2 the blackspot investigation process

Semarang 23rd & 24th April 2012

How engineers investigate

blackspots

Phillip Jordan, Consultant

Road Safety International Pty Ltd

How to investigate a blackspot

Aims of this presentation:

to outline the blackspot investigation process

to encourage you to look for low cost, high benefit countermeasures

to show you some recent Indonesian blackspot investigations

to outline some of the lessons learnt

On Indonesian highways and roads:

• Many crashes – mainly motorcycles, pedestrians

• Road safety is a growing community concern.

• Crash data – getting better and more accurate.

• Few “champions” of road safety engineering – yet!

• There is much to do to improve road safety.

• We (engineers) should start by treating blackspots.

• But limited experience with blackspot treatments.

What is a Blackspot ?

In Victoria (Australia) – it is 3 casualty crashes in 5 years.

In 1980 when the Victorian blackspot program started – it was 12 casualty crashes in 3 years.

There has been great success over 30 years.

A blackspot is a location on a road which has a high number of crashes – fatal, serious or minor. It may be an intersection or it may be a length of road.

For Indonesia we give:

• 10 points for each fatal crash

• 5 points for each serious casualty crash

• 1 point for all other crashes

• Any site with more than 15 points = blackspot

• Any 1km length with more than 30 points/km = black length

• This is the starting point as we sift through candidate sites.

What is a Blackspot ?

Crash occurs

The sequence of actions in the whole blackspot process

Crash occurs

Police

report

Crash occurs

Police

report

Stored in database

Crash occurs

Police

report

Stored in database

Data extracted

Crash occurs

Police

report

Stored in database

Diagnosis

Data extracted

Crash occurs

Police

report

Stored in database

Diagnosis

Data extracted

develop countermeasures

Crash occurs

Police

report

Stored in database

Design, then audit and then build

Diagnosis

Data extracted

Develop countermeasures

Crash occurs

Police

report

Stored in database

Monitor

Develop countermeasures

Design, then audit and then build

Diagnosis

Data extracted

Crash occurs

Police

report

Stored in database

Monitor

Develop countermeasures

Design, then audit and then build

Diagnosis

Data extracted

?

Part D Road safety engineering processes

Blackspot investigations

– 6 examples given

Steps in the blackspot process

To treat a blackspot:

1 Establish a list of blackspots

– Search Police crash data for high crash frequency sites.

– Seek one kilometre lengths with high numbers of crashes.

– Talk with the Police, use local knowledge. Identify those

intersections and lengths within each kilometre where it is

known there have been many crashes.

– Gather all the Police reports for the site – read them.

1

Road safety engineering issues for

Indonesia

Police can assist with blackspot identification

Road safety engineering issues for

Indonesia

Police can assist with blackspot identification

Road safety engineering issues for

Indonesia

Police can assist with blackspot identification

To treat a blackspot:

2 Obtain and read all Police crash report forms.

– Gain a “picture” of the crash history of the site.

– Work with Police – ask them for details of the crashes that may

not be in the reports.

2

To treat a blackspot:

2a Draw a collision diagram.

– Easy to do – but messy, so do a rough draft first

– For each vehicle – draw an arrow to show its direction

– Show m/c, pedestrians, cars, trucks, buses differently

– Make sure that the point of impact is accurately shown

2a

Draw Collision Diagram & Crash Factor Grid

Draw Collision Diagram & Crash Factor Grid

Draw Collision Diagram & Crash Factor Grid

To treat a blackspot:

2b Draw a crash factor grid (Matrix)

– Easy to do – use Microsoft Excel if you have it.

– Paper will also do.

– For each crash – summarise all the known details in one

column.

– Add rows if extra information is known from the Police reports.

2b

Draw Collision Diagram & Crash Factor Grid

DEMAK BLACKSPOT (JALAN SEMARANG - KUDUS 18-19KM)

Crash Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

KM 18.2 18.3 18.3 18.3 18.5 18.6 18.7 18.7 18.7 18.7 18.7 18.7 18.7 18.8 18.8 18.8 19 19

Date 11/11/2011 24/03/2011 06/12/2011 23/02/2012 06/06/2011 11/04/2011 10/03/2012 10/07/2011 11/07/2011 27/02/2011 25/06/2011 19/08/2011 12/12/2011 10/07/2011 30/12/2011 31/12/2011 11/08/2011 29/01/2012

Time 14:30:00 16:30:00 15:30:00 07:00:00 07:50:00 06:15:00 21:45:00 02:00:00 13:30:00 15:00:00 16:30:00 07:30:00 13:00:00 10:30:00 00:15:00 12:30:00 08:15:00 10:00:00

Fatal 1 1 0 0 0 1 0 1 1 0 1 0 0 1 0 0 0 1

Serious Injury 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Light Injury 0 0 1 1 1 0 1 0 0 1 0 3 2 1 1 2 1 0

Light Condition

Weather Fine Fine windy Fine Fine Fine Fine Fine Fine cloudy Fine Fine Fine Fine Fine Fine Fine Fine

Road Condition Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good

Vehicle 1 m/c m/c m/c m/c m/c m/c m/c Medium Truck Medium Truck m/c m/c m/c Unknown m/c m/c Heavy Truck Medium Truck Heavy Truck

Vehicle 2 Unknown Trailer Truck Unknown m/c m/c m/c Mini Bus m/c m/c m/c Heavy Truck m/c m/c

Vehicle 3 B double Truck

Accident type 61 4 63 7 6 9 5 74 81 63 2 64 94 21 66 31 63 5

Traffic controller 1 1 1 7 1 1 0 1 1 1 1 1 1 1 1 1 1 1

Type Jalan 2 2 2 1 1 7 1 2 2 2 8 3 2 2 2 2 3 1

Bentuk Jalan 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Draw Collision Diagram & Crash Factor Grid

7 CRASHES AT ONE LOCATION

Draw Collision Diagram & Crash Factor Grid

6 7 8 9 10 11 12 13 14

18.6 18.7 18.7 18.7 18.7 18.7 18.7 18.7 18.8

11/04/2011 10/03/2012 10/07/2011 11/07/2011 27/02/2011 25/06/2011 19/08/2011 12/12/2011 10/07/2011

06:15:00 21:45:00 02:00:00 13:30:00 15:00:00 16:30:00 07:30:00 13:00:00 10:30:00

1 0 1 1 0 1 0 0 1

0 0 0 0 0 0 0 0 0

0 1 0 0 1 0 3 2 1

Fine Fine Fine Fine cloudy Fine Fine Fine Fine

Good Good Good Good Good Good Good Good Good

m/c m/c Medium Truck Medium Truck m/c m/c m/c Unknown m/c

m/c m/c Mini Bus m/c m/c

9 5 74 81 63 2 64 94 21

1 0 1 1 1 1 1 1 1

7 1 2 2 2 8 3 2 2

1 1 1 1 1 1 1 1 1

Draw Collision Diagram & Crash Factor Grid

To treat a blackspot:

3 Diagnose the problem

Look at the Collision Diagram and the Crash Factor Matrix – are there any patterns?

Day time vs night time?

Wet vs dry?

Type of crash - head on, or run-off-road etc

Type of road user?

Direction of travel?

3

To treat a blackspot:

4 Inspect the site – at the time that the patterns of crashes have happened!

If night time – inspect at night!!

Put yourself in the shoes of the people who had the crashes.

Ask - Why did they have their crash?

4

To treat a blackspot:

4 Be logical ......

Only use countermeasures that will reduce the crashes

(For example, if crashes happened mainly during daytime,

do not install street lighting as a countermeasure).

$$ are always limited – so look first for low cost options.

(Don’t use a bomb to kill a mouse).

4

•Inspect site – day and night.

•Assess likely causes.

•You are like a doctor at this

stage – diagnosing your patient

to prescribe the best medicine!

• If a patient visits a doctor, the doctor asks about his illness.

• The doctor does not just guess about his illness – he does not want to

treat the patient for a headache when he has a heart problem.

• You are like a doctor at this stage – diagnosing your blackspot!

• The blackspot cannot speak – you have to look, listen and ask locals.

• This takes time, skill, patience and logic

Review the Collision Diagram

Review the Crash Factor Grid

Use these on-site to help decide what countermeasures

are needed

6 7 8 9 10 11 12 13 14

18.6 18.7 18.7 18.7 18.7 18.7 18.7 18.7 18.8

11/04/2011

10/03/2012 10/07/2011 11/07/2011

27/02/2011

25/06/2011

19/08/2011

12/12/2011

10/07/2011

06:15:00 21:45:00 02:00:00 13:30:00

15:00:00

16:30:00

07:30:00 13:00:00

10:30:00

1 0 1 1 0 1 0 0 1

0 0 0 0 0 0 0 0 0

0 1 0 0 1 0 3 2 1

Fine Fine Fine Fine cloudy Fine Fine Fine Fine

Good Good Good Good Good Good Good Good Good

m/c m/c Medium

Truck Medium

Truck m/c m/c m/c

Unknown

m/c

m/c m/c Mini Bus

m/c m/c

9 5 74 81 63 2 64 94 21

1 0 1 1 1 1 1 1 1

7 1 2 2 2 8 3 2 2

1 1 1 1 1 1 1 1 1

Police can assist with blackspot information

Police can assist with blackspot information Police can assist with blackspot information

Tips for the site inspection

• Visual deceit

– Not all drivers/riders see the road the same way.

– You need to try to look at the road as others “might”

The driver’s view is straight ahead - but the road goes left!!

Visual deceit USA - RHS

Visual deceit LHS

CRASH

The driver’s view is straight ahead - but the road goes left!!

Pantura – East Java.

How/ why has this barrier been damaged?

Why would anyone run off the road here?

Think of this highway at night!

Visual deceit

To treat a blackspot:

5 Develop countermeasures – talk with colleagues,

with DGLT, with Police

Keep simple, keep low cost

Persevere – there will be many locations where

suitable countermeasures will be possible.

5

Your list of low cost countermeasures

Signs – warning, regulatory, direction

Line marking

Delineation

Shoulder sealing

Roadside hazard removal

Geometric changes

Speed limits

Traffic signals

Roundabouts

Lighting

To treat a blackspot:

6 Design, and then cost the work

- Finalise the design

- Work out the cost of the proposal

6

To treat a blackspot:

7 Write your blackspot report

8 Send for approval for funding; put this site into the Works Program

Ensure to implement the agreed countermeasures(s).

7 & 8

It is no use for the road users unless we make positive changes to the location.

Steps in the blackspot process

Into the future – maybe 3 or 4 years – there will be competition for funding within the blackspot program. Then you will have to

rank sites so that funds are spent on those sites that will return the “best value” to the

people of Indonesia

How will we determine cost and benefits?

1 We need to know the benefits to be gained $

2 We need to know the cost of the countermeasures $

3 Then we calculate the benefit/ cost ratio

How will we determine cost and benefits?

1 We need to know the benefits to be gained $

How many crashes do we expect to save,

and how much does each one cost?

How will we determine cost and benefits?

2. We need to know the cost of the countermeasures $

This is something engineers are good at

calculating.

How will we determine cost and benefits?

1 After you have established countermeasures

2 Get the Crash Reduction Factor (% from list)

3 Have a crash cost ($)

4 Work out the value of the benefits of the countermeasures ($)

5 Calculate the cost of the works ($)

6 Calculate the benefit/ cost ratio

Example of calculating the benefit cost ratio

To work out the BCR we need to know the benefits

(in $) of the countermeasures, and the cost (in $) of

the countermeasures.

Benefits - Indonesia needs to have a table that shows the Crash Reduction Factor for each countermeasure

What percentage of crashes at the blackspot will be reduced if we seal the shoulders of

the highway for one kilometre?

CRASH REDUCTION FACTORS

CRASH REDUCTION FACTORS

Crash reduction factors based on real experience from the

Victorian (Australia) blackspot program since 1980

If there were (say) 16 crashes at the location in 3 years –

and 12 of these are motorcycle crashes - you would aim to

prevent 50% of these 12 crashes in the next 3 years – that

is 6 crashes in the next 3 years

If each crash costs IDR100,000,000 – you will claim

benefits of IDR600,000,000 over 3 years – or

IDR 4,000,000,000 for the life of 20 years

Benefits = IDR4,000,000,000

If the cost to seal the shoulders is (say) IDR200,000,000

The Benefit/Cost Ratio will be 4,000,000,000 / 200,000,000

BCR = 20.0 This project will be compared with all other blackspots in

your Balai – those with the highest BCR’s will be treated

first. The others will wait for next year.....

20:1 BCR is excellent

But for now – concentrate on developing the

most suitable countermeasures

BCR’s will only be needed for new blackspots

after a few more years time

Some Indonesian blackspots

• Two blackspots at bridges – one rural, one urban

• One blackspot at a Y junction

• A blackspot at a small cross road intersection in a small town

• A blacklength on a Highway in Sumatra

• A black spot on a curve on a By-Pass

Before

Recommended

Blackspot location

at Menteng loop

BLACKSPOT LOCATION AT MENTENG LOOP

Blackspot

Location

AERIAL PHOTOGRAPH OF BLACKSPOT LOCATION IN MENTENG, CENTRAL JAKARTA

The visibility before going over the crest of the bridge is obstructed, and the driver has no information about the presence of loop in front. The driver may know the road has four lanes , but the first and second lane are forced to turn left.

74

This direction sign was too late for the road user who wants to turn left to Sumenep/Latuharhary.

The loop has very small radius. It is dangerous if a driver misjudges it and has a higher speed than should be. The driver need to be warned with a speed limit of 30 km/hr.

RECOMMENDATION

The island is not quite visible at a distance. There is a problem of delineation. It needs more guide posts.

RECOMMENDATION

SUDIRMAN MONAS

HARMONI KOTA

MANGGARAI SALEMBA

MONAS HARMONI

KOTA

RECOMMENDATION

MANGGAR

AI

SALEMBA

MONAS

HARMONI

KOTA

RECOMMENDATION

MANGGARAI SALEMBA

MONAS HARMONI KOTA

RECOMMENDATION

A Y JUNCTION AT NAGREG

COLLISION DIAGRAM

RECOMMENDATION

An existing length of National Highway

Recommended option to improve safety on that length of National Highway

Blackspot inspection – near the Mosque, Jambi By-Pass

Blackspot inspection – near the Mosque, Jambi By-Pass

Blackspot inspection – near the Mosque, Jambi By-Pass

Blackspot inspection – near the Mosque, Jambi By-Pass

Blackspot inspection – near the Mosque, Jambi By-Pass

RECOMMENDATIONS

• Repair pot holes

• Seal shoulders

• Install edge lines, centre line

• Install speed restriction signs

• Cut back vegetation to increase sight lines

Pantura (National Highway) Km 18.7

7 crashes in 12 months at U turn

Pantura (National Highway) Km 18.7

7 crashes in 12 months at U turn

What will you recommend to reduce the crashes at this U turn on this busy, fast National Highway?

Blackspot investigations

• The investigation team should put itself in the shoes of the road users...to identify why some of them are have crashes at the site.

Blackspot investigations

Are very effective, and they save Indonesian lives

Questions welcome