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