Civil Engineering - Highway Engineering - Discussion

This answer is wrong because if we are considering only psychological widening we will get the answer as 0.589( the equation is V/9.5√R.)

But mechanical widening is mandatory for any case. In question, it is mentioned that the road is single lane so that the psy. widening will be=0
The psychological widening will be provided due to psychological reasons( only when the opposite vehicle is coming.
In single-lane roads no opposite vehicles).

Here the We=Wm only.
Ie, nl^2/2R= 0.225m is the ansr. i.e, option (a).
If they mentioned considering both mechanical and psychological widening the answer would be 0.225 + 0.589 = 0.813.

Psychological widening : At horizontal curves, drivers have a tendency to maintain a greater clearance between the vehicles than on straight stretches of road. Therefore an extra width of pavement is provided for psychological reasons for greater manoeuvrability of steering at higher speeds and to allow for the extra space requirements for the overhangs of vehicles.

Because of single lane road we only consider mechanical widening i.e, nl^2/2R.

Then we get the answer is 0.225m.

If the radius is in b/w 50 to 300 provide extra widening on both sides equally (half of 0.225).

But in question, they are mentioned the road is hilly. So only 1 side is possible to provide. So the answer is 0.225/2 option D.

@All.

If you didn't consider mechanical widening on hill, it means you give the vehicle to shortcut path about the jump from hill with a minimum radius and 50kmph speed.

So (W = Wmech+Wphy) is correct formula for all types of roads.

R<50 m Provide Extra widening on the inner side.
50m<R<300m Provide Extra widening both sides of Curve.

Here;
V/(9.58*√R).
V=50kmph,
R=80m,
than put value.
50/(9.5*√80)= .588m.

Here not clearly mention what we have to actually determine. Therefore answer should be (D).

Correct answer would be Mechanical + psychological widening = 0.811 m.

Option D is correct because the answer is 0.78,

Since it is for hill road and accordingly we have

E= (18n/R) +(0.1V/√R).

Correct Answer is option-A.
Because For Single Lane Road Phycological Widening Is 0.
So, Mechanical Widening= nl^2/2R.

For single-lane road only mechanical extra widening is required as per IRC i, e V/9.5√R.

Option B is the correct answer.

l^2/2R + V/9.5""R.
0.6^2/2*80 +50/9.5""80 =0.59 answer.