Low Cost Safety Improvements

Module 1-1

Lesson 1 Module 1: Introduction

Low Cost Safety Improvements (LCSIs)

Low Cost Safety Improvements

Module 1-2

Logistics

• Health and safety (emergency exits, procedures for

evacuation, etc.)

• Facility smoking policy

• Please silence cell phones/pagers

• Breaks (when, restrooms, telephones)

• Lunch arrangements

• Other site-specific issues
Low Cost Safety Improvements

Module 1-3

Session Presenters

Keith Knapp

Iowa LTAP and National Center for Rural Road Safety

kknapp@iastate.edu

Nicole Oneyear

National Center for Rural Road Safety

noneyear@iastate.edu

Low Cost Safety Improvements

Module 1-4

Goals for Today

• Summarize some data that defines roadway

safety in the United States

• Discuss methods to identify locations of interest

for safety improvement

• Describe/discuss some potential LCSIs for:

• Roadway Segments & Curves

• Roadsides

• Unsignalized Intersections

• Signalized Intersections

• Apply what we’ve learned in a real life case

study
Low Cost Safety Improvements

Module 1-5

Modules Covered

• Introduction – define the problem and

provide context

• Safety Data, Analysis, & Use – data use and

mitigation location identification

• LCSIs and their impacts

• Roadway segments & curves

• Roadsides

• Unsignalized intersections

• Signalized intersections

• Case study

Low Cost Safety Improvements

Module 1-6

Self Introductions

• Who you are

• Job title & Agency

• Your level of experience with safety

improvements

• Beginner

• Intermediate

• Expert

• Safety issue(s) you would like to

know more about
Low Cost Safety Improvements

Module 1-7

Rules of Engagement

• Ask questions as you have

them

• “Parking Lot” for questions

to be addressed later

• We’ll do some work

• Case study

• Facilitated questioning and

discussions

Discussion

Low Cost Safety Improvements

Module 1-8

Introduction – Learning Outcomes

• Define and quantify roadway

safety in the United States

• Describe the terminology (or

context) within how you define

LCSIs

• Differentiate between nominal

and substantive safety
Low Cost Safety Improvements

Module 1-9

Recent Crash Experience

A quick look at: 

• The more relevant data

• The more recent data

• Helps to see where we’ve been

• And where we seem to be heading

Low Cost Safety Improvements

Module 1-10

Crash Fatalities in the US

Source: National Highway Traffic Safety Administration -

http://www.nhtsa.gov/FARS

1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2

199619971998199920002001200220032004200520062007200820092010201120122013201420152016

29,000

31,000

33,000

35,000

37,000

39,000

41,000

43,000

45,000

Fatalities per 100 Million VMT Fatal crashes Fatalities

Note: There were 

37,133 fatalities in 

2017 (a 0.9% decrease) 2015

2016
Low Cost Safety Improvements

Module 1-11

Percent by Crash Severity

Source: NHTSA National Center for Statistics and Analysis, Traffic Safety Facts 2015 Data, Summary of Motor 

Vehicle Crashes (Early Edition), February 2017

0

10

20

30

40

50

60

70

80

90

100

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Percent of Total Crashes

Police Reported Crashes by Crash Severity and Year, 

2007 – 2016

Fatal Injury Property Damage Only

2015 2016

Low Cost Safety Improvements

Module 1-12

Weather and Light Impacts

Source: National Highway Traffic Safety Administration -

http://www.nhtsa.gov/FARS

0

2000

4000

6000

8000

10000

12000

14000

16000

Normal Rain Snow/Sleet Other/Unknown

Fatal Crashes - 2016

Daylight Dark but Lighted Dark Dawn or Dusk Other/Unknown
Low Cost Safety Improvements

Module 1-13

Roadway or Roadside?

Source: National Highway Traffic Safety Administration -

http://www.nhtsa.gov/FARS

0

2000

4000

6000

8000

10000

12000

14000

Single Vehicle Multiple Vehicles

Fatal Crashes, 2016

On Roadway Off Roadway Shoulder Median Other/Unknown

Low Cost Safety Improvements

Module 1-14

Fatalities by Functional Class

Source: National Highway Traffic Safety Administration -

http://www.nhtsa.gov/FARS

0

5000

10000

15000

20000

Interstate Arterial Collector Local Unknown

Fatalities

2012 2013 2014 2015 2016 2016
Low Cost Safety Improvements

Module 1-15

Rural and Urban Fatalities

Source: NHTSA 2015 Traffic Safety Factors: Rural/Urban Comparison: 

https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812393

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

2012 2013 2014 2015 2016

Fatalities

Rural Urban

2015 2016

Low Cost Safety Improvements

Module 1-16

Rural and Urban Fatality Rates

Source: NHTSA 2015 Traffic Safety Factors: Rural/Urban Comparison: 

https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812393

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2011 2012 2013 2014 2015 2016

Rural Urban

2016 2015 2016
Low Cost Safety Improvements

Module 1-17

Terminology Discussion - Part 1

Which do you use and why?

• Safety

• Safe

• Safer

• More safe

In general, can we make roadways “safe?”

Low Cost Safety Improvements

Module 1-18

Would you like to Play a Game?
Low Cost Safety Improvements

Module 1-19

Exercise

Is this road “safe?” 

Low Cost Safety Improvements

Module 1-20

Exercise

Is this road “safe?” 
Low Cost Safety Improvements

Module 1-21

Exercise

Is this road “safe?” 

Low Cost Safety Improvements

Module 1-22

Exercise

Is this road “safe?” 
Low Cost Safety Improvements

Module 1-23

Terminology Discussion - Part 2

• What is a “low cost” countermeasure?

<$100,000?

<$20,000?

<$5,000?

<$1,000?

• What factors do you think about?

• LCSIs can also be the “70%” solution

until the big fix comes along

Low Cost Safety Improvements

Module 1-24

Exercise

What are some LCSIs?

Discussion
Low Cost Safety Improvements

Module 1-25

Terminology Discussion – Part 3

• Nominal Safety

• Do the design or design elements

meet minimum design criteria

• National or state standards and

guidance documents

• Substantive Safety

• Safety performance of a roadway

(actual or expected)

• Evidence- or data-driven (i.e.,

crash frequency, rates, type,

severity, etc.)

Low Cost Safety Improvements

Module 1-26

Substantive and Nominal Safety

• No direct correlation

• Roadway meeting

minimum design

criteria, may have

higher than

expected crash

experience

• Roadway not

meeting minimum

design criteria may

still function at high

level of safety
Low Cost Safety Improvements

Module 1-27

Example

Nominal Safety – Advance 

Warning Sign + Advisory 

Speed Plaque

Advance Warning Sign + 

Advisory Speed + Chevrons = 

“Safer” = Substantive Safety

Low Cost Safety Improvements

Module 1-28

What’s the Right Choice?

28

Existing Conditions Alternative 1

Alternative 2 Alternative 3
Low Cost Safety Improvements

Module 1-29

What’s the Right Choice?

29

Existing Conditions Alternative 1

Alternative 2 Alternative 3

At 20,000 ADT

26.3 crashes/mile 17.2 crashes/mile

8.6 crashes/mile 4.2 crashes/mile

Low Cost Safety Improvements

Module 1-30

Review Learning Outcomes

• Define and quantify roadway safety in

the United States

• Describe the terminology (or context)

within how you define LCSIs

• Differentiate between nominal and

substantive safety
Low Cost Safety Improvements

Module 1-31

Review Question #1

Approximately, how many times higher is the fatality 

rate in rural areas in comparison to that of urban 

areas?

2x 

Low Cost Safety Improvements

Module 1-32

Review Question #2

Can a roadway have improvements that make it safer, 

more safe, or safe? Pick one or more.

Safer and more safe
Low Cost Safety Improvements

Module 1-33

Review Question #3

This type of safety is met when all required design 

criteria are met?

Nominal Safety 
Low Cost Safety Improvements

Module 2-1

Lesson 2 

Module 2: Safety Data, Analysis & Use

Low Cost Safety Improvements 

Low Cost Safety Improvements

Module 2-2

Learning Outcomes

• Recognize the importance of quality data

• Describe the crash mitigation process

• Select appropriate crash modification factors
Low Cost Safety Improvements

Module 2-3

Safety Data

Name some types of data used to identify 

safety issues

• Crash data

• Traffic volume data

• Roadway data

• Anecdotal data

Low Cost Safety Improvements

Module 2-4

Safety Data Sources

• Statewide crash databases

• Fatality Analysis Reporting System (FARS)

• Motor Carriers Management Information System (MCMIS)

• Crash Outcome Data Evaluation System (CODES)

• NHTSA State Traffic Safety Information (STSI)

https://cdan.nhtsa.gov/stsi.htm#
Low Cost Safety Improvements

Module 2-5

Safety Data Sources

• State roadway inventory data files

• Aerial photography

• Asset management databases

• Vehicle registration databases

• Traffic volume data

• Occupant protection use surveys

• Citation and DUI tracking

• Court records

Low Cost Safety Improvements

Module 2-6

Data on Local Roads

Data on local roads can be collected by:

• Local law enforcement crash reports

• Maintenance/repair reports

• Observing evidence at the site

• Anecdotal from citizens

• Others?
Low Cost Safety Improvements

Module 2-7

Data Quality Measures

• Timeliness

• Accuracy

• Completeness

• Uniformity

• Integration

• Accessibility

Low Cost Safety Improvements

Module 2-8

The six step crash mitigation process

1. Identify Sites

2. Collect Crash Experience

3. Gather Field Conditions

4. Identify Contributing

Factors and

Countermeasures

5. Assess and Select

Countermeasures

6. Implement and Evaluate
Low Cost Safety Improvements

Module 2-9

Step 1: Identify Sites with Potential Safety Problems

Network Screening

1. Conventional

Screening

2. Systemic Screening

Low Cost Safety Improvements

Module 2-10

Conventional Screening

Conventional screening identifies locations with 

safety issues off crash history:

• Crash frequency

• Crash rate

• Equivalent property damage only

2-10
Low Cost Safety Improvements

Module 2-11

Systemic Screening

• Evaluate entire system based on aggregate

crash history to identify high-risk roadway

characteristics correlated with severe crash

types

• Identify improvement locations based on

presence of risk factors

• Improvements are widespread

implementation of low cost safety

Low Cost Safety Improvements

Module 2-12

Systemic Screening

Step 1: Identify Focus Crash Types and Risk Factors

Step 2: Screen and Prioritize Candidate Locations

Look at all locations and use a weighted scoring 

process incorporating risk factors

Location ADT 

>1000

Skew 

angle

In/near 

curve

Lighting 

not 

present

Fatal/ 

Severe 

Injury 

Crashes 

Present

Total

A* * * * * 5

C* * * * 4

B* * 2
Low Cost Safety Improvements

Module 2-13

Conventional 

Screening

• Reactive

• No crashes + risk =

no risk

• Uses site specific

crashes

Systemic 

Screening

• Proactive

• No crashes ≠ no risk

• Uses crashes and

surrogates (risk)

Comparison of Screening

Low Cost Safety Improvements

Module 2-14

The six step crash mitigation process

1. Identify Sites

2. Collect Crash Experience

3. Gather Field Conditions

4. Identify Contributing

Factors and

Countermeasures

5. Assess and Select

Countermeasures

6. Implement and Evaluate
Low Cost Safety Improvements

Module 2-15

Prepare a Crash Diagram

Low Cost Safety Improvements

Module 2-16

Road Safety Audit/Assessment 

• Independent team

• Observe traffic

under conditions

of interest

• Locate potential

safety issues
Low Cost Safety Improvements

Module 2-17

The six step crash mitigation process

1. Identify Sites

2. Collect Crash Experience

3. Gather Field Conditions

4. Identify Contributing

Factors and

Countermeasures

5. Assess and Select

Countermeasures

6. Implement and Evaluate

Low Cost Safety Improvements

Module 2-18

Gather Field Conditions

• Traffic Volume –

Turning Movement,

ADT

• Spot Speeds

• Traffic Conflict Study

• Sight Distance

Evaluation
Low Cost Safety Improvements

Module 2-19

Prepare a Condition Diagram

• Roadway geometry

• Non-motorized facilities

• Traffic control devices

• Land use

• Roadside features

• Sight distance issues

Low Cost Safety Improvements

Module 2-20

The six step crash mitigation process

1. Identify Sites

2. Collect Crash Experience

3. Gather Field Conditions

4. Identify Contributing

Factors and

Countermeasures

5. Assess and Select

Countermeasures

6. Implement and Evaluate
Low Cost Safety Improvements

Module 2-21

Identify Contributing Factors - Example

Low Cost Safety Improvements

Module 2-22

Countermeasure selection

• Crash type

• Location type

• Best practices
Low Cost Safety Improvements

Module 2-23

Countermeasure sources

• Research

• FHWA and NCHRP

publications

• FHWA Office of

Safety Website

• Proven Safety

Countermeasures

• CMF Clearinghouse

Low Cost Safety Improvements

Module 2-24

The six step crash mitigation process

1. Identify Sites

2. Collect Crash Experience

3. Gather Field Conditions

4. Identify Contributing

Factors and

Countermeasures

5. Assess and Select

Countermeasures

6. Implement and Evaluate
Low Cost Safety Improvements

Module 2-25

What is a Crash Modification Factor?

A CMF is a multiplicative factor that indicates the 

proportion of crashes that would be expected after 

implementing a highway safety countermeasure.

• Value < 1.0 -- lower crash frequency

• Value > 1.0 -- increased crash frequency

Low Cost Safety Improvements

Module 2-26

Crash Modification Factor Example

A rural curve had 4 nighttime crashes per year and the 

engineer is thinking of installing chevrons.

• CMF = 0.75

How many crashes are expected in the year following 

installation?

4 ൈ 0.75 ൌ 3 crashes per year
Low Cost Safety Improvements

Module 2-27

Difference Between a CMF and CRF

• Crash Reduction Factors (CRF’s) are generally

referred to as a % reduction that might be

expected

• CRF’s and CMF’s are related as follows:

CRF = 1 – CMF x 100 

• A CRF of 10% = CMF of 0.90

Low Cost Safety Improvements

Module 2-28

How is a CMF used?

• Compare safety consequences among various

alternatives

• Capture the greatest gain with limited funds

• Compare results of new analyses with existing

CMFs to check reasonableness

• Check validity of assumptions in cost-benefit

analyses
Low Cost Safety Improvements

Module 2-29

CMF Clearinghouse

• Structured but

subjective process

• Star quality rating

criteria

(excellent, fair, poor)

1. Study design

2. Sample size

3. Standard error

4. Potential bias

5. Data source

Low Cost Safety Improvements

Module 2-30

Assessing and Choosing CMFs

• Stars

• Area type

• Crash type

• Crash severity

• Study specifics
Low Cost Safety Improvements

Module 2-31

Assessing CMFs

Which CMF 

would one 

choose?

Urban 2 lane site where we want to pave outside 

shoulder

Low Cost Safety Improvements

Module 2-32

Multiple countermeasures

What to do if considering multiple 

countermeasures:

• Look for combination on clearinghouse

• Multiple CMFs together

CMF௖௢௠௕௜௡௘ௗ ൌ CMFଵ ൈ CMFଶ
Low Cost Safety Improvements

Module 2-33

CRFs Presented Today

• Highway Safety Manual

• CMF Clearinghouse

• Additional sources for those not ranked, newer

material

Low Cost Safety Improvements

Module 2-34

Using CMF/CRF to Assess Countermeasures

Contributing factor: Poor delineation at night

Site: Rural curve with no signing and regular pavement 

markings

Which countermeasure would you choose?

Countermeasure CRF Crash Type Crash Severity

Chevrons 25% Nighttime, non intersection All

Raised Pavement Markings 19% Nighttime All
Low Cost Safety Improvements

Module 2-35

The six step crash mitigation process

1. Identify Sites

2. Collect Crash Experience

3. Gather Field Conditions

4. Identify Contributing

Factors and

Countermeasures

5. Assess and Select

Countermeasures

6. Implement and Evaluate

Low Cost Safety Improvements

Module 2-36

Step 6: Implement and Evaluate

• Implement based on available funds

• Evaluate effectiveness

• Economic Analysis

• Crash study

• Speed study
Low Cost Safety Improvements

Module 2-37

Summary

Low Cost Safety Improvements

Module 2-38

Review Learning Outcomes

• Recognize the importance of quality data

• Describe the crash mitigation process

• Select appropriate crash modification factors
Low Cost Safety Improvements

Module 2-39

Review Question 1

Which of the six steps in the crash 

mitigation process involves a site visit? 

3. Gather Field Conditions

Low Cost Safety Improvements

Module 2-40

Review Question 2

True or False?

The CMF with the highest star ranking is always

the best to use.

False
Low Cost Safety Improvements

Module 2-41

Some Resources

Low Cost Safety Improvements

Module 2-42

Some Resources

• FHWA, Systemic Safety Project Selection Tool

• FHWA, Proven Safety Countermeasures

• FHWA, Road Safety Audit Guidelines

• FHWA, Road Safety Audit Guidelines – Prompt

Lists

• FHWA, Tribal Road Safety Audits

• FHWA, Road Safety Audits (RSA)

• Manual of Uniform Traffic Control Devices
Low Cost Safety Improvements

Module 3-1

Background

Module 3: Roadway Curve and Segment 

Safety Improvements

Low Cost Safety Improvements

Low Cost Safety Improvements

Module 3-2

Learning Outcomes

• Define roadway curve and tangent safety in

the U.S.

• Identify/describe some signing and marking

safety improvements for curves and tangents

• Interpret and apply signing and marking

safety improvement crash reduction factors

(CRFs)
Low Cost Safety Improvements

Module 3-3

Roadway Crash Experience

• In 2017:

• 61.1 % (20,942) of total fatal crashes

occurred on the roadway

• 56.7% (11,874) not at an intersection

• 53% of all traffic fatalities from 2014-2016

were roadway departure (vehicle crosses an

edge line, a center line or leaves traveled way)

• Approximately 25% of fatalities on curves

Low Cost Safety Improvements

Module 3-4

Strategies

• Keep vehicles from encroaching into the

opposite lane

• Keep vehicles from encroaching on the roadside

• Minimize the likelihood of crashing into an

oncoming vehicle

• Reduce likelihood of a vehicle leaving its lane

at a curve

• Improve the roadway and driving environment

to better accommodate an aging population

• Reduce the severity of the crash
Low Cost Safety Improvements

Module 3-5

Treatment Categories

Pavement 

Markings Signing Miscellaneous

Low Cost Safety Improvements

Module 3-6

Signing Treatments

• Dynamic speed feedback sign

• Curve warning sign with/without advisory speed

• Doubling up curve warning signs

• Fluorescent sheeting

• Curve warning sign with flashing beacon

• Post mounted delineators

• Reflective barrier delineation

• Arrow signs at horizontal curves

• Traditional and sequential dynamic chevrons
Low Cost Safety Improvements

Module 3-7

Marking Treatments

• Optical speed bars

• In lane pavement markings

• Edgelines

• Centerlines

• Wider lines

• Wet reflective markings

• Raised pavement markings

• Centerline rumble strips

• Bike lanes

Low Cost Safety Improvements

Module 3-8

Miscellaneous Treatments

• Improve friction/skid resistance

• Lighting
Low Cost Safety Improvements

Module 3-9

Signing

Low Cost Safety Improvements

Module 3-10

Dynamic Speed Feedback Signs

Flash or display message when driver is exceeding pre-set 

threshold

Description CRF Crash type Crash severity Area Type Quality

Install dynamic speed 

feedback sign*** 5% All All Rural Curve ★★★★★
Low Cost Safety Improvements

Module 3-11

Dynamic Speed Feedback Signs

Use on tangents:

• Mean speed reduced

0.6 – 5.9 mph

• Saw significant

decreases in those

traveling ≥ 10 & 15 mph

over speed limit

Low Cost Safety Improvements

Module 3-12

Curve Warning Signs

Countermeasure CRF Crash type Crash severity Area Type Quality

Advance static curve 

warning signs*** 30% All Serious Injury, Minor 

Injury

Not 

Specified ★☆☆☆☆
Low Cost Safety Improvements

Module 3-13

Curve Warning Sign with Advisory Speed

Countermeasure CRF Crash type Crash severity Area Type Quality

Install combination 

horizontal alignment/ 

advisory speed signs

13% All Serious Injury, 

Minor Injury Not Specified ★★★☆☆

Low Cost Safety Improvements

Module 3-14

Doubling Up Curve Warning Signs
Low Cost Safety Improvements

Module 3-15

Fluorescent Sheeting on Signs

Countermeasure CRF Crash type Crash 

severity

Area 

Type

Quality

Install new fluorescent curve signs or 

upgrade existing curve signs to 

fluorescent sheeting***

18%

Head on, Nonintersection, Run off 

road, sideswipe

All Rural ★★★★☆

Low Cost Safety Improvements

Module 3-16

Curve Warning Sign with Flashing Beacons

Countermeasure CRF Crash type Crash severity Area Type Quality

Install flashing beacons as 

advance warning*** 30% All All Not 

Specified Not rated
Low Cost Safety Improvements

Module 3-17

Delineation Countermeasures

• Define the roadway operating area

• Define direction and sharpness of curves

• Types of crashes treatments address:

• Run off road

• Head on

• Sideswipe

Low Cost Safety Improvements

Module 3-18

Post Delineators & Post Mounted Delineators

Mixed results on effectiveness
Low Cost Safety Improvements

Module 3-19

Reflective Barrier Delineation

Sheeting

Paint

Reflectors

Low Cost Safety Improvements

Module 3-20

Install Arrow Signs at Horizontal Curves
Low Cost Safety Improvements

Module 3-21

Chevrons

Countermeasure CRF Crash type Crash severity Area Type Quality

Install chevron 

signs on horizontal 

curves***

6% Head on, Non-intersection, Run

off road, Sideswipe All Rural ★★★★☆

22%

Nighttime Head on, Nonintersection, Run off road, 

Sideswipe

All Rural ★★★★☆

Low Cost Safety Improvements

Module 3-22

Sequential Dynamic Chevrons System

• LED lights

illuminate as

the vehicle

passes through

curve

• 58% crash

reduction in

rural areas
Low Cost Safety Improvements

Module 3-23

Additional Signing Countermeasures

• Oversized signs

• Icy curve warning systems

• Full-post reflective treatment to chevron post

• Sign maintenance

Low Cost Safety Improvements

Module 3-24

Pavement Markings
Low Cost Safety Improvements

Module 3-25

Use of Optical Speed Bars

• Mean, median and 85th percentile speed reductions have

been seen (Katz, 2004)

Low Cost Safety Improvements

Module 3-26

In Lane Pavement Markings

Have been found to reduce speeds by 4 mph at rural curves 

(Chrysler and Schrock, 2005).
Low Cost Safety Improvements

Module 3-27

Install Edgeline Markings

Description CRF Crash type Crash severity Area Type Quality

Install edgelines (tangent)*** 6.1% All All Rural ★★★☆☆

Install edgelines (curves)*** 25.9 % All All Rural ★★★☆☆

Low Cost Safety Improvements

Module 3-28

Install Centerline Markings

Description CRF Crash type Crash severity Area Type Quality

Place centerline markings 1.0% All Serious injury, 

Minor injury Rural ★★★☆☆

Place edgeline and centerline 

markings 24.0% All Fatal, Serious 

injury, Minor injury Rural ★★★★☆
Low Cost Safety Improvements

Module 3-29

Install Wider Striping

Description CRF Crash type Crash severity Area Type Quality

Install wider edgelines 

(4 in to 6 in)*** 36.5% All Fatal, Serious 

injury, Minor injury Rural ★★★★☆

Install wider edgelines 

(4 in to 5 in)*** 37.7% All Fatal, Serious 

injury, Minor injury Rural ★★★☆☆

Place wide (8 inches)

edgeline markings -5% All Serious Injury, Minor 

Injury Rural ★★★☆☆

4-inch Width 6-inch Width

Low Cost Safety Improvements

Module 3-30

Upgrade to Wet-reflective Pavement Markings

• Paint, tape, or thermoplastic material

• Improve level of retroreflectivity during wet road surface

conditions

Description CRF Crash type Crash severity Area Type Quality

Upgrade existing markings to wetreflective markings*** 31.5% Wet Road All Not specified ★★★★☆
Low Cost Safety Improvements

Module 3-31

Install Raised Pavement Markers

Description CRF Crash type Crash severity Area Type Quality

Install raised pavement 

markers*** 19% Nighttime All Rural ★★☆☆☆

Install snowplowable, 

permanent raised pavement 

markers

-13% Nighttime All Rural ★★★☆☆

Low Cost Safety Improvements

Module 3-32

Install Centerline Rumble Strips

Description CRF Crash type Crash severity Area Type Quality

Install centerline rumble 

strips 21.0% Head on, Sideswipe Serious injury, 

Minor injury Rural ★★★★☆

Install centerline rumble 

strips*** 37.0% Head on, Sideswipe All Rural ★★★★★
Low Cost Safety Improvements

Module 3-33

Bike Lanes

Description CRF Crash type Crash severity Area Type Quality

Install cycle tracks, bike lanes 

or on-street cycling*** 73% Vehicle/bicycle Serious, minor or 

possible injury Urban ★★★☆☆

Install bicycle lanes*** 60% Vehicle/bicycle Fatal, serious, minor

or possible injury Urban ★★☆☆☆

Install bicycle lanes*** -5% All All Urban ★★★☆☆

Low Cost Safety Improvements

Module 3-34

Additional Marking Countermeasures

• Profiled thermoplastic markings

• Narrow painted median

• Smooth lane narrowing

• High visibility crosswalks
Low Cost Safety Improvements

Module 3-35

Miscellaneous

Low Cost Safety Improvements

Module 3-36

Improved Friction/ Skid Resistance

Description CRF Crash

type

Crash severity Area 

Type

Quality

Improve pavement friction 

(increase skid resistance)*** 65.4 Wet road All Rural ★★★★☆

Improve pavement friction (HFS 

- High Friction Surface)*** 51.9 Wet road All All ★★★★☆ Accident Risk (accidents per 108 veh-km)

• Not necessarily

high friction

• May be epoxybased or chip seals
Low Cost Safety Improvements

Module 3-37

Lighting

Description CRF Crash type Crash severity Area Type Quality

Provide highway lighting 28% Nighttime Serious/Minor 

Injury All ★★★★☆

Install lighting *** 49% Nighttime Fatal All ★★★☆☆

Low Cost Safety Improvements

Module 3-38

Review Learning Outcomes

• Define roadway curve and tangent safety in

the U.S.

• Identify/describe some signing and marking

safety improvements for curves and tangents

• Interpret and apply signing and marking

safety improvement crash reduction factors

(CRFs)
Low Cost Safety Improvements

Module 3-39

Review Question #1

Which of these crash types do delineation 

countermeasures target?

a) Run off road

b) Sideswipe

c) Head on

d) All of the above

Low Cost Safety Improvements

Module 3-40

Review Question #2

Name at least one countermeasure that can 

help improve safety during wet conditions.

• Improving friction/skid resistance

• Raised pavement markings

• Wet reflective pavement markings
Low Cost Safety Improvements

Module 3-41

Resources #1

• Manual on Uniform Traffic Control

Devices (MUTCD)

• FHWA Office of Safety Website

• FHWA, Low Cost Treatments for

Horizontal Curve Safety

• FHWA, Roadway Departure Safety –

A Manual for Local Road Owners

• Toolbox of Countermeasures and

their Potential Effectiveness for

Roadway Departure Crashes

Low Cost Safety Improvements

Module 3-42

Resources #2

• Toolbox of Countermeasure for

Rural Two Lane Curves (CTRE)

• Speed Management Toolbox for

Rural Communities (CTRE)

• FHWA, Good Practices:

Incorporating Safety into

Resurfacing and Restoration

Projects

• ATTSA and NACE – Low Cost Local

Road Safety Solutions
Low Cost Safety Improvements

Module 4 - 1

Module 4: Roadsides

Low Cost Safety Improvements

Low Cost Safety Improvements

Module 4 - 2

Learning Outcomes

• Define the scope of the roadway departure

safety issue in the U.S.

• Identify/describe some safety

improvements and strategies that address

roadside safety

• Interpret and apply the crash reduction

potential of different treatment strategies

related to roadside safety
Low Cost Safety Improvements

Module 4 - 3

Scope of the Issue

• Roadway departure crashes typically account for

more than 50% of all roadway fatalities

• Average of 18,779 (53% of total) roadway departure

fatalities from 2014-2016

Low Cost Safety Improvements

Module 4 - 4

Some Reasons for Roadway Departure

• Adverse roadway conditions

• Collision avoidance

• Vehicle malfunction

• Driver error

• Distractions

• Others?
Low Cost Safety Improvements

Module 4 - 5

Rural Percentages of Top Three

Low Cost Safety Improvements

Module 4 - 6

Driver Limitations

Driver’s make mistakes because of human physical, 

perceptive, and cognitive limitations
Low Cost Safety Improvements

Module 4 - 7

Some Typical Roadside Hazards

• Edge drop off

• Trees

• Utility and light poles

• Sign posts and mailboxes

• Rocks and boulders

• Ditches

• Drainage features and facilities

• Steep slopes

• Others?

Low Cost Safety Improvements

Module 4 - 8

Examples
Low Cost Safety Improvements

Module 4 - 9

General Methods to Address Hazards

• Remove

• Redesign

• Relocate

• Reduce severity

• Shield

• Delineate

Low Cost Safety Improvements

Module 4 - 10

Some Treatments We Will Discuss

• Reduce edge drop

• Add a safety edge

• Paved shoulders

• Shoulder rumble strips and edgeline stripes

• Clear zone

• Flattening slopes

• Clear/relocate/replace obstacles

• Hazardous trees

• Utility poles

• Non-crashworthy sign supports and mailboxes

• Adjust drainage features

• Change/install guardrail

• Sidewalks
Low Cost Safety Improvements

Module 4 - 11

Reduce Edge Drop

• AAA Study (2006)

suggests drop off

becomes

problematic

between 2.25 and

2.5 inches.

• Matches well with

typical 2 inch

maintenance

thresholds

• May be a

relationship below

this height but not

detected in this

study

Low Cost Safety Improvements

Module 4 - 12

Add a Safety Edge

Helps errant vehicles to maintain stability, and more 

reliably gain re-entry

Countermeasure CRF Crash type Crash severity Area Type Quality

Install safety edge treatment*** 6.5% All All Rural ★★★★☆

Install safety edge treatment*** 9.1% Run off road All Rural ★★★★☆
Low Cost Safety Improvements

Module 4 - 13

Paved Shoulders

Countermeasure CRF Crash type Crash severity Area Type Quality

Pave shoulder*** 18% Fixed object, head on, 

run off road, sideswipe

Serious injury, minor 

injury Rural ★★★★☆

Low-Cost Treatments for Horizontal Curve Safety – 2016

Low Cost Safety Improvements

Module 4 - 14

Install Shoulder Rumble Strips

Countermeasure CRF Crash type Crash severity Area Type Quality

Install shoulder 

rumble strips*** 16% Run off road All Rural ★★★★★

Install shoulder 

rumble strips*** 36% Run off road Fatal, Serious

Injury, Minor Injury Rural ★★★★★
Low Cost Safety Improvements

Module 4 - 15

Rumble Stripes (Edgeline)

Countermeasure CRF Crash

type

Crash severity Area Type Quality

Install edgeline rumble strips*** 33% Run off 

road

Fatal, Serious 

Injury, Minor Injury Rural ★★★★☆

Install edgeline rumble strips 

on roadways with a shoulder 

width less than 5 feet***

47% Run off 

road

Fatal, Serious 

Injury, Minor Injury Rural ★★★☆☆

Low Cost Safety Improvements

Module 4 - 16

Rumble Stripes (Combo)

Countermeasure CRF Crash type Crash severity Area 

Type

Quality

Install shoulder rumble 

stripe, widen shoulder 

from 0 to 2 feet, and 

pavement resurface***

12.3% Head on, run off

road All Rural ★★★☆☆

Install shoulder rumble 

stripe, widen shoulder 

from 0 to 2 feet, and 

pavement resurface***

27.1% Head on, run off

road

Fatal, Serious 

Injury, Minor 

Injury

Rural ★★★☆☆
Low Cost Safety Improvements

Module 4 - 17

Clear Zone - General

The unobstructed, traversable area provided beyond 

the edge of the through traveled way for the recovery 

of errant vehicles.

Countermeasure CRF Crash type Crash severity Area Type Quality

Increase distance to

roadside features 

(3.3 to 16.7 ft) 

22% All All Rural ★★★★★

Increase distance to

roadside features 

(16.7 to 30.0 ft) 

44% All All Rural ★★★☆☆

Low Cost Safety Improvements

Module 4 - 18

Flatten Slopes

Traversable Slope

Countermeasure CRF Crash type Crash severity Area Type Quality

Flatten slopes from 1V:3H 

to 1V:4H*** 42% All Serious injury, 

minor injury Rural ★★★★★

Flatten slopes from 1V:4H 

to 1V:6H*** 22% All Serious injury, 

minor injury Rural ★★★★★
Low Cost Safety Improvements

Module 4 - 19

Flatten Slopes

Low Cost Safety Improvements

Module 4 - 20

Clearing/Relocating Obstacles
Low Cost Safety Improvements

Module 4 - 21

Remove Hazardous Trees

• NCHRP 500 Volume 3: A

Guide for Addressing

Collisions with Trees in

Hazardous Locations

• Noteworthy Practices:

Roadside Tree and Utility

Pole Management (2016)

• Highway Safety and Trees:

The Delicate Balance

(Video and brochure)

Low Cost Safety Improvements

Module 4 - 22

Relocate Utility Poles #1

• Two 3-Star CMFs exists

for change in:

• lateral offset of utility

poles***

• longitudinal density of

utility poles***

• CMFs vary by the offset

and density change

• Study concluded that

offset impacts are

larger than spacing
Low Cost Safety Improvements

Module 4 - 23

Relocate Utility Poles #2

Source – NCHRP 440 (originally Zegeer and Parker, 1984)

0.4 1.2 2.0

Low Cost Safety Improvements

Module 4 - 24

Replace/Relocate Non-Crashworthy Sign Supports

Bad Example

Breakaway sign supports, mailboxes and delineators that have a FHWA 

Eligibility Letter are on the FHWA Office of Safety website
Low Cost Safety Improvements

Module 4 - 25

Replace/Relocate Mailboxes

Non-conforming

Non-conforming

Conforming

Low Cost Safety Improvements

Module 4 - 26

Adjust Drainage Features #1

Cross drainage features Parallel drainage features
Low Cost Safety Improvements

Module 4 - 27

Adjust Drainage Features #2

Low Cost Safety Improvements

Module 4 - 28

Change/Install Guardrail

Used to shield 

roadside hazards

Countermeasure CRF Crash type Crash severity Area Type Quality

Change Barrier 

along Embankment 

to Less Rigid Type

32% Run off Road Serious injury, minor 

injury

Not 

specified ★★★★★

New Guardrail along 

Embankment*** 47% Run off Road Serious injury, minor 

injury

Not 

specified

★★★★★

Install W-Beam

Guardrail*** 11% Run off Road Fatal, serious injury,

minor injury Rural ★★★★☆
Low Cost Safety Improvements

Module 4 - 29

Sidewalks

• Help to separate

pedestrians and

vehicles

• Survey of State DOTs

found they used a

reduction in

vehicle/pedestrian

crashes of 65-89%.

Low Cost Safety Improvements

Module 4 - 30

Learning Outcomes Revisited

• Define the scope of the roadway departure

safety issue in the U.S.

• Identify/describe some safety improvements

and strategies that address roadside safety

• Interpret and apply the crash reduction

potential of different treatment strategies

related to roadside safety
Low Cost Safety Improvements

Module 4 - 31

Review Question 1

What are the six options the Roadside 

Design Guide generally provides to 

address roadside obstacles?

• Remove

• Redesign

• Relocate

• Reduce severity

• Shield

• Delineate

Low Cost Safety Improvements

Module 4 - 32

Review Question 2

What are some of the roadside features 

that can present a hazard to vehicles if 

they have left the roadway?

• Pavement edge or shoulder drop off

• Slopes

• Trees

• Utility poles

• Mailboxes

• Non-Crashworthy sign supports

• Drainage features
Low Cost Safety Improvements

Module 4 - 33

Some Resources

• Roadside Design Guide (2011)

• Highway Safety Manual (2010)

• CMF Clearinghouse (www.cmfclearinghouse.org)

• State of The Practice for Shoulder and Center Line

Rumble Strip Implementation on Non-Freeway

Facilities (2017)

• NCHRP 440 – Accident Mitigation Guide for

Congested Rural Two-Lane Highways (2000)

• NCHRP 500 – Volumes 3 (trees, 2003)), 6 (run-offthe-road, 2003), and 8 (utility poles, 2004)

• Low-Cost Treatments for Horizontal Curve Safety

2016
Low Cost Safety Improvements

Module 5 - 1

Module 5: Unsignalized Intersections

Low Cost Safety Improvements

Low Cost Safety Improvements

Module 5 - 2

Learning Outcomes

• Define unsignalized intersection safety in the

U.S.

• Identify/describe some safety improvements

for unsignalized intersections

• Interpret and apply unsignalized intersection

safety improvement crash reduction factors

(CRFs)
Low Cost Safety Improvements

Module 5 - 3

U.S. Fatalities - 2016

• 37,461 total fatalities in U.S.

• 10,267 total intersection fatalities (27.4%)

• 7,122 unsignalized intersection fatalities (69%

of all intersection fatalities)

• 985 pedestrian fatalities

• 200 bicyclist fatalities

• About 19% of all roadway fatalities happened

at unsignalized intersections (2016)

Source: 2014 Fatal Accident Reporting System (FARS)

Low Cost Safety Improvements

Module 5 - 4

Predominant Crash Types

• Rear end

• Angle and turning

• Sideswipe

• Pedestrian/bicyclist
Low Cost Safety Improvements

Module 5 - 5

General Characteristics

• Complex locations

• Crossing movements

• Turning movement

• Merging/diverging movements

• Multiple users

• Autos/Trucks/Buses

• Pedestrian

• Bicyclists

• Traffic control

• Uncontrolled

• Yield

• Stop (two-way and all-way)

• Configurations: Three, four, and more legs

Low Cost Safety Improvements

Module 5 - 6

Configurations and Crashes

• Collision rates at 4-

leg intersections are

1.2 to 1.6 times

those at 3-leg

• Safety of offset 3-leg

intersection

increases as minor

road traffic

increases
Low Cost Safety Improvements

Module 5 - 7

In the HSM the CMF for this 

conversion is related to the 

Minor Street Traffic 

Expected safety improves as 

the percentage of minor street 

traffic increases

Countermeasure CRF Crash type Crash severity Area Type Quality

Convert 4-leg intersection

into two 3-leg intersections 25.0% All Serious injury, 

Minor injury Urban ★★★★☆

Converting a 4-Leg to Two 3-Leg Intersections

Low Cost Safety Improvements

Module 5 - 8

Other Treatments We Will Discuss

• Minor road to all way

stop control

• Roundabouts

• Reduced Left Turn

Conflict Intersections

• Turn lanes

• Change skew angle

• Oversized stop signs

• Double stop signs

• Enhanced signing and

delineation

• Increase stop sign

retroreflectivity

• Flashing LED stop sign

• Flashing beacons

• Intersection collision

warning systems

• Transverse rumble strips

• Intersection lighting

• Improve sight distance

• Pedestrian Refuge
Low Cost Safety Improvements

Module 5 - 9

Convert Minor Road to All-Way Stop Control

• Can reduce right-angle and

turning crashes

• Suitable at moderate volumes

and relatively balanced volume

intersections

• Be selective, look at crash

patterns, and consider delay

impact

Countermeasure CRF Crash type Crash severity Area Type Quality

Minor road stop to all-way stop 75.0% Angle All Urban ★★★★★

Minor road stop to all-way stop 48.0% All All Rural ★★★★★

Low Cost Safety Improvements

Module 5 - 10

Roundabouts

Countermeasure CRF Crash type Crash severity Area Type Quality

Convert intersection with 

minor-road stop control to 

modern roundabout

71.0% All All Rural ★★★★★

Convert intersection with 

minor-road stop control to 

modern roundabout

82.0% All Serious injury, 

Minor injury Rural ★★★★★

Convert high speed rural***

intersection to roundabout 87.0% All Serious injury, 

Minor injury Rural ★★★★☆
Low Cost Safety Improvements

Module 5 - 11

Reduced Left Turn Conflict Intersections #1

• Restricted Crossing U-turn (RCUT) aka J Turn or superstreet

intersection

Countermeasure CRF Crash type Crash severity Area Type Quality

Install J-Turn 

intersection*** 34.8 All All Rural ★★★★☆

Install J-Turn 

intersection*** 53.7 All

Major injury, 

minor injury, 

possible injury

Rural ★★★☆☆

Low Cost Safety Improvements

Module 5 - 12

Reduced Left Turn Conflict Intersections #2

• Median U-Turn aka Michigan left or Thru-Turn Intersection

• 30% reduction in injury related crashes (Jagannathan

2007)
Low Cost Safety Improvements

Module 5 - 13

Left Turn Lanes

• Reduce conflicts between

turning vehicle and following

vehicles

• Can reduce rear-end (major

road), right-angle, and

opposing left turn crashes

Countermeasure CRF Crash type Crash severity Area Type Quality

Provide a left-turn lane on one 

major-road approach 44% All All Rural ★★★★☆

Provide a left-turn lane on both 

major-road approaches 48% All All Rural ★★★★★

Low Cost Safety Improvements

Module 5 - 14

Right Turn Lanes

• Provide storage and

deceleration area

• Reduce conflicts between

turning vehicle and

following vehicles

• Improve operational

performance

Countermeasure CRF Crash type Crash severity Area Type Quality

Install right-turn lane on one 

major road approaches 14% All All All ★★★★☆

Install right-turn lane on both 

major road approaches 26% All All All ★★★★☆
Low Cost Safety Improvements

Module 5 - 15

Offset Left Turn lanes

• Improves intersection sight

distance (left-turn)

• Can help with gap

judgement

Countermeasure CRF Crash type Crash severity Area Type Quality

Install positive offset left 

turn lanes*** 78% Left-turn,

Rear end All Rural ★★☆☆☆

Install positive offset left 

turn lanes*** 50% All All Rural ★★☆☆☆

Low Cost Safety Improvements

Module 5 - 16

Offset Right Turn lanes

Improve minor street traffic sight distance 

Countermeasure CRF Crash type Crash severity Area Type Quality

Install offset right-turn 

lane*** 69.0% Angle All Rural ★★☆☆☆
Low Cost Safety Improvements

Module 5 - 17

Improve Turn Lane Angle

Countermeasure CRF Crash type Crash severity Area Type Quality

Improve angle of channelized 

right turn lane*** 60.3% Right turn, Other All Not 

specified ★★★★☆

Improve angle of channelized 

right turn lane*** 44.2% All All Not 

specified ★★★★☆

Low Cost Safety Improvements

Module 5 - 18

Change Skew Angle

Countermeasure CMF Crash type Crash severity Area Type Quality

Change intersection 

skew angle e0.0054ሺ∆skew angleሻ All All Rural Cannot 

be rated (HSM)

CMF Varies with Difference in Angle
Low Cost Safety Improvements

Module 5 - 19

Enhanced Signing and Delineation

Low Cost Safety Enhancements for Stop-Controlled and 

Signalized Intersections (2009) – Basic Countermeasures

Countermeasure CRF Crash type Crash severity Area Type Quality

Implement systemic 

signing and marking 

improvements at stopcontrolled 

intersections***

10.1% All Fatal, Major Injury, Minor 

Injury, & Possible Injury All ★★★★☆

14.7% Nighttime All All ★★★★☆

Low Cost Safety Improvements

Module 5 - 20

Oversized Stop Sign

A study based on surveys of DOTs found a 

crash reduction of 19%
Low Cost Safety Improvements

Module 5 - 21

Double Stop Sign

11% reduction in all crashes (FHWA Issue Brief #8) but can’t be ranked

Countermeasure CRF Crash type Crash severity Area Type Quality

Install double stop signs*** 55% Angle All Urban ★☆☆☆☆

Low Cost Safety Improvements

Module 5 - 22

Increased Retroreflectivity

Countermeasure CRF Crash type Crash severity Area Type Quality

Increase retroreflectivity 

of stop signs*** 7.6% Angle All All ★★★★☆

Increase retroreflectivity 

of stop signs*** 17.5% Rear end All All ★★★★☆
Low Cost Safety Improvements

Module 5 - 23

Flashing Beacons

• Reinforce driver awareness

of the stop sign

• May help to mitigate

patterns of right-angle

crashes related to stop sign

violations

Countermeasure CRF Crash type Crash severity Area Type Quality

Flashing beacon at stop 

controlled intersection 16% Angle All Rural ★★★★☆

Low Cost Safety Improvements

Module 5 - 24

LED Stop Signs

Countermeasure CRF Crash type Crash severity Area Type Quality

Replace standard stop sign

with flashing LED stop sign*** 41.5% Angle All Not specified ★★★☆☆
Low Cost Safety Improvements

Module 5 - 25

Intersection Conflict Warning Systems

Warns drivers on minor 

or major road that 

traffic is approaching 

the intersection on 

other approaches when 

sign is flashing

Countermeasure CRF Crash type Crash severity Area Type Quality

Install ICWS for two-lane at 

two-lane intersection*** 27% All All Rural ★★★★★

Install ICWS for two-lane at 

two-lane intersection*** 30% All Serious Injury, 

Minor injury Rural ★★★★★

Install ICWS for two-lane at 

two-lane intersection*** 20% Angle All Rural ★★★★★

Low Cost Safety Improvements

Module 5 - 26

Transverse Rumble Strips

• Appropriate on stop-controlled

approaches to rural

intersections where crash data

show control is not currently

being recognized

• 2015 study found reductions of

37% (3 leg) and 29% (4 leg) for

fatal and injury crashes.

Greatest reduction seen for

rear end crashes.

Countermeasure CRF Crash type Crash severity Area Type Quality

Install transverse rumble strips on stop 

control approaches in rural areas*** 21.5% All Fatal, 

Serious injury Rural ★★★★★

Install transverse rumble strips on stop

control approaches in rural areas*** -19.1% All PDO Rural ★★★★☆
Low Cost Safety Improvements

Module 5 - 27

Intersection Lighting

• Install at intersections

with a pattern of

nighttime crashes

• rear-end

• right-angle

• turning crashes

Countermeasure CRF Crash type Crash severity Area Type Quality

Provide intersection 

illumination 38% Nighttime Serious injury, 

minor injury Not specified ★★★★☆

Provide intersection

illumination 42% Nighttime,

Vehicle/Pedestrian

Serious injury, 

minor injury Not specified ★★★★☆

Install intersection 

lighting*** 11.9% Nighttime All Not specified ★★★☆☆

Low Cost Safety Improvements

Module 5 - 28

Improve Sight Distance

• Remove obstructions and maintain sight triangles

• Past work experts indicated 5% decrease in crashes for

fixing each deficient quadrant
Low Cost Safety Improvements

Module 5 - 29

NCHRP Research Report 875

Guidance for Evaluating the Safety Impacts of 

Intersection Sight Distance (2018)

Low Cost Safety Improvements

Module 5 - 30

Pedestrian Refuge

Countermeasure CRF Crash type Crash severity Area Type Quality

Install raised median with marked 

crosswalk (uncontrolled)*** 46% Vehicle/

Pedestrian All Urban and 

suburban ★★★☆☆

Install raised median with or 

without marked crosswalk

(uncontrolled)***

31.5% Vehicle/

Pedestrian All Urban and 

suburban ★★★☆☆

Install raised median with or 

without marked crosswalk

(uncontrolled)***

25.9% Rear end,

sideswipe

All Urban and 

suburban ★★★★☆
Low Cost Safety Improvements

Module 5 - 31

Some Other Treatments

• Sign maintenance

• Access management

• Advanced warning

signs

• Stop bar addition and

location

• Pavement marking

messages

• Addition of splitter

islands on minor

approach

• Turn acceleration

lanes

• Eliminate turning

maneuvers

• Convert 3-Leg offset

intersections to 4-leg

• Shoulder widening

Low Cost Safety Improvements

Module 5 - 32

Learning Outcomes Revisited

• Define unsignalized intersection safety in

the U.S.

• Identify/describe some safety

improvements for unsignalized

intersections

• Interpret and apply unsignalized

intersection safety improvement crash

reduction factors (CRFs)
Low Cost Safety Improvements

Module 5 - 33

Review Question 1

About what percentage of fatalities occur at 

unsignalized intersections?

20%

Low Cost Safety Improvements

Module 5 - 34

Review Question 2

Name 3 treatments that might be used to make 

the driver more aware of the need to stop?

• LED stop sign

• Increase retroreflectivity

• Double up stop signs

• Install oversized stop sign

• Transverse rumble strips
Low Cost Safety Improvements

Module 5 - 35

Resources #1

• Highway Safety Manual – Chapter 14 (2010)

• Crash Modification Factors Clearinghouse

• Intersection Safety, A Manual for Local Rural

Road Owners (2011)

• Manual for Selecting Safety Improvements on

High Risk Rural Roads (2014)

• Low-Cost Safety Enhancements for StopControlled and Signalized Intersections (2009)

Low Cost Safety Improvements

Module 5 - 36

Resources #2

• Unsignalized Intersection Information Guide

(www.ite.org/uiig/)

• NCHRP Report 500 / Volume 5: A Guide for

Addressing Unsignalized Intersection Collisions

(2003)

• Issue Brief #8 – Toolbox of Countermeasures and

Their Potential Effectiveness for Intersection

Crashes (2009)

• Objectives and Strategies for Improving Safety at

Unsignalized and Signalized Intersections
Low Cost Safety Improvements

Module 6-1

Module 6: Unsignalized Intersection Exercise

Low Cost Safety Improvements

Low Cost Safety Improvements

Module 6-2

Learning Outcomes

At the end of this lesson, you will be able to:

1. Analyze crash and visual data

2. Evaluate unsignalized intersections for safety concerns

3. Evaluate potential low cost safety improvement(s) to

improve unsignalized intersection safety.
Low Cost Safety Improvements

Module 6-3

Background Information on Site

• Two-way stop controlled intersection

• History of intersection related crashes during

the last 5 years

Low Cost Safety Improvements

Module 6-4

Exercise Goals

Utilize aerial views, approach views, crash diagram 

and crash summaries to:

1. Determine the types of crashes that are most typical at

the unsignalized intersection

2. Determine potential safety issues at the unsignalized

intersection

3. Determine additional data that may be helpful in

identifying issue

4. List potential low cost safety improvement(s) which may

be appropriate to help address the safety issue(s)

5. Discuss how you might prioritize the low cost safety

improvement(s) suggested
Low Cost Safety Improvements

Module 6-5

Aerial View

Low Cost Safety Improvements

Module 6-6

West Approach to Intersection
Low Cost Safety Improvements

Module 6-7

North Approach to Intersection

Low Cost Safety Improvements

Module 6-8

East Approach to Intersection
Low Cost Safety Improvements

Module 6-9

South Approach to Intersection

Low Cost Safety Improvements

Module 6-10

Crash Diagram

Crash 

History

2011-2013
Low Cost Safety Improvements

Module 6-11

Crash History

Manner of Impact

Rear‐end 3 42.85%

Angle, oncoming left turn 2 28.55%

Broadside (front to side) 1 14.3%

Sideswipe, same direction 1 14.3%

Surface Condition

Dry 6 85.7%

Wet 1 14.3%

Crash Severity

Minor Injury 3 42.85%

Possible Injury 1 14.3%

Property Damage Only 3 42.85%

Alcohol Involved

No 7 100%

Yes 0 0%

Major Cause

FTYROW: Making left turn 2 28.55%

Crossed centerline (undivided) 1 14.3%

Followed too close 1 14.3%

Swerving/Evasive Action 2 28.55%

Other 1 14.3%

Low Cost Safety Improvements

Module 6-12

Questions to answer

1. What are the most prevalent types of crashes?

2. What safety issues may be leading to these types of crashes?

3. What other data would be helpful to have?

4. What low cost safety improvement(s) might help address

these issues?

5. How might you prioritize the different countermeasures?
Low Cost Safety Improvements

Module 6-13

Review Learning Outcomes

1. Analyze crash and visual data

2. Evaluate unsignalized intersection for safety concerns

3. Evaluate potential low cost safety improvement(s) to

improve unsignalized intersection safety.