The Difference Between NTSB and State Police Investigations

Two major motor vehicle accidents which occurred in the Pittsburgh area in recent days triggered large scale investigations by both the National Transportation Safety Board (NTSB) and the Pennsylvania State Police.  This article will take an inside look at how the NTSB and the State Police investigate major accidents and will highlight certain of the key differences in their procedures and rules.  Some of those differences may surprise you, especially as it relates to public access to their reports and limitations on testimony in lawsuits.

Both accidents occurred in the early morning hours of January 5, 2019. In the first one, a bus headed from New York City to Ohio lost control on a steep downgrade to the Turnpike outside of New Stanton, flipped over and came to rest in the middle of the westbound lanes and was then struck by a pair of tractor-trailers headed in the same direction.  This accident, in which icy weather may have been a factor, involved ejection of passengers, five deaths and scores of injuries ranging from minor to significant.  The second accident, which happened just several minutes later and only ten miles away on Interstate 70 near Smithton, PA, involved an EMS first responder who had just arrived at an accident and was struck and killed by an on-coming vehicle.

Over the years, our office has handled several major trucking cases and aviation accidents (including serving as one of the lead counsel for the plaintiffs in the US Air Flight 427 litigation in the 1990s) which has allowed us to become familiar with the particular investigative practices of the NTSB and the State Police.

The following paragraphs will offer a compare and contrast summary of how these two agencies conduct their investigations.

Scope and Purpose

The NTSB is an independent, stand alone agency created by an Act of Congress in 1974.  It operates out of a Washington, DC headquarters and has a handful of other regional officers throughout the United States.  While they are most often involved with investigating aviation accidents, the NTSB also has jurisdiction over certain railroad, marine and highway accidents.  The agency’s historic role is to determine a probable cause of accidents and then make any necessary safety recommendations to prevent future accidents.  (Some of the motor vehicle safety improvements inspired by NTSB recommendations include the use of graduated driver=s license; use of air bags; and rear-mounted brake lights.)   Given that role, the NTSB usually only investigates major highway accidents which have an element of public interest at stake.  Here,  the bus accident clearly is such a case, and not surprisingly the NTSB was involved within hours of the accident.  The more routine, though no less tragic, fatality involving the EMS responder would not typically lead to NTSB involvement.  The State Police, by contrast, are charged with enforcing laws which regulate operation of motor vehicles on our highways.  Thus, they will investigate both accidents and focus mainly on vehicle operation, all for the purpose of determining whether any criminal charges should be filed, although criminal charges are not likely in the bus accident since most of the involved drivers died in the collision. 

Organization and Structure

An NTSB investigation, at least one involving a major accident,  is initiated by one of the agency’s several go teams, a group of investigators which literally has their bags packed at all times ready to respond to accidents within their jurisdiction.  Once on site, the NTSB team is headed by an individual designated as the Investigator-in-Charge, commonly referred to as the IIC.  Depending on the complexity of the accident, it is then up to the IIC to establish and oversee various working groups which will look at different aspects of the accident.  Common types of working groups include Weather, which obviously focuses on meteorologic conditions having a bearing on the accident; Operations, which focuses on the conduct of the bus and trucking companies; Structures and Maintenance, which focuses on the suitability of the vehicles  for safe driving and whether there was a failure of any operational system; Human Performance, which focuses on driver conduct; and Survival, which focuses on safety features of the vehicles which may be improved to mitigate injury or improve survival.  Each working group is headed by a Chairperson.

The State Police have a different structure to their investigation.  First on the scene would typically be a regular patrol trooper who was dispatched to the accident.  Upon arrival they would initially assess the scene and immediately determine the need for medical assistance and take steps to control traffic. Simultaneously a call would go out for other troopers to assist at the scene in both of those functions, medical management and traffic control, as well as some basic investigation and evidence collection. This would include talking to witnesses and documenting debris and vehicle markings (skid marks, gouges, etc.).

But the critical work to determine the cause of the accident is not done by the regular troopers in any case involving fatalities which may lead to criminal charges. Instead, a special unit of the State Police is called in to assume that responsibility, the Collision Analysis and Reconstruction Specialist, commonly referred to as the ACARS Unit.  There are several such units around the state, and they are headed by state troopers who have specialized training in accident reconstruction.

Data Collection

The NTSB and the State Police both have an interest in many of the same bits of data whereas some evidence will only be of interest to one body.   Here is a very brief list and cursory description of typical data collected.

Documenting the Scene

Both bodies have an interest in documenting the accident scene, e.g. locating, photographing, and securing wreckage, vehicle  resting positions, debris, tire tracks, gouges, and skid marks, etc.  The State Police will shoot the scene with GPS equipment in order to confirm the location of key evidence, and then all of those GPS data points will be input into software which will allow the CARS Unit to produce a scale diagram of the accident scene showing travel path of vehicles and location of key evidence.

Black Box Data

Unlike in an aviation accident, there is no actual black box on trucks, buses or cars.  Instead, they typically have what is referred to as an engine control module (ECM) which tracks and records various bits of operational information or parameters.  There are different types of ECMs made by a host of private companies and the number and type of parameters which any device records can vary.  Most all ECMs will document basic information such as speed, throttle position, brake application, and the like.  Not all ECMs, however, will track other information such as steering inputs.  Once in possession of the ECM, both the State Police and the NTSB will utilize special software needed to download or extract the retained data and print it out into a usable format.

On Board Cameras

In recent years, tractor-trailers, and in some instances buses, are equipped with a variety of hi-tech equipment including forward-looking cameras.  These can provide critical information on the moments preceding a loss of control.

Log Books

Both agencies, particularly the State Police, are interested in obtaining driver log books (actually they are now usually in electronic format rather than paper) to see whether there may be an issue of driver fatigue due to an operator exceeding the allowable number of hours of operation.   Truck drivers have a 14 hour window in which they can drive up to 11 total hours, but no more than 8 consecutively.  Bus drivers, once having been off duty for 8 hours, are permitted 10 hours of total driving, all consecutive if they prefer.

Investigation Participants

Here there is a major difference between the two agencies.  One of the most unique features of an NTSB investigation is their custom of inviting party participation in the investigation, i.e., involvement of select representatives from the parties under investigation, but not their attorneys.  In typical aviation accidents, that might involve representatives of the airline or the company that manufactured the plane, whereas in this recent multi-vehicle Turnpike accident it could involve representatives of the truck or bus companies or the manufacturers.  The long-held philosophy of the NTSB is that party participation gives the agency access to expertise that may help them to decipher accident cause and/or make safety recommendations.  Interestingly, victims or their families are never granted participant status in NTSB investigations.

By contrast, the only people who participate in State Police investigations are State Police personnel.  While they certainly may speak with and obtain statements from involved individuals, those persons or their employers are never granted participant status in the investigation.

Conclusion of Investigation

The conclusion of an NTSB investigation, which may take one to two years to reach,  involves a few final steps.  First, the IIC and their team produce a detailed Factual Report which is often several hundred pages in length and includes reports from each working group.  That report is then submitted to the five person Board of the NTSB for its consideration.   If they deem it necessary, the Board has the power to convene public hearings and call witnesses as it considers the details of the Factual Report.  (In the US Air Flight 427 accident, the NTSB rented out the largest ballroom in downtown Pittsburgh for a week long hearing.) At the conclusion of its work, the Board issues its report and final determination or probable cause of the accident.  That Board report may also make safety recommendation to other public bodies or government agencies.  In the case of aviation accidents, those recommendations are typically made to the Federal Aviation Authority (FAA), and in the case of highway accidents, the recommendations most commonly would be made to the National Highway Traffic Safety Administration.  In the Pittsburgh area bus accident, which involved ejection of passengers, it is anticipated that the NTSB will once again weigh in on the need for seat belts or shoulder harnesses on buses.

The conclusion of a State Police investigation is more narrow and limited.  Within days of the accident, the initial responding trooper and those who assisted immediately at the scene will write their standard form Commonwealth Police Crash Report.  Several months later, the CARS Unit will produce its much more detailed Accident Reconstruction Report which usually reaches a conclusion as to the cause of the accident. 

Public Availability

The NTSB is a fairly transparent federal agency and, thus, most if its investigative work, including the Factual Report as well as the Board Report and its probable cause determination, are available at the agency website.

Access to State Police investigations is more limited.  While the initial Police Crash Report is typically available upon written request, the more detailed and revealing Accident Reconstruction Report is not publicly available and can only be obtained by issuance of a subpoena to the State Police Commissioner.

Use in Civil Litigation

The extent to which parties can obtain and make use of investigations by these agencies in civil litigation is another area of difference.

Whereas the NTSB is more transparent in making its documents available to the public, it is more restrictive than the State Police in making its investigators available to private parties in personal injury litigation.  For example, a private party must go through a strict process with the NTSB’s Office of General Counsel to secure the deposition of any NTSB investigator (49 CFR ‘835.6), and once having done so, in the typical case the investigator is only permitted by statute to answer factual questions; opinions are off limits (49 CFR ‘835.3(b)).  Also, NTSB investigators cannot be called or subpoenaed to appear as witnesses at trial (49 CFR ‘835.5a), the theory being that such  demands would unreasonably encroach on their time and distract them from their investigative duties.  Relevant portions of Factual Reports can be admitted into evidence or cited by privately retained experts, but the NTSB’s conclusion as to probable cause is never admissible.  (49 USC ‘1154(b) and  49 CRF ‘835,2)

As to depositions of state troopers, be they regular patrol officers or members of the CARS unit, they too must be subpoenaed through the Commissioner’s Office in Harrisburg, although the process is not as strict as the NTSB’s.  But during the deposition itself there is no restriction on an attorney’s ability to ask, or the investigator’s authority to answer, opinion questions.  Further, there is no prohibition on State Police personnel appearing as witnesses at trial, and when qualified to do so, they may offer opinion testimony on accident cause.


We trust that this brief article gives the reader at least an introductory appreciation for some of the major features of State Police and NTSB accident investigations, particularly some of the difference between the two agencies and how they do their work; what reports are available to the public; and what restrictions are placed on their investigations’ participation in civil litigation.