DEPARTMENT OF CIVIL CONSTRUCTION AND ENVIRONMENTAL ENGINEERING
CEEN 4615 HIGHWAY PLANNING AND DESIGN
REVIEW TOPICS FOR TEST 2
Updated 04/23/2018 by Dr. Drakopoulos
Be prepared on the following topics, as well as topics pertaining to all class projects (e.g., using the value matrix, how superelevation is introduced, earth quantities calculations, etc.) Make sure to review your homework solutions. Green Book Exhibits may be provided --you should be able to use them to answer test questions. These equations will be provided. You should be familiar with their correct application, including appropriate units.
Bring with you a straight edge with metric and English gradations, a good eraser and a calculator.
PLEASE TURN OFF ALL CELL PHONES, PAGERS, iPODS, iPads etc.
For full credit:
Provide the Figure/Table number/page number you used.
Show calculations and provide a few words to explain their meaning.
Use proper symbols and show units.
Mark the answer clearly.
Draw a neat sketch of the situation where appropriate.
Follow specific full-credit instructions provided with a problem.
HORIZONTAL ALIGNMENT (Curvature and Superelevation)
Be able to provide a degree of curve definition, accompanied by a clear figure of all pertinent information (closed book).
Be able to calculate the degree of curve, based on the definition of D.
Horizontal curve Design Rules of thumb. Know at least five rules of thumb and be able to draw simple figures to explain the concepts.
Definition, need for, concerns about Superelevation.
Maximum superelevation when snow and ice are a concern.
How is blending-in superelevation accomplished? Be able to draw a simple figure to explain these concepts:
Typical pavement cross-sections: shapes, cross-slopes.
Runoff with medians: Cases I, II and III describe what each is and where it is applicable.
AASHTO recommendations for superelevation for Low-speed Urban streets.
Be able to use the minimum radius formula and Figures.
Calculations for horizontal curves--see homework assignment and related handouts (open book part).
Typical values for coefficient of side friction at 10 mph and at 80 mph recommended for design.
Be able to use appropriate Figures to recommend a Radius of Curvature, a superelevation and a superelevation runoff length combination for a given design speed and a given number of rotated lanes.
If a spiral is provided to transition into a circular curve, where should the superelevation runoff be placed in relation to the spiral?
How does a downgrade affect the superelevation value chosen?
Know the meaning of Table 3-16 and be able to use it.
Be able to reproduce Figure 3-16 part A with all pertinent technical terms.
VERTICAL DESIGN
Types of terrains, terrain classifications.
Up to what percentage grade has no effect on passenger car speeds?
Why is special attention warranted for trucks on grades?
How can trucks be accommodated on grades?
Should grade steepness vary between the bottom and the top of the grade to better accommodate trucks? Why? How?
What is the minimum recommended grade? Why is it necessary? Is it more important when there is or when there is no curb? Why?
What is critical length of grade? What factors does critical length of grade depend on?
How is critical length of grade used to help in highway design?
What typical criteria are used for climbing lanes?
Types of vertical curves
Main concerns for the vertical curve designer--explain how each concern is addressed-which is the main concern?
Crest Vertical Curves: How are min lengths determined?
Discuss sight obstructions due to crests and horizontal curves. Be able to draw a graph to explain concepts, including dimensions and assumptions.
Provide graph indicating stopping sight distance design criterion for crests, with dimensions, assumptions and explanations.
Provide graph indicating passing sight distance design criterion for crests, with dimensions, assumptions and explanations.
Are truck drivers at an advantage or a disadvantage compared to passenger car drivers on crest vertical curves? Why? Explain, use a drawing.
Sag Vertical Curves: How are min lengths determined?
Provide graph indicating stopping sight distance design criterion for sags, with dimensions, assumptions and explanations.
Provide graph indicating sight distance problem at undercrossings for sag vertical curves, with dimensions, assumptions and explanations.
All vertical curves:
What is K for vertical curves? Formula, explanation.
What does a higher K value signify for the vertical curve?
What concerns do we have about low K values?
What concerns do we have about high K values?
What is the critical K value for hydraulic concerns? What concern do we have? How can this concern be addressed?
What formulas are applied to find the shortest acceptable length for a vertical curve (crest, sag)?
What are visibility concerns at vertical curves at night when no lighting is available (crests, sags)?
General rules of thumb for vertical curves: what does AASHTO recommend-draw simple sketches to demonstrate.
CROSS SECTION ELEMENTS--URBAN
What is a "roadway?" What is the "traveled way?"
What pavement types does the AASHTO Green Book use?
What factors is pavement selection based on?
Cross Slope:
Shapes of cross-section surfaces
Divided highways: Pros and cons for each traveled way/roadway crowned separately; pros and cons for unidirectional slope across entire traveled way/roadway. Pictures, explanations.
Cross Slope Considerations: what is desired for good drainage, comfortable driving (minimum and maximum values, desired function of cross-slope, contradicting goals between desired functions).
How pavement type affects cross-slope values. Typical values for high type and low type pavements. Why is a higher cross slope desired for low type pavements?
What are the four most prominent reasons for reduced pavement skid resistance?
Lane widths: minimums, desired values. Effects of lane width, presence of lateral obstructions.
If a wider and a narrower lane need to be used where should each be placed? Why?
Examples of auxiliary lanes (typical placements/functions and dimensions: explanations, pictures)
Dual left turn lanes-typical min and max width, benefits and disadvantages, sketch.
Curbs: Types and their functions/proper usage-safety concerns in relation to speed and clearance (pictures, dimensions, explanations)
Gutters: typical dimensions coordination with other design elements for proper functioning.
Should gutter width be included in lane width? (Discuss)
Curb Placement: where and how should barrier and mountable curbs be used?
How should curbs be introduced when following a section without curbs? (Picture. Explanations).
Gutters: dimensions, function, effect of using different material than pavement, concerns with grates, concerns with bicycles, concerns with barriers.
Medians: Functions, delineation, typical cross sections and their pros and cons, safety concerns (pictures, dimensions, explanations)
Sidewalks: recommended widths and other dimensions
Handicapped ramps: where should they be placed. Design for wheelchair accommodation when crossing intersection. (Picture, explanations)
CROSS SECTION ELEMENTS--RURAL
Shoulder purposes
Graded shoulder; usable shoulder definitions
Typical shoulder widths
Other shoulder characteristics
Shoulder cross section: drainage goals and direction of drainage (median or otherwise), slopes depending on materials; delineation from driving lanes
Clear zone definition, purpose and characteristics
Sideslope design: important safety elements; foreslope and backslope slope limits and reasons for limits; what to do when forced to use steep slopes
AT GRADE INTERSECTIONS
Design vehicle selection
Assumptions for turning vehicle position. (Picture, English)
Draw a picture of problems with inadequate turning radii
Discuss the sequence from simplest curve to most complex curve design: simple circular curve to asymmetric compound curve (Drawing for each) Benefits/disadvantages. Show tapers, offsets etc.
How can curb parking be used to facilitate large turning vehicles.
Median openings: Desired features-best design. What problems are addressed with the best design, compared to a simpler design.
Auxiliary Lanes: Uses, width, length, taper, deceleration, storage (English, drawing)
Traffic islands: size, shapes, categories based on how they are physically defined, categories based on delineation and approach end treatment.
Factors affecting widths of turning roadways at intersections Cases I, II and III, Traffic conditions A, B and C. (Discussion, definitions, use in English)
GRADE SEPARATION-INTERCHANGES
Major benefits
When is grade separation warranted?
Interchange types: be able to draw T, Y, Trumpet, Diamond, Partial and full cloverleaf, directional.
Be able to discuss applicability of each interchange type (Urban/rural application; appropriateness when turning volumes are low/high; space requirements). Major advantages and disadvantages (cost, number of structures, safety, capacity, potential problem areas etc.)
What is a "ramp" what is a "turning roadway?"
Ramp max gradient, pavement width.