Transcript Document
InsertSafety
the title
of your
Route
Management
presentation
here
and
Evaluation
Presentedby
byShaun
Name Helman
Here
Presented
Job
Title - Date2008
th November
25
Page 1
Scope of research
• Literature survey
• Data and case studies from Local Highway Authorities
‘Route Safety’:
• How is it managed and evaluated?
• What is the impact so far?
• Guidance
• Recommendations
Page 2
What is a ‘route’ in this context?
A road with broad consistency in terms of usage, traffic flow and
other characteristics:
• Rural roads
• Some mixed-priority and semi-urban roads
• Strategic A and B roads (whether rural, urban or mixed-priority)
• Usually single carriageway
• Does not include roads around schools and / or in town centres
Page 3
What is ‘Route Safety’?
A road safety treatment - consisting of a package of interventions
- to reduce accident risk and severity along a route.
• Accidents are distributed along a route rather than clustered
• Normally low-cost
• Treatment may comprise any of the 3 ‘E’s, or a combination
• Consistent approach to treatment
• Does not necessarily exclude site specific interventions
Page 4
How is route safety managed and evaluated?
Local Authority responses include:
• Systematic approach to problem
identification
• Mapping
• Thresholds
• Prioritisation
• Accident analysis
• Review of progress
Evaluation:
• Mainly accident numbers / rates
• Sometimes speed
Page 5
What is the impact on casualties?
• Typical casualty reductions of between 30% and 70%
• Example 1 - B4012 south of Thame (Oxfordshire)
• Double white lines / warning signs / illuminated road studs
• 32 accidents in five years ‘before’
• 16 accidents in five years ‘after’
• Severity ratio also down
Page 6
What is the impact on casualties?
• Example 2 – A631 in Nottinghamshire
• Cats’ eyes / double white lining improved / red surfacing / central
hatching / high visibility signing / 50mph speed limit introduced /
average and mobile speed cameras
• £900,000 spent
• Before: 21 accidents per year – 9 KSI
• After: 13 accidents per year – 5 KSI
• Example 3 – A259 West Sussex
• Speed limits revised / dual carriageway reduced to single
carriageway / Pegasus crossing
• Traffic speeds fell by 25%
• Before: 18 casualties per year
• After: 4 casualties per year
Page 7
What is the impact on behaviour?
• Very little is known about the
impact on other driver behaviours
• Lack of data
Some evidence of the impact of
route treatments on behaviour
Page 8
Why consider behavioural change?
• Different roads with similar flows may have different accident
rates
• Road features?
• e.g. more bends per km, greater junction density …
• Driver types and journey purposes?
• Address inconsistencies between:
• Driver behaviours, and
• Road characteristics
Page 9
Driver behaviours
• Can be used as proxies for accident risk to some degree
• Much shorter evaluation period
• Depending on funding, accident types and road characteristics,
could include:
• Speed
• Overtaking
• Close following
• Lateral position
• Fatigue
•…
Page 10
De Almeida Roque and Cardoso (2001)
IP5 route in Portugal – various route treatments along 170km
stretch
- improvements to
- drainage
- sign visibility
- curves
- deceleration lanes
- signing of climbing lanes
Page 11
De Almeida Roque and Cardoso (2001)
IP5 route in Portugal – various route treatments along 170km
stretch
- 90km/h speed limit
- suppression of overtakes in most dangerous sections
- rumble strips on edge of road
- mandatory day-time running lights on some sections
- 50m following distance minimum for lorries
Page 12
De Almeida Roque and Cardoso (2001)
Before and after evaluation
- hourly traffic flow
- spot speed
- following distance
- distance between front wheel and edge of road
- lights on/off
Page 13
De Almeida Roque and Cardoso (2001)
Several changes found
- Lower speed on curves
- Greater distance from edge of road
- Daytime running lights from 11% to 90%
- Sub 50m headway for trucks did not change
Page 14
De Almeida Roque and Cardoso (2001)
6% flow increase
But reduction in fatal accidents from 46 to 28
Fact that behaviours changed as well as accidents (especially in
light of flow changes) supports claim that treatment made route
safer
Page 15
Outline guidance
Collect data
& analyse
Page 16
Choose
interventions
Monitor &
evaluate
Collect data
& analyse
Data
Analysis
• Accident and casualty data
• Road user type
• ‘Contributory’ factors
• Junction / non-junction
• Traffic flow data
• Time of day
• Speed data?
• Road condition
• EuroRAP ratings?
• Driver profile
• Local knowledge
• Average accident rate
• Other relevant information …
Compare with control(s)
Page 17
Collect data
& analyse
Depending on results of initial analysis, investigate possible
additional explanatory factors:
• Traffic flow
• Signing
• Junction density
• Lighting
• Bendiness
• Route consistency
• Hilliness
• Speed
• Road widths and alignment
• Headways
• Visibility
• Overtaking
• Road markings
• Lateral position
Page 18
Choose
interventions
• Target interventions to address the problem(s)
• If removing problem is too expensive, apply mitigation measures
• Might include speed reduction measures
• Might include treating roadside features to reduce severities
• Adopt consistent approach along whole route
Page 19
Choose
interventions
• Gateway treatments
• Signs and markings
• Passive safety
• Safety cameras
• Media campaigns
Rural:
Urban:
• Speed limit review
• Pedestrian crossings / refuges
• In village treatments
• Median treatments
• Bend treatment
• 20mph limit
• Wide single 2 + 1 design
• Widened footways
• Route Alert
• Kerb build-outs
Page 20
Monitor &
evaluate
Monitor changes in:
• Relevant behaviours
• Soon after
• Longer term
• Accident and casualty data
• Preferably after several years
• Control for changes in flow and accident trend
Page 21
Monitor &
evaluate
• Has behaviour changed as intended?
• How and why have accident and casualty rates changed?
• Link intervention to changes in driver behaviour AND accident rate
• What other factors have contributed to the success or otherwise?
• Share knowledge gained about what works AND what doesn’t
Page 22
Thank you
Presented by Shaun Helman
25th November 2008
Tel: 01344 770650
Email: [email protected]
Page 23
IHT/CSS Conference 25 November 2008
NEW DIRECTIONS FOR ROUTE SAFETY
Rob Salmon
Page 24
SUMMARY OF TRL RESEARCH
Current approach ? - varied
Impact so far ? - positive overall
Evaluation ? - some
Evidence ? - limited
Behaviour is
a key component
Guidance
Page 25
THE DYNAMIC INTERFACE
Driver awareness
Skills but distractions
Variable demands
Inconsistent route standards
Different environments
Can the driver cope ?
Page 26
POOR
GOOD
DEMAND
ROUTE /
ENVIRONMENT
STANDARD
DRIVER
REQUIREMENT
DRIVER ABILITY
RESPONSE
GOOD
Page 27
POOR
FUTURE DIRECTION ?
Improve the evidence base
Understand, measure and influence driver behaviours
Refresh route safety strategies
Invest in route infrastructure
Integrate the 3 E’s
Role of local safety partnerships
Page 28