Breaking the Silence

About Road Surfacesand

Accident Rates

By R A Rallings, ME, FIE(Aust) CP Eng

Road Surfaces- Breaking the SilenceReasons for Paper

1. The silence distorts the public’s understanding of road safety.

2. Public’s right for reliable information.

3. Silence will not attract needed funds.

4. Opportunity to pose questions.

Road Surfaces- Breaking the SilenceScope of Paper

1. Tasmanian Select Committee on Road Safety.2. Principles and tools of Risk Management.3. WDM’s review of ILs for SFC in Tasmania.4. Additional analysis of WDM’s data.5. Engagement and ownership of ILs.

Road Surfaces- Breaking the Silence Legislative Council’s Committee on Road Safety

1. Seven (7) Terms of Reference• Road surface properties relevant to 3 terms

2 Committee received:• 76 written submissions• 83 oral presentations in 4 Australian states

3 Made 69 findings and 52 recommendations

Road Surfaces- Breaking the SilenceALARP Principle

1. Basic principle of Risk Management: “ Risks should always be set at”:

As Low As Reasonably Practical2 It requires demonstration that: • Sacrifice in reducing risks>> Benefits

Road Surfaces- Breaking the Silence*Site Categories -Investigatory Levels ILs

Site Category Grade % HorizontalRadius (m)

IL SFC

2 => 5 or < 250m 0.50

4 (single) <5 >250m O.40

5 (dual) <5 >250m O.35

6 =< 100m 0.60

*Vicroads/ DMR (1995)

Manoeuvre Free Roadways

Road Surfaces- Breaking the SilenceWDM’s Report

Road Surfaces- Breaking the SilenceWDM’s data- Tas Road Network

• 6300 lane km (100m sections)• 2145 Wet road accidents (2003 to 2006)• 6 site categories (single and dual)• 3 sub categories in Cat2• Average Annual Daily Traffic (AADT)• 10 SFC bands/bins from <0.30 to > 0.70

WDM/RAR

Road Surfaces- Breaking the SilenceWDM, Site Category 4 - Equal Risk Policy

WDM

Road surfaces- Breaking the SilenceIls derived from Equal Risk Policy

5

50

500

SFC

We

t R

d A

cc

ide

nts

/10

8 v

eh

icle

km

20

Category 6 Single

Category 2 Single

Category 4 Single

Category 5 Dual

WDM ,RAR

Road Surfaces- Breaking the SilenceVariation in Accident Rates in Cat 2

5

50

500

SFC

We

t R

d A

cc

ide

nts

/10

8 v

km

Grades > 5%Radii > 250m

Grades < 5%Radii < 250m

Grades > 5%Radii< 250m

(WDM, RAR)

20

Road Surfaces- Breaking the SilenceAADT and SFC

0

500

1000

1500

2000

2500

3000

3500

SFC

Av

era

ge

AA

DT

Site Category 4

Site Category 2

Site Category 6

WDM, RAR

Road Surfaces- Breaking the SilenceDistribution of Travel and Accidents

0

5

10

15

20

25

30

Category 2 (b) single

SFC

% o

f A

cc

ide

nts

%

of

Tra

ve

l Travel

Wet Rd Accidents

34%

(Grades< 5%, radii < 250m)

WDM, RAR

Road surfaces- Breaking the SilenceSFC and Wet Rd Accidents/lane.km

1

10

100

SFC

Ac

cid

en

ts (

x1

0-2

)/la

ne

km

/ye

ar Category 5 Dual

Category 2 Single

Category 4 Single

WDM, RAR

Road Surfaces- Breaking the SilenceSafety Policy Questions

1. Should the goals in setting ILs be to:• Provide equal risk to all road users, or• To minimise the number of accidents within the

road network.

2 Breach of the ALARP principle?

3 Road authority, community, government?

Road surfaces- Breaking the Silence Engagement and Ownership of ILs

Manages Network

Establishes Road Needs

Information/Expertise

Safe Environment

Allocated funds

Makes laws, regs

Carries risk

Pays taxes

Votes

RoadAuthority

Elected Government

Community Road Users

ILs