TDOT - Engineering Countermeasures and Treatments

This article summarizes the logic for recommended Countermeasures and Treatments for the Tennessee Department of Transportation.

Written by Greg Olsen
Updated over a week ago

# Countermeasure and Treatment Summary

The following Countermeasures and their associated Treatments will be recommended within Safety Analysis, and can be used as filters in all AASHTOWare Safety applications. The logic for each countermeasure and treatment is documented in the next section.

Click on each Countermeasure or Treatment below to view its associated logic.

# Countermeasures and Treatment Logic

The logic for each Countermeasure, and their associated Treatments are listed below.

## Intersections - Countermeasure

The following logic is used to determine if crashes would be potentially mitigated by the Intersections Countermeasure:

IF

Crash Location = At an Intersection

THEN

Countermeasure Category = Countermeasure: Intersections

## Intersections - Treatments

The following logic is used to determine if crashes would be potentially mitigated by the following treatments:

### Improve Sight Distance -CMF ID 9656

IF

Countermeasure Category = Countermeasure: Intersections

AND

Manner of First Collision = Angle

AND

Traffic Control Type ≠ Signal

THEN

Treatments = Improve Sight Distance -CMF ID 9656

### Traffic Signal (Urban - Angle)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Angle

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type ≠ Signal

AND

Functional Class Starts With (U, Urban)

THEN

Treatments = Traffic Signal (Urban - Angle)

### Traffic Signal (Urban - Rear-End)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision =Rear End

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type ≠ Signal

Functional Class Starts with any of the following (U, Urban)

THEN

Treatments = Traffic Signal (Urban - Rear-End)

### Traffic Signal (Urban - Non-Angle & Rear-End)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Angle, Rear End

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type ≠ Signal

AND

Functional Class Starts with any of the following (U, Urban)

THEN

Treatments = Traffic Signal (Urban - Non-Angle & Rear-End)

### Traffic Signal (Rural - Angle)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Angle

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type = Any of the following (1-Way Stop, 2-Way Stop, All-Way Stop)

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Traffic Signal (Rural - Angle)

### Traffic Signal (Rural - Rear-End)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Rear End

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type = Any of the following (1-Way Stop, 2-Way Stop, All-Way Stop)

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Traffic Signal (Rural - Rear-End)

### Traffic Signal (Rural - Non-Angle & Rear-End)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Rear End

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type = Any of the following (1-Way Stop, 2-Way Stop, All-Way Stop)

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Traffic Signal (Rural - Non-Angle & Rear-End)

### Install J-Turn Intersection -CMF ID 5555

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Any of the following (Angle, Head-on, Sideswipe Same Dir, Sideswipe Opp Dir)

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type = Any of the following (1-Way Stop, 2-Way Stop)

And

Thru Lanes = 4

AND

Operation = 2-Two Way

AND

Feature Type = Median

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Install J-Turn Intersection -CMF ID 5555

### Lighting Conditions (Rural) - At Intersection -CMF ID 10993

IF

Countermeasure Category = Countermeasure: Intersection

AND

Light Conditions = Any of the following (Dark-Not Lighted, Dark-Unknown Lighting)

AND

Traffic Control Type ≠ Signal

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Lighting Conditions (Rural) - At Intersection -CMF ID 10993

### Roundabout (Urban) -CMF ID 209

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Any of the following (Angle, Head-on)

AND

AND

Traffic Control Type = Any of the following (Signal, 1-Way Stop, 2-Way Stop, All Way Stop)

AND

Functional Class Starts with any of the following (U, Urban)

THEN

Treatments = Roundabout (Urban) -CMF ID 209

### Roundabout (Rural) -Stop controlled Intersection into Single-Lane Roundabout CMF ID 207

IF

Countermeasure Category = Countermeasures: Intersection

AND

Manner of First Collision = Any of the following (Angle, Head-on)

AND

Traffic Control Type = All-Way Stop

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Roundabout (Rural) -Stop controlled Intersection into Single-Lane Roundabout CMF ID 207

### Roundabout (Rural) -Convert From Signalized -CMF ID 9157 (A, B, C only)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Type of Crash = Any of the following ((A) Suspected Serious Injury), (B) Suspected Minor Injury, (C) Possible Injury)

AND

Manner of First Collision = Any of the following (Angle, Head-on)

AND

Traffic Control Type = Signal

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Roundabout (Rural) -Convert From Signalized -CMF ID 9157 (A, B, C only)

### Roundabout (Rural) -Convert from Signalized CMF IDs 9156 (Fatal)

IF

Countermeasure Category = Countermeasure: Intersection

AND

Type of Crash = (K) Fatal Injury

AND

Manner of First Collision = Any of the following (Angle, Head-on)

AND

Traffic Control Type = Signal

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Roundabout (Rural) -Convert from Signalized CMF IDs 9156 (K only)

### Roundabout (Rural) -Minor-Road Stop Control to Modern Roundabout CMF ID 229

IF

Countermeasure Category = Countermeasure: Intersection

AND

Manner of First Collision = Any of the following (Angle, Head-on)

AND

Traffic Control Type = Any of the following (1-Way Stop, 2-Way Stop)

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Roundabout (Rural) -Minor-Road Stop Control to Modern Roundabout CMF ID 229

### Adjust Left Turn Phasing -CMF ID 4270

IF

Countermeasure Category = Countermeasure: Intersection

AND

Traffic Control = Signal

AND

Manner of First Collision = Any of the following (Angle, Head-on, Sideswipe Opp Dir)

THEN

Treatments = Adjust Left Turn Phasing -CMF ID 4270

## Pedestrian/Bicyclist - Countermeasure

The following logic is used to determine if crashes would be potentially mitigated by the Pedestrian/Bicyclist Countermeasure:

IF

First Harmful Event = Any of the following (Pedestrian, Pedalcycle)

AND

Functional Class ≠ Any of the following (Urban / Interstate, Rural / Interstate)

THEN

Countermeasure Category = Countermeasures: Pedestrian/Bicyclist

## Pedestrian/Bicyclist - Treatments

The following logic is used to determine if crashes would be potentially mitigated by the treatments below:

### Road Diet - Convert 4-Lane Undivided to 3-Lane w/Bike Lanes -CMF ID 2841

IF

Thru Lanes = 4

AND

Functional Class Starts with any of the following (U, Urban)

AND

Feature Type = Pavement

AND

Feature Width ≥ 38

AND

Manner of First Collision = Any of the following (Head-on, Rear-end)

THEN

Treatments = Road Diet - Convert 4-Lane Undivided to 3-Lane w/Bike Lanes -CMF ID 2841

## Roadway Departure (Rural) - Countermeasure

The following logic is used to determine if crashes would be potentially mitigated by the Roadway Departure (Rural) Countermeasure:

IF

Total Vehicles = 1

AND

Crash Location = Along Roadway

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Relation to First Roadway = Any of the following (Roadside – Left, Roadside – Right, Shoulder, Off Roadway – Location Unknown, Outside Trafficway)

AND

Thru Lanes = 2

AND

Operation = 2-Two Way

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Countermeasure Category = Countermeasure: Roadway Departure (Rural)

## Roadway Departure (Rural) - Treatments

The following logic is used to determine if crashes would be potentially mitigated by the following treatments:

### Roadway and Lane Departure -CMF ID 10613

IF

Countermeasure Category = Roadway Departure (Rural)

THEN

Treatments = Roadway and Lane Departure -CMF ID 10613

### Shoulder Widening (Rural) -CMF ID 6657

IF

Countermeasure Category = Countermeasure: Roadway Departure

AND

Feat Width <25

THEN

Treatments = Shoulder Widening (Rural) -CMF ID 6657

### High Friction - Spot Treatments on 2-Lane Rural Roads -CMF ID 10318

IF

Countermeasure Category = Countermeasure: Roadway Departure

AND

Roadway Surface Conditions = Any of the following (Wet, Snow or Slush, Ice)

AND

Vehicle Maneuver = Negotiating a Curve

THEN

Treatments = High Friction - Spot Treatments on 2-Lane Rural Roads -CMF ID 10318

### Wet Weather Crashes - Resurface Pavement -CMF ID 7271

IF

Countermeasure Category = Countermeasure: Roadway Departure

AND

Roadway Surface Conditions = Any of the following (Wet, Snow or Slush, Ice)

THEN

Treatments = Wet Weather Crashes - Resurface Pavement -CMF ID 7271

## Wildlife Related - Countermeasure

The following logic is used to determine if crashes would be potentially mitigated by the Wildlife Related Countermeasure:

IF

Crash Location = Along Roadway

AND

First Harmful Event = Any of the following (Deer (Animal), Other Animal)

THEN

Countermeasure Category = Countermeasure: Wildlife Related

## Wildlife Related - Treatments

The following logic is used to determine if crashes would be potentially mitigated by the following treatments:

### Wildlife Fencing, Crossing, or Other Treatment

IF

Countermeasure Category = Countermeasure: Wildlife Related

THEN

Treatments = Wildlife Fencing, Crossing, or Other Treatment

## Speed Management - Countermeasure

The following logic is used to determine if crashes would be potentially mitigated by the Speed Management Countermeasure:

IF

Driver Actions = Any of the following (Speed too fast for conditions, Exceeding Posted Speed Limit, Racing)

THEN

Countermeasure Category = Speed Management

## Speed Management - Treatments

The following logic is used to determine if crashes would be potentially mitigated by the following treatments:

### Speed Management

IF

Countermeasure Category = Speed Management

THEN

Treatments = Speed Management

## Treatments with No Associated Countermeasure

The following treatments are available in AASHTOWare Safety, but have no associated Countermeasure.

The following logic is used to determine if crashes would be potentially mitigated by the following treatments:

### Curve Signing or Delineation -CMF ID 10613

IF

Crash Location = Along Roadway

AND

Vehicle Maneuver = Negotiating A Curve

AND

First Harmful Event ≠ Any of the following (Pedestrian, Pedalcycle)

AND

Manner of First Collision = Any of the following (Head-on, Sideswipe Opp Dir)

OR

Relation to First Rodway = Any of the following (Roadside - Left, Roadside - Right, Shoulder, Off Roadway – Location Unknown, Outside Trafficway)

AND

Thru Lanes = 2

AND

Operation = 2-Two Way

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Curve Signing or Delineation -CMF ID 10613

### Enforcement of Drug Impaired Driving

IF

Driver Factors Condition = Any of the following (Had Been Drinking, Illegal Drug Use

OR

Alcohol Involved (Y/N) = Yes

THEN

Treatments = Enforcement of Drug Impaired Driving

### Install Left Turn Lane

IF

Location = At an Intersection

AND

Manner of First Collision = Any of the following (Rear-End, Angle, Sideswipe Opp Dir)

AND

Vehicle Maneuver = Turning Left

THEN

Treatments = Install Left Turn Lane

### Install Right Turn Lane

IF

Location = At an Intersection

AND

Manner of First Collision = Any of the following (Rear-End, Angle, Sideswiep Opp Dir, Sideswipe Same Dir)

AND

Vehicle Maneuver = Any of the following (Turning Right-RTOR Permitting, Turning Right-TROR Permitted Not Known)

THEN

Treatments = Install Right Turn Lane

### Install Sidewalks or Pedestrian Crossings

IF

Crash Location = Any of the following (Along Roadway, At an Intersection)

AND

First Harmful Event = Any of the following (Pedestrian, Pedalcycle)

AND

Feature Composition ≠ Any of the following (Curb & Sidewalk, Curb Gutter & Sidewalk, Sidewalk Only)

THEN

Treatments = Install Sidewalks or Pedestrian Crossings

### Pedestrian & Bicycle - Signalized Locations

IF

First Harmful Event = Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type = Signal

THEN

Treatments = Pedestrian & Bicycle - Signalized Locations

### Pedestrian & Bicycle -Unsignalized Locations

IF

First Harmful Event = Any of the following (Pedestrian, Pedalcycle)

AND

Traffic Control Type ≠ Signal

AND

Functional Class ≠ Any of the following (Urban / Interstate, Rural / Interstate)

THEN

Treatments = Pedestrian & Bicycle -Unsignalized Locations

### Rumble Strips / Stripes -CMF ID 6850

IF

Relation to First Roadway = Any of the following (Roadside - Left, Roadside - Right)

AND

Manner of First Collision = Any of the following (Head-on, Sideswipe Opp Dir)

AND

Thru Lanes = 2

AND

Operation = 2-Two Way

AND

Functional Class Starts with any of the following (R, Rural)

Then

Treatments = Rumble Strips / Stripes -CMF ID 6850

### Lighting Conditions - Along Roadway CMF ID 7776

IF

Crash Location = Along Roadway

AND

Light Conditions = Any of the following (Dark-Not Lighted, Dark-Unknown Lighting)

THEN

Treatments = Lighting Conditions - Along Roadway CMF ID 7776

### Passing Lane (Rural) -CMF ID 10267

IF

Vehicle Maneuver = Passing or Overtaking Another Vehicle

AND

Thru Lanes = 2

AND

Operaton = 2-Two Way

AND

Functional Class Starts with any of the following (R, Rural)

THEN

Treatments = Passing Lane (Rural) -CMF ID 10267

### Install Guardrail (K & A only)

IF

Crash Location = Along Roadway

AND

Thru Lanes ≥ 2

AND

Relation to First Roadway = Any of the following (Roadside - Right, Shoulder, Off Roadway – Location Unknown, Outside Trafficway, Roadside - Left)

AND

Type of Crash = Any of the following ((K) Fatal Injury, (A) Suspected Serious Injury)

THEN

Treatments = Install Guardrail (K & A only)

### Install Guardrail (B, C, & O only)

IF

Crash Location = Along Roadway

AND

Thru Lanes ≥ 2

AND

Relation to First Roadway = Any of the following (Roadside - Right, Shoulder, Off Roadway – Location Unknown, Outside Trafficway

AND

Type of Crash = Any of the following ((B) Suspected Minor Injury, (C) Possible Injury, (O) Property Damage Only (Under), (O) Property Damange Only (Over))

THEN

Treatments = Install Guardrail (B, C, & O only)

### Install Cable or Concrete Barrier; Median

IF

Crash Location = Along Roadway

AND

Manner of First Collision = Any of the following (Head-on, Sideswipe Opp Dir)

OR

Relation to First Roadway = Roadside - Left

AND

Thru Lanes ≥ 4

AND

Operation = 2-Two Way

AND

Feature Type = Median

AND

Functional Class = Any of the following (U/ Interstate, Urban Interstate, R/ Interstate, Rural Interstate, U FWY OR EXP, Urban Freeway or Expressway, R FWY OR EXP, Rural Freeway or Expressway)

THEN

Treatments = Install Cable or Concrete Barrier; Median