1. Using GPS to Track Pole Truck Turning Movements
Presented by:
John Wolf, PE
Senior Designer
ODOT, Region 1 Preliminary Design
&
Ron Singh, PLS
Chief of Surveys/Geometronics Manager
ODOT, Technical Services

2. The Problem Intersection at Bennett Road & US 30
High volume, multilane highway
3 Crashes in 2008 involving passenger cars and log trucks
2 injuries and 1 fatality resulted
Permitting issue regarding overhang on long loads
Maximum Overhang was dependant on wheelbase and trailer type
Overhang was measured from rear axle
Pole trucks need access to pole yard

3. Bennett Road
Conflict Point

4. Bennett Road

5. Accidents at Bennett Road

6. Accidents at Bennett Road

7. The Challenges Timing was critical
Motor Carrier issued a pilot car requirement on log trucks with large overhang, effective 9/12/08, for over 260 permit holders
Variable vehicle configurations (What should be analyzed?)
Pivoting trailer bunks influence log sweep path
Turning movement software limitations?
The need to applying the turning movements to multiple situations
Multiple intersection configurations
Freeway ramp terminals
Multilane Roads

8. Unique Elements of A Pole Truck
Long Wheelbase
Large Overhang
Rear Bunk/Pivot Point
Front Bunk/Pivot Point
Adjustable Stinger Hitch and Compensator

9. Extendable Stinger
12’6” Total Length
5’6” Available Adjustment
Compensator
Vehicle #2

10. 12’
13’

11. AutoTURN v5.1
AutoTURN is a CAD-based program that simulates low speed turning maneuvers for highway vehicles
Vehicle inputs
Default vehicle configurations
User defined vehicle configurations
Inputs include number of axles, axle spacing, tractor/trailer length, and distance to pintle hitch
Limitations
AutoTURN v5.1 does not account for adjustable length “stinger” pintle hitch
Turning accuracy for this type of tractor/trailer uncertain

12. AutoTURN Inputs Default truck templates Modified pole truck templates
Critical measurements include bumper, axle spacing, hitch location, axle location, bunk location, overhang, front of load
Modified pole truck templates

13. AutoTURN Outputs

14. Course of Action
Collected data from ODOT Motor Carrier on common pole truck configurations
Research other turning simulator software
ODOT Maintenance staff coordinated field testing of two pole trucks using GPS tracking data
Note: ODOT Motor Carrier Division also collected data on accident history of pole trucks on Oregon highways and neighboring states log truck permitting requirements
Investigated older versions of AutoTURN as well as a log truck turning software developed by the forestry service.

15. OREGON STATE FAIRGROUNDS – TEST SITE

16. The Survey Approach

17. Truck Turning Sequence

23. GPS Devices
12’ Between Cones 5’ 5’ 5’ 5’ 5’
Ribbons Spaced at 5’ Intervals From Rear Bunk
Test Vehicle #2
12’ Between Cones
Cones Offset 2’ from Path for Driver’s Side Front Tire

24. After Data Collection
Create vehicle configurations to replicate field test
Run AutoTURN analysis
Compare results
Run sensitivity analysis of sweep path based on overhang length
Report Results to Motor Carrier and the Trucking Industry

25. No Scale

26. RAW GPS DATA COLLECTED

29. Comparison of Field Tests to AutoTURN – Vehicle #1

30. Comparison of Field Tests to AutoTURN – Vehicle #2

31. General Findings of Field Test and Analysis
Sweep path is dependent on vehicle configuration and length of overhang from the rear bunk
Sweep path is the same for both left and right turns
AutoTURN v 5.1 reasonably predicts pole truck turning movements for various conditions
Path generated using AutoTURN v 5.1 predicted log sweep within 2’ for Vehicle #1 and 1’ for Vehicle #2 compared to GPS
AutoTURN's maximum error in the trailer off tracking was between ½’ and 2’ (2’ occurred as the vehicle exits the curve)
Multiple curves compound the error in the AutoTURN software

32. Outcomes
ODOT Motor Carrier changed permitting requirements for overhang, effective 11/24/2008
Length of overhang was limited to 1/3 Wheelbase with a 25’ maximum for multilane roads
Changed the point which overhang is measured from
Lifted the temporary pilot car restriction for vehicles meeting these requirements
Requirements are posted at:
Currently investigating an intersection improvement project at US 30 and Bennett Road to better accommodate pole trucks

33. Questions?