Countermeasures

What is a Countermeasure

A safety countermeasure is any activity undertaken with a goal to prevent crashes or reduce the severity of injuries caused by crashes. There are generally two types of countermeasures:

1. Infrastructure: Infrastructure countermeasures involve physical changes to the roadway, roadway environment, or roadway operations that are targeted to address a specific type of crash or event.

2. Behavioral: Behavioral countermeasures typically involve education, media campaigns, or legislation designed to promote safe behaviors or discourage unsafe behaviors. 

This article focuses primarily on infrastructure countermeasures, with minimal discussion of behavioral countermeasures.

Countermeasure Resources and Fact Sheets

There are several online resources for countermeasure suggestions and information. The following are nationally published and recognized sources.

1. FHWA Proven Safety Countermeasures

   • https://safety.fhwa.dot.gov/provencountermeasures/

2. Bicycle Countermeasure Selection Guidance

   • https://www.pedbikesafe.org/bikesafe/

3. Pedestrian Countermeasure Selection Guidance

   • https://www.pedbikesafe.org/pedsafe/

4. Countermeasures That Work (NHTSA)

   • https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/812478_countermeasures-that-work-a-highway-safety-countermeasures-guide-.pdf

5. NCHRP 500 Series Reports (Available via the UDOT library)

   • https://www.trb.org/Main/Blurbs/152868.aspx

In addition to these resources, UDOT has developed two-page fact sheets to provide information about select countermeasures that are used in Utah. These fact sheets include the following information:

• Key statistics about the countermeasure

• What the countermeasure does

• Why the countermeasure is important

• How effective the countermeasure is

• Project examples and results of where it has been implemented

The fact sheets are intended to help explain these countermeasures to roadway designers, engineers, project managers, public officials, or other project stakeholders. The fact sheets are designed for an audience that is familiar with engineering and transportation principles; they can be shared with anyone who is interested but are not written for a broad public audience.

Searching/Filtering Crashes for Countermeasures

A primary task in crash data analysis is correlating crashes to an applicable countermeasure. This requires filtering crashes based on specific data attributes that are associated with a countermeasure. For example, filtering crashes that include the crash event “ran off road right” is a way to identify crashes where a shoulder rumble strip countermeasure may be appropriate. Due to the complexity of crash data and variety of countermeasure options, this can be a difficult and time-consuming task even for experienced analysts.

To assist with this step, UDOT has created countermeasure rollup fields that apply pre-defined logic to countermeasure identification. Please see the “Rollups” section of the Crash Data Overview article for an explanation of what a rollup field is. These rollup fields use a variety of data rules to allow analysts to quickly identify countermeasures that may be applicable in a specific location or area. Some countermeasure rollup fields also account for existing roadway conditions and assets. For example, if rumble strips are already installed they will not be flagged as a potential countermeasure.

Some countermeasure rollups represent specific mitigations, such as “Left Turn Lane”, “Raised Median”, or “Shoulder Rumble Strips”. Other rollups are less specific, only identifying types of applicable countermeasures such as “Active Transportation Improvements” and “Horizontal Curve Improvements”.

These countermeasure fields jump-start the analysis process by guiding the analysts attention to specific crash trends and potential countermeasure options. However, additional data review is always required. These rollups use pre-defined rules and are therefore not perfect for every situation; after applying a filter the analyst should perform a deeper review to make sure the countermeasure really will be effective for that location. In addition, be aware that there may be additional crashes not captured by the filter that could still be mitigated by that countermeasure. These filters simplify the early steps of analysis, but they do not remove the need for detailed human review.

The link for countermeasure rollup field logic is provided below. These countermeasures are available as filters in UDOT’s AASHTOWare Safety program online (Numetric) for use in crash analysis.

Selecting the Right Countermeasure

Note: This section references benefit-cost analysis and CMF’s, please refer to those articles for an explanation of those concepts.

Identifying a countermeasure that addresses a pattern of crashes does not guarantee that implementing the countermeasure is the best option. Selecting the right countermeasure requires consideration of many factors. At a minimum, the following items should be considered: 

Effectiveness of the Countermeasure

Some countermeasures are considered active measures meaning they provide a level of effectiveness regardless of drivers choices. Examples of this include barriers and high friction surfaces. These countermeasures provide physical benefits in all situations and therefore present a higher likelihood of success and will typically yield a more significant benefit. Other countermeasures are passive and only help the driver to make safer decisions, these measures in themselves will not guarantee any improvement and therefore they are less effective and typically result in lower benefits. Examples of this are signs, rumblestrips, and flashing yellow arrows. These countermeasures provide information to drivers and encourage them to make safe decisions, but they don’t provide protection independently because driver awareness and decision making is still involved.

Cost of the Countermeasure

For each countermeasure the benefit (crash reduction) can be compared to the cost of construction, resulting in a benefit/cost ratio that partially illustrates the value of the proposed countermeasure. When the benefit is high a more expensive countermeasure can be justified, but this will also impact the benefit/cost ratio. The cost of the countermeasure must be considered in order to select a countermeasure appropriate for the situation. The benefit/cost ratio is not the only measure of effectiveness; at times a high cost improvement is required in order to be effective even if it results in a lower benefit/cost ratio. Construction costs can also vary widely based on the location and how familiar contractors are with the proposed countermeasure.

Severity of Crashes

A set of crashes with consistent serious or fatal injury events will likely require a more effective and potentially more expensive countermeasure, but the benefit will also be more significant. A set of low severity crashes will usually not justify a high-cost countermeasure, so typically a less expensive passive countermeasure is more appropriate.

Context

The context of the proposed site must always be considered. For example, a pattern of roadway departure crashes in a suburban area may suggest rumblestrips, but these are not feasible due to noise concerns. Instead sinusoidal rumble strips, shoulder widening, or other options could be considered. Another example is a corridor with a wide variety of crash types. Rather than implementing several different measures there may be broader treatments such as speed management or automated enforcement that may be effective at addressing  multiple unsafe behaviors.