Benefits and Challenges

The Value of Traffic Crash Scene Investigation

The value of thoroughly capturing information at the scene of an auto crash is indisputable.  The possibility of insurance disputes, liability litigation or an investigations by the National Highway Traffic Safety Administration (NHTSA) means that the data gathered at an crash scene can be very valuable. However, it is not always apparent at the time whether the data from a particular crash will be used.  Police and other public safety agencies are therefore left to balance the value of the information that could be gathered with the cost of collection.  These costs are not insignificant and include the time taken by full-time and reserve officers, the substantial inconvenience to the public of temporary road closures and the cost of equipment and training for accurate measurement of the crash scene.

Current Practice Using Survey Total Stations

Current practice is to determine the extent of evidence to be gathered based upon the nature of the incident. While there is no standardized and formal scoring mechanism to make this determination the decision often considers the number of vehicles involved, the extent of injuries/fatalities and the extent to which the cause of the accident is evident.

Where a thorough crash investigation is warranted a common approach is to perform a scene survey using a Total Station and to gather photographic evidence of the broad scene and the damage to individual vehicles.  An investigation of this type typically takes 3-5 hours and gathers hundreds of data points that can later be used to diagram the scene accurately.  Both the initial data capture and the subsequent diagramming are time consuming.

UAS Crash Scene Data Capture - A Better Solution

UAS are colloquially called drones but the military connotation of drone means that UAS is preferred terminology for civilian police forces.

Using small unmanned aerial vehicles (sUAS) provides a better solution for capturing evidence from a auto accident crash site. The benefits include:

Richer Data Capture

  • Full 3-dimensional model reconstruction with millions of data points
  • Equal or better accuracy - with careful model reconstruction sub-centimeter accuracy is achievable
  • Retroactive measurement ability of any dimension - unlike the Total Station approach which requires useful point to be selected at the scence, with UAS capture the distance between any two points of interest can be measured at any time later.

Reduced Elapsed Time for Data Capture

  • Reduce road closures - the time to capture the required aerial photography can be reduced to 15-20 minutes.  Survey measurements are no longer the bottleneck for reopening the road to the public
  • Reduce demand for police resources -- with reduced time for road closure, police resources can be freed to resume their normal duties more quickly
  • Fewer secondary crashes -- shorter road closures will result in fewer secondary crashes

Compelling evidence

One of the most exciting aspects of using UAS for auto accident investigation is the compelling nature of the final models that can be produced.  It is possible to recreate a three dimensional color scene in which you can change your point of view to any location within the scene -- whether or not the UAS actually capture any photos from that location.  It becomes possible to answer questions such as "Would the traffic sign have been visible from this location?" or "Could a witness have had a clear view from where they were standing".  In court, such models should be much more persuasive that two dimensional line drawings or primitive animations.

New Technology, New Challenges

As is often the case, new technology comes with some new challenges.

Limited Operating Conditions

Depending on the UAS that is deployed there are limitation to the conditions under which they can be operated.  A fairly typical set of operating parameters might be

  • Maximum wind speed 20-25 knots
  • Temperature 14oF to 104oF
  • Minimal Precipitation, Fog or Smog
  • Requires daylight or significant area lighting

Evolving FAA UAS regulatory environment

  • Current FAA Requirements
  • Government Entity: COA (Certificate of Operations)
  • Commercial Entity: Section 333 exemption
  • Hobbyist: (no filing requirement)

Future FAA requirements (~June 2016)

  • 14 CFR
    • VLOS, < 400’, Daylight only
    • Operator requirements
      • must pass FAA knowledge test every 24 months
      • Obtain unmanned aircraft operator certificate w/ UAS rating
    • Proposes a “microUAS” category w/ lesser restrictions