A CASE STUDY ON TRAFFIC ISLANDS
P.AJAY (24RS5A0141)
K.ASHWINI (24RS5A0127)
G.SRIJA (24RS5A0120)
M.VISHWA CHARAN (24RS5A0134)
MD.NASIHA (24RS5A0135)
K.JASHWANTH(24RS5A0128)
Department of Civil Engineering
Jawaharlal Nehru Technological University Hyderabad
University College of Engineering Rajanna Siricilla
Agraharam, Rajanna Siricilla Dist. - 505301, Telangana
2025
A CASE STUDY ON TRAFFIC ISLANDS
REAL TIME RESEARCH PROJECT REPORT
SUBMITTED IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF BACHELOR OF TECHNOLOGY IN
CIVIL ENGINEERING
BY
P.AJAY (24RS5A0141)
K.ASHWINI (24RS5A0127)
G.SRIJA (24RS5A0120)
M.VISHWA CHARAN (24RS5A0134)
MD.NASIHA (24RS5A0135)
K.JASHWANTH (24RS5A0128)
Department of Civil Engineering
Jawaharlal Nehru Technological University Hyderabad
University College of Engineering Rajanna Siricilla
Agraharam, Rajanna Siricilla Dist. - 505301, Telangana
2025
Jawaharlal Nehru Technological University Hyderabad
University College of Engineering Rajanna Sircilla
Agraharam, Rajanna Siricilla Dist. – 505 302, Telangana
Department of Civil Engineering
CERTIFICATE
Date:
/05/2025
This is to certify that the project work entitled A CASE STUDY ON TRAFFIC ISLANDS is a
bonafide work carried out by P.AJAY, K.ASHWINI,G.SRIJA, M.VISHWA CHARAN,
MD.NASIHA
and
K.JASHWANTH
bearing
Roll
Nos.
24RS5A0141,24RS5A0127,
24RS5A0120, 24RS5A0134, 24RS5A0135and 24RS5A0128in partial fulfillment of the
requirements for the degree of BACHELOR OF TECHNOLOGY in CIVILENGINEERING
by the Jawaharlal Nehru Technological University Hyderabad during the academic year 2024-25.
The results embodied in this report have not been submitted to any other University or Institution
for the award of any degree or diploma.
---------------------
---------------------------------
------------------------------
MD.MOHISIN
B.RANJITH KUMAR
DR.T.VENUGOPAL
GUEST FACULTY
Head of the Department I/c.
PRINCIPAL
Project Guide
Acknowledgements
The success in this project would not have been possible without timely help and
guidance by many people. We wish to express our sincere gratitude to all those who have helped
and guided us for the completion of the project.
It is our pleasure to thank to our Project Guide and Project Coordinator, MD.Mohisin,
Guest faculty in Department of CE, for the guidance and suggestions throughout the project,
without which we would not have been able to complete this project successfully.
We express our sincere gratitude to Prof. T. Venugopal, Principal, JNTUH UCER, for
their encouragement and providing facilities to accomplish our project successfully.
We would like to thank our classmates, all faculty members and non-teaching staff of CE
Department, JNTUH UCER for their direct and indirect help during the project work.
Finally, we wish to thank our family members and our friends for their interest and
assistance that has enabled to complete the project work successfully.
i
ABSTRACT
The traffic island for the channelization purpose has advantages that decrease traffic
accidents at the intersections with the decrease in crossing distance and increase in right-turn
traffic flow capacity, but can be a hazard to drivers, which includes collision accident against the
fixed object of the traffic island installation and increase in casualties according to secondary
accident induction. This study aimed to which can discriminate the effects of the traffic island in
advance, through discriminant analysis classifying locations into those that have traffic accidentreducing effects and those that have no effect or may have effects not caused by the traffic island,
based on the traffic accident data before and after the improvement project for the nationwide
intersections, where the traffic island installation is top priority matter among ‘improvement
projects for the locations of frequent traffic accidents.
ii
CONTENTS
CHAPTER-1: INTRODUCTION
1.1 Introduction
1.2 Literature Review
1.3 Aim Of the Project
1.4 Significance
CHAPTER-2: TRAFFIC ISLANDS
2.1 Introduction
2.2Types of Traffic Islands
2.2.1 Divisional Islands
2.2.2Channelizing Islands
2.2.3Pedestrian Loading Islands
2.2.4 Rotary Islands
2.3 Objectives
2.4 Functions
2.5Advantages
2.6 Disadvantages
CHAPTER-3:-DESIGN CONSIDERATIONS , IS CODES AND IRC
CODES USED IN TRAFFIC ISLANDS
3.1 Design consideration for Traffic islands
3.2 IS codes used in Traffic islands
3.3
IRC codes used in Traffic islands
CHAPTER-4:-MATERIALS , CONSTRUCTION AND FLOW ANALYSIS
OF TRAFFIC ISLANDS
4.1 Materials used in traffic islands
4.1.1 Structural Materials
4.1.2 Finishing and Functional Materials
iii
4.1.3 Land Scaping Materials
4.2 Construction methods of Traffic Islands
4.2.1Prelimimary works
4.2.2 Foundation and Substructure
4.2.3 Super Structure Construction
4.2.4 Finishing Works
4.3 Traffic Flow analysis
4.3.1Purpose
4.3.2 Key Observations
4.3.3 Flow analysis Method
CHAPTER-5:-SPECIFICATIONS AND COST ANALYSIS OF TRAFFIC
ISALNDS
5.1 Specifications for traffic islands
5.1.1Geometric specifications
5.1.2 Structural and MaterialSpecification
5.1.3 Surface Finishing and Road Markings
5.1.4 Land Scaping and Urban design Features
5.1.5 Smart Island integration
5.1.6 Safety and Accessibility
5.2 Cost Analysis Of Traffic Island Installation
5.2.1 Key Cost components
5.2.2 Influencing Factors
5.2.3 Cost-Saving Opportunities
5.2.4 Pie Chart of Cost Analysis
 CONCLUSION
 REFERENCES
iv
CHAPTER-1
INTRODUCTION
1.1 INTRODUCTION
A traffic island is a solid or painted object in a road that channels traffic. It can also be a narrow
strip of island between roads that intersect at an acute angle. If the island uses road markings
only, without raised curbs or other physical obstructions, it is called a painted island or
(especially in the UK) ghost island. Traffic islands can be used to reduce the speed of cars
driving through or to provide a central refuge to pedestrians crossing the road.
When traffic islands are longer, they are instead called traffic medians, a strip in the middle of a
road, serving the divider function over a much longer distance.
Some traffic islands may serve as refuge islands for pedestrians. Traffic islands are often used at
partially blind intersections on back-streets to prevent cars from cutting a corner with potentially
dangerous results, or to prevent some movements totally, for traffic safety or traffic calming
reasons. IN certain areas of the United Kingdom, particularly in The Midlands, the term island is
often used as a synonym for round about. a raised or marked-off area between lanes of a
roadway, used by pedestrians to get out of the flow of traffic, as a place for traffic signals, for
separating lanes, etc. Traffic Island is physical structure or a painted object found on roads and
roadside. Traffic island serve various purposes depending it type. It is usually seen as a raised
area along the road for a better & orderly flow of traffic or act as a stopping/ resting area for
pedestrians.
A traffic island is a solid or painted object in a road that channels traffic. It can also be a narrow
strip of island between roads that intersect at an acute angle. Traffic control can be utilized to
deal with the movement and development of cars and other sorts of transportation framework.
Without traffic control, these vehicles will be unable to move from one place to Islands are
designated areas between travel lanes used for pedestrian sanctuary and traffic control. These
areas are used in channelized intersections to direct entering traffic into definite travel paths
another with ease. When that happens, accidents would unavoidably occur.
An island is defined as an area between traffic lanes used for control of traffic movements.
Raised medians and islands provide space to locate pedestrian safety features and traffic control
devices, amenities, landscaping and stormwater management. A rotary intersection or traffic
rotary is an enlarged road intersection where all converging vehicles are forced to move round a
large central island in one direction before they can weave out of traffic flow into their respective
directions radiating from the central island.
The traffic islands provide space for the vehicles making the weaving movements at intersection,
dividing the through moving traffic and left turning vehicles, provision for pedestrians to wait at
the intersection during stop signal.
1
1.2 LITERATURE REVIEW :1. Yuan-wen Lai,JianRong,and Ping Shangguan (2011) Pedestrians have a significant effect
on capacity of signalized intersections with channelization island. This paper analyzes the
regular arrival pattern of pedestrians and shows that the arrival frequency of pedestrians is
consistent with negative binomial distribution. When comparing different processes of
pedestrians crossing between signalized intersection with channelization island and the typical
one, pedestrians spillover quantity mainly influenced by the total amount of traffic volume,
direct proportion changes with the traffic volume volatility. It also discusses the capacity
calculation of right-turn lane with accept gap model and how pedestrians influence the capacity
of the right-turn lane. Pedestrian influence of straight lane capacity is focused on headway and a
sound sample typical value and variance from P-P figure found that the randomness of
intersection capacity of Dongda and Wuyi Road signalized intersection in Fuzhou meet the
normal distribution well.
2.Prof.Shubham Agrawal and Akash Sharma (2019) Traffic Rotary at road intersections is
special form of grade change of lanes to channelize movement of vehicles in one direction
around a central traffic island. With rapid growth of traffic it is experienced that widening of
roads and providing flyovers have become imperative to overcome major conflicts at
intersections such as collision between through and right turn movements. In this way, major
conflicts are converted into milder conflicts like merging and diverging. The vehicles entering
the rotary are gently forced to move in a clockwise direction. They then weave out of the rotary
to the desired direction. The crossing of vehicles is avoided by allowing all vehicles to merge
into a stream around the rotary and then to diverge out to the desired radiating road. Thus the
crossing conflicts eliminate and convert into weaving manoeuvre or a merging operation from
right and a diverging operation to the left.
3. Abraham Leung and Stefan Baumeister (2024) Island transport systems are as unique as the
islands themselves, shaped by geography, politics, and community needs. Transport development
raises key questions: does increased connectivity enhance or diminish islandness? Can largescale projects balance economic goals with environmental sustainability and community needs?
This special section brings together seven studies from four island jurisdictions to explore how
transport configurations influence and redefine islandness. From the transformative role of fixed
links in the Faroe Islands to the challenges of seasonal air travel in Akureyri, Iceland, and the
extensive ferry networks in Hong Kong, these articles underscore the complexities of island
connectivity. A case from Penang, Malaysia, illustrates grassroots resistance to artificial island
creation, highlighting tensions between development and conservation. Together, these
contributions offer fresh perspectives on the evolving role of transport in shaping island life and
identity.
2
1.3AIM OF THE PROJECT
 To study traffic island.
 To observe the types of traffic island.
 To study different types of traffic island.
1.4 SIGNIFICANCE
Traffic islands enhance road safety by providing a refuge for pedestrians and reducing vehicle
speeds. They also help in organizing traffic, making intersections more efficient.
Figure 1: TRAFFIC ISLAND
3
CHAPTER-2
TRAFFIC ISLANDS
2.1 INTRODUCTION
The traffic island for the channelization purpose has advantages that decrease traffic accidents at
the intersections with the decrease in crossing distance and increase in right-turn traffic flow
capacity.
‘Improvement project of potentially hazardous roadway segments,’ which is one of the
improvement projects of traffic safety, improves more than 600 intersections every year, and
installs traffic islands at 38-56 locations a year as a top priority detailed improvements in
Channelizing the intersections as an improvement scheme.
However, referring to the laws, guidelines and rules for the road design such as ‘Rules for
structure and installation standards of the road,’ appropriate channelization increases road’s
capacity, improves safety, and makes drivers comfortable, resulting that the drivers win a
confidence in themselves. However, it is true that there are no quantitative criteria for installing a
traffic island except a caution, ‘As an excessive channelization can be confusing to the drivers
and make its operation difficult, be ware that inappropriate channelization will make it worse’.
Accordingly, this study attempted to develop a model, which can discriminate the effects of the
traffic island in advance, through discriminant analysis, one of the multivariate statistical
methods, classifying locations into those that have traffic accident-reducing effects and those that
have no effect or may have effects not caused by the traffic island, based on the traffic accident
data before and after the improvement project for the nationwide intersections, where the traffic
island installation is top priority matter among ‘improvement projects for the locations of
frequent traffic accidents
2.2 TYPES OF ISLANDS




Divisional islands
Channelizing islands
Pedestrian loading islands
Rotary islands
4
2.2.1 DIVISIONAL ISLAND
Divisional islands serve the crucial purpose of segregating opposing traffic streams on
highways boasting four or more lanes. This ingenious design effectively splits the
highway into two one-way road sections, thereby eradicating the risk of head-on
collisions and, generally, reducing the occurrence of other accidents as well. To optimize
their functionality, it’s imperative that the width of these divisional islands be substantial,
particularly to diminish headlight glare during nighttime driving. Furthermore, the height
of the kerb should be sufficient to deter vehicles from inadvertently encroaching
onto these islands.
These are used along the roads. These are elongated structures which can be considered
as median or divider but used for the traffic moving in the same direction. These also
provide slip roads which are meant to bypass the traffic signal for straight moving
vehicles. These are not meant to aid turning but helps in orderly movement off vehicles
and might form a part of channelizing island which further assist in reducing
conflict points
Figure 2:DIVISIONAL ISLAND
Purpose: Separates opposite streams of traffic, preventing head-on collisions.
Design: Can be narrow or wide, depending on road width.
Often landscaped with plants, trees, or lighting.
Applications:


Highways
Urban arterial road
5
Advantages:


Improves road safety
Reduces glare from oncoming headlights at night.
2.2.2 CHANNELIZING ISLANDS
These go by the name and functions like a channelizer which provides direction to the vehicles.
The most prominent use of this type is turning points, these allow smooth and easy turning of
traffic and prevents interference with the other straight moving vehicles
These are also found where the roads converge or diverge as they helps in reducing conflict
points and allow easy merging and diverging of traffic. These can be raised or marked off area, a
painted island or a pedestrian refuge.
Figure 3.CHANNELIZING ISLAND
Purpose: Guides or directs vehicular movement at intersections, merges, or diverging points
Design:
1. Often triangular or elongated.
2. Painted markings or raised curbs.
Applications
1. Intersections
2. Entry/exit ramps (highways, flyovers)
6
Advantages:
1. Reduces confusion at complex junctions
2. Helps separate turning traffic from through traffic.
3. Reduces accidents by managing vehicle paths.
2.2.3 PEDESTRIAN LOADING ISLAND
A raised area located at crosswalks that serves as pedestrian refuge separating traffic lanes or
directions, particularly on wide roadways. Also known as a “median refuge island.” Used at
pedestrian crossings when a full raised median is not feasible. A pedestrian safety island confers
most of the same benefits as a full Raised Median at pedestrian crossings. Full raised medians
should be used rather than pedestrian safety islands wherever possible.
Figure 4.PEDESTRIAN LOADING ISLANDS
Purpose: Provides a safe midway stopping point for pedestrians crossing wide roads.
Design: Typically a narrow, raised platform with ramps on both sides and sometimes with
protective rails.
Advantages
Enhances pedestrian safety and accessibility by reducing crossing distances and providing refuge
for pedestrians to cross the road in stages
Calms traffic, especially left turns and through- movements, by narrowing roadway at
intersection
7
Reduces risk of vehicle left-turn and head-on collisions at intersection
Can green and beautify the streetscape with trees and/or vegetation, potentially including
stormwater source controls
Trees increase the visibility of the island, potentially enhancing safety
Figure 5.PEDESTRAIN LOADING ISLAND
2.2.4ROTARY ISLANDS
The raised platforms of suitable shapes built on the road intersections are called traffic
islands or rotary island. A rotary intersection or traffic rotary is an enlarged road
intersection where all converging vehicles are forced to move round a large central island
in one direction before they can weave out of traffic flow into their respective directions
radiating from the central island. The main objects of providing a rotary are to eliminate
the necessity of topping even for crossing streams of vehicles and to reduce the area of
conflict. The crossing of vehicles is avoided by allowing all vehicles to merge into the
streams around the rotary and then to diverge out to the desired radiating road.
Figure 6.ROTARY ISLAND
8
Purpose: Controls traffic flow at intersections through circular movement.
Design:
A raised, usually landscaped circular island.
Central point around which vehicles move counter-clockwise (in countries driving on the right)
or clockwise (on the left).
Applications
Busy intersections
Replacement for traditional 4-way stops or signals.
Advantages:
Reduces severe crashes.
Improves continuous traffic flow.
2.3 Objectives:
 Enhance Road Safety: To minimize vehicular conflicts and reduce accident rates by
clearly channelizing traffic movements.
 Organize Traffic Flow: To streamline vehicle paths, reduce driver confusion, and improve
overall intersection efficiency.
 Provide Pedestrian Safety: To offer refuge spaces for pedestrians crossing wide roads,
ensuring safe staged crossings.
 Traffic Calming: To slow down vehicular speeds at critical areas like intersections, school
zones, and commercial centers.
 Improve Urban Aesthetics: To enhance the visual appeal of roads and intersections by
integrating landscaping and beautification elements.
 Environmental Benefits: To contribute to urban greenery, reduce air pollution, and
mitigate heat island effects through planted islands.
 Support Smart Traffic Systems: To accommodate the installation of smart traffic sensors,
cameras, and lighting systems.
 Facilitate Emergency Movements: To maintain clear access paths for emergency vehicles
by channelizing and regulating regular traffic.
 Assist in Signage and Guidance: To provide locations for road signage, lighting, and
signals that enhance traffic guidance and management.
9
 Promote Sustainable Urban Development: To align with modern urban planning
principles focused on sustainability and inclusivity.
2.4 Functions:
 Traffic Streamlining











Traffic islands organize and guide vehicular movements at intersections, roundabouts,
and road merges, ensuring smooth transitions between different lanes and directions.
Conflict Reduction
By segregating movements (especially left, right turns, and straight paths), islands
drastically reduce the number and severity of potential vehicle conflict points.
Enhancing Safety for Vulnerable Road Users
Pedestrians and cyclists benefit from mid-block refuge areas, where they can wait safely
before completing a crossing. Some designs now also integrate bicycle waiting areas.
Traffic Calming and Speed Management
Physical elements like raised islands naturally force drivers to slow down, especially
around sensitive areas like schools, markets, and residential zones.
Deflection and Geometric Control
In roundabouts and rotaries, islands create deflection paths that reduce entry and
circulating speeds, crucial for crash mitigation.
Visual Cues and Wayfinding Assistance
Clearly visible islands (using paint, landscaping, or structures) act as powerful visual
tools, indicating direction changes, lane bifurcations, or transitions.
Structural Support for Infrastructure
Traffic islands often house utility poles, traffic signal posts, surveillance cameras, Wi-Fi
antennas, and other urban technology without occupying valuable carriageway space.
Green Infrastructure and Microclimate Regulation
Landscaped islands help in carbon dioxide absorption, dust filtration, and contribute to
cooling effects, reducing the urban heat island impact.
Stormwater Drainage Support
Some islands are designed with permeable pavements or bioswales to manage
stormwater, reduce surface runoff, and recharge groundwater.
Emergency Vehicle Facilitation
Properly designed islands ensure clear demarcation of lanes, preventing blockage during
emergencies and enabling faster response times.
Smart City Applications
New-age traffic islands integrate smart sensors for traffic density monitoring, automatic
incident detection, environmental monitoring (pollution sensors), and dynamic lighting
systems.
Urban Beautification and Branding
10

Artistic sculptures, city emblems, or vertical gardens on islands enhance urban identity
and promote tourism.
Cost-Efficiency in Traffic Management
Compared to traffic signals, islands offer passive traffic control that requires little
energyreducing long-term operational costs
Figure 7.DIVERTING SIGN.
2.5 Advantages of traffic islands:






Improved Traffic Flow:
They help organize vehicle movements, making intersections more efficient and reducing
congestion.
Enhanced Safety:
By controlling the directions vehicles can move, traffic islands reduce the risk of
accidents, especially head-on and side collisions.
Pedestrian Protection:
In large roads, islands serve as safe waiting areas for pedestrians crossing in two stages,
making crossings safer.
Traffic Calming:
Islands force drivers to slow down, particularly at intersections and sharp turns,
improving safety.
Better Channelization:
They guide vehicles into correct lanes or directions, reducing confusion at complex
junctions.
Aesthetic Value:
Landscaped or decorated islands can beautify roads and urban areas, improving the
environment visually.
11












Space for Signage and Signals:
Islands offer a place to install traffic lights, signs, or streetlights without obstructing
lanes.
Environmental Benefits:
Green islands can reduce pollution slightly by absorbing dust and emissions, and they
help manage stormwater runoff.
Reduction of Conflict Points:
They minimize points where vehicle paths cross, reducing opportunities for collisions.
Control of Illegal Movements:
Islands can physically prevent unsafe maneuvers like illegal U-turns or wrong-way
driving.
Efficient Use of Space:
Properly designed islands make better use of wide intersections, helping to avoid wasted
space.
Emergency Use:
Some islands can serve as emergency stopping points for vehicles with breakdowns,
especially pedestrian refuge islands.
Reduced Travel Time:
By streamlining vehicle flow, they can reduce delays and improve overall travel
efficiency.
Traffic Discipline:
Vehicles must follow a more organized pattern, leading to more disciplined and
predictable driving behavior.
Reduced Pollution and Noise:
Smoother traffic flow from well-designed islands reduces idling and frequent stops,
lowering vehicle emissions and noise.
Support for Urban Planning:
Traffic islands are part of “complete streets” design, promoting better integration of
vehicles, bicycles, and pedestrians.
Nighttime Visibility:
Illuminated or reflective islands improve road visibility at night, aiding in safer driving.
Flexibility for Future Modification
Islands can be modified, expanded, or removed relatively easily compared to other
road structures.
12
2.6 Disadvantages:











Increased Construction Cost:
Building and maintaining islands add extra cost compared to simpler road designs.
Space Consumption:
They require additional space, which can be a problem in narrow or congested urban
areas.
Potential Obstruction:
If poorly designed, islands can obstruct large vehicles like buses, fire trucks, or trailers
during turn
Confusion for Drivers:
In unfamiliar areas, poorly marked islands can confuse drivers and lead to erratic driving
behavior.
Maintenance Issues:
especially landscaped ones, need regular maintenance (cleaning, painting, gardening),
which can be costly and time-consuming.
Pedestrian Inconvenience:
If not properly designed, islands can make pedestrian crossings longer and more
complicated.
Reduced Road Capacity:
Sometimes islands reduce the number of usable lanes, causing bottlenecks if traffic
volume is high.
Visibility Problems:
If trees, signs, or structures on islands are too large, they can block drivers' line of sight,
leading to accidents.
Difficulty in Snow Removal:
In snowy regions, traffic islands can interfere with plowing and street cleaning
operations.
Accident Hazard:
In high-speed areas, if drivers don’t notice an island in time, they may crash into it.
13
CHAPTER-3
DESIGN CONSIDERATIONS , IS CODES AND IRC CODES
USED IN TRAFFIC ISLANDS
3.1 Design consideration for Traffic Islands
Traffic islands play a crucial role in urban planning and traffic management. When designing
traffic islands, several key considerations must be taken into account:










Selection of appropriate island type: The site and traffic conditions in each intersection
are different and hence the island type suitable for cach requires separate attention. The
traffic island selected varies from barrier type islands to flush islands marked on the
roadway surface.
Determination of shape and size of islands: The shape of the island and its size in
proper shape and size of the island (in the case of raised islands) must be selected so that
it is able to both channelized the traffic and not pose any type of hazard
Location relative to adjacent traffic lanes: The islands must be offset from the roadway
by some distance to remove the risk of a vehicle dashing against the same. The width of
offset is maximum at the entry of the island and decreases gradually as one move towards
the end of it.
Visibility: Traffic islands should be clearly visible to approaching vehicles.
Safety: Ensure that the design minimizes risks for both pedestrians and
drivers.appropriate signage and lighting
Accessibility: Design should accommodate all users, including pedestrians, cyclists, and
those with disabilities.
Landscaping: Incorporate vegetation that does not obstruct visibility but enhances
aesthetics.
Size and Shape: The dimensions should be appropriate for the traffic volume and speed
in the area.
Materials: Use durable materials that can withstand weather conditions and traffic wear.
Maintenance: Consider ease of maintenance in the design to ensure long-term
functionality.
14
3.2 IS CODES USED IN TRAFFIC ISLANDS
IS Code
Title/Description
IS 456:2000
Plain and Reinforced Concrete – Code of For concrete works in foundations, curbs,
Practice
medians.
IS 3370
2):2009
Usage in Traffic Islands
(Part Code of Practice for Concrete Structures for Used for drainage design within traffic islands to
Storage of Liquids
prevent waterlogging.
Applicable for high-strength elements
modular curbs and island structures.
like
IS 1343:2012
Code of Practice for Prestressed Concrete
IS 287:2015
Recommendation for Maximum Permissible If wooden elements (seating/landscaping) are
Moisture Content in Timber
used on islands.
IS 9833:1981
Guidelines for Colours for Ready Mixed Used for thermoplastic road markings and
Paints
reflective paints on islands.
IS 7436 (Part 1 &
Road Traffic Signs – Guidelines
2):1985
IS 10262:2019
Guidelines for
Proportioning
Concrete
Mix
For installation of signboards and signals
integrated with islands.
Design Ensures durable and high-strength concrete mix
for traffic island construction.
IS 2386 (Part 1-8) Methods of Test for Aggregates for Concrete
Ensures good quality aggregates for curb and
pavement concrete.
IS 12089:1987
For sub-grade material under island bases and
approach ramps.
Specification for Granular Sub-base Material
15
3.3 IRC Codes Used in Traffic Islands
IRC Code
Title/Description
Usage in Traffic Islands
IRC 35
Code of Practice for Road Markings
For painting markings around traffic islands and
channelization lanes.
IRC SP 41
Guidelines
Facilities
IRC 65
Guidelines for Planning and Design of Planning and geometric design for rotary traffic
Roundabouts
islands.
IRC 86
Geometric Design Standards for Urban General urban road features including islands and
Roads
medians.
IRC 99
Guidelines for Traffic Calming Measures
Using traffic islands as part of speed reduction
and calming methods.
IRC 103
Guidelines for Pedestrian Facilities
For island pedestrian connectivity and safe
crossing facilities.
IRC SP 67
Guidelines for Use of Rubberized and For island-mounted
Painted Road Furniture
bollards.
IRC SP 84
Manual of Specifications & Standards for Full technical specifications for traffic islands on
Urban Roads
urban roads.
MoRTH
Specifications
Specifications for Road and Bridge Works
for
Designing
Pedestrian Pedestrian refuge islands and crossings design
standards.
16
delineators,
signage,
General construction standards for roads, curbs,
medians, traffic islands.
CHAPTER-4
Materials, Construction, and Flow Analysis of Traffic Islands
4.1 Materials Used in Traffic Islands
4.1.1 Structural Materials:


Reinforced Concrete (RCC):
o
Used for curbs, island bases, edge walls.
o
Designed as per IS 456:2000 and IS 10262:2019 for durability and strength.
Precast Concrete Units:
o

Bituminous Asphalt:
o

Modular blocks or curbs for faster installation and easy repairs.
For island surfaces where flexible pavement is preferred.
Granular Sub-base (GSB):
o
Used below concrete or asphalt layers for load distribution, as per IS 12089:1987.
4.1.2 Finishing and Functional Materials:

Thermoplastic Paint:
o

Reflective Studs ("Cat Eyes") and Tapes:
o

For visible road markings around and on the islands (IRC 35).
Enhance night-time visibility and safety.
Signage and Poles:
o
Traffic control and guidance using galvanized poles and boards (IS 7436).
17
4.1.3 Landscaping Materials:

Soil Beds and Fertilizers:
o

Prepared for planting vegetation in large islands.
Drought-resistant Plants:
o
Minimizes maintenance needs and enhances sustainability.
4.2 Construction Methods of Traffic Islands
4.2.1 Preliminary Works:

Site Survey and Soil Testing:
o

To assess ground conditions, load-bearing capacity.
Geometric Design Finalization:
o
Ensuring compliance with IRC standards and local road dimensions.
4.2.2 Foundation and Substructure:

Earthwork Excavation:
o

Sub-Base Laying:
o

Removal of existing surface and preparation of sub-grade.
Placement of compacted granular sub-base material.
Concrete Foundation:
o
RCC slab or compacted base for structural stability.
4.2.3 Superstructure Construction:

Curb Setting:
o
Installation of precast curbs or cast-in-situ edges.
18

Surface Layering:
o

Bituminous or concrete topping for durability.
Drainage Provisions:
o
Proper slopes and inlets to prevent water stagnation.
4.2.4 Finishing Works:

Markings and Signages Installation:
o

Following IRC 35 and IS 9833 standards.
Landscaping and Lighting Installation:
o
Greening the islands and fixing solar or electric lights.
4.3 Traffic Flow Analysis
4.3.1 Purpose:

Evaluate the effectiveness of the island in managing vehicle movement.

Ensure smooth merging, diverging, and crossing patterns.
4.3.2 Key Observations:

Channelization:
o

Islands direct the movement of vehicles into designated lanes, reducing driver
confusion.
Conflict Point Reduction:
o
At intersections, islands separate streams, minimizing points where vehicles paths
cross.
19

Speed Management:
o

Rotaries/roundabouts naturally slow vehicles without needing speed bumps.
Pedestrian Safety Improvement:
o
Refuge islands allow pedestrians to cross one direction of traffic at a time.
4.3.3 Flow Analysis Methods:

Traffic Volume Surveys:
o

Conflict Studies:
o

Observation of near-miss incidents at intersections.
Delay and Queue Length Measurements:
o

Manual or sensor-based vehicle counting.
Assessing the efficiency of traffic movement during peak hours.
Simulation Modelling:
o
Using software to predict future traffic patterns after island construction.
20
CHAPTER-5
SPECIFICATIONS AND COST ANALYSIS OF TRAFFIC
ISALNDS
5.1 SPECIFICATIONS FOR TRAFFIC ISLANDS
5.1.1 Geometric Specifications
Specification Area
Recommended Dimensions / Features
Minimum Island Width
1.2 m (pedestrian/refuge) – 3.0 m (divider/channelizing)
Preferred Length
≥ 3.5 m for stability and visibility
Curb Height
100 mm (urban); 150 mm (rural)
Tapered Ends
Provided for safe vehicle movement and pedestrian access
Turning
entry/exit)
Radius
(at
10–20 m depending on design speed and lane width
Cross Slope
1–2% slope for drainage toward road surface or inlet drains
Offset Distance
0.5–1.0 m from traffic lane edges for channelizing islands
21
5.1.2 Structural and Material Specifications
Element
Description / Code Reference
Sub-base Layer
Granular sub-base per IS 12089; 150–250 mm thick
Base Layer
RCC slab (M-20 min) as per IS 456:2000 / IS 10262:2019
Surfacing
Bituminous or non-skid cement concrete finish
Curbs & Edges
Precast or cast-in-situ concrete (150 mm × 300 mm typical size)
Reinforcement
8 mm or 10 mm dia. steel bars spaced at 150 mm C/C (if required)
Drainage Provision Open side drain or vertical outlet through curb
5.1.3 Surface Finishing and Road Markings

Paints:
- Retro-reflective thermoplastic paint conforming to
- Color: Yellow for central islands; White for edge markings
IS
164

Studs
&
- Embedded cat-eye reflectors or flexible PVC delineators as per IRC 79

Signboards:
- Fixed on galvanized poles conforming to IS 875 and IS 2713
5.1.4 Landscaping and Urban Design Features

Soil Depth for Planting: Minimum 300 mm

Drainage: Small stormwater inlets or permeable soil if no paving

Tree Planting: Native, low-maintenance species with shallow roots
22
/
IS
9833
Delineators:

Barrier Protection: Small guardrails or concrete blocks for large islands

Urban Furniture (optional): Benches, planters, or smart kiosks
5.1.5 Smart Island Integration (Modern Urban Design)

SmartLighting:-Solar LED lights with motion sensors or dusk-dawn controllers

CCTV Cameras: - Installed for traffic surveillance and public safety

Environmental Sensors:- Air quality, noise, and temperature sensors for smart cities

EV Charging Points: - Can be integrated on larger islands with public footfall
6. Safety and Accessibility

Tactile Ground Surface Indicators (TGSI):-Provided for visually impaired pedestrians

Curb Cuts / Ramps:- Slope < 1:12 for universal accessibility

Refuge Zones:- Located in medians for safe mid-block crossings (per IRC SP 41)
23
5.2 COST ANALYSIS OF TRAFFIC ISLAND INSTALLATION
5.2.1Key Cost Components
Sl. No. Component
Typical Cost Range (INR) % of Total Cost
1
Site Survey & Design
₹40,000 – ₹70,000
5–10%
2
Earthwork & Land Preparation
₹80,000 – ₹1,50,000
15–20%
3
Construction Materials (concrete, curb, asphalt) ₹2,00,000 – ₹3,50,000
30–35%
4
Labor and Equipment Hire
₹1,00,000 – ₹2,00,000
20–25%
5
Road Markings, Signs, and Safety Fixtures
₹60,000 – ₹1,00,000
10–12%
6
Lighting (solar/electric)
₹50,000 – ₹1,00,000
5–8%
7
Landscaping (plants, soil, irrigation)
₹30,000 – ₹80,000
5–7%
8
Contingency
₹50,000 – ₹75,000
5–8%
5.2.2 Influencing Factors

Road width and traffic type (urban arterial vs local street)

Choice of materials (bituminous vs concrete surfacing)

Landscaping features (green vs paved)

Smart technologies (sensors, lighting)

Labor and equipment availability
24
5.2.3Cost-Saving Opportunities

Use of precast elements to reduce construction time

Solar-powered lights to minimize long-term energy costs

Drought-resistant native plants to reduce maintenance

Modular design for faster installation and lower manpower cost
5.2.4PIE CHART OF COST ANALYSIS
Figure 8.PIE CHART OF COST ANALYSIS
25
CONCLUSION
1. Improved Safety: Traffic islands reduce collision points, manage turning movements, and
provide safe pedestrian crossings.
2. Efficient Traffic Flow: They streamline vehicle movements at intersections, minimizing
congestion and confusion.
3. Compliance with Standards: Following IS codes and IRC guidelines ensures effective and
durable design and construction.
4. Environmental & Aesthetic Benefits: Landscaped islands contribute to urban greenery and
enhance the visual appeal of roads.
5. Scope for Smart Infrastructure: Integration of solar lighting, sensors, and modular designs
prepares traffic islands for future urban needs.
26
REFERENCES






Indian Roads Congress (IRC) Publications
Bureau of Indian Standards (BIS) Codes
Ministry of Road Transport and Highways (MoRTH) Specifications
World Road Association (PIARC)
International Road Assessment Programme (iRAP) Reports
McShane, W.R., Roess, R.P., and Prassas, E.S. — Traffic
(International Editions)
 Journal of Traffic and Transportation Engineering
 International Journal of Urban Planning and Development
27
Engineering