Infrastructure Needs: North Dakota’s County, Township, & Tribal Roads & Bridges, 2015-2034
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This document summarizes a study of infrastructure needs for North Dakota's county, township, and tribal roads and bridges from 2015 to 2034. Key factors influencing road and bridge conditions are increased oil and gas development and agricultural production. The study analyzed pavement and traffic data, forecasted 60,000 new oil wells and increased crop yields, and modeled resulting vehicle trips. It estimates total biennial investment needs, including $548 million for unpaved road maintenance, $377 million for paved roads, and $70 million for bridge replacements. Converting very high traffic gravel roads to pavement would cost an additional $58 million for the first biennium.
Infrastructure Needs: North Dakota’s County, Township, & Tribal Roads & Bridges, 2015-2034
- 1. Infrastructure Needs: North Dakota’s County, Township, & Tribal Roads & Bridges 2015-2034 June 25, 2014 Upper Great Plains Transportation Institute North Dakota State University
- 2. Contents • History/purpose of road studies • Data collection/field studies • Major factors influencing results • Analysis procedures/models • Results and distributions of impacts – Region – Time period • Next steps Slide 2
- 3. Road Infrastructure Studies • 2010 study: UGPTI estimated road investment needs for the 2011 session – 21,500 new wells & increased ag. production • 2012 study: updated investment needs – 46,000 new wells, ag. production, & initial bridge study • Current study: more comprehensive data – Higher roadway costs, ag. production, & 60,000 new wells Slide 3
- 4. Study Horizon • 20 year time frame • Traffic and investment needs estimated annually • Results summarized by: – Biennium – Region • Detailed results (by) – County – Jurisdiction Slide 4
- 5. pg. 5 Key Factors in Road Study (1) Oil and Gas Agriculture Number of wells Cultivated acres Well locations Crop mix Production rate/curve Yield Inputs/outputs Crop densities Gathering pipeline Elevator network
- 6. Key Factors in Road Study (2) Slide 6 Traffic Road Truck trips Surface type Truck axles/weights Width & design ESALs Age & condition Avg. Daily Traffic Soil
- 7. pg. 7 Data Sources (1) Oil production ND Oil & Gas Division Pipeline/transload network ND Pipeline Authority Base road network NDDOT GIS Hub Crop production USDA-NASS Elevator demand ND PSC
- 8. pg. 8 Data Sources (2) Traffic Vehicle counts and classifications Surveys/elevator reports Paved road condition Pathways/surveys Paved road structure Falling Weight Deflector Ground Penetrating Radar Unpaved roads Surveys
- 9. 2013 Slide 9 1000+ counts 670 classifications
- 10. Pavement Data Collection • Condition data – NDDOT Pathway van – Summer/fall 2013 – 4,786 miles of paved county roads • Pavement and shoulder width data – Scaled from video images – 4500 miles Slide 10
- 11. Slide 11
- 12. Pavement Data Collection • Non-destructive testing - verify prior estimates on subgrade strength – Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) – Western ND – all rural pavements not recently improved, not under construction, and not in failure state (785 mi) – Eastern ND – selected based on agricultural production facilities and other major traffic generators (734 mi) Slide 12
- 13. Modeled Movements • Agriculture – Wheat (including durum), corn, soybeans, barley, canola, sunflowers, sugar beets, potatoes, & beans – Fertilizer movements – Transshipments • Oil Exploration/Production – Freshwater, sand, equipment, supplies, pipe, outbound saltwater, & outbound crude oil Slide 13
- 14. Agriculture Production Forecasts • Production data: ND-NASS • Production estimated at township level • Elevator and plant demands from NDPSC and industry groups • Forecasts of future production, yield and mix derived from multiple sources – USDA/NASS – NDSU/Extension – Industry Slide 14
- 15. Oil Development • 2,300 truck trips per new well (drilling related) – 3 million gallons of freshwater – 4 million pounds of sand • Initial production (IP) rate varies by county • Outbound oil to transload locations – Base year: 67% truck, 33% pipe – 2024: 20% truck, 80% pipe, – 2,400 new miles of gathering pipeline/year Slide 15
- 16. Forecasting/Modeling Process Slide 16 Trips generated Trips originated or terminated E.g., wells and farms Trips attracted Rail & pipeline transfer facilities Grain elevators Routes taken Fastest path Truck trips: segment Oil-related, ag.-related, other Calibration Traffic data Truck types and loads Annual ESALs
- 17. Oil Exploration Traffic Projections Slide 17 Example of predicted traffic flows over road network Crude oil movements
- 18. Crop Movement Projections - Wheat Slide 18
- 19. Unpaved Road Analysis • Unpaved road miles grouped by traffic volume categories • “Normal” practices established for each county based upon traffic observations and reported maintenance practices • For traffic volumes above normal levels responses for oil impacted roads used to establish upper categories of maintenance Slide 19
- 20. Unpaved Improvement Types • Traffic Category Improvement – Low: low volume average – Baseline: county average – Elevated: county average increased by 50% – Moderate: county average increased by 100% – High: county average increased by 150%, dust suppressant – Very high: county average increased by 200%, dust suppressant Slide 20
- 21. To Pave or Not? • Conversion of gravel roads to hot mix asphalt (HMA) not directly considered, except for highest traffic roads • Needs for the significantly increased gravel maintenance may be sufficient for paving of some road segments • Surface type choice left to county – Reflect practices and local issues – Coordination with an overall planning effort Slide 21
- 22. Life Cycle Cost Comparison Slide 22
- 23. Slide 23 Unpaved Road Investment Needs (millions) Period Statewide Oil Patch Non-Oil 2015-2016 $548.0 $299.4 $248.6 2017-2018 $547.9 $299.2 $248.7 2019-2020 $547.5 $298.6 $248.9 2021-2022 $545.6 $296.6 $249.0 2023-2024 $541.9 $292.7 $249.2 2025-2034 $2,667.5 $1,422.9 $1,244.6 2015-2034 $5,398.4 $2,909.4 $2,489.0
- 24. Paved Road Analysis Steps • AASHTO 1993 Design Guide • Predict year & type of improvement • Improvement threshold based on pavement condition • Year of improvement based on: – Existing structural capacity – Existing condition – Forecasted ESALs Slide 24
- 25. 25 0.645 1 1.47 2.09 2.89 Single Axle Load in Thousand Pounds 16 18 20 22 24 0 0.5 1 1.5 2 2.5 3 ESAL Factors: Single Axle
- 26. Paved Road Improvements/Maint. • Improvement type – Overlay – Sliver widening – Reconstruction – Mine & blend • Normal maintenance – Chip seals – Crack sealing and patching – Other Slide 26
- 27. Paved Road Improvement Criteria • Reconstruction – Condition and traffic volume – Subgrade modulus – Rutting • Mine & Blend – Condition and traffic volume – Widening needed but thin/weak base • Overlay – Pavement condition Slide 27
- 28. 28 Pavement Serviceability Rating (PSR) PSR Range General Rating 5 to 4 Very Good 4 to 3 Good 3 to 2 Fair 2 to 1 Poor 1 to 0 Very Poor
- 29. 29 Effects of Soil Support Resilient Modulus (thousand psi) 4 5 6 7 8 9 10 0 0.1 0.2 0.3 0.4 0.5 0.6
- 30. pg. 30 Paved Road Improvements Type Miles Percent Resurface 5,005 88.1% Reconstruct 253 4.5% Mine/Blend 219 3.9% Widen 201 3.5%
- 31. pg. 31 Paved Road Investment Needs (millions) Period Statewide Oil Patch Non-Oil 2015-2016 $377 $186 $191 2017-2018 $323 $120 $203 2019-2020 $285 $158 $127 2021-2022 $236 $133 $103 2023-2024 $138 $52 $86 2025-2034 $1,326 $513 $812 2015-2034 $2,685 $1,162 $1,522
- 32. Bridge Analysis • NBI: county and local • Open bridges (other than culverts): 2,556 • Not considered: recently replaced or minimum maintenance roads • Improvements considered: replacement or rehabilitation • Maintenance Slide 32
- 33. Bridges Costs (1) • Unit cost model – Based on 2011-2014 NDDOT bid reports – Discussed with NDDOT & counties – Includes approach roadway, engineering, etc. • Replacement cost projections: – Bridges: $250-$275/sf. deck area – Culverts: $400,000-$600,000 /project Slide 33
- 34. Bridges Costs (2) • Rehabilitation – Deck widening 50% replacement cost – Deck replacement 45% replacement cost • Preventive maintenance – Annualized maintenance cost $0.24 per sq. ft./year – $0.29 per sq. ft. deck washing/sealing Slide 34
- 35. Bridge Investment Needs • 2015-2034: $327 million • 77% of costs for replacements • Backlog of 480+ bridges • Backlog spread over 5 biennia • Approx. $70 million per biennium Slide 35
- 36. Next Steps • Feedback from Legislature, NDDOT, and counties • Written report/documentation (July 8) • Detailed maps and data tables posted on webpage (July 8) • Additional study requests Slide 36
- 38. Addendum • Consideration of converting very high traffic (500+ trucks/day)gravel miles to asphalt • 37 miles @ $1.5 million/mile = $58M Slide 38 Category 2014 Dollars 2015-2016 Biennium Gravel Needs $548M Gravel to Pavement $58M Paved Needs $377M Total Road Needs $983M