Chapter 4 - Elements of Design

Chapter 4 Contents

4.1. Sight Distance

4.1.1.     General Considerations

4.1.2.     Stopping Sight Distance

4.1.3.     Passing Sight Distance

4.1.4.     Decision Sight Distance

4.1.5.     Intersection Sight Distance

4.2. Horizontal Alignment

4.2.1.     General Considerations

4.2.2.     Types of Curves

4.2.3.     Pavement Widening on Curves

4.2.4.     Lane Width Transitions and Shifts

4.2.5.     Transition in Number of Lanes

4.3. Vertical Alignments

4.3.1.     General Considerations for Vertical Alignments

4.3.2.     Maximum Vertical Grades

4.3.3.     Minimum Vertical Grades

4.3.4.     Vertical Curves

4.3.5.     Maximum Change in Vertical Grade with out Using Vertical Curves

4.3.6.     Vertical Grade Changes at Intersections

4.3.7.     Minimum Profile Elevation Above High Water

4.3.8.     Reporting Changes in Vertical Clearances

4.4. Combined Horizontal and Vertical Alignments

4.4.1.     Aesthetic Considerations

4.4.2.     Safety Considerations

4.4.3.     Divided Highways

4.5. Superelevation

4.5.1.     Maximum Superelevation Rates

4.5.2.     Sharpest Curve without Superelevation

4.5.3.     Axis of Rotation

4.5.4.     Superelevation Transitions

 

List of Figures

Figure 4.1. Crowned Traveled Way Revolved About Centerline

List of Tables

Table 4.1. Maximum Horizontal Alignment Deflection  without Use of a Curve

Table 4.2. Pavement Widening on Curves on Two-Lane Roadways

Table 4.3. Miscellaneous Transition Tapers

Table 4.4. Turn Lane Transition Tapers

Table 4.5. Maximum Vertical Grades     

Table 4.6. Minimum Vertical Grades for Roadways  where Drainage Spread is a Consideration

Table 4.7. Maximum Change in Grade  that Does Not Require a Vertical Curve

Table 4.8. Vertical Profile Clearance Based on High Water

Table 4.9. Maximum  Superelevation Rates

Table 4.10. Superelevation Rotation Points and Rotation Widths

Table 4.11. Maximum Relative Gradients

Table 4.12. Adjustment Factor for Number of Rotated Lanes