1. What is the deceleration rate assumed for design in calculating stopping sight distance? A. 32.2
ft/sec^2 B. 9.81 ft/sec^2 C. 62.4 lb/ft^3 D. 11.2 ft/sec^2 Stopping sight distance is the sum of
A. Braking distance and passing distance B Braking distance and decision making distance C.
Perception reaction distance and passing distance D. Perception reaction and braking distance
Which one is not true? A. Accuracy is degree of perfection obtained in a measurement B B.
Precision is the closeness of one measurement to another Better precision also means better
accuracy Precision is defined as the ratio of error of measurement to distance measured In
leveling, all arc true except? The backsight reading is added to the elevation of the known point
to compute the height of instrument? Elevation of a point is the height of instrument (HI) plus
foresight (FS) The initial backsight must be taken to a point of known elevation Intermediate
sight (IS) and foresight (FS) arc treated alike when determining elevation Systematic errors: A.
are due to limitations in the measuring system and cannot be removed B. are removed by
applying corrections C. are blunders caused by a bias in the measurement D. are compensating in
nature
Solution
i) According to American Association of state highway and transport officals (AASTHO) based
on studies recomendations were made on 90 th( or 10th) values recommendations were made
Perception Brake time-2.5 s
Driver decelration =3.4 m/s2(11.2ft/sec2)
Driver height and object height=1080 mm and 600 mm respectively
So answer id (D)
ii)Stopping sight distance =Perception reaction distance+Bracking distance
It is because the driver has to first percept that there is danger,then react and then apply brakes
before the vehicle comes to a halt.
Answer is D
iii) A.Accuracy is the degree of conformity with a standard or accepted value
Since measurement B is not a accepted value,Statement A is false
B.Precision is the degree of refinement in the performance of an operation (procedures and
instrumentation) or in the statement of a result. It is a measure of the uniformity or
reproducibility of the result. So statement B is incorrect
C.The accuracy of a field survey depends directly upon the precision of the survey.So statement
C is correct
D.Precision as explained is about refinement of performance of operation based of procedures
and instruments and is not related to measurement of results.Statement D is incorrect.

2. The answer is C
iv)The elevation is determined by subtracting its foresight reading from the the height of
instrument .So B is false
v) Systematic errors are removed by applying corrections. For example, if a tape is P cm short
and if it is stretched N times, the total error in the measurement of the length will be P´N cm
.So the answer is B.