Design Policy Manual 10/4/2021 Revision 6.5 Atlanta, GA 30308 This document was developed as part of the continuing effort to provide guidance within the Georgia Department of Transportation in fulfilling its mission to provide a safe, efficient, and sustainable transportation system through dedicated teamwork and responsible leadership supporting economic development, environmental sensitivity and improved quality of life. This document is not intended to establish policy within the Department, but to provide guidance in adhering to the policies of the Department. Your comments, suggestions, and ideas for improvements are welcomed. Please send comments to: State Design Policy Engineer Georgia Department of Transportation One Georgia Center 600 W. Peachtree Street, 26th Floor Atlanta, Georgia 30308 DISCLAIMER The Georgia Department of Transportation maintains this printable document and is solely responsible for ensuring that it is equivalent to the approved Department guidelines. Design Policy Manual Revision History Revision Number Revision Date Revision Summary 1.0 5/12/06 Original Manual 2.0 5/21/07 General reformatting to provide a user-friendly online version 3.0 6/11/10 Editorial and formatting changes to Chapter 1-7 and the addition of Chapter 8, Roundabouts. 4.0 8/11/14 Reformatted manual to new standard template 4.1 8/25/14 Removed list paragraphs throughout manual Chapter 3 - Added “Easement for Temporary Bridge Construction Access” to Section 3.8.3 Special Types of Right-of-Way Chapter 9 - Removed "FHWA Requirements for Curb Ramps" from Section 9.4.1; Added reference to Section 11.1 (ADA Requirement to Provide Curb Ramps) under "Curb Ramps" in Section 9.5.1; Added "Mid-Block Crossing" to Section 9.5.1 Chapter 11 - Added “ADA Requirements to Provide Curb Ramps” to Section 11.1 Chapter 14 - Updated Section 14.3.3 to include the 80' criteria from RP-22-11 4.2 9/23/14 This edit updated the language in Section 9.5.1 that references Section 11.1. 4.3 10/7/14 Chapter 4 – Added language to state that Design Exception is required if the State’s superelevation rate cannot be met. Chapter 6 - Added language to discuss the use of method 1 temporary barrier for construction staging of a roadway. 4.4 11/5/14 Chapter 4 - Removed the paragraph referring to the Department’s org-chart from section 1.4. The chart is already mentioned in section 1.2. 4.5 11/21/14 Chapter 2 - Section 2.2 was updated to include the new email address for project managers and designers to electronically submit all design exceptions and design variances. 4.6 3/23/15 Chapter 11 - Added note to Table 11.1 regarding safety enhancement 4.7 5/11/15 Acronyms and Definitions – Updated hyperlinks Chapter 1, 2, 3, 6, 7, 8, 9, 11, 13, 14 - Updated hyperlinks References – Updated hyperlinks 4.8 6/5/15 Chapter 2 – Updated minor info Page i Design Policy Manual Chapter 3 - Updated Green Book info Chapter 4 - Removed statement requiring an exception for determining and locating superelevation runoff, runout and transitions. Updated Green Book info. Chapter 5 - Updated Green Book info. Chapter 6 - Changed “Interstate Medians” to “Freeway Median”, 6.12.1. Updated Green book info Chapter 8 - The "SIDRA Standard" method environmental factors of the opening year and design year were changed. Chapter 9 - Added a reference in regards to FHWA has posted a new separated bike lane planning and design guide. 4.9 6/19/15 Chapter 6 - Updated Curb and gutter method of construction 4.10 9/18/15 Chapter 3 – Updated Table 3.1 to correct line layout of Interstate/Freeway Ramp to have the word Ramp on a separate line. 4.11 1/5/16 Chapter 4 – Deleted minor info Chapter 8 – Deleted contact info for safety assessments Chapter 9 – This chapter is a rewrite. Updated with new and current practice. Updated list of publications. The illustration of sidewalk along rural roadways was updated. Language regarding “structurally impractical” and “technically infeasible” for not meeting PROWAG requirements was added. A design criterion for bus loading pads was added. Language for bike lanes, intersections and connections between different bikeway types was added. Chapter 11 – Updated 11.1 title 4.12 2/17/16 Chapter 5 5.2 Added a policy that all bridge columns should be protected regardless of median width. 5.3 In addition to the minimum lateral offsets given in Table 5.3, the designer shall ensure there is a minimum of 1.5-ft from the face of curb to the face of tree at tree’s mature growth. 5.4 Relocated barrier section from chapter 6.11 to chapter 5.4. 5.4.3 Added an end terminal selection flow chart. 5.4.3 Added language for end treatments and crash cushion types. 5.4.3 Developed a crash cushion selection flowchart. Page ii Design Policy Manual Chapter 6 6.11 Removed chapter 6.11 barriers. This was relocated to chapter 5.4. 6.13 Back-in angle parking was added as a preferred type of on-street parking. 6.15 Added the requirement bicycle lanes should be 5-ft when adjacent to header curb, guardrail or other vertical surface. A 6-ft width bicycle lane should be used adjacent to a concrete barrier, where practical. 6.15 Revised illustrations for clarity on the bikeable shoulder. Chapter 7 - Section 7.3 median opening spacing policy was updated to allow for flexibility on innovative intersections. The spacing may be closer if an operational study supports this finding. Chapter 11 Updated chapter to current AASHTO Green Book & 2011 AASHTO Roadside Design Guide standards. Added language from the Roadside Safety Hardware announcement made on January 1, 2016. This is the implementation of MASH. 11.1 Added the criteria that on alteration projects adjacent sidewalk must be upgraded (if needed). 11.1 Added language that the omission of the installation of curb ramps or upgrade adjacent sidewalk shall require the prior approval of a Design Variance. Changed table 11.1 to match the memo sent to FHWA on 31Aug15. 4.13 5/6/16 Chapter 2 - Shoulder Width was added to the list of GDOT Standard Design Criteria. Chapter 5 - An illustration for the guidelines of w- beam guardrail placement was added. Minor changes in wording were made regarding high speed roadways. This change more aligns with wording in the AASHTO Green Book. Chapter 6 - Modifications were made on when 4% cross slope on a tangent section can be applied. It now requires an engineering study be placed in the project record when used. Shoulder Width for high volume high speed rural collectors and rural arterials was clarified as being a GDOT Standard Design Criteria. Minor changes in wording were made regarding high speed roadways. This change more aligns with wording in the AASHTO Green Book. Illustration of Typical Dimensions for Rural Freeway was added. Chapter 8 - Minor changes in wording were made regarding high speed roadways. This change more Page iii Design Policy Manual aligns with wording in the AASHTO Green Book. Chapter 11 - An illustration of guardrail placement in areas with restricted right of way and limited shoulder width was added. 4.14 6/17/16 Chapter 14 – Revised entire Lighting procedures 4.15 7/21/16 Acronyms and Definitions – Added new definitions Chapter 2 - Tangent Lengths on Reverse Curves with a design speed ≥ 50 mph was added to the list of design variances. Table 2.1 Exception to Design Standards was added to clarity on when a design exception or design deviation is required. Chapter 3 - 3.2 The entire section regarding a design vehicle was updated. Clarification was made between a design vehicle and a check vehicle. An illustration for designing verses accommodating a vehicle was added. Oversize overweight need and accommodation was introduced. Chapter 4 – 4.2.2 Tangent Lengths on Reverse Curves with a design speed ≥ 50 mph was added to the list of design variances. Section 4.3.2 PROWAG requirements and its effect on vertical alignment language was modified for clarification. The Vertical Profile Clearance Based on High Water Table was removed due to information is in the GDOT Drainage Manual. The Superelevation Rotation Points and Rotation Widths table was modified for consistency on the horizontal location of rotation point. Chapter 5 - Design exceptions and design variances were updated to reflect the change in policy from the FHWA Memorandum. Updated other minor info Chapter 6 - Design exceptions and design variances were updated to reflect the change in policy from the FHWA Memorandum. Updated other minor info. Chapter 11 - Design exceptions and design variances were updated to reflect the change in policy from the FHWA Memorandum. Updated other minor info, References - AASHTO, A Policy on Design Standards – Interstate System 2016 edition replaced the 2005 edition. Several IESNA publications were updated to the current editions. 4.16 9/13/16 Chapter 4 – Corrected Design Speed in Table 4.10 Chapter 9 – Added reference to Design Reference 4.17 9/29/16 Chapter 3 – Updated Design Vehicles procedures Chapter 4 – Updated minor info 4.18 1/20/17 Chapter 6 – Updated pedestrian crossings info. Added reference to Pedestrian Streetscape Guide and Public Rights-of-Way Page iv Design Policy Manual Chapter 7 – Added reference to Pedestrian Streetscape Guide and Public Rights-of-Way Accessibility Guidelines manual Chapter 9 – Added reference to Public Rights-of- Way Accessibility Guidelines manual 4.19 4/4/17 Chapter 7 – Updated PROWAG hyperlink. Section 7.3 Clarification was made on intersection control for median openings on six-lane roadways. Chapter 13 – Revised sections 13.1 and 13.2 to reference Traffic Forecasting Manual.