Study Guide Quiz 3

1.     Alignment Design

Horizontal Alignment

What are the elements of the horizontal alignment?

What is the purpose of the spiral curve?  What are the basic properties of the spiral curve?

Circular Curve

Know how to sketch a circular curve and to label the key locations. Know the definition of degree of curvature (D). Know how to derive the relationship between R and D. Know how to derive the relationship between L and R.

Horizontal Curve Design

Explain the physical basis for determining minimum radius.  What are the factors that limit e_max?

Vertical Alignment

Parabolic Curve

Know how to sketch a parabolic curve and to label the key locations. Know the difference between sag and crest curve. Know the definition for the rate of change of curvature parameter (K). Know how to calculate A. Know the definition of the rate of change of grade (r).  Know how to determine station and elevation of the turning point. Know how to determine elevation at all locations on a vertical curve.

Vertical Curve Design

Describe the criteria for determining minimum length of crest vertical curves. Describe the criteria for determining minimum length of sag vertical curves.

Continuous Alignment

Why is a continuous alignment recommended? Explain the term "continuity of form". Give specific factors needed to achieve ‘continuity of form”.  Explain the term "continuity of scale". Give specific factors needed to achieve continuity of scale in the horizontal and vertical alignment, respectively. Explain why it is important to coordinate H and V alignments for design. Discuss the main guidelines for coordinating H and V alignments. Know how to make and interpret 1/R plot.

2.     Street Design

Street and Highway Classification

Explain the purpose or need for street classification in design: Explain the basics of the AASHTO method of classification – land use, highway types, access versus mobility, the hierarchical network: Explain the basics of the CNU/ITE method of classification – context zones, thoroughfare types, urban street networks: Explain the difference between these two methods of classification and their relative pros and cons.

Urban Street Design Elements

Know the pros and cons of the hierarchical versus the connected street network. Know the features that can be used to distinguish different types of streets in a connected street network. Know the typical elements of the cross-section of the most common type of urban street.  Know the relationship between speed and fatality risk. Know how different features affect driver’s choice of speed. Know the site design and building design features that affect the appearance, appeal and function of a street as a place.

Shared Space

Know the difference between shared space and conventional design philosophy.  Understand the difference between context time and system time.  Give specific examples of shared space design.

Roundabouts

Know the difference in design and operations between roundabouts and other types of circular intersections. Know the pros and cons of roundabouts vis-à-vis conventional intersection types. Know the basic elements of a modern roundabout. Know how the individual elements affect the vehicle speed and operations. Know how pedestrian and bike traffic are handled in roundabouts.