District and county safety plans
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District and County Safety Plans. Brad Estochen State Traffic Safety Engineer Minnesota Department of Transportation. Outline. Safety, Crashes, MnDOT approach to Safety MnDOTs Risk Assessment Process Intersections Curves Segments

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District and county safety plans

District and County Safety Plans

Brad Estochen

State Traffic Safety Engineer

Minnesota Department of Transportation


Outline

Outline

  • Safety, Crashes, MnDOT approach to Safety

  • MnDOTs Risk Assessment Process

    • Intersections

    • Curves

    • Segments

  • Summary of Projects typical projects developed through safety plans


Crashes

Crashes

  • Crashes are the safety performance measure

  • Historically safety focused on locations with lots of crashes

    • Black spots

    • High Crash Rates

  • SAFETEA-LU (2005) signaled a new direction for traffic safety

    • Reducing fatal and serious injury crashes


Minnesota s shsp

Minnesota’s SHSP

Funds available for local roads (HSIP, HRRR, …)

Funding levels varied by ATP

Application required to receive funding

Priority on proactive (systemic) projects


Mndot tzd initiative

MnDOT TZD Initiative

  • www.minnesota tzd.org


Safety prioritization

Safety Prioritization

  • Fatal and Serious Injury crashes – primary focus

    • Reduction – try to reduce crashes in locations experiencing crashes

    • Prevention – prevent crashes from occurring

  • TZD mission: To create a culture for which traffic fatalities and serious injuries are no longer acceptable through the integrated application of education, engineering, enforcement, and emergency medical and trauma services.

  • Reducing other crashes – secondary focus


Traffic fatalities

Traffic Fatalities


Strategic highway safety plan

Strategic Highway Safety Plan

  • MnDOTs framework for evaluating and selecting safety programs based on the ability to reduce fatal and serious injury crashes

  • Leverages AASHTO emphasis areas

    • Drivers

      • Licensed, aggressive, impaired, belted,

    • Special Users

      • Pedestrians, bicyclists,

    • Vehicles

      • Trucks, motorcycles, passenger car safety systems

    • Roadways

      • Intersections, road/lane departure, safe work zones


Strategic highway safety plan1

Strategic Highway Safety Plan

  • Critical Emphasis Areas

    • Seat Belt Use – 52%

    • Impaired Driving – 36%

    • Intersection crashes – 33%

    • Road Departure – 32%

    • Aggressive Driving – 28%

    • Young Drivers – 24%

    • Head-on Crashes – 20%


Greater minnesota crash data overview

Source: MnCMAT Crash Data, 2006-2010

Severe is fatal and serious injury crashes (K+A).

Greater Minnesota Crash Data Overview

5 Year Crashes

156,182

4,902

-ATP’s 1, 2, 3, 4, 6, 7, and 8 – NO Metro

Example

All – %

Severe – %

CSAH/CR

36,716 – 24%

1,963 – 40%

State System

70,808 – 45%

2,000 – 41%

City, Twnshp, Other

48,658 – 31%

939 – 19%

Urban

14,086 – 38%

337 – 17%

Rural

22,630 – 62%

1,626 – 83%

Not Animal

18,616 – 82%

1,566 – 96%

Animal

4,009 – 18%

60 – 4%

Unknown/Other

1,577 – 11%

17 – 5%

Not Inters-Related

5,177 – 37%

175 – 52%

Inters-Related

7,332 – 52%

145 – 43%

Unknown/Other

1,276 – 7%

61 – 4%

Inters-Related

5,487 – 29%

463 – 30%

Not Inters-Related

11,849 – 64%

1,042 –66%

Run Off Road – 1,202 (23%), 69 (39%)

Head On – 366 (7%), 27 (15%)

“Other” – 540 (10%), 25 (14%)

Rear End – 1,336 (26%), 17 (10%)

Other/Unknown

2,600 – 47%

228 – 49%

Signalized

209 – 4%

4 – 1%

All Way Stop

164 – 3%

15 – 3%

Thru-Stop

2,511 – 46%

216 – 47%

Head On, SS Opp.

751 – 6%

132 – 13%

Run off Road

7,891 – 67%

675 – 65%

Signalized

2,308 – 31%

32 – 22%

All Way Stop

445 – 6%

5 – 3%

Thru-Stop

2,697 – 37%

65 – 45%

Other/Unknown

1,881 – 26%

43 – 30%

Run Off Road – 999 (38%), 95 (42%)

Right Angle – 268 (10%), 39 (17%)

“Other” – 303 (12%), 29 (13%)

Head On – 112 (4%), 21 (9%)

On Curve

247 – 33%

46 – 35%

On Curve

3,222 – 40%

339 – 50%

Right Angle – 633 (27%), 15 (47%)

Rear End – 799 (35%), 5 (16%)

Left Turn – 375 (16%), 5 (16%)

Head On – 100 (4%), 4 (13%)

Right Angle – 1,268 (47%), 37 (86%)

“Other” – 252 (9%), 9 (21%)

Left Turn – 268 (10%), 4 (9%)

Rear End – 333 (12%), 3 (7%)

Right Angle – 849 (34%), 122 (56%)

“Other” – 464 (18%), 33 (15%)

Run Off Road – 342 (14%), 21 (10%)

Left Turn – 184 (7%), 10 (5%)


Fatal and serious injury crashes

Fatal and Serious Injury Crashes

  • Challenge to determine where to focus safety funds

    • Black spots are infrequent on local/low volume roads

    • Fatal and Severe injury crashes are random on local/low volume roads

County Roads

  • 2,089 Severe Crashes

  • 45,000 miles of road

  • 0.05 severe crashes per mile

Trunk Highway

  • 2,168 Severe Crashes

  • 12,000 miles of road

  • 0.18 severe crashes per mile


Safety plan genesis

Safety Plan Genesis

  • HSIP funds available to local agencies

  • Projects solicited by ATP (District)

  • Technical assistance needed to identify safety projects

  • SHSP has some guidance at local level

  • Safety Plans produce a mini SHSP at the local level

    • 87 counties, 8 MnDOT districts


A systemic approach

A Systemic Approach

  • The average county in Minnesota includes:

    • 500 miles of county highway

    • 400 horizontal curves

    • 180 controlled intersections

  • The key questions:

  • Is every element of the county system equally at risk?

  • Where to Start?

  • A new approach to safety planning

    Old Approach

    Crashes = Risk & No Crashes = No Risk

    New Approach

    No Crashes ≠ No Risk

    Use surrogates of crashes (roadway and traffic characteristics) to identify risk and prioritize – the 5  (or 6) Ranking System


Systemic approach to safety

Systemic Approach to Safety

  • Severe Crashes are rare/random

  • Usually not location specific

    • Investigated thousands of intersections, curves, miles of roads

    • No dead man’s curve

    • No killer corner

  • Traditional approaches such as crash rates, densities, or severity ratios will not identify infrequent crashes that are spread throughout the network


Systemic approach

Systemic Approach

  • Traditional approaches look for locations that have crashes and investigate the root cause

  • MnDOT is looking at the predominant type of crashes causing serious injuries or death and then gathering information on where they are occurring.

  • Leverage AASHTO emphasis areas

    • Intersections, run off road crashes, unbelted, impaired


Atp 4 8 safety emphasis areas

ATP 4 & 8 – Safety Emphasis Areas


Sample of safety emphasis areas

Sample of Safety Emphasis Areas


Rural paved segments

Rural Paved Segments

  • 47 counties in ATP 3, 4, 6 & 8

  • 13,813 rural paved miles

    • Rural Road Departure Crashes

      • 21,611 total, 1,464 severe, 637 Severe RD

      • Average Density of Sev RD Crashes= 0.009 crashes/mi/year

  • Risk Rating Criteria

    • Density of Road Departure Crashes

    • Traffic Volume

    • Curve (Critical Radius) Density

    • Access Density

    • Edge Risk Assessment


Segment traffic volume

Segment Traffic Volume

  • 600-1,200 ADT was selected to receive a star in ATP 4, 400-1,000 in ATP 8


Access density

Access Density

  • Previous Minnesota research shows a statistically significant relationship between Access Density and Crash Rates – the greater the number of access points the higher the crash rate on Trunk Highways.

  • The County Roadway Safety Plans indicates a similar access effect is present along the County Highway system


Edge risk assessment

Edge Risk Assessment

1 – Usable Shoulder, Reasonable Clear Zone

2– No Usable Shoulder, Reasonable Clear Zone

2– Usable Shoulder, Roadside with Fixed Obstacles

3– No Usable Shoulder, Roadside with Fixed Obstacles


Edge risk assessment1

Edge Risk Assessment

Phase I and II Segments – 13,290 miles, 589 severe RD crashes

Rural Segment Prioritization

High Priority


Rural curves

Rural Curves

  • 11,660 total curves in ATP 3, 4, 6 & 8

    • 9,592 (82%) curves with no crashes

    • Crashes

      • 3,061 total, 326 severe crashes

      • 4 curves with multiple fatal crashes (5 years)

      • 33 curves with multiple severe crashes

      • 0.006 severe crashes/curve/year


Curve related roadway departure

Curve-Related Roadway Departure

  • ATP 4, 61% of roadway departure crashes are curve related (39% in ATP 8)

  • Are all curves equally at-risk?

    • No

  • Risk Rating Criteria:

    • ADT Range

    • Radius Range

    • Severe Crash on curve

    • Intersection on curve

    • Visual Trap on curve


Curve radius

Curve Radius

  • The majority of severe crashes occurred on curves with 500’-1,200’ radii.


Horizontal curve risk rating criteria

Horizontal Curve Risk Rating Criteria

High Priority


Sample curve prioritization

Sample Curve Prioritization

  • Complete census of 490 curves

  • 50 High Priority Curves (10%)


Rural intersections

Rural Intersections

  • 5,725 rural thru/stop (yield) intersections in ATP 3, 4, 6 & 8

    • 4,794 total crashes

    • 373 Severe Crashes

      • 172 severe right angle

    • Intersections with Multiple Severe Crashes: 28 (8 had 2 Fatals)

    • 0.17 crashes/intersection/year

    • 0.01 severe crashes/intersection/year


Rural thru stop risk rating criteria

Rural Thru STOP Risk Rating Criteria

  • Geometry

    • Skewed minor leg approach

    • Intersection on/near horizontal curve

  • Volume

    • Minor ADT/Major ADT ratio

  • Proximity

    • Previous STOP sign

    • Railroad crossing

  • Intersection Related Crashes

  • Commercial Development in quadrants


Rural thru stop risk rating criteria1

Rural Thru STOP Risk Rating Criteria

  • There was a higher severe crash density at intersections where risk factors are present.

  • Phase I and II intersections - 5,725 intersections included in analysis of each risk factor. Minimum of 150 intersections and 16 severe crashes in each category


Intersection ranking

Intersection Ranking

Phase I and II intersections - 5,520 intersections, 359 severe crashes

6 Intersections, 1 Severe Crash


Project development high priority segments

Project Development – High Priority Segments


Project development high priority curves

Project Development – High Priority Curves


Project development high priority intersections

Project Development High Priority Intersections


Proactive project summary

Proactive Project Summary


Safety workshop

Safety Workshop

Objective: Multidisciplinary discussion of a short list of safety strategies

  • Date: December 13

  • Location: Otter Tail

    Government Center

  • Agenda

    • 8:30 – Coffee and Registration

    • 9AM – Introductions

    • Presentations – Law Enforcement and/or Local Safety Advocates

    • Background Information/Desired Outcomes

    • Breakout Sessions – Prioritize Strategies

    • 12PM – 1PM - Lunch

    • Report Back/Final Presentation

    • 2:45 – 3PM - Wrap-up


List of unsignalized intersection strategies

List of Unsignalized Intersection Strategies


Project team

Project Team

  • MnDOT OTST

  • MnDOT State Aid for Local Transportation

  • DPS Office of Traffic Safety

  • CH2M Hill

  • SRF

  • PE Services

  • URS

  • $4 million ($45,000/county and district)

  • 3 year project

  • Received the 2011 Partners for Roadway Safety Award


Highway safety in minnesota

Highway Safety in Minnesota

  • On an average day:

    • 201 total crashes

    • 1.1 deaths

    • 3.5 serious injuries

    • $4,097,549 estimated cost

    • Questions?


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