IRC 73-2023_presentation for highway design

Presentation on
IRC 73:73-2023
GEOMETRIC DESIGN STANDARDS
FOR NON-URBAN ROADS
By
Geetashree Paul
Date: 14/08/2024

CONTENTS
1. Introduction & Classification of Non-Urban Roads
2. Control Factors Affecting Geometric Design
3. Cross-Sectional Elements
4. Sight Distance
5. Horizontal Alignment
6. Vertical Alignment
7. Horizontal and Vertical Alignment Coordination
8. Lateral and Vertical Clearances
9. References

 General
Geometric design deals with the visible elements of a roadway. Sound geometric
design results in economical operation of vehicles and ensures safety.
The revised IRC:73 guidelines cover the geometric design features for different
classification of roads.
This standards deals with geometric design guidelines with respect to Expressways,
2/4/6/8 lane highways as well as Major District roads (MDR), Other District Roads
(ODR) and Village Roads (VR).
Introduction and Classification
of Non-Urban Roads
Classification of road
Urban Roads Non-Urban Roads

Functional Classification of Non-Urban Roads (as
per IRC:73-2023)
 Primary System
a) Expressway (EW)
b) National Highways (NH)
 Secondary System
a) State Highways (SH)
b) Major District Roads
(MDR)
 Tertiary System
a) Other District Roads
(ODR)
b) Village Roads (VR)
Increased
Mobility
Expressway
National Highway
Village Road
State Highway
Major District Road
Other District Road
Increased Access

Control Factors of Geometric Design
Sl no. Terrain Classification Cross Slope of the Country
1 Plain Less than 10% 1 in 10 or more
2 Rolling 10%-25% 1 in 10 to 1 in 4
3 Mountainous 25%-60% 1 in 4 to 1 in 1.67
4 Steep Greater than 60% Less than 1 in 1.67
TOPOGRAPHY
While deciding the terrain classification, short isolated stretches (say
less than 1 km) of varying terrain met with on the road stretch should
not be taken into consideration.

DESIGN SPEED (km/h)
 For 2/4/6/8 lane highways, wherever service roads are provided, recommended design
speed of 40 km/h should be adopted on the service roads.
 For 2/4/6/8 lane highways, the acceleration and deceleration lanes of service roads
should be designed for a speed differential of 60 km/h.
Sl
No.
Nature of
Terrain
% cross
slope of
the
country
4/6/8-lane
NH/SH
2-lane
NH/SH
MDR ODR/VR
Ruling
Minimum
Ruling
Minimum
Ruling
Minimum
Ruling
Minimum
1 Plain 0-10 100 80 100 80 80 65 50 40
2 Rolling 10-25 100 80 100 80 65 50 50 40
3 Mountai
nous
25-60 60 40 50 40 40 30 30 20
4 Steep >60 60 40 40 30 30 20 30 20

OTHER FACTORS
DESIGN VEHICLES
TRAFFIC
ENVIRONMENT
&
ECONOMY
DRIVER’S
PERFORMANCE

Cross Sectional Elements
Road land width (also termed the Right-of-Way) is the land acquired for road
construction purposes and provision of utilities along the length of road.
1. RIGHT-OF-WAY
Recommended ROW for Highways & Expressways
Sl No. Road Classification Minimum ROW
1 2-lane Highways 30m
5 Expressways 90-120m
6 2-lane Highways 45-60m
7 2-lane Highways in Open Areas (Mountainous
& Steep Terrain)
24m
18m (Exceptional)
8 2-lane Highways in Built-up Areas
(Mountainous & Steep Terrain)
20m
18m (Exceptional)

Road land width (also termed the Right-of-Way) is the land acquired for road
construction purposes and provision of utilities along the length of road.
1. RIGHT-OF-WAY
Recommended Right-of-Way for Other Classes of Roads (in m)
Sl
no.
Road
Clas
sific
atio
n
Plain & Rolling Terrain Mountainous & Steep Terrain
Open Areas Built-up Areas Open Areas Built-Up Areas
Normal Range Normal Range Normal Exceptio
nal
Normal Excepti
onal
1 MDR 25 25-30 20 15-25 18 15 15 12
2 ODR 15 15-25 15 15-20 15 12 12 9
3 VR 12 12-18 10 10-15 9 9 9 9

The total width should be determined in relation to the design traffic and capacity of
the roadway.
2. WIDTH OF CARRIAGEWAY
WIDTH OF CARRIAGEWAY
TYPE OF FACILITY SINGLE LANE MULTI-LANE
PAVEMENTS ON
HIGHWAYS,MDR,OD
R and VDR, width
per lane
MULTI-LANE
PAVEMENTS ON
EXPRESSWAYS,
width per lane
Width (m) 3.75 3.5 3.75
 Where the carriageway width changes, e.g. from single lane to two lanes or two
lanes to four lanes or vice-versa, the transition should be affected through a
taper of 1 in 15 when it is from narrower to wider and it shall be 1 in 20 when it
is from wider to narrower.
 Where the carriageway width changes from four lanes to six lanes or six lanes to
eight lanes or vice-versa, the transition should be affected through a taper of 1
in 50.

3.1 MEDIAN WIDTH
The median width is the distance between inside edges of individual
carriageways of a divided highway segment.
For 4/6/8 lane highways
 All multi-lane highways shall be provided with depressed/flush median
depending upon availability of land. No raised/kerb median shall be
provided.
 Minimum width of the depressed median shall be 7.0 m in plain and rolling
terrain. In mountainous and steep terrain and in built-up areas of plain and
rolling terrain, where there are constraints in terms of availability of land
and available median width is 2.5 m or less, flush median could be provided
with collapsible crash barrier and anti-glare measures.
 As far as possible, the median shall be of uniform width in a particular
section of the highway. However, where changes are unavoidable, a
transition of 1 in 50 shall be provided.
 Edge strips, 0.6 m wide, adjacent to the carriageway towards depressed
median in either direction shall be paved with same specifications as of the
adjoining carriageway.

3.1 MEDIAN WIDTH
The median width is the distance between inside edges of individual
carriageways of a divided highway segment.
For Expressways
 Only depressed median shall be provided on expressways. No raised
median/kerbs shall be provided.
 The desirable width of depressed median shall be 15 m between the outside
edge of inside shoulder of the two carriage ways that slope down towards
the median center line in 6 H:1 V resulting in a 'V' shaped ditch to act as
median drain.
 As far as possible, the median shall be of uniform width in a particular
section of the highway. However, where changes are unavoidable, a
transition of 1 in 50 shall be provided.
 Edge strip of 0.75 m width, adjacent to the carriageway towards depressed
median in either direction shall be paved with same specifications as of the
adjoining carriageway.

3.2 MEDIAN OPENINGS
 In open country, median openings shall not be spaced closer than 2 km.
 In built up area, median opening shall be provided as per site requirement
and the spacing between two median openings in built up area shall not be
less than 500 m.
 Median opening shall not be provided in front of the service road entry. The
distance between the service road entry and the median opening shall be at
least equal to the sum of length of acceleration lane or deceleration lane
and weaving length. This distance shall however be not less than 150 m.
 All median openings shall be provided with additional 3.5 m wide shelter
lane/ storage lane by the side of median in both directions for vehicles
waiting to take U-turn.
 Length of median opening shall be 18 to 20 m only. Length of median
opening can be more than 20 m in case of median opening without storage
lane, to serve as neutral place for small vehicles to wait.
 n case of expressways, there shall be no median opening between any
successive ramps causing conflict with the on-coming traffic that needs to
be controlled by signals. There shall, however, be a collapsible or movable
median barrier at every 5 km interval for traffic management, maintenance
works and removal of vehicles involved in accidents.

SHOULDERS
Width of Shoulders(m) on either side in Plain and Rolling
Terrain (2-Lane Highways)
Type of Section Paved Earthen Total
Open country with
isolated built up area
1.5 1.0 2.5
Built up area (2-lane
section)
2.5 - 2.5
Built up area (4-lane
section
- - -
Approaches to grade
separated structures
1.5 - 1.5
Approaches to bridges 1.5 1.0 2.5

SHOULDERS
Width of Shoulders(m) on either side in Plain and Rolling
Terrain (4/6/8 Highways)
Type of Section Paved Earthen Total
Open country with
isolated built up area
2.0 1.5 3.5
Built up area 2.0 - 2.0
Approaches to grade
separated structures
2.0 - 2.0
Approaches to bridges 2.0 1.5 3.5

SHOULDERS
Width of Shoulders in Mountainous & Steep Terrain
Type of Section
Width of Shoulder (m)
Paved Earthen Total
Open country with
isolated built up
area
Hill Side 1.5 - 1.5
Valley Side 1.5 1.0 2.5
Built up area and
Approaches to grade
separated
structures/bridges
Hill Side
0.25 + 1.5
(Raised)
- 1.75
Valley Side
0.25 + 1.5
(Raised)
- 1.75

ROADWAY WIDTH
The width of roadway shall depend upon sum of the widths of
carriageway, shoulders and the median.
 Passing Places for Roads in Mountainous and Steep Terrain
Passing places or lay-byes should be provided on single lane roads in mountainous
and steep terrain to cater to the following requirements:
a) To facilitate crossing of vehicles approaching from opposite direction
b) To tow aside an out-of-order vehicle so that it does not obstruct the main
stream traffic.
Normally the passing places/lay-byes should be 3.75 m wide, 30 m long on the
inside edge (i.e. towards the hill side), and 20 m long on the valley side. The exact
location of passing places shall be judiciously determined taking into consideration
the available extra width and visibility. In general, passing places should be
provided at the rate of 2-3 numbers per kilometer.

PAVEMENT CAMBER/CROSSFALL
 The cross fall on straight sections of road carriageway, paved shoulders
and paved portion of median shall be 2.5 percent for bituminous
surface and 2.0 percent for cement concrete surface for all classes of
roads.
 For 2/4/6/8 lane highways, the cross fall for earthen shoulders on
straight portions shall be at least 0.5 percent and desirably 1.0 percent
steeper than the slope of the pavement and paved shoulder.
 In case of expressways, the cross fall for earthen/granular shoulders on
straight portions shall be at least 1.0 percent steeper than the slope of
the pavement and paved shoulder.
 On super elevated sections of highways and expressways, the earthen
portion of the shoulder on the outer side of the curve shall be provided
with reverse cross fall so that the earth does not drain on the
carriageway and the storm water drains out with minimum travel path.

SERVICE ROADS & ACCELERATION/DECELERATION
LANES
Service roads are provided to control the haphazard access of road users to the
high-speed facilities, mostly near the built-up areas, and to make the movement of
slow-moving vehicles safe and streamlined without hampering the flow of the
traffic along the main carriageway.
 2-Lane Highways
The width of service roads should be generally 7 m but in any case, not less than 5.5 m depending
on the availability of ROW.
 4-Lane Highways
The width of service roads in open country with isolated built up area should be 7 m with 1.5 m
earthen shoulder. In built up area, the service road width shall be 7.5 m (including kerb shyness of
0.25 m on either side) with raised footpath/separator and for more details IRC:SP:84 can be
referred.
 6-Lane and 8-lane Highways
The width of service roads in open country with isolated built up area should be 7 m with 1.5 m
earthen shoulder. In built up area, where separator is provided between main carriageway and
service road and RCC/Cement Concrete lined drain-cum-footpath on ROW side are provided, no
earthen shoulder shall be provided for service road. The minimum service road width shall be 7 m
(excluding kerb shyness of 0.25 m on either side) with raised footpath/separator and for more
details IRC:SP:87 can be referred.

Typical Cross Section of 2-Lane Highway (Open Country in
Plain/Rolling Terrain)

 Visibility is an important requirement for safe and efficient operation of vehicles
on a roadway. Therefore, in order to ensure greater safety in the roadway
alignments, the design must ensure that the sight distance at every section of the
road is of adequate length to permit drivers enough time and distance to control
their vehicles in different situations so as to avoid unforeseen and unwarranted
incidents.
 Types of sight distance : (as per IRC:73-2023)
1. Stopping Sight Distance (SSD)
2. Overtaking Sight Distance (OSD)
3. Intermediate Sight Distance (ISD)
4. Intersection Sight Distance
5. Headlight Sight Distance
Sight Distance
Sight Distance Driver’s Eye Height Height of Object
Safe stopping sight distance 1.2 m 0.15 m
Intermediate sight distance 1.2 m 1.2 m
Overtaking sight distance 1.2 m 1.2 m

 Stopping Sight Distance (SSD)
Stopping Sight Distance is the minimum sight distance available on a road to stop
vehicle without collision.
Where,
V= speed of vehicle in kmph,
t= Reaction time in second,
f= Design co-efficient of friction
G= Longitudinal Grade in percent
d2 = braking distance formula amended to take
the effect of grade into account.
Sight Distance
f
Vt
SSD V
254
278
.
0
2


Stopping Sight Distance(SSD) = Lag Distance + Braking Distance

Sight Distance
f
V
254
2
Stopping Sight Distance at
Horizontal and Vertical Curves
The requisite sight distance should be available across the inner side of horizontal
curves. In case, where horizontal and summit curves overlap, the required sight
distance should be available in both horizontal direction i.e., along the inner side
of the curve and vertical direction i.e., along the pavement.

 Overtaking Sight Distance (OSD)
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 ‘minimum overtaking sight distance’ (OSD) or the ‘safe passing sight
distance’ available.
Sight Distance

 Intermediate Sight Distance (ISD)
Intermediate Sight Distance is defined as twice the safe stopping sight distance.
Sections of roads where overtaking sight distance cannot be provided should be
designed considering intermediate sight distance. This is also known as desirable
minimum sight distance.
 Intersection Sight Distance
Visibility is an important requirement at intersections. To avoid collisions, it is
essential that sufficient sight distance is available along the intersecting roads and
their corners, to enable the operators of vehicles simultaneously approaching the
intersection to see each other in time.
At-grade intersections can be divided in two parts:
i. Uncontrolled Intersections
ii. Priority Intersections
Sight Distance

For Approach
Sight Triangles
(Left)
For
Departure
Sight
Triangles
(Left)
Sight Distance

 Headlight Sight Distance
During day time, visibility is not a major issue on valley curves. However, for travel
at night the design must ensure that the roadway ahead is illuminated by vehicle
headlights to a sufficient length, enabling the vehicle to brake to a stop if necessary.
This distance, called the headlight sight distance.
 Headlight sight distance should at least equal the safe stopping sight distance.
 Height of headlight above the road surface is 0.75m.
 The useful beam of headlight is one degree
upwards from the grade of the road.
 The height of object is nil.
Sight Distance

H.I.P. = Horizontal Intersection
Point
T.S. =Point of change from Tangent
to Spiral
S.T. =Point of change from Spiral to
Tangent
S.C. =Point of change from Spiral to
Circular
C.S. =Point of change from Circular
to Spiral
Δ=Total Deviation Angle
Δc=Deviation and Central angle of
circular arc
θs =Deviation angle of transition
curve
Rc= Radius of circular curve
S = Shift
Ts = Tangent Distance
Es = Apex Distance
Ls = Length of Transition
Lc = Length of Circular Curve
Horizontal Alignment
Elements of Circular Curve with Transition Curve

 Horizontal Curve Radius
Radii of Horizontal Curves for EW/NH/SH
Nature of Terrain Desirable Min Radius Absolute Min Radius
Plain & Rolling Terrain
(Expressways)
1000 m 650 m
Plain & Rolling Terrain
(NH/SH)
400 m 250 m
Mountainous & Steep
Terrain (NH/SH)
150 m 75 m

 Horizontal Curve Radius
Minimum Radii of Horizontal Curves for MDR/ODR/VR (m)

 Superelevation
In order to counteract the effect of centrifugal force and to reduce the tendency of
the vehicle to overturn or skid, the outer edge of pavement or outer edge of paved
shoulders (roads with paved shoulders) is raised with respect to inner edge, thus
providing a transverse slope throughout the length of horizontal curve. This
transverse inclination to the pavement surface is known as super-elevation or cant
or banking.
Where
V = design speed in km/h
e = super elevation in m/m
f = coefficient of side friction
between vehicle tyres and
pavement (taken as 0.15)
R = radius in m
R
f
e V
127
2


R
e V
225
2


 Superelevation
Page 14
PI : Point of intersection of main tangents
TS: Tangent to spiral
SSD: Start of superelevation development
ESD: End of superelevation development
SC: Spiral to curve
Lp: Length of spiral (TS to SC)
Le:Length of superelevation development
n: Normal pavement crossfall (%)
e: Pavement superelevation (%)
Tro: Tangent Runout
Sro: Superelevation Runoff

 Three different methods for
attaining the super elevation
1. Revolving Pavement about the
centre line.
inner edge.
outer edge.
I
O

Extra Widening on Curves
When vehicles negotiate a curve, the rear wheels generally do not follow the same
track as that of front wheels. Therefore, extra widening of the pavement is
necessary to provide for this change in the overall track width required for travel
at various speeds.
Extra widening(We)= Mechanical Widening(Wm)+ Psychological widening(Ws)
⸫ We = Wm + Ws
=
Where,
n = no. of traffic lanes
V = Design speed in km/h
R = Radius of horizontal curves in m
l = length of wheelbase of longest vehicle in m

Extra Widening on Curves
Extra Width of Pavement and Roadway for 2/4/6/8
lane highway
Radius of Curve Extra Width
75-100 m 0.9 m
101-300 m 0.6 m
Extra Width of Pavement at Horizontal curves for MDR/ODR/VR
Radius of
Curve (m)
Up to 20 21-40 41-60 61-100 101-300
Two-Lane 1.5 1.5 1.2 0.9 0.6
Single Lane 0.9 0.6 0.6 Nil Nil

Setback distance on Curves
Sight distance across the
inside of horizontal curves
is an important element of
design. Lack of visibility in
the lateral direction may
arise due to obstructions
like walls, cut slopes,
buildings, wooded areas,
high farm crops, median
plantation, etc. The
straightforward manner of
achieving the necessary
setback in these situations
is to remove the
obstruction. If somehow
this is not feasible,
alignment of the road may
need adjustments.

 Transition Curve
Transition curve has a radius which decreases from infinity at the tangent point to
a designed radius of the circular curve. When a transition curve is introduced
between straight and circular curve, the radius of the transition curve decreases,
becomes equal to the radius of circular curve at start of the circular curve.
Minimum Length
Transition Curve
Ls = Length of Transition Curve (m)
V = Design Speed (km/h)
R = Radius of Circular Curve (m)
(allowable rate of change of
centrifugal acceleration, m/sec3)
V
C


75
80
Ls = Length of Transition Curve (m)
e = Rate of Superelevation
1 in N = Rate of change of Superelevation
(1 in 150 or 1 in 60)
W = Normal Pavement width (m)
We = Extra widening provided at the
Curve
𝐿𝑠=
𝑒𝑁
2
(𝑊 +𝑊𝑒)
𝐿𝑠=𝑒𝑁(𝑊 +𝑊𝑒)

Transition for Compound Curves
Transitions are used between curves of
different radii to change gradually from one
circular motion to another of greater or less
degree and to permit a corresponding
change in superelevation.
Ls=

Transition for Reverse Curves
Transition curves should be inserted when
two curves of opposite direction are in close
proximity to one another
Ls=

Transition for Hairpin Bends (IRC:52)
A hair-pin bend may be designed as a circular curve
with transition curves at each end. Alternatively,
compound circular curves may be provided.
 Minimum design speed - 20 km/h
 Minimum roadway width at apex
i. National/State Highways — 11.5 m for double-
lane, 9.0 m for single-lane
ii. Major District Roads and Other District Roads -
7.5 m
iii. Village Roads — 6.5 m
 Minimum radius for the inner curve - 14.0 m
 Minimum length of the transition —15.0 m
 Gradient
i. Maximum - 1 in 40 (2.5%)
ii. Minimum — 1 in 200 (0.5 %)
 Super-elevation — 1 in 10 (10 %)

Gradient & Deviation Angle
Gradient is defined as the rise or fall along the longitudinal profile of the road. This change in
angle or angle between the two intersecting grade lines is known as 'deviation angle' or 'angle
of intersection’.
Vertical Alignment

Gradients
Vertical Alignment
Recommended Gradients for 2/4/6/8- Lane highways in Different Terrains
Sl No. Terrain Ruling Gradient Limiting Gradient
1 Plain or Rolling 2.5% 3.3%
2 Mountainous 5% 6%
3 Steep 6% 7%
Recommended Gradients for MDR/ODR/VR in Different Terrains
Sl No. Terrain Ruling Gradient Limiting Gradient Exceptional
Gradient
1 Plain or Rolling 3.3% 5% 6%
2 Mountainous & Steep
terrain (Elevation>3000
m above the MSL)
5% 7% 10%
3 Steep terrain (Elevation
up to 3000 m above the
MSL)
6% 8% 10%

 Vertical Curves
Vertical Alignment
Types of Vertical
Curve
Summit Curve Valley Curve

 Length of Vertical Curve for Different Speeds (L>S)
Vertical Alignment
Design Speed
(km/h)
Length of Summit Curve (m) for
Length of
Valley curve for
HSD (m)
SSD ISD OSD
20 0.9N 1.7N - 1.8N
25 1.4N 2.6N - 2.6N
30 2.0N 3.8N - 3.5N
35 3.6N 6.7N - 5.5N
40 4.6N 8.4N 28.4N 6.6N
50 8.2N 15.0N 57.5N 10.0N
60 14.5N 26.7N 93.7N 14.9N
65 18.4N 33.8N 120.4N 17.4N
80 38.4N 70.4N 230.1N 27.9N
100 73.6N 135.0N 426.7N 41.5N
Note: Deviation angle ‘N’ is expressed as percentage.

 Length of Vertical Curve for Different Speeds (L<S)
Vertical Alignment
Design Speed
(km/h)
Length of Valley
curve for HSD (m)
SSD ISD OSD
20 40-4.4/N 80-9.6/N - 40-2.2/N
25 50-4.4/N 100-9.6/N - 50-2.4/N
30 60-4.4/N 120-9.6/N - 60-2.6/N
35 80-4.4/N 160-9.6/N - 80-2.9/N
40 90-4.4/N 180-9.6/N 330-9.6/N 90-3.1/N
50 120-4.4/N 240-9.6/N 470-9.6/N 120-3.6/N
60 160-4.4/N 320-9.6/N 600-9.6/N 160-4.3/N
65 180-4.4/N 360-9.6/N 680-9.6/N 180-4.7/N
80 260-4.4/N 520-9.6/N 940-9.6/N 260-6.1/N
100 360-4.4/N 720-9.6/N 1280-9.6/N 360-7.8/N

 Minimum Length of the Vertical Curve
Vertical Alignment
Design Speed
(km/h)
Length of Valley
curve for HSD (m)
SSD ISD OSD
20 40-4.4/N 80-9.6/N - 40-2.2/N
25 50-4.4/N 100-9.6/N - 50-2.4/N
30 60-4.4/N 120-9.6/N - 60-2.6/N
35 80-4.4/N 160-9.6/N - 80-2.9/N
40 90-4.4/N 180-9.6/N 330-9.6/N 90-3.1/N
50 120-4.4/N 240-9.6/N 470-9.6/N 120-3.6/N
60 160-4.4/N 320-9.6/N 600-9.6/N 160-4.3/N
65 180-4.4/N 360-9.6/N 680-9.6/N 180-4.7/N
80 260-4.4/N 520-9.6/N 940-9.6/N 260-6.1/N
100 360-4.4/N 720-9.6/N 1280-9.6/N 360-7.8/N

Guidance in the Coordination of
Horizontal and Vertical Alignment
Optical Guidance
Surface Guidance
Spatial Guidance
Coordination

 Optical Guidance
Optical guidance means a good view of the road such that the road appears to
blend with the surroundings and direction of the road becomes readily
apparent.
Coordination

 Surface Guidance
Surface guidance can be provided through the combination of cross-sectional
elements of the road i.e. shoulders, carriageway width, traffic lanes,
pavement markings with the design elements of horizontal and vertical
alignment thus resulting in a three-dimensional design.
Coordination

 Spatial Guidance
Spatial guidance is achieved through consistent sequence of three-
dimensional design elements in driving space which should be balanced in
terms of relationship of the design parameters among themselves.
Coordination

 Grade Compensation
When horizontal curve is placed on a gradient then vehicle traversing that combination
experiences two resistances, grade resistance and curvature resistance. Combined effect of
these resistances will be detrimental to the performance of the vehicle. In such conditions it
is advisable to compensate the gradient. The gradients should be eased by an amount known
as the 'grade compensation' which is intended to offset the extra tractive effort involved at
curves.
Maximum allowed compensation,
GC= 75/R percent
Where,
R =radius of horizontal curve in meters
GC =Grade Compensation subjected to maximum allowed compensation
Coordination

Lateral & Vertical Clearances
Minimum Lateral/Horizontal Span of Underpass/
Overpass
Sl No.
Type of
Underpass/
Overpass
Minimum
Horizontal
Clear Span
(m)
Remarks
1 VUP 20.0
*for 2 Lane road
lateral/horizontal
clearance shall
not be less than 12.0 m
(7.0 m carriageway +
2*2.5
m shoulder width on
either side)
2 LVUP 12.0
*the lateral clearance
shall not be less than
10.5 m
including 1.5 m wide
raised footpaths on
either side
3 SVUP 7.0 -
4 PUP 7.0 -
5 CUP 7.0 -
6 VOP -
*full roadway width
including service road
and
future widening
Minimum Vertical Clearance of Underpass/ Overpass
Sl No.
Type of
Underpass
/ Overpass
Minimum
Vertical
Clearance (m)
Remarks
1 VUP 5.5
-
2 LVUP 4.0
-
3 SVUP 4.0 -
4 PUP 3.0 -
5 CUP 3.0 -
6 VOP 5.5
Clear height of 5.5 m
should be available to
pass
the vehicle. It is defined
as from maximum road
level at crossing to soffit
level at lowest level.

1. IRC:73-2023, “Geometric Design Standards for Non-Urban Roads”.
2. “Highway Engineering” book (10th
edition) by S. K. Khanna, C.E.G. Justo & A.
Veeraragavan.
References

IRC 73-2023_presentation for highway design

IRC 73-2023_presentation for highway design

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IRC 73-2023_presentation for highway design