21. The following data are related to a horizontal curved portion of a two-lane highway: length of curve = 200 m, radius of curve = 300 m and width of pavement = 7.5 m. In order to provide a stopping sight distance (SSD) of 80 m, the set back distance (in m) required from the centre line of the inner lane of the pavement is

1. 1. 2.54

   
   
   

   2. 4.55

   
   
   

   3. 7.10

   
   
   

   4. 7.96

   
   
   

---

1. View Hint View Answer Discuss in Forum

   
   

   Q =		SSD		×	180	=	80	×	180	= 14.9°
   		R + 7.5			π		(300 + 7.5)		π

   
   

   S =		R +	d			1 - cos	θ		= 2.54 m
   			4				2

   Correct Option: A

   
   

   Q =		SSD		×	180	=	80	×	180	= 14.9°
   		R + 7.5			π		(300 + 7.5)		π

   
   

   S =		R +	d			1 - cos	θ		= 2.54 m
   			4				2

---

22. A rod is being designed for a speed of 110 km /hr on a horizontal curve with a super elevation of 8%. If the coefficient of side friction is 0.10, the minimum radius of the curve (in m) required for safe vehicular movement is

1. 1. 115.0

   
   
   

   2. 152.3

   
   
   

   3. 264.3

   
   
   

   4. 528.5

   
   
   

---

1. View Hint View Answer Discuss in Forum

   e + f =	V²
   	127R

   
   

   ∴ R =	V²	=	110²	≈ 528.5 m
   	127(e + f)		127(0.08 + 0.1)

   Correct Option: D

   e + f =	V²
   	127R

   
   

   ∴ R =	V²	=	110²	≈ 528.5 m
   	127(e + f)		127(0.08 + 0.1)

---

---

23. On a circular curve, the rate of superelevation is e. While negotiating the curve a vehicle comes to a stop. It is seen that the stopped vehicle does not slide inwards (in the radial direction). The coefficient of side friction is f. Which of the following is true:

1. 1. e ≤ f

   
   
   

   2. f < e < 2f

   
   
   

   3. e > 2ƒ

   
   
   

   4. none of the above

   
   
   

---

1. View Hint View Answer Discuss in Forum

   Since stopped vehicle does not slide inside,
   
   F ≥ w.sinq
   F = P cosθ
   P = w.f
   where,
   P = centrifugal force
   ƒ = coeff of lateral friction
   ⇒ P.cosq ≥ w sin θ
   wƒ. cosq ≥ w sin θ
   f ≥ tan θ
   ⇒ ƒ ≥ e
   ⇒ e ≤ ƒ

   Correct Option: A

   Since stopped vehicle does not slide inside,
   
   F ≥ w.sinq
   F = P cosθ
   P = w.f
   where,
   P = centrifugal force
   ƒ = coeff of lateral friction
   ⇒ P.cosq ≥ w sin θ
   wƒ. cosq ≥ w sin θ
   f ≥ tan θ
   ⇒ ƒ ≥ e
   ⇒ e ≤ ƒ

---

24. A superspeedway in New Delhi has among the highest super-elevation rates of any track on the Indians Grand Prix circuit. The track requires drivers to negotiate turns with a radius of 335 m and 33° banking. Given this information, the coefficient of side friction required in order to allow a vehicle to travel at 320 km/h along the curve is:

1. 1. 1.761

   
   
   

   2. 0.176

   
   
   

   3. 0.253

   
   
   

   4. 2.530

   
   
   

---

1. View Hint View Answer Discuss in Forum

   e + ƒ =	V²
   	9R

   
   V = 320 km/h
   

   =	320 × 1000	= 88.89 m/s
   	3600

   
   e = tanq = tan33°
   

   ∴ tan33 + ƒ =	88.89²	= 2.404
   	9.81 × 335

   
   ⇒ ƒ = 1.76

   Correct Option: A

   e + ƒ =	V²
   	9R

   
   V = 320 km/h
   

   =	320 × 1000	= 88.89 m/s
   	3600

   
   e = tanq = tan33°
   

   ∴ tan33 + ƒ =	88.89²	= 2.404
   	9.81 × 335

   
   ⇒ ƒ = 1.76

---

---

25. What is the length of valley curve (in m) based on the head light sight distance condition ?

1. 1. 153.6636

   
   
   

   2. 154.4582

   
   
   

   3. 151.2546

   
   
   

   4. 152.0256

   
   
   

---

1. View Hint View Answer Discuss in Forum

   N =		-	1	-	1		= 0.09
   			25		20

   
   

   S = 0.278 × 90 × 2.5 +	90²	= 62.55 + 91.1136 = 153.6636
   	254 × 0.35

   
   Assume L > SSD

   Correct Option: A

   N =		-	1	-	1		= 0.09
   			25		20

   
   

   S = 0.278 × 90 × 2.5 +	90²	= 62.55 + 91.1136 = 153.6636
   	254 × 0.35

   
   Assume L > SSD

---