Blueprints for Improving Intersection Safety Overview and Purpose This presentation will Review the intersection safety challenge Introduce Intersection Safety Implementation Plans ISIPs Present noteworthy ISIP practices and case studies from several States ID: 690013
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Slide1
Intersection Safety Implementation Plans
Blueprints for Improving
Intersection SafetySlide2
Overview and Purpose
This presentation will:
Review the intersection safety challenge
Introduce Intersection Safety Implementation Plans (ISIPs)
Present noteworthy ISIP practices and case studies from several StatesSlide3
Intersection Safety Problem
Intersections are planned points of conflict among motorists, pedestrians, and bicyclists
On average, crashes within or near an intersection account for 26% of all traffic-related fatalities and about half of all traffic-related injuries nationwide
There were 8,664 intersection fatalities in 2014
Data for Intersection Focus Area from FHWA Safety Data Dashboard at:
https://rspcb.safety.fhwa.dot.gov/Dashboard/Default.aspx
Slide4
Focused Approach to Safety
Reducing injuries and fatalities at intersections is one of three technical focus areas along with Roadway Departure and Pedestrian/Bicycle
FHWA provides resources to Focus States to address these critical safety challenges through staff assistance, tools, and training (
http://safety.fhwa.dot.gov/fas/
)
A key component is that it is a data-driven approach to safetySlide5
Intersection Safety Program
Address intersection safety through data analysis, design, and implementation guidance
Variables impacting intersection safety:
Human factors
Pedestrians and Bicycles
Intersection Design
Rural and Local ISIPs are just one tool available through the program (http://safety.fhwa.dot.gov/intersection/)Slide6
Approaches to Safety ImprovementSlide7
Traditional Approach (aka Hot Spot)
Based on “High-crash Locations”
Purely reactive; identified by very high number of crashes at specific intersection
Usually involves application of countermeasures with high CRF values, but also at high cost (e.g., reconstruction or grade separation)
Usually fewer than 10-20 per year in a average size State
Site-specific success, but due to random nature of crashes, negligible impact on reducing statewide totals
TraditionalSlide8
Systemic Approach
Reverses
the traditional approach, then enhances it
Start with known
effective, low-cost
countermeasures
Install systemically at large number of intersections with both moderate and high crash histories where cost-effective results are expectedTypically find that 3-8% of the intersections with any crash history account for 25-40% of the statewide intersection problem
Substantial reduction of statewide intersection injuries/ fatalities can be realized with this approach (ties directly to SHSP goals)
Plan can be tailored to available resources
Can also include a Corridor/Community 3E component
SystemicSlide9
Traditional vs. Systemic
$3M Budget
Construct Roundabout at 3 intersections
$1M / intersection
$1M
$1M
$1M
Minor improvements at 500 intersections
$6K / intersection
24 crashes reduced/
yr
*
APPROACH
75 crashes reduced/
yr
**
*40% reduction in total crashes; 20 crashes/intersection/year before treatment
**5% reduction in total crashes; 3 crashes/intersection/year before treatment
BENEFIT
OR
3 Times the Benefit in Crash ReductionSlide10
Systemic Safety Project Selection ToolSlide11
ISIP DevelopmentSlide12
ISIP Process
Developed by FHWA to create an implementation plan and guide activities related to intersection safety improvements
Overall aim: focus
less on high-dollar
, major improvements at a relatively few intersections and focus
more on deploying lower-cost, cost-effective countermeasures at many intersectionsSlide13
ISIP Process
Set Crash Reduction Goal
Expand Current Approach to Achieve Goal
Identify Intersection Countermeasures
Analyze Data, Identify Target Intersection
Develop Straw Man Outline
Conduct Workshop to Refine Countermeasures and Budget
Develop Draft ISIP
Present Draft to Upper Management
Implement Management Suggestions
Implement Plan,
Monitor Progress,
Evaluate ResultsSlide14
Reduction in Absolute Numbers
Example: Reduce fatalities by a total number, by a given date
Reduction in Rate
Example: Reduce fatality rate for each year of the last 5 years of data
Set Crash Reduction GoalSlide15
The End Goal
It is estimated that deploying these countermeasures will cost $__M and prevent ____ fatalities and serious injuries over a _ year period.
The projected Benefit-Cost Ratio is approximately __:1
With continued observation/evaluation, most successful treatments to be considered for
systemwide
policy/standardization
Set Crash Reduction GoalSlide16
Systemic
Expand Current Approach to Achieve Goal
Comprehensive
TraditionalSlide17
Identify Intersection CountermeasuresSlide18
Stop-Controlled Intersections
Basic sign and marking improvements
6-ft or greater raised divider on stop approach
Flashing solar LED beacons on advance intersection warning signs and STOP signs
Flashing overhead intersection beacons
Reflective stripes on sign posts
Dynamic warning signs: advise through traffic of a stopped vehicle in intersection; advice traffic on high-speed stop approach that a stopped condition is ahead
Transverse rumble strips across stop approach lanes in rural areas (where noise is not an issue)
Extension of through edge line using short skip pattern
Identify Intersection CountermeasuresSlide19
Signalized Intersections
Identify Intersection Countermeasures
J-Turn modifications on high-speed arterials
Basic signal and sign improvements
Change of permitted and protected left-turn phase to protected-only
Advance cross street name signs for high-speed approaches on arterial highways
Advance left and right “Signal Ahead” warning
One signal face per approach
Advance detection control systems
Signal coordination
Pedestrian countdown signals
Separate pedestrian phasing
Pedestrian ladder/cross-hatch crosswalk and advanced pedestrian warning signsSlide20
New/upgraded lighting
Skid resistant surface
Lane narrowing using pavement marking and shoulder rumble strips
Peripheral transverse pavement markings
Dynamic speed warning sign on through approach to reduce speed
“Slow” pavement markings
High-friction surface treatmentRoundaboutsLeft-turn lanes
Other geometric improvements (e.g., elimination of skew, vertical curve)
Both Stop-Controlled and Signalized Intersections
Identify Intersection CountermeasuresSlide21
Separate Intersection Crashes into Sub-Groups
Calculate Average Crash Costs and Severities
Determine Target Crash Types
Determine Distribution of Crash Densities
Prepare Data Analysis Package
Analyze Data, Identify Target IntersectionSlide22
Crashes Sub-Groups
State rural signalized
State rural stop-controlled
State urban signalized
State urban stop-controlled
Local rural signalized
Local rural stop-controlled
Local urban signalized
Local urban stop-controlled
Analyze Data, Identify Target IntersectionSlide23
Sample Table
STATE
Area Type
Total # of Crashes
Fatal
A
B
C
PDO
Unknown
Signalized
Rural
8,134
40
276
953
1,454
5,361
50
Signalized
Urban
131,363
381
3,396
15,649
29,749
81,289
899
Unsignalized
Rural
14,819
206
749
2,160
2,556
8,985
163
Unsignalized
Urban
84,564
340
2,009
9,059
17,520
54,620
1,016
Unknown
Rural
1,431
1137150
2251,0017Unknown
Urban15,043872781,136
2,62410,784134Subtotal
255,3541,0656,74529,107
54,128162,0402,269LOCAL
SignalizedRural1,141424
1331738007
SignalizedUrban137,0332673,102
16,67034,45981,4861,049
UnsignalizedRural6,94235225
8031,0234,605251
UnsignalizedUrban176,8864343,983
19,66438,102108,7615,942Unknown
Rural458111
45583376Unknown
Urban19,3681003321,542
3,97913,056359Subtotal
341,8288417,677
38,85777,794209,0457,614
OTHER
SignalizedRural1700
24110Signalized
Urban2,739588
4436851,50414Unsignalized
Rural1900430
211314Unsignalized
Urban2,077643190
3841,40549Unknown
Rural15000
1131UnknownUrban
2080324
361405Subtotal
5,24611138689
1,1313,20473
Analyze Data, Identify Target IntersectionSlide24
Working With Data
Common challenges:
Missing or incomplete statewide databases
Missing or incomplete data for non-State-maintained roads
Incompatible data sources
Solution: Use the
available data to develop logical solutions for the existing problems….Don’t let the perfect stand in the way of the good!
Analyze Data, Identify Target IntersectionSlide25
Establish Threshold Crash Levels
Compile a Summary Outline
Develop Detailed Tables for Each Countermeasure
Develop Straw Man OutlineSlide26
Look for opportunities to integrate the ISIP with other statewide programs and funding streams:
* Highway Safety Improvement Program
* Strategic Highway Safety Program
* Statewide partnerships
Implement Plan,
Monitor Progress,
Evaluate Results
Implement Management Suggestions
Present Draft to Upper Management
Develop Draft ISIP
Conduct Workshop to Refine
Countermeasures and BudgetSlide27
ODOT provided districts with HSIP funding, standardized sign order form, and implementation guidance on rural intersection signage improvements
District personnel received list of 1,004 stop-controlled intersections for review and potential upgrading
ODOT sign shop produced the signs and district maintenance forces installed the signs
All 12 districts in Ohio completed the effort by 2014
A typical signing detail for stop-controlled T-intersections. This image was included in a slide presentation that the ODOT central office provided to the districts.
Noteworthy Practice: OhioSlide28
Engage local agencies, MPOs/RPOs, and other stakeholders to enhance:
* Data systems and sharing
* Project funding
* Project implementation
Implement Plan,
Monitor Progress,
Evaluate Results
Implement Management Suggestions
Present Draft to Upper Management
Develop Draft ISIP
Conduct Workshop to Refine
Countermeasures and BudgetSlide29
TxDOT launched ISIP in 2015 utilizing the robust crash records information system (CRIS) as the basis for prioritizing projects
Once gaps in the data were recognized, TxDOT worked with transportation agencies at the State and local levels to develop strategies to address the issues
MPOs and local agencies provide traffic volumes and other roadway characteristics to enhance the data systems
Noteworthy Practice: TexasSlide30
ISIP StatesSlide31
Other Lessons from ISIP States
Formal adoption helps establish buy-in from decision makers
Draft plans allow for more flexibility
Use the ISIP development process to lay the groundwork for implementationSlide32
ISIP ImplementationSlide33
Implementation Strategies Slide34
Approach:
Treating locations with low to moderate crash histories
Focus on widespread deployment of only low cost packages of improvements
Most common approach and best used when extensive data are not available
Typical Treatments:
Multiple enhanced guide, warning and regulatory signs and pavement markings
Multiple enhanced traffic signal visibility/conspicuity treatments
Partial SystemicSlide35
Approach:
Consistent treatment of multiple intersections along an extended distance of roadway with the low-cost treatment packages
Multiple intersections identified as having low to moderate crash histories along a defined corridor
Typical Treatments:
Multiple enhanced traffic control devices
Corridor access management
Intersection geometry (e.g., J-turns, roundabouts)
Corridor SystemicSlide36
Approach:
Treating intersections entirely on risk characteristics identified through rigorous safety data analysis
Full SystemicSlide37
In-House
Successful in decentralized States
Standardized forms, policies, and processes
Requires more staff time and resources
Difficult to track implementation
External Contractor
Useful for States with limited resources/staffMay not understand the systemic approach Combined countermeasures in one bid may lead to higher costsProject Letting and BiddingSlide38
Completed 3 statewide contracts: signs, markings, limited signal enhancements
Eliminated several construction items to accelerate time and reduce costs
Renewable 3-year contract, treat one-third of ISIP intersections each year for 3-years
No in-house maintenance staff due to size of project
Noteworthy Practice: South Carolina
Advance Signal Ahead warning sign with cross street name. Source: SCDOT.Slide39
Policies and Standards
Maintenance policies: Implement enhancements in conjunction with regular maintenance
Systemic guidance: Detail the role of systemic process in project development, funding, and implementation
State HSIP Manual: Define the ISIP approach and detailed overview of projects
ISIP guidance: Low-cost, easily implemented enhancements for specific intersection typesSlide40
Missouri adopted a signal enhancement effort as part of the regular maintenance schedule
Maintenance teams implement low-cost countermeasures when conducting regular maintenance: reflectorized
backplates
, adjusting clearance intervals, limiting the use of late-night flashing operations
This also includes addressing any inconsistencies with statewide standards for 12-in LED lenses and one signal head per lane
Noteworthy Practice: MissouriSlide41
Funding Optimization
Lay the groundwork for implementation when developing the ISIP
Tie the ISIP to funding streams for implementation
Coordinate with local agencies for widespread implementationSlide42
PennDOT
waited until one-third of HSIP funding was set aside for systemic intersection and roadway departure improvements
The central office reviewed HSIP applications and districts delivered the projects
Focused on low-cost projects that improved safety quickly and with limited right-of-way impacts (primarily at signalized intersections)
ISIP identified over 3,000 intersections ($56 million investment), and the list is becoming short due to successful implementation
Noteworthy Practice: Pennsylvania
Signage upgrades that include doubling up the intersection warning signs, adding cross street names, and yellow flags above the signs. Source:
PennDOT
.Slide43
ISIP EvaluationSlide44
Evaluating the Systemic Approach
Widespread, multiple countermeasure implementation can make it more difficult to isolate cause and effect
Outcomes at individual sites may be small and incremental but…
…cumulative progress towards the overall goal will be more substantial!Slide45
Louisiana
South Carolina
Success Stories From the FieldSlide46
LA DOTD Experiences
ISIP completed in 2008
RSIP Grant Projects (Delta Parishes’ Rural/Federal Aid System)
February 2009 letting
$1 million award
88 stop controlled, 16 signalized intersections
September 2010 letting$0.9 million awarded 90 rural stop controlled, 10 rural signalized intersections Average cost = $10,000 per intersection
46Slide47
Louisiana Results
Rural 3-leg Stop:
67% reduction All Crashes
56% reduction Severe Crashes
Rural 4-leg Stop:
53% reduction All Crashes
64% reduction Severe Crashes
Louisiana evaluation can be found at
http://safety.fhwa.dot.gov/local_rural/delta/
Slide48
South Carolina Results
Stop-Controlled
433 treated intersections
Crashes reduced:
8.3% (all crashes)
10.7% (F&I crashes)
14.7% (night crashes)Signalized84 treated intersectionsCrashes reduced:
4.5% (all crashes)
10.7% (F&I crashes)
11.7% (right angle crashes)Slide49
Louisiana
South Carolina
Statewide dataset
Low-to-moderate crash histories
Empirical Bayes methodology
Expected crash savings per location lower than other treatments
Low-cost allows for more treatments at more locations
Positive benefit/cost ratio
Success Stories From the Field
Smaller sample size
Moderate-to-high crash histories
Highway Safety Manual
evaluation techniques
Successful crash reductionsSlide50
SummarySlide51
ISIPs—Overall, a Success Story
States are using ISIPs, with flexibility, to implement safety countermeasures
Evidence is amassing to show significant safety improvements and validate the benefits of an ISIP Slide52
Other Useful Resources
Signalized Intersections Informational Guide (2013)
South Carolina Study on Systemic Intersection Experience (2012)
Systemic Safety Implementation Multi State Peer Exchange Reports (2014)
Systemic Safety Project Selection Tool (2013)
Intersection Safety Implementation Plan Process (2009)Slide53
Other Useful Websites
FHWA Intersection Safety Program (
www.safety.fhwa.dot.gov/intersection
)
Unsignalized Intersection
Improvement Guide (UIIG) (http://www.ite.org/uiig) FHWA Roadway Safety Noteworthy Practices (
https://rspcb.safety.fhwa.dot.gov/noteworthy) CMF Clearinghouse (http://www.cmfclearinghouse.org/)Slide54
For More Information…
Jeffrey Shaw, P.E.
FHWA Office of Safety
Jeffrey.Shaw@dot.gov
(708) 283-3524
http://safety.fhwa.dot.gov/intersection/