3. New Location and Reconstruction (4R) Design Criteria | Roadway Design Manual | TxDOT Manual System

♦Manual Notice 2006-2
►Preface
►1. Design General
- ►1. Overview
- ►2. Design Exceptions, Design Waivers and Design Variances
  - ♦Overview
  - ♦Design Exceptions
  - ♦Design Waivers
  - ♦Design Variances
- ►3. Schematic Layouts
  - ♦Overview
- ►4. Additional Access to the Interstate System
  - ♦Requirements
- ►5. Preliminary Design Submissions
  - ♦Submissions
- ►6. Maintenance Considerations in Design
  - ♦Maintenance
►2. Basic Design Criteria
- ►1. Functional Classifications
  - ♦Overview
- ►2. Traffic Characteristics
  - ♦Overview
  - ♦Traffic Volume
  - ♦Traffic Speed
  - ♦Turning Roadways and Intersection Corner Radii
- ►3. Sight Distance
  - ♦Overview
  - ♦Stopping Sight Distance
  - ♦Decision Sight Distance
  - ♦Passing Sight Distance
  - ♦Intersection Sight Distance
- ►4. Horizontal Alignment
  - ♦Overview
  - ♦General Considerations for Horizontal Alignment
  - ♦Curve Radius
  - ♦Superelevation
  - ♦Sight Distance on Horizontal Curves
- ►5. Vertical Alignment
  - ♦Overview
  - ♦Grades
  - ♦Vertical Curves
  - ♦Grade Change Without Vertical Curves
  - ♦Combination of Vertical and Horizontal Alignment
- ►6. Cross Sectional Elements
  - ♦Overview
  - ♦Pavement Cross Slope
  - ♦Slopes and Ditches
  - ♦Median Design
  - ♦Lane Widths
  - ♦Shoulder Widths
  - ♦Sidewalks and Pedestrian Elements
  - ♦Curb and Curb and Gutters
  - ♦Roadside Design
  - ♦Horizontal Clearances to Obstructions
- ►7. Drainage Facility Placement
  - ♦Overview
  - ♦Introduction
  - ♦Design Treatment of Cross Drainage Culvert Ends
  - ♦Parallel Drainage Culverts
  - ♦Side Ditches
- ♦8. Roadways Intersecting Department Projects
▼3. New Location and Reconstruction (4R) Design Criteria
- ►1. Overview
  - ♦Introduction
- ►2. Urban Streets
  - ♦Overview
  - ♦Level of Service
  - ♦Basic Design Features
  - ♦Medians
  - ♦Median Openings
  - ♦Borders
  - ♦Berms
  - ♦Grade Separations and Interchanges
  - ♦Right-of-Way Width
  - ♦Intersections
  - ♦Speed Change Lanes
  - ♦Auxiliary Lanes on Crest Vertical Curves
  - ♦Horizontal Offsets
  - ►Bus Facilities
  - ♦Bus Streets
- ►3. Suburban Roadways
  - ♦Overview
  - ♦Basic Design Features
  - ♦Access Control
  - ♦Medians
  - ♦Median Openings
  - ♦Speed Change Lanes
  - ♦Right of Way Width
  - ♦Horizontal Clearances
  - ♦Borders
  - ♦Grade Separations and Interchanges
  - ♦Intersections
  - ♦Parking
- ►4. Two-Lane Rural Highways
  - ♦Overview
  - ♦Basic Design Features
  - ♦Access Control
  - ♦Transitions to Four-Lane Divided Highways
  - ♦Passing Sight Distances
  - ♦Speed Change Lanes
  - ♦Intersections
- ►5. Multi-Lane Rural Highways
  - ♦Overview
  - ♦Level of Service
  - ♦Basic Design Criteria
  - ♦Access Control
  - ♦Medians
  - ♦Turn Lanes
  - ♦Travel Lanes and Shoulders
  - ♦Intersections
  - ♦Transitions to Four-Lane Divided Highways
  - ♦Converting Existing Two-Lane Roadways to Four-Lane Divided Facilities
  - ♦Grade Separations and Interchanges
- ►6. Freeways
  - ♦Overview
  - ♦Basic Design Criteria
  - ♦Access Control
  - ♦General
  - ♦Mainlane Access
  - ♦Frontage Road Access
  - ♦Driveways and Side Streets
  - ♦Methods
  - ♦Designation
  - ♦Design
  - ♦Mainlanes
  - ♦Design Speed
  - ♦Level of Service
  - ♦Lane Width and Number
  - ♦Shoulders
  - ♦Medians
  - ♦Outer Separation
  - ♦Crossing Facilities
  - ♦Vertical and Horizontal Clearance at Structures
  - ♦Frontage Roads
  - ♦Function and Uses
  - ♦Planning
  - ♦Design Speed on Frontage Roads
  - ♦Capacity and Level of Service
  - ♦Frontage Road Design Criteria
  - ♦Conversion of Frontage Roads from Two-Way to One-Way Operation
  - ♦Interchanges
  - ♦Three Leg Interchanges
  - ♦Four Leg Interchanges
  - ♦Diamond Interchanges
  - ♦Cloverleaf Interchanges
  - ♦Directional Interchanges
  - ♦Ramps and Direct Connections
  - ♦General Information
  - ♦Design Speed
  - ♦Horizontal Geometrics
  - ♦Distance Between Successive Ramps
  - ♦Cross Section and Cross Slopes
  - ♦Sight Distance
  - ♦Grades and Profiles
  - ♦Metered Ramps
  - ♦Collector-Distributor Roads
  - ♦Frontage Road Turnarounds and Intersection Approaches
- ►7. Freeway Corridor Enhancements
  - ♦Overview
  - ♦Freeways With High Occupancy Vehicle Treatments
  - ♦Light Rail Transit
►4. Non-Freeway Rehabilitation (3R) Design Criteria
- ►1. Purpose
  - ♦Overview
  - ♦Design Guidelines
- ►2. Design Characteristics
  - ♦Pavement Design
  - ♦Geometric Design
  - ♦Design Values
  - ♦Alignment
  - ♦Design Speed
  - ♦Side and Backslopes
  - ♦Lane Widths
- ►3. Safety Enhancements
  - ♦Overview
  - ♦Safety Design
  - ♦Project Specific Design Information
  - ♦Basic Safety Improvements
  - ♦Other Safety Enhancements
- ►4. Frontage Roads
  - ♦Overview
- ►5. Bridges, Including Bridge-Classification Culverts
  - ♦Overview
- ►6. Super 2 Highways
►5. Non-Freeway Resurfacing or Restoration Projects (2R)
- ►1. Overview
  - ♦Guidelines
►6. Special Facilities
►7. Miscellaneous Design Elements
- ►1. Longitudinal Barriers
  - ♦Overview
  - ♦Concrete Barriers (Median and Roadside)
  - ♦Guardrail
  - ♦Attenuators (Crash Cushions)
- ►2. Fencing
  - ♦Right-of-way
  - ♦Control of Access Fencing on Freeways
- ►3. Pedestrian Separations and Ramps
  - ♦General Requirements
  - ♦Overcrossings
  - ♦Undercrossings
- ►4. Parking
  - ♦Overview
  - ♦Fringe Parking Lots
  - ♦Parking Along Highways and Arterial Streets
- ►5. Shoulder Texturing
- ►6. Emergency Median Openings on Freeways
  - ♦Overview
  - ♦Conditions
  - ♦Spacing of Openings
  - ♦Construction
- ►7. Minimum Designs for Truck and Bus Turns
  - ♦Overview
  - ♦Application
  - ♦Channelization
  - ♦Alternatives to Simple Curvature
  - ♦Urban Intersections
  - ♦Rural Intersections
►8. Mobility Corridor (5 R) Design Criteria
- ►1. Overview
  - ♦Introduction
- ►2. Roadway Design Criteria
  - ♦Lane Width and Number
  - ♦Shoulders
  - ♦Pavement Cross Slope
  - ♦Vertical Clearances at Structures
  - ♦Stopping Sight Distance
  - ♦Grades
  - ♦Curve Radii
  - ♦Superelevation
  - ♦Vertical Curves
- ►3. Roadside Design Criteria
  - ♦Horizontal Clearance
  - ♦Slopes
  - ♦Medians
- ►4. Ramps and Direct Connections
  - ♦Overview
  - ♦Design Speed
  - ♦Lane and Shoulder Widths
  - ♦Acceleration and Deceleration Lengths
  - ♦Distance between Successive Ramps
  - ♦Grades and Profiles
  - ♦Cross Section and Cross Slopes
►A. Metal Beam Guardrails
- ►1. Overview
  - ♦Introduction
- ►2. Barrier Need
  - ♦Overview
- ►3. Structural Considerations
  - ♦Overview
  - ♦Post Spacing, Embedment, and Lateral Support
  - ♦Rail Element
  - ♦Deflection Considerations
- ►4. Placement of Guardrail
- ►5. End Treatment of Guardrail
  - ♦Overview
- ►6. Determining Length of Need of Barrier
  - ♦Overview
  - ♦Variables
  - ♦Design Equations
  - ♦Using Design Equations to Determine Length of Guardrail
- ►7. Example Problems
  - ♦Example Problem 1
  - ♦Example Problem 2
  - ♦Example Problem 3
►B. Treatment of Pavement Drop-offs in Work Zones
- ►1. Overview
  - ♦Scope
  - ♦Types of Treatment
  - ♦Factors Affecting Treatment Choice
  - ♦Edge Condition
  - ♦Guidelines for Treatment
  - ♦Use of Positive Barriers
►C. Driveway Design Guidelines
- ♦1. Purpose
- ►2. Introduction
  - ♦General Guidelines
  - ♦Definitions
- ►3. Driveway Design Principles
  - ♦General Guidelines
  - ♦Geometrics for Two-Way Driveways
  - ♦Divided Driveways
- ►4. Profiles
- ♦5. Driveway Angle
- ►6. Pedestrian Considerations
  - ♦General Guidelines
  - ♦Sidewalk and Driveway Intersections
- ♦7. Visibility
- ♦8. References

Chapter 3: New Location and Reconstruction (4R) Design Criteria

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Section 1: Overview

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Introduction

This chapter presents guidelines that are applicable to all new location and reconstruction projects for several different classes of roadways including the following:

urban streets
suburbanways
two-lane rural highways
multilane rural highways
freeways.

Departures from these guidelines are governed in Design Exceptions, Design Waivers and Design Variances, Chapter 1.