Unifying Alabama's Traffic Safety Efforts
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Available Crash Facts Books may be accessed from links  at the bottom of this page.
Crash Facts
Alabama has put out a crash facts book for several decades. Many in the Alabama traffic safety community have used these reports to compare the numbers from year to year. See the article within the 2009 Crash Facts book for reasons that these results should be viewed with considerable caution when making comparisons with previous years. This is mainly due to the transition to eCrash that started in 2009 and is continuing in 2010. Considerations are being made to restructure the 2011 Crash Facts book taking advantage of the enhanced data elements within eCrash.

For the most recent Crash Facts book, Click Here
2010 Data Issues
There are a number of inconsistencies between the data collected within eCrash and that obtained from the paper forms. The deployment of eCrash was on June 1, 2009 for all DPS and some city agencies. Additional cities were added througout the remainder of 2009 and 2010. The purpose of this article is to address these issues so that the users of the Crash Fact Books, the Strategic Highway Safety Plan, the ADECA Highway Safety Plan, or CARE will be able to better interpret data that is found in these documents or produced by CARE.

CHANGES IN INJURY SEVERITY INTERPRETATIONS

The following shows the tremendous disparity between 2009 and 2010 in the reporting of Incapacitatint and Non-Incapacitating injury classifications.

Severity 2009 2010
Fatal 850 862
Incapacitating 15131 10523
Non--Incapcitating 7689 13879
Non Visible ... 12367 13935
Unknown 347 1330
No Injury 285457 288102
TOTAL 321841 328631

The Incapacitating Injury category decreased by 4608, which is about a 30% decrease. At the same time, the Non-Incapacitating category increased ty 6190, which is an increase of over 80%. Those familiar with crash severity statistics will recognize that this types of change in injury severity is not at all realistic. Thus, it is important that those who are using severity statistics understand the reason for this change, which appears to be the result of a change in the interpretation of these categories in the reporting process.

The eCrash system was implemented and was gradually phased in beginning in June 2009. Prior to that the old paper form had the categories in the first column of the table below, while eCrash has the categories in the second column.

Old Paper Form eCrash Equivalents
K-Killed 1-Fatal
A-Visible or Carried from Scene 2-InCapacitating
B-Bruise/Abrasion/Swelling 3-Non-Incapacitating
C-Not Visible by Has Pain/Faints 4-Not Visible but Complains of Pain
99-Unknown 99-Unknown
In 2009, the proportion of eCrash submissions was a little over 29%. The proportion in 2010 rose to close to 85%, so there was a major change in the way in which these codes were not only being entered but apparently the way that they were being interpreted as well.

According to those who were involved in making this coding change, “it was very difficult for a victim to suffer much of an injury without it fitting into the original A category. The new codes allow the officer a better opportunity to differentiate between the old A and B codes.” There is general agreement that the new system is much more accurate and useful.

As far as the use of this data element is concerned, we strongly advise that any injury comparisons over years 2008 through 2011 either combine A and B (1 and 2) or use all three classifications. This will make for a more accurate comparison until we get to a point where all crashes in the databases are reported via eCrash.

Users of eCrash can also click on the field and obtain the manual detail immediately when in this field. This would bring up the following narrative description:

Section 7.5 VICTIM INJURY TYPE from the eCrash Coding Manual

From the definitions given below the codes that follow, enter the injury type to the best of your estimation based on available evidence:

1 -- Fatal Injury
2 -- Incapacitating
3 -- Non-incapacitating
4 -- Not visible but complains of pain
99 -- Unknown Injury

Notes:

1 Fatal. This code will be entered if a victim is pronounced dead at the scene or before the report is completed. If not, one of the other codes will apply. However, if a victim dies later as a result of the crash this code will need to be updated according to the following di-rections. The Department of Public Safety uses a thirty (30) day counting period for traffic fatalities. If a person dies as a result of injuries received in a traffic crash within thirty days of the date of the crash, that victim is considered to be a traffic fatality, and the victim injury type must be updated to Code 1 in this data item. When it is learned that a victim has died after the Crash Report has been sent to the Department of Public Safety: (1) Call the FARS representative with this information at 334-242-4427 AND (2) Follow the normal amendment procedure to amend the eCrash given in Item 1.1.1.

2 Incapacitating. This means that the victim must be carried or otherwise helped from the scene. If the victim needs no help, then either a code 3 or 4 applies even though medical assistance may have been administered at the scene.

3 Non-incapacitating. If the victim has visible signs of injury, either in a physical or mental sense (e.g., had passed out), but is judged able to walk away from the scene without help, this code applies. The difference between this code and code 4 is strictly in the external evidence of injury.

4. Not visible but complains of pain. If the victim complains of pain, but there are no visible signs of it, and he or she is able to walk away from the scene of the crash, then this code applies. There is no code for uninjured, in that uninjured occupants are not to be considered in the victim section. There are no codes allowed for 97 or 98 since if a victim is identified some assessment must be made of the severity of the injury according to the classifications given above.

A code of 99 should only be used if there is a known victim but the severity of their injury is unknown at the time the report is filled out.

Injury Code 1 (Fatal) must be used for a victim that dies within thirty days of the date of the crash as a result of injuries received in the crash (notify the FARS unit for delayed fatalities at 242-4427).

END OF EXCERPT FROM CODING MANUAL
Probability of Being Involved in a Serious Crash
This article is to explain the rationale for the following statement that is made in the 2010 Crash Facts Book:

Based on 2010 data, if you are a typical driver in Alabama, there is greater than a one in three chance that you will be involved in an injury or fatal crash while driving an automobile over your lifetime. The probability of your being in a crash of any severity is greater than 98%. The following web page gives a recent count of the number of licensed drivers in Alabama:

Number of drivers in Alabama = 3,598,034 from the above web site.

Assuming that each crash involves a different driver, the CARE results from Driver-Vehicle dataset are as follows:

Number of drivers involved in injury crash 2010 = 26,978 drivers involved in injury crashes.

This leads to the calculation of the following probabilities:

Pr (crash in one year for any driver) = 26,978/3,598,034 = 0.007498

Pr (any driever not being in an injury crash) = (1-0.007498) = 0.992502

The "driving life" of any driver is estimated to be 60 years (76-16 = 60). This assumes that the average life span of an Alabama driver is 76, and that most will obtain their drivers license at age 16 and retain it for the rest of their lives.

Pr (any driver not being in a crash over 76-16 = 60 years) = 0.992502 ** 60 = 0.636625

Pr (being in a crash over 60 years) = 1 - 646625 = 36%

This is used as the basis for the "greater than a one in three chance," since a one in three chance is 33.33%.

Similar techniques were used to estimate the probability of being in any type of crash over a driver's lifetime.