Attachment J.11 2021 CISS Sampling Stratifcation Rules 26-27 Manual.pdf

Page 20 CISS SAMPLING

2.1.2 Sampling Categories

There are twelve PCR sampling categories used by the CISS. The strata are based on the tow status of the vehicle as described earlier and the injury of the occupants. Each state has different injury classification codes that police use to indicate injury severity, however all can be mapped to the CISS K-A-B-C-O-U scheme. If your state does not use the “KABCOU” scheme, refer to the Occupant Assessment Variable “Injury Severity (Police Rating)” in the NHTSA Crash Investigation Coding and Editing Manual .

Most severe police reported injury is the indication on the police report of injury severity, if any, to any person involved in the CISS crash. Each person's severity should be translated into the KABCO codes, if necessary (see explanation of Occupant Assessment Form variable “Injury Severity” in the NHTSA Field Crash Investigation Coding and Editing Manual ). Only the injury coding boxes on the police report are considered; an injury severity should not be upgraded or downgraded due to additional details in the narrative section. Categorize based only on the injury coding boxes.

An exception would be if the narrative contains a positive indication of death as a direct result of the crash. In this case, the crash would be categorized as a fatal.

An exception would be if the narrative contains a definitive medical statement that a fatality was not impact related, ex. due to disease, illness, medical emergency, then we downgrade K injury to U injury. This should be extremely rare occurrence.

For purposes of categorization, the CISS is hierarchal, based on the model year and occupant injury of towed CISS applicable vehicles.

The reporting process of some states creates a situation where it may be known that a person was injured, but it may NOT be reported in which vehicle the person was an occupant. A similar circumstance may be created by hit and run crashes. If a person is known to be injured, but the vehicle they were in is not known, categorize the crash as if the person were in the oldest model year vehicle involved in the crash.

Police Reported Injury Severity

K = Fatal Injury

A = Incapacitating Injury

B = Non-incapacitating Injury

C = Possible Injury

O = Not Injured

U = Unknown if Injured

Refer to the current NHTSA Field Crash Investigation Coding and Editing Manual / Occupant Injury Form section for state specific injury severity.

Attachment J.11

Page 21 CISS SAMPLING

When categorizing a crash, work from the top category downward on the CISS Sampling - 2021 chart (shown on the following page). Practice question 8 on page 23 provides an example of applying the category hierarchy correctly.

Categories 1-10 require a towed CISS applicable vehicle. The most severe injury is assessed in the towed vehicle(s). If no towed CISS applicable vehicles are present, Category “O” or “N” may apply.

The practice questions on pages 23 and 24 provide clarity on assigning categories correctly.

CISS Category 1 - At least one occupant of towed passenger vehicle received a "K" injury (fatal) in any model year

CISS Category 2 - Crashes not in Category 1 involving: a towed recent model year passenger vehicle in which at least one occupant received an "A” injury.

CISS Category 3 - Crashes not in Category 1 or 2 involving: a towed recent model year passenger vehicle in which at least one occupant received a "B," “C,” or “U” injury.

CISS Category 4 - Crashes not in Category 1-3 involving: a towed recent model year passenger vehicle in which no occupants are injured, “O” injury rating.

CISS Category 5 - Crashes not in Category 1-4 involving: a towed mid-model year passenger vehicle in which at least one occupant received an "A” injury.

CISS Category 6 - Crashes not in Category 1-5 involving: a towed mid-model year passenger vehicle in which at least one occupant received a "B," “C,” or “U” injury.

CISS Category 7 - Crashes not in Category 1-6 involving: a towed mid-model year passenger vehicle in which no occupants are injured, “O” injury rating.

CISS Category 8 - Crashes not in Category 1-7 involving: a towed older model year passenger vehicle in which at least one occupant received an "A” injury.

CISS Category 9 - Crashes not in Category 1-8 involving: a towed older model year passenger vehicle in which at least one occupant received a "B," “C,” or “U” injury.

CISS Category 10 - Crashes not in Category 1-9 involving: a towed older model year passenger vehicle in which no occupants are injured, “O” injury rating.

CISS Category O - Other - All "other" crashes. These are listed, but will not be eligible for selection as a case (not-towed vehicles, heavy truck only crashes, etc.)

CISS Category N - NTS (Non-Traffic Surveillance) A motor vehicle crash off of the trafficway involving an injury, and at least one vehicle designed for the road.