1. The speed corresponding to the summit of the frequency distribution curve of spot speeds is _______
a) Peak speed
b) Ruling speed
c) Modal speed
d) Mean speed
Explanation: The speed corresponding to the summit of the frequency distribution curve of spot speeds is Modal speed. It is the speed at which largest number of vehicles travel.
2. What is the use of a cumulative speed distribution curve?
a) To determine the speed above or below which certain percentages of vehicles are moving
b) To determine the traffic volume
c) To determine the modal speed
d) To determine the PCU
Explanation: Cumulative speed distribution curve is used to determine the speed above or below which certain percentages of vehicles are moving. This graph has the mean values of each speed group on the x-axis and the cumulative percentage on the y-axis.
3. Which of the following is considered to be the safe speed limit?
a) 98 percentile speed
b) 85 percentile speed
c) 50 percentile speed
d) 10 percentile speed
Explanation: 85 percentile speed is considered to be the safe speed limit. 85 percentile speed is the speed beneath which 85% of the vehicles are travelling at a point (15% of the vehicles exceed this speed at the point).
4. Which of the following is considered to be the minimum speed limit on a highway?
a) 98 percentile speed
b) 85 percentile speed
c) 15 percentile speed
d) 10 percentile speed
Explanation: 15 percentile speed is considered to be the minimum speed limit on a highway. Speed less than this is generally prohibited since it leads to congestion and accidents.
5. 98 percentile speed is _____
a) design speed
b) safe speed
c) minimum speed
d) median speed
Explanation: 98 percentile speed is design speed. It is the speed that is used for geometric design purposes. Median speed is the 50 percentile speed, safe speed is 85 percentile speed and the minimum speed is 15 percentile speed.
6. What is Modal speed?
a) Speed that is most likely to occur
b) Speed that is least likely to occur
c) Peak speed
d) Minimum speed
Explanation: Modal speed is the speed that is most likely to occur. Modal speed is a measure of central tendency. It is a value of speed that occurs often in the sample of spot speed in the given data.
7. Which curve helps to determine Modal speed?
a) Frequency distribution curve
b) Uniform distribution curve
c) Normal distribution curve
d) Poisson distribution curve
Explanation: Frequency distribution curve helps to determine Modal speed graphically. A vertical line is drawn from the crest of the curve and the modal speed is the value on horizontal axis of the graph.
8. What is Median speed?
a) Speed that divides the distribution in to equal parts
b) Speed that divides the distribution in to unequal parts
c) Speed that is most likely to occur
d) Speed that is least likely to occur
Explanation: Speed that divides the distribution in to equal parts is known as median speed. This means that there are equal number of observations of speeds which are higher than the median as there are lower than the median.
9. Median speed is a negative value.
a) True
b) False
Explanation: The statement, “Median speed is a negative value” is false. The accurate statement is, “Median speed is a positive value”. Median speed value is not affected by the absolute value of extreme observations
10. Median speed is the 50th percentile speed in _______
a) Frequency distribution curve
b) Normal distribution curve
c) Cumulative frequency curve
d) Uniform distribution curve
Explanation: The Median speed of the speed distribution is the 50th percentile speed in Cumulative frequency curve. 50% of all the observed speeds should be below the median speed.