CHAPTER 9 - HIGHWAY DESIGN

1 ICHAPTER 9 - HIGHWAY DESIGNTABLE OF CONTENTSPage of the Standards Exceptions3. Mitigating DESIGN Aided DESIGN and Drafting (CADD) AND REFERENCES .. Study and Mapping Data Plans Contacts DEVELOPMENT .. DESIGN .. Consideration in HIGHWAY DESIGN 2. Horizontal and Vertical Alignment Relationship 3. Establish Control Points 4. Horizontal Alignment Alignment Distance Cross Section Grade Location and Cross Slope and Shoulder Widths d. Foreslopes e. Roadway Ditches and Fill Slopes g. Rock Cut Slopes h. Serrated Slopes I. Slope Rounding and Clearing Limits Roadway Widening 9. RRR ConsiderationsiiTABLE OF DEVELOPMENT (continued) Page B.

2 Intersection DESIGN .. Types Vehicle 4. Sight Distance 5. Channelization 6. Traffic Islands 7. Left-Turn Lanes 8. Right-Turn Lanes DESIGN ..9-71 and Grubbing of Structures and Obstructions of Roadway Excavation and Swell Factors Cut and Fill Slopes Earthwork 8. Haul 9. Mass Diagram Structural Excavation Quantities Treatment Obliteration Steps Using IHDS Retaining Structures .. of Need Wall Systems Guidelines of Wall Types Wall Systems of New Retaining Wall SystemsiiiTABLE OF PS&E DEVELOPMENT (continued)Page DESIGN .. and and Pipe Basins and Inlets Drains/Storm and Horizontal Protection Dissipators and Outlet Control DESIGN Elements.

3 Facilities of the Disabled and Roadside Development and Utilities .. Encroachments Grade Crossings Source Reclamation Plans .. Drawings 's Estimate .. of Quantities of Contract Time of Prices ivTABLE OF PS&E DEVELOPMENT (continued)Page of Specifications Special Contract Requirements Special Contract Requirements FORMAT .. of Plans of of and Control Drawings, Standard Details, and Special Package OF FIGURESF igurePage 9-1 Superelevation Transition on Short Tangents Between Broken-Back Transitions for Broken-Back Flat Sections Between ReversingCurves with Short Clearance for Stopping Sight Distance.

4 9-319-6 ADesirable Horizontal Stopping Sight Horizontal Stopping Sight Distance ..9-339-7 Determining Low Points on Vertical Curves with Unequal Broken-Back Vertical road Cross Section Cut Slope End Rock Rock Turn Deceleration Lanes for Non-controlled Access Turn Acceleration Lanes for Non-controlled Access Moving Vehicle Turn Storage Guidelines for Unsignalized TwoLane HIGHWAY Turn Storage Lengths for Unsignalized TwoLane HIGHWAY Intersections (60 km/h) ..9-669-19 Left Turn Storage Lengths for Unsignalized TwoLane HIGHWAY Intersections (80 km/h) ..9-679-20 Left Turn Storage Lengths for Unsignalized TwoLane HIGHWAY Intersections (100 km/h).

5 9-689-21 Right Turn Lane Turn Pocket or OF TABLEST ables Page 9-1 DESIGN Signing for Curves and Listing of a Determination ofSuperelevation Distance of Grades on Stopping Sight Distance ..9-309-6(K) Values for Determining Lengths of Vertical and Maximum DESIGN Distance Adjustment Distance for Turning Distances for Barrier Left Turn Storage for Trucks atUnsignalized Two-Lane HIGHWAY for Railroad Crossing Usage of Words and Sizes and Styles ..9-1579 - 1 CHAPTER 9 - HIGHWAY GENERALThis CHAPTER provides policies, procedures, and methods for developing and documenting the DESIGN ofhighways. It also includes the preparation of plans, specifications and estimates (PS&E) for new highwayconstruction, reconstruction and RRR (Resurfacing, Restoration and Rehabilitation) Role of the Designer.

6 The designer shall gather all the engineering and environmental input requiredto provide a complete and acceptable PS&E assembly. The PS&E package depicts the commitments madeduring the planning, programming, and project development designer is responsible for applying guidance from CHAPTER 8, Safety and CHAPTER 9, HIGHWAY DESIGN . In addition, the following named chapters provide information on collecting background data for thedevelopment of the PS& 2 - Planning and Programming. Information on the planning and programming functions,interagency agreements, and general data on the scope and funding levels for individual projects arecovered in this 3 - Environment. This CHAPTER provides information about environmental requirements andpublic involvement.

7 Environmental documents will include commitments made for mitigation andpublic acceptance of the project. The designer will review all environmental documents forcommitments made during the conceptual studies phase that affect development and construction of theproject or operation of the HIGHWAY following construction. Any proposed deviation from themitigating measures and commitments must be coordinated with the Division environmental unit andaffected resource 4 - Conceptual Studies. These studies result in a recommended roadway location and basicdesign criteria for a facility. Such studies are generally developed in conjunction with theenvironmental process. Conceptual studies generally include significant input from the owner agencyand from other interested 5 - Survey and Mapping.

8 The survey unit provides information on the field survey, property,utility locations, and related data. The data collected provides topographic maps, site maps, right-of-way and utility plats, and base information for developing the 6 - Geotechnical. The geotechnical unit provides subsurface data and recommendations forearthwork slopes, materials, and pavement structure DESIGN . When applicable the report includesfoundation DESIGN for bridges, retaining walls, and other structures, along with landslides andsubsurface water 7 - Hydrology/Hydraulics. The hydraulics unit provides runoff data for roadside drainagedesign. This unit also provides data to the structural unit (for major structures) and designs majorhydraulic structures and special water resource 10 - Structural DESIGN .

9 The structural unit designs bridges, major retaining structures, andspecial structural elements. The unit will provide complete structural plans, proposed specifications,and an estimate of cost for incorporation into the PS&E package. DESIGN - 2B. DESIGN Standards. Guidelines for geometric DESIGN have changed significantly over the years. Today's emphasis is on balancing the factors of safety, economy, environmental concerns, energyconservation, and social effects with the traditional concerns for volume and FHWA has adopted policies and standards for Federal-aid HIGHWAY DESIGN that recognize all theseprecepts. They are listed in 23 CFR 625 and supplemented in the FAPG. These standards basically adoptAASHTO policy and are applicable to Federal Lands HIGHWAY Federal agencies, States and many local HIGHWAY agencies have adopted standards implementingAASHTO policy with supplemental and clarifying criteria.

10 Table 9-1 lists the principle FLH programs and corresponding DESIGN standards. The appropriate standardsare normally identified in the planning, programming, or conceptual studies document for the project. Occasionally the designer will need to determine which standards are approved for use on a specificproject. The appropriate unit chief should be DESIGN Standards. (continued)9 - 3 The DESIGN criteria shown in Table 9-1 represent both desirable and minimum standards. Each designshould be evaluated on the basis of desirable DESIGN criteria for the safest overall , social and environmental factors often require standards that are less than desirable. This isparticularly true for RRR projects.