Roadway Vertical Alignments
In Roadway Vertical Alignments, you'll learn ...
- Methods for determining stopping (SSD), decision (DSD), passing (PSD) and intersection (ISD) site distances
- Guidelines for designing vertical grades for consistent operation throughout the proposed roadways
- Design criteria for crest (convex) and sag (concave) vertical curves
- Design procedures for coordinating horizontal and vertical alignments
Roadway vertical alignments are a combination of various parabolic curves and connecting tangent grades. Along with the roadway cross section (lanes and shoulders, curbs, medians, roadside slopes and ditches, sidwalks) and horizontal alignment (tangent and curves), the vertical alignment (grades and vertical curves) helps provide a three-dimensional roadway model. Its ultimate goal is to provide a safe, smooth-flowing facility that is crash-free.
In today’s environment, designers must do more than apply design standards and criteria to ‘solve’ a problem. They must understand how various roadway elements contribute to safety and facility operation, including the vertical profile.
This course focuses on the geometric design of vertical alignments for modern roads and highways. Upon course completion, you should be familiar with the general design of these alignments. The course objective is to give engineers and designers an in-depth look at the principles to be considered when designing roadway vertical alignments.
A Policy on Geometric Design of Highways and Streets (also known as the “Green Book”) published by the American Association of State Highway and Transportation Officials (AASHTO) is considered to be the primary guidance for U.S. roadway design. For this course, Chapter 3 (Section 3.4 Vertical Alignment) will be used exclusively to present fundamental roadway geometric design principles.
Specific Knowledge or Skill Obtained
This course teaches the following specific knowledge and skills:
- The two components that comprise stopping sight distance (SSD)
- Decision site distance (DSD) values based on the roadway's location and the type of avoidance maneuver required
- Driver behavior assumptions when determining passing site distance (PSD)
- Methods for determining intersection sight distance (ISD)
- How topography of the land to be traversed plays a major role in the alignment of roadways
- Why heavy vehicles, such as trucks, control traffic speeds on uphill grades
- Minimum grade value for roadway surface drainage
- Design methods for determining the critical length of grade
- Justification criteria for climbing lanes
- Methods for increasing passing opportunities
- Passing lane design procedures
- Emergency escape ramp types and design criteria
- Design guidelines for vertical curve lengths
- Design criteria for crest (convex) vertical curves
- Design criteria for sag (concave) vertical curves
- AASHTO design guidelines for horizontal and vertical alignments
Certificate of Completion
You will be able to immediately print a certificate of completion after passing a multiple-choice quiz consisting of 20 questions. PDH credits are not awarded until the course is completed and quiz is passed.
|This course is applicable to professional engineers in:|
|Alabama (P.E.)||Alaska (P.E.)||Arkansas (P.E.)|
|Delaware (P.E.)||Florida (P.E. Area of Practice)||Georgia (P.E.)|
|Idaho (P.E.)||Illinois (P.E.)||Illinois (S.E.)|
|Indiana (P.E.)||Iowa (P.E.)||Kansas (P.E.)|
|Kentucky (P.E.)||Louisiana (P.E.)||Maine (P.E.)|
|Maryland (P.E.)||Michigan (P.E.)||Minnesota (P.E.)|
|Mississippi (P.E.)||Missouri (P.E.)||Montana (P.E.)|
|Nebraska (P.E.)||Nevada (P.E.)||New Hampshire (P.E.)|
|New Jersey (P.E.)||New Mexico (P.E.)||New York (P.E.)|
|North Carolina (P.E.)||North Dakota (P.E.)||Ohio (P.E. Self-Paced)|
|Oklahoma (P.E.)||Oregon (P.E.)||Pennsylvania (P.E.)|
|South Carolina (P.E.)||South Dakota (P.E.)||Tennessee (P.E.)|
|Texas (P.E.)||Utah (P.E.)||Vermont (P.E.)|
|Virginia (P.E.)||West Virginia (P.E.)||Wisconsin (P.E.)|