Intersection Design & Operation for Road Safety - IRF India ...

Intersection Design & Operation

for Road Safety

International Road Federation -India Chapter2nd Webinar

Road Safety Engineering for Improving Safety12 March 2021

Prof. (Dr.) Gaurang J JoshiProfessor

Transportation Engineering & PlanningCivil Engineering Department, SVNIT Surat 1

Road Safety Challenges in

India and Preparation of

Action Plan

Planning

Operation &

Manage-ment

Efficiency

Safety

Delay

Design

Traffic Facility Provision /

Improvement

Sustainability• Economical

• Environmental• Social

Background

• Traffic safety: nation's economy and people's welfare.

• Intersections are the most critical locations: Efficiency and safety.

• Complex intersections: continual developments/alterations in urban

areas

• Confusing, overbuilt and unavoidable: difficult locations on a road

network.

• To ensure safe and efficient movement: controls at different levels.

• Due to the heterogeneity and non-lane based traffic delay arise.

• India, most of the intersections are uncontrolled

• Inappropriate traffic control at intersection

• Inadequate sight distance at intersection

• Inadequate guidance for motorists

• Vehicle conflicts with pedestrian

• Poor operational performance of signalised intersection

• Misjudgement of gaps in traffic

• Over-Speeding and Dilemma

• Non-compliance with intersection traffic control devices

• Signs and Marking are absent

• Lack of proper visibility

• Facilities for users like pedestrian and non-motorized

vehicles are rarely provided

Major Problems Observed at Intersections

Auxiliary lanes Provision

Pedestrian Facilities

On-street parking

Accidents, persons killed and injured by type of traffic control 2017-2018

Accident by type of road junction at the All India level for 2017-2018

As per report of Road Accident in India (MoRTH 2018)

Need for Safety in Design of Intersections

Junction

Type

Number of Accidents Persons Killed Persons Injured

2017 2018 2017 2018 2017 2018

T-Junction56,363

(12.1%)

57,652

(12.3%)

16,939

(11.5%)

15,608

(10.3%)

57,072

(12.1%)

55,589

(11.8%)

Y-Junction31,249

(6.7%)

26,220

(5.6%)

9,806

(6.6%)

7,866

(5.2%)

31,108

(6.6%)

24,003

(5.1%)

Four arm

Junction

34,630

(7.4%)

28,125

(6%)

9,832

(6.6%)

7,652

(5.1%)

32,341

(6.9%)

26,178

(5.6%)

Staggered

Junction

26,695

(5.7%)

22,557

(4.8%)

8,790

(5.9%)

7,921

(5.2%)

26,526

(5.6%)

21,411

(4.6%)

Round about

Junction

26,916

(5.8%)

50,515

(4.4%)

8,706

(5.8%)

6,765

(4.5%)

27,032

(5.7%)

19,193

(4.1%)

Others*2, 89,057

(62.2%)

3, 11,975

(66.8%)

93,939

(63.5%)

1, 05,605

(69.7%)

2, 96,896

(63%)

3,

23,044

(68.8%)

*Any other type not covered by the specified road junction

given above such as junction with greater than 4 arm,

Manned and unmanned rail crossing, expressway.

Traffic ControlNumber of Accidents Persons Killed Persons Injured

2017 2018 2017 2018 2017 2018

Traffic Light

Signal

16,563

(3.6%)

13,726

(2.9%)

4,058

(2.7%)

3,325

(2.2%)

15,547

(3.3%)

12,468

(2.7%)

Police

Controlled

13,577

(2.9%)

12,793

(2.7%)

4,114

(2.8%)

4,090

(2.7%)

12,590

(2.7%)

11,519

(2.5%)

Stop Sign11,140

(2.4%)

6,513

(1.4%)

3,346

(2.3%)

2,491

(1.6%)

10,812

(2.3%)

5,665

(1.2%)

Flashing

Signal/Blinker

10,549

(2.3%)

7,904

(1.7%)

2,896

(2%)

2,757

(1.8%)

10,644

(2.3%)

7,378

(1.6%)

Uncontrolled1, 24,024

(26.7%)

1, 14,133

(24.4%)

39,560

(26.7%)

33,149

(21.9%)

1,24,486

(26.4)

1, 09,344

(23.3%)

Others*2, 89,057

(62.2%)

3, 11,975

(66.8%)

93,939

(63.5%)

1, 05,605

(69.7%)

2, 96,896

(63%)

3, 23,044

(68.8%)

Intersection Hierarchy by control

• Uncontrolled Intersection (stop-control)

• Uncontrolled Intersection with Channelizers (Free-Left

turn)

• Uncontrolled Intersection with Central Traffic Island

• Uncontrolled Intersection with Roundabout

• Partially Controlled Interaction (Police-Controlled)

• Signalized Intersection

• Toggled Signal Timings

• Grade Separators

Red

uce

d C

on

flic

ts -

Imp

rove

d S

afet

y

Hierarchy of Operation Control for Different Intersections

Right of WayA – 60m/45mB – 36m C - 30m D – 18m E - < 9m

Hierarchy of Rural Intersections

Class Type

AA Rotary / GS

AB Rotary /Roundabout

AC Priority

BB Priority / Roundabout

BC Priority

BD Priority

CC Priority / Roundabout

CD Priority / Roundabout

DD Priority

DE Priority

EE Priority

Category of Road

Category of Road

(NH) National Highway -(A)

(SH) State Highway-(B)

(MDR) Major District Road-(C)

(ODR) Other District Road-(D)

(VR) Village Road -(E)

(NH) National Highway -(A) AA AB AC - -

(SH) State Highway-(B) - BB BC BD -

(MDR) Major District Road-(C) - CC CD -

(ODR) Other District Road-(D) - - DD DE

(VR) Village Road -(E) - - - EE

Intersection Matrix – Non Urban (Rural) Roads

Criteria for Upgradation of Intersection

• Justification of a traffic signal should be mainly based on traffic signal warrants. (IRC: 93-1985)

1. Diversion of Traffic

2. Geometric Correction

3. Provision of Roundabout

4. Signalization

5. Grade separated Interchange

6. Traffic demand management:

Diversion / Change in Composition

Steps for Upgradation of Intersection so as to meet traffic demand:

Intersection Selection based on Traffic Flow Combination (U.K. Practice)

Design of a safe intersection depends on :

Human Factors

Driving habits

Ability to make

decisions

Driver expectancy.

Decision and reaction

time

Conformance to natural paths of

movements

Pedestrian use and habits.

Traffic Considerations

Design and actual

capacities

Design hour turning

movements

Size and operating

characteristics of

vehicles,

Types of movement

Vehicle speeds.

Transit involvement

Source: (IRC:SP:41-1994)

Design of a safe intersection depends on :The major factors can be classified as under:

Road and Environmental considerations

Vertical and horizontal alignment

at the intersection

Sight distance

Angle of the intersection

Conflict area.

Character and use of abutting property

Speed-change lanesGeometric

features

Traffic control devices

Lighting equipment

Safety features

Environmental

features.

Need for future

upgrading

Economic factors

• Cost of Improvements

• Effects of controlling or limiting right-of-way on

abutting residential or commercial properties

where channelization restricts or prohibits

vehicular movements.


Basic Design Principles


1. Uniformity

and Simplicity

2. Minimise Conflicts

points

3. Safety

4. Alignments and Profile

Road Safety : 2 Approach

REACTIVE APPROACH PROACTIVE APPROACH

Crash Data Based ~ Black Spot Management: Operational Stage (Existing Road Stage Audit)

Formal examination of traffic and roadway elements:Planning/Design-Construction-Preopening -Existing

2021-03-11 13MMGSY-GOG-AIIB RSAEM

http://www.google.co.in/imgres?start=99&rls=com.microsoft:en-us:IE-SearchBox&biw=1016&bih=496&tbm=isch&tbnid=ZCAZnHYZulCw9M:&imgrefurl=http://creative.sulekha.com/global-road-safety-week_224432_blog&docid=XOjk9h88gggkKM&imgurl=http://www1.sulekha.com/mstore/vanivis/albums/default/Accident_India.jpg&w=500&h=375&ei=cvCMUqiHEIGPrgeBg4HQBw&zoom=1&iact=rc&dur=328&page=7&tbnh=148&tbnw=219&ndsp=14&ved=1t:429,r:11,s:100,i:37&tx=120&ty=83

• Improper geometry and inadequate channelization of traffic flow provoking conflicting traffic movements

• Insufficient pavement markings on the pavement and on channelizing islands.

• Junction signage is insufficient.

• Absence of lighting resulting in insufficient illumination.

• Inadequate sight distance to/from the side road approaches.

• Parking near junctions and encroachment of junction area by roadside hawkers

Intersections: Planning and Design Issues

Kamrej- Shampur Road (SH-167) Mahuva – Anawal Road (SH-165) Mahuva – Anawal Road (SH-165)

LOS SIGNALISED UNSIGNALISED ROUNDABOUT

DELAY (Indo-HCM 2017)

(s)V/C (Indo-HCM 2017) DELAY (HCM-2000) (s) V/C (Indo-HCM 2017)

DELAY (Indo-HCM 2017)

(s)

A 20 <0.45 <10 <0.15 ≤ 5

B 20 -40 0.45-0.75 10 to 15 0.16-0.35 6 ≤ d ≤ 15

C 40-65 0.76-0.95 15 to 25 0.36-0.55 16 ≤ d ≤ 20

D 65-95 0.96-1.05* 25 to 35 0.56-0.80 21 ≤ d ≤ 35

E 95-130 1.06-1.10 35 to 50 0.81-1 36 ≤ d ≤ 65

F >130 >1.10 >50 >1 >65

Level of Service (LOS): Monitoring Operations

1. Forecasted vs existing level of service

2. Effect of each of the improvement

3. Effect of traffic monitoring

4. Optimised signal design

5. Monitoring performance and maintenance of unsignalized and

signalised intersections

Source: Google Satellite Image

Study Area : Kamrej Intersection Kamrej Intersection : Major Movements

A Case study ~ Kamrej Intersection improvement (Nh-48 & Surat-Kamrej BRT Corridor)

Illegal Parking on roadsides

Kamrej Gam Approach

Mumbai to Surat Approach

Roadside friction at Kamrej

Mumbai to Surat Approach

Ahmedabad to Kamrej Gam Approach

Vendors occupied space on footpath

Sight distance is reduced at turning

Lack of proper pedestrian infrastructure

Safety of Pedestrians is big issue

Wrong (Illegal) side movement of vehicles

Ahmedabad Approach

Mumbai Approach

Many illegal movements are observed due to nearby residential areas

Reconnaissance survey

• Site visit

Road Traffic Survey• Traffic Videographic

survey

Traffic Data extraction• Traffic count from

recorded video

Traffic analysis• V/C ratio• Traffic flow• Traffic composition

Design of intersection• Traffic island• Slip lane• Median

Drawing preparation• Development Plan• Road signages• Road markings • Typical cross sections

Demarcation queriesWhile actual

implementation

Intersection Re-design Methodology

� Proposed channelizing island for separation of

Left turning traffic for each approach.

� Large amount of pedestrian flow is observed.

Speed table is recommended considering safety of

pedestrian while crossing the road.

� Continuous footpath protected with railing for safe

pedestrian movement.

� Central island is proposed with four lanes, which

can regulate traffic coming from various directions

and prevent traffic jam condition.

Improvement Measures

� Haphazard parking is observed at

intersection area which is affecting

traffic flow.

� To prevent haphazard parking on

road, separate parking space is

proposed for auto rickshaw, taxi, etc.

ENTRYEXIT

Proposed auto rickshaw stand at MFZ (Multi functional zone)


Space below the bridge can be used as multi functional zone.


Design model – Base condition

Ahmedabad

KamrejRoyal residency

MumbaiSurat

Design model – Central Island

Design model – Widened Roads

Design model – Central Island + Free Left

Ahmedabad KamrejRoyal residency

MumbaiSurat

Ahmedabad

KamrejRoyal residency

MumbaiSurat

Ahmedabad Kamrej

Royal residency

MumbaiSurat

Traf

fic

Sim

ula

tio

n

Aggregate Improvement Model

Ahmedabad

Kamrej

Royal residency

MumbaiSurat

Ahmedabad Kamrej Royal residency

MumbaiSurat

Royal residency

Mumbai

Surat

Ahmedabad

Kamrej

Royal residency Mumbai

Surat

Ahmedabad

Kamrej

MovementsBase Model

(s)Central Island

(s)Widened Roads

(s)

Central Island + Widened Roads

(s)

Central Island+ Free left

(s)

Final Model(s)

Surat-Ahmedabad 18 20 21 23 13 12

Surat-Kamrej 92 83 93 83 68 63

Surat-Mumbai 92 83 91 87 78 76

Ahmedabad-Kamrej 78 76 79 79 8 7

Ahmedabad-Mumbai 72 73 64 79 86 62

Ahmedabad-Surat 73 67 70 80 87 61

Kamrej-Mumbai 82 84 85 89 14 15

Kamrej-Surat 80 83 78 91 85 71

Kamrej-Ahmedabad 79 84 76 94 81 69

Mumbai-Surat 15 20 13 20 4 3

Mumbai-Ahmedabad 107 60 60 62 47 51

Mumbai-Kamrej 115 58 56 61 38 39

Delay For Different Scenarios

Movements Base Model Roundabout Widened RoadsCentral Island + Widened Roads

Central Island + Free left

Final Model

Surat-Ahmedabad C C B B A ASurat-Kamrej F F D D D C

Surat-Mumbai F F D D D DAhmedabad-Kamrej F F D D A A

Ahmedabad-Mumbai F F C D D CAhmedabad-Surat F F D D D CKamrej-Mumbai F F D D A A

Kamrej-Surat F F D D D DKamrej-Ahmedabad F F D D D D

Mumbai-Surat B B A A A AMumbai-Ahmedabad F F C C C C

Mumbai-Kamrej F F C C B B

Level of Service (LOS): Simulation

Haphazard Parking creates traffic jam

condition

BEFORE

Field Implementation

AFTER

Anuvrat Dwar Intersection Design (Urban)

Google Satellite View of Existing Anuvrat Dwar Junction

Anuvrat Dwar Intersection Turning Movement Diagram

Anuvrat Dwar Intersection Design

Anuvrat Dwar Intersection Conflict Diagram (IS-1) : Existing vs Proposed Comparison

Vehicle conflicts Points

Intersection 1

Crossing Type

1 Crossing 3

2 Merging 3

3 Diverging 4

Total 10

• Existing

• Proposed



Intersection 2

Crossing Type

1 Crossing 4

2 Merging 8

3 Diverging 7

Total 19

• Existing

• Proposed



Intersection 3

Crossing Type

1 Crossing 7

2 Merging 9

3 Diverging 3

Total 19

• Existing

• Proposed

Intersection Design Implementation Stage- 1

• Diverting all the traffic movements from

Panas Gam Approach towards Indian Oil

Petrol Pump Approach by Temporary

Barricading.

• Temporary diversion is recommended to see

response of road users for proposed design.


• Restricting all types of vehicle movements

on road adjacent to Veer Hanuman

temple by temporary Barricading.

• This area can be developed with

horticulture and/or landscaping.


• One-way Traffic Movement on Indian Oil

Petrol Pump Approach and Veer Hanuman

Mandir Approach.

• This is major modification proposed from

traffic operation point of view.


• Demolition of RCC Wall Structure under

Fly Over and temporary construction of

Central Elliptical Island as per design.


• Temporary construction of Central Circular

Island as per design.

• Since, existing U-turn is very near to

intersection area, shifting of existing U-turn is

proposed by 80 m towards Breadliner circle.


• Temporary Construction of Channelizing Island

as per design.

• It is essential for free left turning movement.


• Shifting of Evershine Marble Gates as per design to

ensure that provision of property access near

intersection area may cause serious safety issues for

road users.


• Providing continuous pedestrian footpath and

pedestrian crosswalk as per design along all the

approaches.

• Continuous and safe pedestrian movement from one

approach to any other is the measure for pedestrian

safety.


• Provision of Public Bike Sharing (PBS) docking

stations at locations proposed in design drawing.

Intersection Design Implementation Stage- 10• Installing road traffic signs and providing road

marking as per design.

• Provide Traffic Calming Measures to reduce vehicle

speed at intersection approach . i.e. Transverse Bar

Markings at exact location indicated in design.


• Provision of parking for car and two-wheeler as per

design drawing.

Pictorial View of Study Site: (a) Rachana Circle, Surat (b) Vadodara (c) Udhana, Surat (d) Prime Arcade, Surat (e) Faridabad, Delhi

Intersection Operations’ Safety Analysis ~ Crossing Conflicts

(a) (b) (c)

(d) (e)

Spatial distribution of Crossing Conflicts

Varying Proportion of 2w in Conflicting Volume

StudySite

2w % in Conflicting Stream Probability of

Crash

Rachana Circle

<45 0.10 (201)46-60 0.18 (973)>61 0.26 (1244)

Vadodara<50 0.18 (1124)

51-55 0.19 (673)>60 0.20 (303)

Udhana<50 0.16 (521)

51-55 0.16 (409)>60 0.13 (498)

Prime Arcade

<50 0.21 (314)51-60 0.22 (295)>70 0.22 (281)

Parenthesis () Number of conflicts observed

Varying Proportion of 2w in Offending Stream

StudySite

2w % in Offending Stream

Probability of Crash

Rachana Circle

<45 0.12 (232)46-60 0.17 (395)>75 0.23 (1909)

Vadodara<40 0.19 (711)

41-50 0.19 (859)>60 0.18 (530)

Udhana<50 0.14 (400)

51-60 0.15 (640)>70 0.16 (305)

Prime Arcade

<45 0.19 (70)46-60 0.23 (560)>75 0.22 (260)

Effect of Conflicting Traffic Composition

Risk Characterization

Severity varying with speed??

PET Value (s)Speed of Conflicting

vehicle (kmph)Risk Characterization Conflict Location

-1 to 0 35-50 Fatal Accident

Rear-end of conflicting vehicle

-2.13 to -1 30-45 Grievous Injury Accident

-3.73 to -2.14 25-37 Minor Injury Accident

-6 to -3.74 12-32 Non-Injury Accident

0 to 1 35-50 Fatal Accident

Front-end of conflicting vehicle

1 to 2.33 25-45 Grievous Injury Accident

2.34 to 3.9 15-35 Minor Injury Accident

4 to 6 12-32 Non-Injury Accident

Validation with crash data

Obtained through clustering

Disordered and Ordered Traffic Flow Conditions

a) ITO intersection, New Delhi, India

b) MI Road Jaipur, India

c) Old RTO intersection, Surat, India

d) USA: Universal Studio City, Lankershim

Boulevard, California

Signalized Intersections

Spatio-Temporal Characteristics

• Conflicts exist in the upstream area

of the stop line during red phase.

• As time progresses, occurrence zone

of conflict, shifts away from the stop

line in the upstream section

• At the end of the red phase and

start of the green phase, the conflict

intensive zone starts appearing at

and immediately after the stop line

Involvement of Vehicle class in conflicts

2W’s involve in more

numbers of conflicts

Comparison of Conflicts between Ordered and Disordered Traffic flow conditions

• Spatial plot of interactions

• X-Axis: Longitudinal Distance

• Y-Axis: Carriageway Width

• Zero on x axis represents stop line

Identified Probable Conflicts

(USA)

Identified Probable Conflicts (India)

Challenges ~ Safety at Intersections

Intersection Design

• Based on single value of design vehicle, design driver, normal weather

• Considering full compliance by users

• Inequity among provisions for different road users

• Expecting perfect implementation of what is designed

• Assuming ideal traffic operation / perfect roadway conditions

Intersection Operation

• Variability in road user characteristics

• Variability in traffic ~ vehicle & pedestrian characteristics

• Varying compliance level by different road users ~ Driver Behaviour

• Inadequate / implementation and enforcement

• Static Controls / Communication

Adequate & Reliable Traffic Data Availability ?????

IRC: 35-2015IRC: 67-2012 IRC: 79-2019 IRC: 99-2018 IRC: 108-2015

References- IRC Codes

IRC:65-2017IRC:SP 41-1994 IRC:92-2017IRC:93-1985 IRC:103-2012

RESEARCH GROUP

THANK YOU…!

SVNIT

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