Highway Engg Flashcards
SITUATION. Commuter trains travel between stations spaced 1.0 mi apart. A train arrives every 5 min, and the trains can attain a maximum speed of 80 mph. Only one train is permitted between stations at a time. Each train has 5 cars, with a maximum capacity of 220 people per car. When the train stops, it must wait 1.0 min to allow for passenger movement. The uniform acceleration of the train is 5.5 ft/s2. Deceleration is 4.4 ft/s2.
1. What is the top speed of the train?
A.60mph
B.70mph
C.80mph
D.90mph
80 mph
- What is the maximum capacity of the line in people per hour?
13200
- What is the average train speed?
A. 26.8 mph B. 27.9 mph C. 29.7 mph
27.9 moh
What is the average running speed?
A. 52.2 mph B. 25.2 mph C. 22.5 mph
52.2 mph
How much time would be saved between stations if the
maximum speed was increased to 100 mph?
A.2sec
B.3sec
C.4sec
D.5sec
B.3sec
SITUATION. A rural Class I two-lane highway has a design speed of 60 mph in both directions. One particular segment of the highway is a 3% uphill grade lasting for 2 mi with 40% of that length unavailable for passing. There are no access points along the segment. The lane width is 11 ft. The shoulders are 2 ft wide on the uphill side and 6 ft wide on the downhill side. In the peak 60 min of travel, vehicular volume is near the maximum for level of service B for level terrain. The traffic distribution is 5% trucks, 15% buses, and 80% cars. 70% of the traffic goes uphill during the peak hour, while the remaining 30% travels in the opposite direction.
6. What is the highest possible two-way flow rate for extended lengths of a level, two-lane highway without flow becoming oversaturated?
A. 1500 pcph each lane
B. 1700 pcph each lane
C. 3200 pcph both lanes combined
D. 6400 pcph both lanes combined
C. 3200 pcph both lanes combined
Using average travel speed (ATS) criteria, what is the uphill grade adjustment factor for a specific upgrade?
A. 0.91 B. 0.93 C. 0.97 D. 0.99
C. 0.97
Using average travel speed criteria, what is the heavy vehicle adjustment factor for a specific upgrade going uphill?
A. 0.505 B. 0.550 C. 0.606 D. 0.660
A. 0.505
Using average travel speed criteria, what is the passenger car equivalent volume for the uphill lane during the peak 15 min period?
A. 750 pcph B. 1150 pcph C. 1300 pcph D. 1800 pcph
D. 1800 pcph
Assuming a free flow speed of 57 mph, what is the average travel speed on the uphill segment?
A.42mph B.50mph C.54mph D.56mph
A.42mph
What is the percent time spent following for this segment? A. 45% B. 55% C. 65% D. 65%
65%
What treatments might be made to improve the level of service?
A. adding a median and providing curbs along the lane edge
B. addingasidewalk,addingatrafficsignal,andimproving the pavement markings.
C. adding roadway lighting and reducing the speed limit
D. realigning the roadway to improve sight distance and adding a passing lane
D. realigning the roadway to improve sight distance and adding a passing lane
One lane of a two-lane highway was observed for an hour during the day. The following data were gathered.
average distance between front bumpers of successive cars
spot mean speed space mean speed
80 ft
30 mph 29 mph
What is the average headway in sec/veh?
A. 1.88 B. 1.77 C. 1.55 D. 1.66
A. 1.88
What is the density in vehicles per mile?
A.44 B.66 C.55 D.33
66
What is the traffic volume in vehicles per hour?
A.1914
B. 1419
C. 1941
D. 1491
A.1914
What is the maximum (ideal) capacity in pcph in both directions sustainable for short distances?
A. 2800 B. 3200 C. 4400 D. 4800
B. 3200
- NOV 2021. Which is a more accurate parameter of traffic capacity: volume or density? Why?
A. Density is more accurate: Only density is a function of
cars in a given length of roadway.
B. Density is more accurate: Only density has units of time. C. Volume is more accurate: Only volume is a function of
cars in a given length of roadway.
D. Volume is more accurate: Only volume has units of time.
D. Volume is more accurate: Only volume has units of time.
What is the maximum (ideal) capacity of one lane of a four- lane freeway?
A. 1900 pcph B. 2400 pcph C. 4400 pcph D. 8800 pcph
B. 2400 pcph
A benefit/cost analysis is to be performed to justify the installation of safety-related road improvements such as flexible barriers and breakaway poles. What records could be used to obtain an economic value for property damage prevented and human lives saved by the safety improvements?
A. police records, telephone directories, and voting records B. school bus incident reports, municipal building permits,
and zoning records
C. hospital emergency room reports and paramedic files
D. insurance records, state disability fund records,
accepted federal standards (e.g., OSHA), and property damage reports on file with police
D. insurance records, state disability fund records,
accepted federal standards (e.g., OSHA), and property damage reports on file with police
SITUATION. Two cars are moving at 60 mph in the same direction and in the same lane. The cars are separated by one car length (20 ft) for each 10 mph. The coefficient of friction (skidding) between the tires and the roadway is 0.6. The reaction time for each driver is 0.5 sec.
21. If the lead car hits a parked truck, what is the speed of the second car when it hits the first (stationary) car?
A.13mph
B.24mph
C.38mph
D.47mph
D.47mph
If the lead car hits a parked truck and comes to an abrupt halt, at what speed does the rule of one car length of spacing for every 10 mph of speed become unsafe?
A. 23 mph B. 33 mph C. 55 mph D. 85 mph
23 mph
At 60 mph, what should the rule for every 10 mph actually be?
A. 30 ft B. 40 ft C. 50 ft D. 60 ft
40 ft
SITUATION. You have been hired by the owner of a damaged house to investigate a car crash that caused the damage. From the police report, you learn that the car was traveling down a 3% grade at an unknown speed. The skid marks are 56 m long, and the pavement was dry at the time of the accident. The police report was 40 kph. From an inspection, you know that the car’s tires were new. The house owner does not believe the estimate of initial speed. You have the following data from tests performed on dry, level roadways.
Findtheminimuminitialspeedofthecar.
A. 78 kph B. 81 kph C. 89 kph
78 kph
If the police report was mistaken in assuming the road surface was dry, what was the minimum initial speed of the car?
A. 63 kph B. 66 kph C. 69 kph D. 72 kph
B. 66 kph
You are hired as a consultant to give expert evidence in a court action arising from a vehicle collision. The two vehicles collided head-on while traveling on a curve tangent with a 4% grade. Vehicle A skidded 59.4 m downhill before colliding with vehicle B. Vehicle B skidded 43.3 m. The police report estimates that both vehicles were traveling at 40 kph prior to the collision, based on vehicle deformation. Assume a coefficient of friction of 0.48.
What was the speed of vehicle A prior to the application of brakes?
A. 90 kph B. 91 kph C. 97 kph D. 99 kph
B. 91 kph
What was the speed of vehicle B prior to the application of the breaks?
A. 86 kph
B. 91 kph
C. 97 kph
D. 99 kph
A. 86 kph
Which of your assumptions (impact speed or coefficient of friction) produces the greatest possible error in your initial speed calculations?
A. The impact speed is more sensitive to error.
B. The impact speed and coefficient of friction are equally sensitive to error.
C. Theimpactspeedismoresensitivetoerrorover80kph.
D. The coefficient of friction is more sensitive to error.
D. The coefficient of friction is more sensitive to error.
The mass of a core of asphalt concrete in air is 1150 g. The mass of the core in water s 498.3 g. What is the core’s density in lbm/ft3?
A. 111.10 B. 122.20 C. 110.11 D. 120.22
C. 110.11
The specific gravity of voidless mixture (i.e., the maximum theoretical specific gravity) of an asphalt concrete is 2.550. The components are specified as follows:
Material
asphalt cement limestone dust sand
gravel
Specific Gravity
1.020 2.820 2.650 2.650
Apparent Specific Gravity - 2.650 2.905 2.873
By Weight (%)
6.3 13.7 30.4 49.6
30.
What is the air void content if the bulk specific gravity of the mixture is 2.340?
A. 8.42% B. 8.24% C. 6.24% D. 6.42%
B. 8.24%
What is the bulk specific gravity of the aggregate?
A. 2.67 B. 2.69 C. 2.73 D. 2.75
2.67
- What is the VMA of the mixture?
A. 16% B. 17% C. 18% D 19%
18%
What is the effective specific gravity of the aggregate?
A. 2.80 B. 2.82 C. 2.84 D. 2.68
C. 2.84
What is the asphalt absorption?
A. 1.90% B. 2.05% C. 2.13% D. 2.18%
2.18
What is the effective asphalt content of the mixture?
A. 4.3% B. 4.5% C. 4.7% D. 5.0%
4.3%
What is the VFA of the mixture?
A. 52.4% B. 53.8% C. 54.3% D. 54.6%
54.3%
What is the apparent bulk specific gravity of the aggregate?
A. 2.4 B. 2.6 C. 2.7 D. 2.8
2.8
How much would the percent air voids of the mixture change if the weight of the asphalt is increased by 2%?
A. 0.05% decrease
B. 0.14% decrease
C. 0.14% increase
D. no change
B. 0.14% decrease
How much would the VMA of the mixture change if the weight of the asphalt is increased by 2%?
A. 0.1% decrease C. 0.1% increase
B. 0.2% decrease D. no change
C. 0.1% increase
Given the following minimum thickness and unit costs and a required structural number of 6, design the most economical pavement section.
A. asphalt concrete, 4 in; base, 6 in; subbase, 28 in
B. asphalt concrete, 4 in; base, 6 in; subbase, 43 in
C. asphalt concrete, 6 in; base, 6 in; subbase, 28 in D. asphalt concrete, 4 in; base, 8 in; subbase, 30 in
How much water must be added to the following materials to obtain 6 gal net of mixing water?
47.08 lbf
All normal curves are bell shaped and
Symmetric
What are the sources of errors
Natural, instrumental, and personal
Most important in avoiding bias in surveying
Picking a sampling in which every combination of people has the same chance of being selected
A simple random sample is defied by
The method selection
