definitions of some terms that you are likely to use whenpreparing the working plans for a road:1. CUT. Has two connotations: (1) an excavationthrough which the road passes and (2) the verticaldistance the final grade is below the existing grade.2. FINAL, OR FINISHED, GRADE. Theelevation to which the road surface is built.3. SURFACE. That portion of the road thatcomes into direct contact with traffic.4. EXISTING GRADE. The undisturbed earthbefore construction begins.5. FILL. Has two connotations: (1) earth that hasbeen piled up to make the road and (2) the verticaldistance the final grade is above the existing grade.6. SUBGRADE. The foundation of a road whichcan be either undisturbed earth (for a cut) or materialplaced on top of the existing grade.7. BASE. Select material (crushed stone, gravel,etc.) placed in a layer over the subgrade for the purposeof distributing the load to the subgrade.8. TRAFFIC LANE. That portion of the roadsurface over which a single line of traffic traveling inthe same direction will pass.9. TRAVELED WAY. That portion of theroadway upon which all vehicles travel (both lanes fora two-lane road).10. SHOULDERS. The additional widthimmediate y adjacent to each side of the traveled way.11. ROADBED. The entire width (including thetraveled way and the shoulders) upon which a vehiclemay stand or travel.12. ROADWAY. The entire width that lies withinthe limits of earthwork construction.13. ROADWAY DITCH. The excavation, orchannel, adjacent and parallel to the roadbed.14. DITCH SLOPE. The slope that extends fromthe outside edge of the shoulder to the bottom of theditch. (Sometimes called front slope or side slope.)15. BACK SLOPE. The slope from the top of thecut to the bottom of the ditch (Sometimes called cutslope.)16. FILL SLOPE. The slope from the outside edgeof the shoulder to the toe of the fill. (Also, sometimescalled front slope or side slope.)17. TOE OF SLOPE. The extremity of the fill(where the existing grade intercepts the fill).18. INTERCEPTOR DITCH. A ditch cut tointercept the water table or any subsurface drainage.Also, a ditch cut along the top of fills to intercept surfacedrainage.19. WIDTH OF CLEARED AREA. The width ofthe entire area that is cleared for the roadway.20. SLOPE RATIO. A measure of the relativesteepness of the slope, expressed as the ratio of thehorizontal distance to the vertical distance.21. CENTER LINE. The exact center, or middle,of the roadbed.22. BLANKET COURSE. A 1- or 2-inch layer ofsand or screening spread upon the subgrade to preventmixing of base and subgrade.23. CROWN. The difference in elevation betweenthe center line and the edge of the traveled way.24. SUPERELEVATION. The difference inelevation between the outside and inside edge of thetraveled way in a horizontal curve.25. STATION. A horizontal distance generallymeasured in intervals of 100 feet along the centerline.26. STATION NUMBER. The total distance fromthe beginning of construction to a particular point (forexample, 4 +58 is equal to 458 feet).SURVEYWhen it is decided that a road is needed through aparticular area, the first and logical step is to determinea route for it to follow. This mute may be chosen by theuse of maps, aerial photographs, aerial reconnaissance,ground vehicle reconnaissance, walk-throughreconnaissance, or by any combination of these. Oncethe route is chosen, a surveying crew makes thepreliminary survey. This survey consists of a series oftraverse lines connecting a series of traverse stations.A survey party will stake in each of the traversestations and determine the bearing and distance of theconnecting traverse lines. From this information, anEngineering Aid will draw the points of intersection(PI) and the connecting lines. Then an engineer willcompute the horizontal curves at each point ofintersection, and an Engineering Aid will draw thecurves and mark the stationing. This drawing is theproposed center line.3-2