Consider Incorporating the Use of Unmanned Aircraft Systems (UAS) and UAS-Based Platforms To Support Traffic Incident Management Instead of Acquiring UAS Alone.

Simulated and Field Testing of Unmanned Aircraft Systems in Texas Revealed Lessons Learned for Traffic Incident Management and Crash Scene Reconstruction.

Date Posted

Using Unmanned Aircraft Systems for Crash Reconstructions during Suboptimal Conditions

Summary Information

The use of Unmanned Aircraft Systems (UAS) has been shown to aid transportation agencies in various initiatives, including traffic incident management (TIM). To better understand the feasibility of using UASs for this purpose, this study identified key challenges, developed and tested procedures for data collection and processing in TIM. The researchers reviewed historical crash data trends between 2010 and 2019 in Texas to establish correlations with environmental factors, performed field tests of UAS-based crash data collection activities under a variety of conditions, and developed recommendations for updates of the Texas DOT’s UAS Flight Operations and User’s Manual. During field testing, a total of seven UAS flights were conducted at real or simulated crash locations in Texas between August 2020 and March 2021. Evaluated environmental factors included the impact of wind speed and direction on UAS flight operations, impact of aerial imaging network design on 3D crash scene reconstructions using a commercial Structure-from-Motion (SfM) software, impact of ambient lighting and low visibility on scene reconstructions, self-calibration versus preflight calibration procedures for consumer-grade nonmetric digital Red, Green, and Blue (RGB) cameras, impact of suboptimal conditions on visual image quality, and impact of camera properties on UAS image quality to inform crash scene imaging practices. 

  • Consider incorporating the use of UAS and UAS-based platforms to support traffic incident management instead of acquiring UAS alone. While the initial acquisition of UASs without the assistance of a UAS-based platform, such as SfM software, might seem attractive, this approach would considerably restrict the potential and benefits that a UAS-based platform can provide for traffic incident management initiatives. In the absence of such a platform, UASs would be limited to solely capturing images and video files.
  • Measure distances between targets in the field for scaling purposes later during image processing. In this study, it was observed that, after applying the scale constraint determined during drone mapping, measured distances from mapping (using Pix4D) and image processing (with SfM software) were closer to each other, therefore confirming the benefit of using the scale constraint method for crash reconstructions using UASs.
  • Be cautious of poor lighting during nighttime flights. The study found that the effectiveness of using built-in LEDs or supplemental lighting for nighttime SfM processing heavily relies on the type and characteristics of the surface texture, as well as the presence or absence of shadows.
  • Focus on low-cost, consumer-level UAS to achieve the accuracy levels typically required for crash reconstruction to support traffic incident management activities. This study showed that it is not necessary to acquire more expensive, surveying-level UAS platforms to achieve the required accuracy levels for crash reconstructions. Instead, low-cost UAS along with commercially available SfM photogrammetry software platforms can be considered.
  • Monitor the evolution of the UAS market as well as federal and state laws and regulations governing the flights of UASs for public use. UAS marketplace may experience significant changes within the span of several years because of government regulations that encourage the increased availability of competitive UAS products from a wide variety of vendors.
  • Establish a program to test and certify UAS equipment and software. This would increase capability to anticipate and prevent any problems that otherwise might not be apparent to users until they have already spent a significant amount of time and resources using the UAS platforms.
  • Partner with public safety agencies to encourage the use of UAS-SfM platforms for traffic incident management, including crash reconstructions. The researchers in this study emphasized the importance of partnerships to support the needs of other public safety agencies and exploring funding mechanisms to support these initiatives.

Using Unmanned Aircraft Systems for Crash Reconstructions during Suboptimal Conditions

Using Unmanned Aircraft Systems for Crash Reconstructions during Suboptimal Conditions
Source Publication Date
Quiroga, Cesar; Michael J. Starek; Jorge Maldonado; Edgar Kraus; Stanton Taylor; Youngjib Ham; and Tianxing Chu
Prepared by Texas A&M Transportation Institute for Texas DOT
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