Curves highway

Curves of
constant
radius
required to
connect two
straights set
out on the
ground.
The curves
are designed
and built to
connect the
straight lines
with circular
curves
The curves
are designed
and made to
join two
different
straight
slope.
CURVES - DEFINITON
Horizontal curves Transition curves Vertical curves
For the convenience
of road users
To connect the
straight lines with a
horizontal curve
To avoid the
situation where a
sudden change in
the vehicle entering
the curve from a
straight round
To avoid the
situation where a
sudden change in
the vehicle when it
starts down the
road after climbing
a hill or otherwise.
C
U
R
V
E
S
-
P
U
R
P
O
S
E
Horizontal curves Transition curves Vertical curves

C
U
R
V
E
S
-
T
Y
P
E
S
-Circular curves
-Transition curves
-Compound curves
-Reverse curves
None Crest curves
Sag curves
Horizontal curves Transition curves Vertical curves
The parabola has the desirable
characteristics of
(1)a constant rate of change of
slope, which contributes to
smooth alignment transition,
(2)ease of computation of
vertical offsets, which permits
easily computed curve
elevations
T1 T2
Crest curves
T1 T2
Sag curves
T1T2
I
O
P R
CURVES - GEOMETRY
Horizontal curves Transition curves Vertical curves

Offset From The
Tangent line
Offset From The
Long chords line
Deflection angle
method
Sub chords line
method
Wacky turn
Setting out the
transition curves
from T1 to T2
Setting out the
transition curves
from T4 to T3
Setting out the
circular curves from
T2 to T3
None
CURVES SETTING OUT METHOD
Horizontal curves Transition curves Vertical curves
Circular curves - types
Simple circular curves
Compound curves
Reverse curves R2
R2
R
R
R1
R1
R1
R2