It is also provided on horizontal curve so as to

• It is also provided on horizontal curve so as to
provide a better night visibility of the curves
under the head light of the vehicle.

Guard rail

Road margins
Parking lane:
• These are provided on urban roads to allow kerb parking
• As far as possible only parallel parking should be allowed
as it is safer for moving vehicle.
• It should have sufficient width say 3m
Lay bay:
• These are provided near the public conveniences with
guide map to enable driver to stop clear off the
carriageway.
• It has 3m width,30m length with 15m end tapers on both
sides.
Bus bays:
• These may be provided by recessing the kerb to avoid
conflict with moving traffic.
• It is located atleast 75m away from the intersection.

Frontage road:
• These are provided to give access to properties along an important
highway with control access to express way or free way
• It may run parallel to the highway and are isolated by separator.
Driveway:
• It connect the highway with commercial establishment like fuel stations,
service stations etc…
• It should be located away from the intersection.
Cycle track:
• It provided in urban areas when the volume of cycle traffic on the road
is very high.
• A minimum width of 2m is provided for cycle track.
Footpath:
• These are provided in urban areas when the vehicular as well as
pedestrian traffic are heavy.
• To protect the pedestrian and decrease accident.
• Minimum width of 1.5m is provided.

Bus
bays

Frontage
road

c/s of highway in hilly area

c/s of road in built-up area

C/S of Flexible pavement
C/S of Rigid pavement

c/s of road in cutting

Guard rails

Bibliography
• Khanna , S. K., & Justo, C. E. G. “ Highway
engineering”. Nem Chand & Bros.
• IRC Codes.

Lecture -3
Sight Distance & Horizontal Alignment
Civil Engineering Department
College of Engineering and Technology(CET)
Bhubaneswar
TRANSPORTATION ENGINEERING-I
PCCI4302

SIGHT DISTNCE
• Sight distance available from a point is the actual
distance along the road surface, which a driver
from a specified height above the carriageway
has visibility of stationary or moving objects. OR
• It is the length of road visible ahead to the driver
at any instance.

Types of sight distance
• Stopping or absolute minimum sight
distance(SSD)
• Safe overtaking or passing sight distance (OSD)
• Safe sight distance for entering into uncontrolled
intersection.
• Intermediate sight distance
• Head light sight distance

Stopping sight distance:
• The minimum sight distance available on a highway at any spot
should be of sufficient length to stop a vehicle traveling at design
speed, safely without collision with any other obstruction.
Over taking sight distance:
• The minimum distance open to the vision of the driver of a vehicle
intending to overtake slow vehicle ahead with safety against the
traffic of opposite direction is known as the minimum overtaking
sight distance (OSD) or the safe passing sight distance.