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PE Civil/Transportation Exam with
Complete Solutions
A freeway segment is observed to have normal speeds and various flow rates. How would this flow be best described? - ANSWER-Undersaturated Flow When is the low point on a sag vertical curve at the PVI station? - ANSWER-When G1 = G What is the minimum distance from the edge of a trench that spoils can be stored? - ANSWER-2 ft How would the conversion of a natural grassland to a paved lot (without stormwater detention facilities) affect the time of concentration and runoff? - ANSWER-The runoff would increase, while Time of concentration would decrease What is the difference between spacing and headway? - ANSWER-Spacing is defined in units of distance, while headway is defined in units of time. Both measure from a common point on two consecutive vehicles. Where to find: Channelization at intersections - ANSWER-AASHTO Green Book 9.6. Where to find: Islands - ANSWER-AASHTO Green Book 9.6.3. Assumed Driver's Eye height: - ANSWER-3.5 ft Assumed TRUCK Driver's Eye height: - ANSWER-7.6 ft Object heights for passing and stopping: - ANSWER-Passing: 3.5 ft Stopping: 2 ft (AASHTO GB 3.4.6.2) What is NOT included in AASHTO's criteria for safe design speed on highway curves? - ANSWER-Shoulder Width, Speed Limit Posting, Traffic Volume In rural areas, what type of islands are preferred? - ANSWER-Painted/Flush islands are preferred over raised islands
Daily Traffic Adjustment Factor: - ANSWER-Vavg / Vday (DEPENDENT ON GIVEN) Where to find: Greenshields - ANSWER-AASHTO Green Book 2.3. OR Civil PE Handbook 5.1. What is "Pace" in traffic? - ANSWER-A 10 mph increment in speeds that encompasses the highest portion of observed speeds (Typically mean speed +/- 5 mph) How is Saturation Flow Rate calculated? - ANSWER-S = 3,600 / Saturation Headway (h) How does the observed hourly vehicle volume differ from the design peak-period flow rate? - ANSWER-Observed hourly vehicle volume includes a mix of heavy vehicles... while design peak-period flow rate has been adjusted for PCE of heavy vehicles, PHF, and lane quantity What criteria are used to specify traffic density as determined by the HCM? - ANSWER- PCE, Vehicle Length, Vehicle Spacing What is the acceptable range of PHF? - ANSWER-0.25 - 1. As traffic flow density increases, approaching the critical density, traffic flow does what?
- ANSWER-Traffic flow decreases What causes alligator cracking? - ANSWER-Bottom up-fatigue developed from mechanical failure caused by tensile strains at the bottom of the asphalt concrete layers propagates upwards Is punchout a distress in rigid or flexible pavement design? - ANSWER-Rigid pavement design Present Serviceability Index (PSI) is used to measure: - ANSWER-Pavement roughness What is the minimum vertical clearance of a traffic signal (pavement to bottom of mounting plate)? - ANSWER-15 ft What is the maximum elevation of a traffic signal (pavement to top of mounting plate)? - ANSWER-25.6 ft What is the minimum required number of primary signal faces for a given intersection approach? - ANSWER-2 signal faces (MUTCD 4D.11)
With increased side friction on superelevated curves, driver comfort will: - ANSWER- Decrease What are three functional roadway classifications (FHWA)? - ANSWER-Arterials, Locals, Collectors What affect would roundabouts have when implemented within an intersection? - ANSWER-Increased traffic/pedestrian safety and decreased vehicle speeds What can be used to classify a roadway improvement project as cost effective? - ANSWER-Reduced crash frequency, Reduced crash severity, Reduced liability costs AASHTO recommends that the length of a deceleration lane should be based on: - ANSWER-Highway (Approach) Design Speed, Grade of Deceleration Lane, Design Speed of Exit-Ramp Curve What equation compares velocity and acceleration to distance traveled? - ANSWER- Vf^2 = Vi^2 + 2ax What equation compares velocity and acceleration to travel time? - ANSWER-Vf = Vi + at Is the resilient modulus of aggregate soil dependent on temperature? - ANSWER-No, it is only dependent on Moisture Content, Soil Type, and Applied Repetitive Stress What is Pavement Pumping? - ANSWER-The ejection of water and soils through cracks in pavement caused by heavy axle loads Where to find Axle Loading tables: - ANSWER-AASHTO GDPS Appendix D- Assumed pedestrian walking speed (MUTCD): - ANSWER-3.5 ft/sec What is the minimum taper length in an urban area? - ANSWER-100 ft If a signal is warranted according to the MUTCD, what else is recommended for making this determination? - ANSWER-A location with a 50' wide median should be considered at one intersection AND an engineering study is needed to indicate improvement of safety/operation What is the required height of a pedestrian signal head? - ANSWER-The bottom of the signal housing must be located between 7'-10' above sidewalk level.
The SPT-N value best represents what? - ANSWER-The relative density of cohesionless soils What soils are not subjected to consolidation? - ANSWER-Sands and Gravel What is a major cause of edge cracking in pavement? - ANSWER-Lack of shoulder support What are three stormwater erosion classifications? - ANSWER-Sheet, Rill, and Gully Erosion What is Manning's Equation used for? - ANSWER-Water flow parameters in Open Flow Does pressure head increase or decrease with a decrease in pipe diameter? - ANSWER-Decreases Where to find compound curve radii specifications: - ANSWER-AASHTO GB (Table 3-
What is the assumed start-up loss time at an intersection? - ANSWER-2 seconds What is the assumed driver perception/reaction time? - ANSWER-1.0 (perception) + 2. (reaction) What is the acceptable range of yellow clearance intervals? - ANSWER-3 - 6 seconds What is the assumed design life of concrete? - ANSWER-20 years What is the minimum pedestrian clearance time? - ANSWER-7 seconds How many conflict points are there at a typical 4-leg roundabout? - ANSWER- How many conflict points are there at a typical 3-leg roundabout? - ANSWER- For a W36 x 135 Steel Beam, what is the height and what is the weight? - ANSWER- Height (Depth): 36" Weight: 135 lb/ft How to determine LOS on a typical freeway segment - ANSWER-HCM Vol 2 Ch 12. (LOS Criteria) What is the ramp density of a highway segment with 4 interchanges in 8 miles? - ANSWER-1 ramp/mi
What is Traffic Condition B? - ANSWER-Sufficient SU vehicles to govern design, with some consideration for semitrailer vehicles What is Traffic Condition C? - ANSWER-Sufficient buses and combination trucks to govern design Where to find Clear-Zone widths - ANSWER-AASHTO RSDG Ch 3- Where to find Conservation of Momentum - ANSWER-AASHTO RSDG Ch 8-36 (Sec 8.4.3) What is the maximum grade of a curb ramp according to ADA standards? - ANSWER- 8.33% How is the offset of a signalized corridor calculated? - ANSWER-Offset (t) = L (ft) / S (ft/sec) What is the gravitational constant (g)? - ANSWER-32.2 ft/sec^ What are the three types of conflict points? - ANSWER-Diverging, Merging, Crossing Where to find Lateral Offsets of roadways: - ANSWER-RSDG Section 10 Name two crash treatments which are NOT crashworthy. - ANSWER-Turndown-Style End Terminals & Flared End Terminals Where to find off-ramp shoulder width requirements: - ANSWER-AASHTO GB Ch 10- 122 How wide should the paved shoulders be for off-ramps with 40+ mph speed limits? - ANSWER-8' - 10' (right) & 1' - 6' (left) T/F: Higher walking speeds are assumed to improve pedestrian safety and travel along streets. - ANSWER-False - Lower walking speeds are assumed Where to find Length of Tangent (Superelevation) Runout: - ANSWER-AASHTO GB Ch 3.3.8.2 (Sec 3-66) What is the ratio for compound curb radii? - ANSWER-2: How to calculate the Station of the High/Low point station on a vertical curve: - ANSWER-x = -g1/2a
How is offset calculated for a successive signal coordination system? - ANSWER- Length/speed(fps) = Offset (sec) What group index number indicates a "poor" pavement subgrade material? - ANSWER- Group Index: 20+ Is Distress an input or output factor of the Mechanistic Approach to flexible pavement design? - ANSWER-Output (Foundation, Climate, and Traffic are inputs) Is punchout a distress for flexible pavement design? - ANSWER-No T/F: AASHTO recommends that deceleration characteristics for large vehicles are used to govern the design of deceleration lanes. - ANSWER-False. The use of any vehicle characteristics is not recommended. What is the ADA's minimum clear space required on sidewalks and pedestrian areas? - ANSWER-5' What is Punchout? - ANSWER-Punchouts are localized areas where the slab is cracked and broken into several pieces (rigid pavement distress)
