pop + 9 (R2 = 0.90)

Where emp is total employment

pop is total population

Page 13: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Productions & Attractions (Continued)

Regression Model Examples: (P.M. Peak Period Non-work trips)

Pi = 0.1346pop+0.2897emp+0.0043GLA (R2 = 0.76)

Aj = 0.0888emp+ 0.6204DWEL+0.0045GLA+221 (R2 = 0.80)

Where emp: is total employment

pop: is total population

GLA: shopping centre gross leasable area (ft2)

DWEL: Dwelling units

Page 14: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Productions & Attractions (Continued)

RegressionModel Development

Data Required

Zone Pi*

Aj*

pop emp GLA DWEL

1 …. .… …. …. …. …..

2 …. .… …. …. …. …..

.

_____________________________________________

* from O-D survey

Data on other variables obtained from city data base

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Trip Productions & Attractions (Continued)RegressionModel Development (Continued):

Check on :

- Partial correlation coefficient (r)

. Should be high between P (the dependent variable) & other variables (the independent variables) & Should be high between A (the dependent variable) & other variables (the independent variables)

. Should be low between pop, emp, GLA, DWEL (I.e. between independent variables)

- Other statistical measures (“t” statistic for each independent variable)

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Trip Productions & Attractions (Continued)RegressionModel Development (Continued):

Check on :

- R Multiple correlation coefficient (max. value of 1.0)

- R2 Coefficient of multiple determination (max. value of 1.0)

- Standard Error of Estimate (for the dependent variable - e.g. for Pi)

Its value can be checked against the estimated values of the dependent variable.

Example: A range of Pi values: 1,000-5,000; St. Error of 100 (very low!)

Page 17: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Productions & Attractions (Continued)Trip Generation Rates (Cross Classification Approach)

Trip Production: Step 1

Family Size Auto Ownership

0 1 2 or more

1 Trips/household/day

2

3

4 or more

Page 18: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Productions & Attractions (Continued)Trip Generation Rates (Cross Classification Approach)

Trip Production: Step 2

Trip productions for Zone i = (Trips/household/day) x (No. of households of that classification).

Trips/household/day: is based on O-D survey

No of households of a given classification: to be forecasted.

Page 19: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Distribution Models• Many models; most common is gravity model

Zone i

Pi

Zone jAj

Zone j Aj

Zone j Aj

Tij

Page 20: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Distribution Models

Origin-Constrained Gravity Model

Tij = Pi [ Aj Fij Kij

Σ for j(Aj Fij Kij)

]

Where

Tij = Trips produced in zone I and attracted to zone j

Pi = Trips produced by zone i

Aj = Trips attracted to zone j

Fij = Impedance of travel from zone I to zone j (a travel time factor -- expressing an area-wide effect of distance)

Kij = A zone-to -zone adjustment factor

Page 21: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Trip Distribution Models

Destination-Constrained Gravity Model

Tij = Aj [ Pi Fij Kij

Σ for i(Pi Fij Kij)

]

Where

Tij = Trips produced in zone I and attracted to zone j

Pi = Trips produced by zone i

Aj = Trips attracted to zone j

Fij = Impedance of travel from zone I to zone j (a travel time factor -- expressing an area-wide effect of distance)

Kij = A zone-to -zone adjustment factor

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Gravity ModelThe Fij is usually a some function of the travel time or

generalized cost of travel between zones

Fij = C-α ij or Fij = t-α ij Fij

tij or Cij

Where α is the calibration constant

Fij = Travel time factor

C ij = Generalized cost function

t ij = Travel time

Kij = A zone-to-zone adjustment factor (takes into account special characteristics of ij combinations

Zone 1 Zone 2

River Example

Page 23: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Gravity ModelNote:

Pi = Σ for j Tij

Aj = Σ for i Tij

Pi

Aj

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Gravity Model

Example

Using a gravity model with an impedance term of the form C-α , estimate the number of of trips from zone 1 to all other zones. α = 1.80. Other inputs are shown below.

Zone Travel time to zone 1 (min) Productions Attractions

1 -- 5000 1000

2 10 2000 4000

3 20 4000 5000

4 15 3000 4000

__________________________________________________

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Gravity ModelHere, Pi for i = zone 1 are to be distributed to other zones by

using the gravity model. Assume all K = 1

For α = 1.80 and given travel times Cij,, and Aj, we find:

______________________________________________

Zone Aj Cij C-α AjC- α ij Tij

1 1000 -- -- -- --

2 4000 10 1/63.1 63.40 2716*

3 5000 20 1/219.7 22.76 975

4 4000 15 1/130.91 30.56 1309

Sum 116.72 5000

* T from 1 to 2= 5000(63.40/116.72) = 2716

Page 26: Transportation Planning, Transportation Demand Analysis Land Use-Transportation Interaction Transportation Planning Framework Transportation Demand Analysis.

Gravity Model

• Following iteration 1 of finding Tij from every zone to all zones, check to see if Ajs match the known values

• If yes, the trip distribution problem is solved.

• If not, the Ajs have to be adjusted.

• The adjustment process is an iterative one (not covered here)