Standard Road Plans - DR Series Drainage English DR-101 Pipe Culvert (Bedding and Backfill) DR-102 Pipe Culvert (Cover and Camber) DR-103 Pipe Culvert (Installation Details) DR-104 Depth of Cover Tables for Concrete and Corrugated Pipe DR-111 Box Culvert DR-121 Connected Pipe Joints DR-122 Construction of Type "C" Concrete Adaptors for Pipe Culvert Connections DR-141 Pipe Bends and Half Pipe DR-142 Culvert Pipe Tee Sections DR-201 Concrete Aprons DR-202 Low Clearance Concrete Pipe Aprons DR-203 Metal Pipe Aprons and Beveled Ends DR-204 Metal Arch Aprons (for Corrugated Metal Pipe) DR-205 Concrete Apron with End Wall DR-206 Low Clearance Concrete Pipe Apron With End Wall DR-211 Metal Safety Slope Apron (6:1 Slope) DR-212 Beveled Pipe and Guard DR-213 Pipe Apron Guard DR-301 Subdrains for Fill or Foundation Drainage (Standard) DR-302 Subdrains Standard (Farm Tile Replacement) DR-303 Subdrains (Longitudinal) DR-304 Outlets for Longitudinal, Transverse and Backslope Subdrains DR-305 Subdrain Outlets (Standard Subdrain, Pressure Release and Special) DR-401 Scour Protection for Bridge End Drain DR-402 Rock Flume for Bridge End Drain DR-501 Corrugated Metal Type "A" Diaphragm DR-502 Slotted Drain for Median Crossovers DR-503 Safety Grates for Box Culverts DR-601 Reinforced Concrete Pipe Culvert DR-602 Reinforced Concrete Pipe Culvert with Tees DR-611 Reinforced Concrete Pipe Culvert Letdown Structure DR-612 Apron Tee Inlet DR-621 Pipe Extension DR-622 Pipe Extension Horizontal Bend One or Both Ends DR-623 Pipe Extension with Flume DR-624 Pipe Extension Horizontal Bend with Flume DR-625 Pipe Extension Letdown Structure with Metal Apron DR-626 Pipe Extension - Adding Lanes DR-627 Pipe Extension Horizontal Bend - Adding Lanes DR-628 Pipe Extension Both Ends Horizontal Bend (Optional) - Adding Lanes DR-629 Pipe Extension Letdown Structure Horizontal Bend (Optional) - Adding Lanes DR-631 Corrugated Pipe Culvert Letdown Structure with Single Elbow DR-632 Corrugated Pipe Culvert Letdown Structure with Double Elbow DR-641 Concrete/Corrugated Pipe Culvert Letdown Structure with Metal Apron DR-642 Apron Pipe Tee Inlet DR-643 Concrete Pipe Letdown Structure DR-644 Reinforced Concrete Pipe Culvert with Tees and Flume Section DR-651 Unclassified Pipe Culvert DR-652 Unclassified Letdown Structure Single Elbow DR-653 Unclassified Roadway Letdown Pipe with Metal Apron