MPC
Research Projects (2001-02)

Identifying Number

MPC-221

Project Title

Trip Generation Rates for Grain Elevators: A Tool for State and Local Highway Planners

University

North Dakota State University

Project Investigator

Denver Tolliver
Upper Great Plains Transportation Institute
North Dakota State University
Fargo, ND 58105
(701)231-7190
denver.tolliver@ndsu.edu

Kim Vachal
Upper Great Plains Transportation Institute
North Dakota State University
Fargo, ND 58105
(701)231-6427
kim.vachal@ndsu.edu

John Bitzan
Upper Great Plains Transportation Institute
North Dakota State University
Fargo, ND 58105
(701)231-8949
john.bitzan@ndsu.edu

External Project Contact

N/A

Project Objective

The overall objective is to provide state and local transportation planners with information regarding truck trips generated from grain elevators of various types and size. The specific objectives of the project are to: (1) Describe the land-use and transportation demand characteristics of grain elevators, (2) Collect and synthesize the facility and traffic data necessary to analyze truck trip rates, (3) Formulate and test statistical models for predicting truck trip rates to and from grain elevators, (4) Estimate trip generation models and evaluate the statistical properties of these models, and (5) Use the models to create a set of trip generation tables for various land-use classifications.

Project Abstract

This project will develop truck trip generation models and rates for grain elevators. There are 8,000 to 10,000 of these facilities located in the United States. A large elevator may handle 20 million bushels per year, which is equivalent to approximately 22,000 inbound semi-trailers or approximately 40,000 single-unit farm trucks. At present, highway planners have no way of estimating potential trips to and from these facilities other than by direct surveys or local traffic counts, which are costly and time-consuming. Elevator managers may be reluctant to release proprietary shipment data during a survey. In such situations, trip generation tables are a useful and cost-effective source of information for highway planners. The ITE trip generation tables, which are widely-used by highway planners, include the aggregate categories of "Ports & Terminals" and "Industrial." However, land uses such as "light industrial," "heavy industrial," or "warehouse" do not adequately describe grain elevators. Grain elevators are a very heterogenous group. Smaller facilities may handle less than 500,000 bushels per year while the largest facilities may handle over 20 million bushels. Moreover, there are considerable differences among facilities which are generically classified as unit-train shippers. This study will utilize data from a comprehensive inventory and field survey of more than 450 elevators in North Dakota and a broader survey of grain elevators and processors in the Great plains region. The trip generation models will predict truck trips as a function of fixed facility attributes (e.g., train loading and storage capacities), crops handled, county crop production levels and densities, elevator density in the surrounding market area (e.g., elevators or storage capacity per square mile in the county), and transportation system access and performance factors (e.g., distance from NHS, distance from river, rail access). The trip generation models will predict both inbound and outbound truck trips and include seasonal variance factors for adjusting average daily trips.

Task Descriptions

• Task 1 – Create database from North Dakota elevator reports and Great Plains elevator survey (currently in progress). Fixed facility and land-use data elements such as storage capacity and rail track capacity will be added from other sources, as needed.
• Task 2 – Formulate and test statistical models for predicting truck trip rates.
• Task 3 – After testing, estimate trip generation models and evaluate the statistical properties of the models.
• Task 4 – Use the models to generate a set of trip generation tables for various land-use classifications.
• Task 5 – Prepare a draft report describing the trip generation models/tables and illustrating their uses.
• Task 6 – Modify the report based on comments of peer reviewers.
• Task 7 – Publish final peer-reviewed research report.
• Task 8 – Develop and present a seminar for state transportation department personnel and other transportation engineers or planners via the TEL8 telecommunication network.

Milestones, Dates

• Starting Date: July 1, 2001
• Project Milestones:
  • Creation of database: December, 2001
  • Estimation and testing of statistical trip generation models: March 1, 2002
  • Generation of draft report: May 1, 2002
  • Publication of final report: June 1, 2002
  • TEL8 seminar for state transportation departments, universities, and other interested groups in region 8 August 30, 2002
• Ending Date: August 30, 2002

Yearly and Total Budget

$74,500

Student Involvement

N/A

Relationship to Other Research Projects

None

Technology Transfer Activities

A seminar will be presented for transportation practitioners that documents the data sources, modeling process, and potential applications.

Potential Benefits of the Project

In addition to the models, the project will produce a set of truck trip rate tables classified by facility size, county crop production ranges, and other informational variables. A set of parameter tables also will be produced for the states in the survey area. Information from the parameter tables (such as crop production and elevator storage capacity, by county) will allow for quick application of the rate tables or models. The trip rate tables and models will be useful to highway engineers and planners in the Mountain-Plains region as well as in other sections of the country.

TRB Keywords

Agricultural, roads, planning, truck, traffic