Travel Demand Model VLMPO CAC-TAC

Valdosta-LowndesMetropolitan Planning

Organization

What is the Travel Demand Model?

VLMPO CAC-TAC Joint MeetingApril 23, 2014

Why are we here?

• Assumption: Land use policy decisions impact transportation infrastructure (investment and costs)

• Demonstrate how the VLMPO-JLUS 2035 Travel Demand Model can be used to show impacts on transportation infrastructure based on land use policy decisions.

Agenda

• What is the Model?• How does the Model Work?• How is the Model used in

Transportation?• How is the Model used in Land-Use

Policy?• What will Local Officials Learn about

Land-use and transportation policy from the Model Outputs?

What is the Model?

The Travel Demand Model is a tool (one of many) that can be used to

provide more information to decision makers on transportation issues.

The TDM should not be used as the final determining factor in any

decision, it should be one of many resources and inputs considered.

What is the Model?

• The model is the data, not the software– Traffic Analysis Zones (TAZs)– Road Networks– Socioeconmic Data (tabulated at TAZ level)

• Population• School Enrollment (school location)• Retail Employment• Wholesale Employment• Service Employment• Manufacturing Employment• Households• Income• Lots of Regional and National Defaults (can be changed)

Traffic Analysis Zones

Highway Network

Two Models

• VLMPO 2035 Model– Covers only MPO Jurisdiction

• VLMPO-JLUS 2035 Model– Covers MPO Jurisdiction plus JLUS Study

Area

• VLMPO 2040 Model– Covers expanded MPO Jurisdiction

What do drivers tend to do when a roadway becomes

congested?

Travel Demand Model

Socioeconomic Data

Future Growth Consensus

Socioeconomic Data

Socioeconomic Data

Travel Demand Model

4-Step Model

1. Trip Generation– Number and Type of Trips Each TAZ Produces or Attracts is

Calculated

2. Trip Distribution– Trips are Distributed by TAZ from Origins to Destinations

3. Mode Split– Assigns Trips to Cars, Public Transit, Biking, Walking, etc.– Not Used in VLMPO TDM, Alternative Modes not Large Enough

4. Trip Assignment– Trips are Assigned to Highway Network, Using Shortest Path– Once Roadway Becomes Congested, Next Shortest Path is Used

What do the Outputs Look Like?

What does it mean?

• Roads are assigned a Level of Service (A thru F) Grading Scale– A=Good, Free Flowing Traffic at Peak Travel

Time– F=Very Bad, Standstill Traffic at Peak Travel

Time

• Planners and Engineers then develop transportation projects to ease congestion on links where Level of Service is improved

LOS

Examples

• Exit 2 Lake Park Bellville Road• Oak St/Woodrow Wilson Area• Bemiss Rd and Forest Street

Corridors

Scenarios

1. Land Use Inputs for Forrest St.2. 2035 No Build – 2 lane, other inputs3. 2035 Build – 5 lane, with school,

Park 3 lane4. 2035 – 4 lane, w/o school, Park 3

lane5. 2035 – 5 lane, w/o school, Park 3

lane

Scenarios

• Can be changed at any time, most all assumptions can be tweaked to answer the questions of local officials

• Is macro, not parcel specific