Surface Drainage Crown (flat A shape) c Dirt & Gravel: 1/2” - 3/4” per foot (4 - 6 inches in 10 feet)

Surface Drainage Superelevated Roadway (Curves) Dirt & Gravel: 1/2” - 3/4” min. per foot

Surface Drainage - Shoulders Flush with road Avoid “shoulder drop – off” Slightly steeper cross slope Avoid secondary ditches Supports roadway Allows water to flow further away from road

Drainage Systems c c Wrong Right Crown Surface Material Ditch Shoulder Subgrade Base Surface Material Subgrade Base

Subsurface Drainage Free draining road base beneath the surface Collector systems comprised of perforated pipe surrounded by well- graded aggregate with an outlet pipe or other prefabricated systems

Subdrains Road Shoulder SubdrainWell-graded aggregate Perforated Pipe Cut or Fill Sections

3 Most Important Items in Road Maintenance Drainage

Road Materials Durability (Hardness) Soundness pH (acidity/alkalinity)

Road Aggregates Granular Well Graded (8 – 15% fines) Free of Vegetation Angular / Irregular (Source) Crushed Not rounded

Basic Road Maintenance Create a good hard crust surface with a proper cross slope (crown)

Basic Road Maintenance Blading or smoothing Grading or reshaping Adding new material Transitions

Basic Road Maintenance All work should be done when some moisture is present Need moisture for proper compaction Avoids dust

Blading or Smoothing Use grader or drag Mold board tilted forward Light down pressure 30 to 45 degree angle on moldboard 10 to 15 degree tilt on front wheels 3 to 5 miles an hour

Grading or Reshaping Moldboard tilted backward Sufficient down pressure to produce cutting action 4 passes minimum Windrow & spread each lane Check cross slope Compact

Adding New Material Scarify existing surface Spread new material Blend old and new material & establish cross slope Compact

Transitions Road Intersections Driveways Curves Railroad Crossings Bridges

Road Intersections Gradually eliminate crown 50 to 100 feet from intersection Be sure shoulders have cross slope at point of intersection Do not spread aggregate on paved road

Driveways Grade to driveway Grade low point at ditchline Do not leave windrow across driveway

Curves Transition crown to superelevation (and vice versa) within 100 feet of curves

Railroad Crossings Gradually eliminate crown on both sides Do not blade aggregate onto rails Brush off loose aggregate

Bridges If bridge has crown, maintain on road If not, gradually eliminate crown Road approaches to bridge may need more frequent attention

Maintenance Frequency Depends on: Road Type Drainage Weather Traffic Volumes Special Events “As Needed!”

The Professional Operator Knows good techniques & practices Knows his equipment Notices and records other problems that need to be taken care of