# Traffic Characteristics and Traffic Studies - IES Previous Year Questions

1.â€ƒIn desire-line diagram, _____ .

**[IES 1995]**

- Length of the desire-line is proportional to the number of trips in both directions.Â
- Width of desire-line is proportional to the number of trips in both directions.Â
- Both length and width of the desire-line are proportional to the number of trips in both directions.Â
- Width of desire-line is proportional to the number of trips in one direction.

**Answer:**Option B

**Explanation:**

The desire line diagrams are drawn such that the width of desire lines are proportional to the number of trips in both directions.

2.â€ƒRatio of the width of the car parking area required at kerb for 30Â° parking relative to 60Â° parking is approximately _____ .

**[IES 1996]**

- 0.7
- 0.8
- 2.0
- 0.5

**Answer:**Option B

**Explanation:**

As per IRC, the standard dimension of a car is 2.5 m x 5.0 m.

The width of the car parking area at kerb for 30Â°= 2.5 Cos 30Â° + 5.0 Sin 30Â° = 4.67 m

The width of the car parking area at kerb for 60Â° = 2.5 Cos 60Â° + 5.0 Sin 60Â° = 5.58 m

Thus, the ratio of the width of the car parking area at kerb for 30Â° parking and 60Â° parking =

Here, the closest option is 0.8.

3. â€ƒFor the relationship u = 55 – 0.44k, where, â€˜uâ€™ is the speed in kmph and â€˜kâ€™ is the density in vpkm. What will be the maximum flow in vph ?

**[IES 1996]**

- 1250
- 625
- 125
- 1718

**Answer:**Option D

**Explanation:**

Given that u = 55 - 0.44 k = 55 (1 -

As per Greenshield model, the relationship between speed and density is given by,

u = v

_{sf}( 1 -

_{j}

Comparing the above equation with u = 55 - 0.44 k = 55 (1 -

Free mean speed, v

_{sf}= 55 kmph and jam density k

_{j}=

Thus, Maximum flow, Q

_{max}=

_{sf}x k

_{j}/ 4

⇒ Q

_{max}= 1718.75 ≈ 1719 vph

Here, the closest answer is 1718 vph.

4. â€ƒConsider the following statements:Â

Collision diagram is used toÂ

- Study accident pattern
- Eliminate accidents
- Determine remedial measures
- Make statistical analysis of accidents

Which of these statements are correct ?

**[IES 1996]**

- 1 and 3
- 3 and 4
- 2 and 4
- 1 and 2

**Answer:**Option A

**Explanation:**

Collision diagram shows the approximate path of vehicles and pedestrians involved in a particular accident. Collision diagrams are useful to compare the accident patterns before and after taking the remedial measures.

5. â€ƒIn which one of the following grades of a highway is an emergency escape ramp provided ?

**[IES 1996]**

- 1 in 200
- Zero grade
- Down grade
- Up grade

**Answer:**Option C

**Explanation:**

The emergency escape ramps are provided in case of a downgrade section of highway. These are helpful in isolating the out of control vehicles from the main traffic stream and thus preventing traffic accidents.

6. â€ƒIt is a common practice to design a highway to accommodate the traffic volume corresponding to _____ .

**[IES 1998]**

- Peak hour
- ADT
- 15 min-peak period
- 30th hour

**Answer:**Option D

**Explanation:**

- Peak hour traffic volume is usually not considered to design a highway because it is too high. As the frequency of occurrence of peak hour traffic volume is lesser, it will be uneconomical to design a highway which accommodates peak hour volume.
- The Average Daily Traffic (ADT) and 15 min-peak period traffic will not be sufficient for a considerable period of a year.
- The 30th highest hourly volume is the hourly volume that will be exceeded only 29 times in a year. The design of the highway based on 30th highest hourly volume is found to be satisfactory in terms of both facility and economic considerations.

7. â€ƒIt was noted that on a section of road, the free speed was 80 kmph and the jam density was 70 vpkm. The maximum flow in vph that could be expected on this road is _____ .

**[IES 1998]**

- 1400
- 2800
- 5600
- 800

**Answer:**Option A

**Explanation:**

Maximum Flow, Q

_{max}=

_{sf}x k

_{j}/ 4

⇒ Q

_{max}= 1400 vph

8. â€ƒAn observer travelling at a constant speed of 70 kmph with the traffic stream over aÂ 5 km stretch is passed by 17 vehicles more than what he passes. When the observer travels against the stream at the same speed, the number of vehicles he meets is 303. The flow of the traffic stream is _____ .

**[IES 2001]**

- 4160 vph
- 2240 vph
- 2002 vph
- 4480 vph

**Answer:**Option B

**Explanation:**

Let,

n

_{a}- number of vehicles travelling in opposite direction, when the observer is travelling against the stream = 303

n

_{y}- number of overtaking vehicles - number of overtaken vehicles, when the observer is travelling with the stream = 17

t

_{a}, t

_{y}- average time taken by the observer to travel 5 km stretch when he passes against the flow and along the flow respectively.

t

_{a}= t

_{y}=

Thus, Flow of vehicles, q =

_{a}+ n

_{y}/ t

_{a}+ t

_{y}

⇒ q = 2240 vph

9. â€ƒIf the total seven-day traffic volume for the week is 3625 and the traffic volume for Monday is 650, then the monthly expansion factor for Monday would be _____ .

**[IES 2001]**

- 1.25
- 0.8
- 0.25
- 5.6

**Answer:**Option A

**Explanation:**

Total seven day traffic volume = 3625

The traffic volume per day =

Monthly Expansion Factor for Monday =

Thus, Monthly Expansion Factor for Monday =

10. â€ƒBased on â€˜30th hour volumeâ€™ for how much percent time during the year can the designer willingly tolerate the unfavourable operating conditions ?

**[IES 2002]**

- 29
- 2.5
- 0.33
- 30

**Answer:**Option C

**Explanation:**

The 30th highest hourly volume is the hourly volume that will be exceeded only 29 times in a year. Thus, percentage of time during a year in which a designer can willingly tolerate the unfavourable operating conditions =