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T.P.D.M.V.2.3
(Al/2001)
33.3 Horizontal Curvature
3.3.3.1 Minimum Radii
Table 3.3.3,1 shows the appropriate radii and superelevation for various Design Speeds.
Wherever possible, radius of R3 or greater should be used. Radii less than R3 should only
be used at isolated locations, where excessive cost would result from the use of R3. For new
roads with a design speed of 80 fcm/h or above, a desirable minimum radius of R4 should be
adopted. (Radii should be related to the inside curve of the carriageway).
Table 3.3.3.1
Appropriate Radii and Superelevation
Radius and Superelevation
Design Speed
km/h
Normal
Minimum
Radius
Absolute
Minimum
Radius
R8
(m)
R7
(m)
R6
(m)
R5
(m)
R4
(m)
R3
(m)
R2
(m)
Rl
(m)
120
2800
2000
1400
1000
700
500
350
250
100
2000
1400
1000
700
500
350
250
175
85
1400
1000
700
500
350
250
175
125
80
1280
900
650
450
320
230
160
115
70
1000
700
500
350
250
175
125
88
60
700
500
350
250
175
125
88
63
50
500
350
250
175
125
88
63
44
Superelevation
2.5%
2.5% 3.5% "
5%
7%
10%
10%
10%
3.3.3.2 Elimination of Adverse Camber
Adverse camber should be replaced with favourable crossfall of
than R7 are used.
2.5% when radii greater
3.3.3.3 Superelevation
For radii between R7 and R3, superelevation should be provided such that:
v 2
2.828^
where : S = superelevation %
V = Design Speed km/h
R = Radius m