Civil Engineering - GATE Exam Questions - Discussion


On sag (or valley) curves the available sight distance is determined based on :

[A]. design speed
[B]. height of obstacle
[C]. height of driver eye
[D]. night-time driving conditions

Answer: Option C


No answer description available for this question.

Malini said: (Sep 15, 2015)  
Someone please give explanation.

Malini said: (Sep 16, 2015)  
Someone please explain me.

Nishit said: (Sep 22, 2015)  
Because driver can see the obstacles or vehicle which moves at either side of curvature & reduce the accident.

Tauseef said: (Oct 17, 2015)  
Because of such alignment.

Lechu said: (Dec 1, 2015)  
The valley curves are mainly designed for comfort of passengers and considering sight distance at night time.

Jyoti Chaudhary said: (Jan 17, 2016)  
In valley curves two conditions are required-comfort zone (in which the change in centrifugal acceleration is limited upto a certain level).

Safety criteria: In which the driver should have adequate light during night.

So option (D) is correct.

Raghavendra said: (Mar 23, 2016)  
In valley curves, the design shall be made considering head light sight distance; not the height of driver's eye.

Vasanth said: (Apr 5, 2016)  
How it depends on the height driver eye if driver is short then.

Suraj said: (Sep 25, 2016)  
Option D is the correct answer.

Sachin said: (Jan 18, 2017)  
It is, Night conditions option D is Correct.

Kunjita Dashore said: (Feb 1, 2017)  
Option D is correct. On the basis of night Time driving conditions on valley curve available sight distance is determined.

Dheeraj said: (Feb 6, 2017)  
Yes, Option D is the correct answer.

Asaithambi said: (Feb 9, 2017)  
Normally design sag or valley curve IRC considering driver observing the 15cm height of objectives.

Suresh said: (Feb 19, 2017)  
D is the correct answer. I too agree.

Sagar said: (Mar 16, 2017)  
Sight distance depends upon height of the headlight i.e. 0.75m in turn is used only in nighttime driving condition.

Duraisamy said: (Apr 12, 2017)  
Option D is Wrong because road alignment is considered into height of driver.

M.Suna said: (Jun 20, 2017)  
Answer c should be correct. Because according to the relation L= NS2/2h+2stan (α).

Alpha should be always 1 as per IRC. So hear, if we find out "h" i.e. height of the driver then we can get SSD easily.

Naveen said: (Jul 19, 2017)  
It has to be Head Light Sight Distance i.e. Option D.

Ismail said: (Aug 28, 2017)  
The valley curve should be designed such that there is enough headlight sight distance. Improperly designed valley curves result in extreme riding discomfort as well as accident risks, especially at nights. The length of valley curve for various cases was also explained in the section. The concept of Valley curve is used in underpasses.

Roy said: (Dec 31, 2017)  
Yes, it's D.

Bapuji Pradhan said: (Feb 2, 2018)  
Explain the answer.

Venu Gopal said: (Jul 25, 2018)  
Option D is correct I think.

Chanti said: (Oct 12, 2018)  
In summit (hog) curves available sight sight distance is based on SSD.

In valley (sag) curves available sight distance is based on head light distance.

Sachin said: (Nov 2, 2018)  
Yes, I too agree Option D is correct.

Aniket said: (Jan 18, 2019)  
I think Option D is the correct answer.

Puja said: (Jan 30, 2019)  
Option D is correct.

Ahsen said: (Jan 16, 2020)  
Should it not be option D?

As there are no visual restrictions on sag curve and the only concern remaining is the glare due to vehicle headlight at night time.

Murtaza said: (Jul 13, 2020)  
Option D should be the right answer.

Gurjant Singh said: (Jul 17, 2020)  
Yes, Agree, Option D is right.

Blackie said: (Jan 5, 2021)  
Yes, D is correct.

Sneha Mathai said: (Jan 17, 2021)  
In a valley or sag curve, the design is based on headlight sight distance only. It is because night time driving is to be taken at almost care in valley curves.

Muluneh said: (Feb 27, 2021)  
Answer is B because the height of the obstacle have constant height for every one who drive.

Tian said: (Aug 19, 2021)  
Yes, right. Agree @Sneha.

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