Mobile and slow moving operations, such as striping, sweeping, bridge flushing and pothole patching, are critical for the efficient and safe operation of highway transportation system. For example, in the state of Missouri slow moving operations have been crashed into over 80 times since 2013, resulting in many injuries to MoDOT employees. Such a high number indicates the risk of operating a slow moving maintenance truck is much higher than driving a regular vehicle, which jeopardizes state DOT employees’ lives and calls for the need of safer infrastructure maintenance technologies. Autonomous Truck Mounted Attenuator/Impact Protection Vehicles (ATMA/AIPV) is a quickly emerging technology and is expected to bring considerable potentials in transportation infrastructure maintenance by removing drivers from the risk. The system includes a lead truck (LT), a follow truck (FT), a truck mounted attenuator (TMA) installed on the FT, and a leader-follower system that enables the FT to drive autonomously and follow the LT. 

While exciting technology is being developed and shows promising benefits in roadway maintenance, what’s not well studied is the impacts of such autonomous system to traffic operation and roadway safety, and subsequently how should DOT develop deployment strategies with those aspects taken into consideration. In essence, what’s preventing such research from being done previously is the missing of real data from the field and the integration of such data with traffic modeling and management practices. With this in mind, in this project we seek answers to the following questions at the deployment stage: 1) Traffic operation-wise, how much delay would ATMA/AIPV bring for different roadway facilities under various circumstances, e.g. freeway versus highways with intersections, multiple lane versus one lane highway, daytime versus night operation, etc., and how should DOT properly schedule ATMA/AIPV maintenance sequence to minimize its impact to traffic operation? Note even maintenance at night will cause road/lane closure and requires other vehicles to detour, or creates vehicle queue which may lead to spillback that could lead to dangerous situations. 2) What are the safety concerns brought by ATMA/AIPV system under different contexts, e.g. daytime versus night operation, multiple lane versus one lane highway, curve versus straight road, etc., and how should DOT accounts for those factors to optimize the scheduling of ATMA/AIPV maintenance workplan? For example, for the locations where sight distance is short or crash rates are high due to various geometric design issues, it’s probably better to perform maintenance in the day time, while for the multilane highway with good geometric condition, night maintenance won’t be an issue. Unfortunately, existing literature, current national standard and federal policy fail to touch base on those important practical issues.

To bridge this important gap, this project aims to develop a practical software tool that takes in DOT inputs such as roadway network GIS shapefile, traffic counts and ATMA/AIPV system characteristics, and outputs a set of recommended deployment strategies, including the roadway maintenance sequence, staffing plan and needed resource, potential impacts to the traffic network and any suggested traffic management plan to ensure a smooth and safe traffic flow while effectively maintaining the roadway facilities. To fulfill these goals, a few technical tasks will be developed. 1) Traffic flow models and mathematical algorithms will be developed to quantitatively assess ATMA/AIPV’s impact to the transportation roadway network, including both traffic congestion and safety concerns that may occur. Simulation software will also be adopted. 2) Data will be collected from field testing to derive key parameters that can describe ATMA/AIPV system characteristics. Multiple sensors, including LiDAR, Radar, high resolution GPS, high definition camera, accelerometer and gyroscope will be installed on the ATMA/AIPV trucks to collect real data from the field. 3) The traffic models and algorithms will be calibrated with the data collected, which to the best of our knowledge, has never been done due to the missing of ATMA/AIPV field data. 4) Optimal deployment strategy will be developed to minimize ATMA/AIPV system’s impact to the traffic flow and roadway safety while maintaining the roadway facilities. 5) Open-source software tools development, which will produce an executable program with clearly defined input and output and enable DOT to determine optimal deployment strategy in the future.

An open source practical software tool that supports DOT in developing recommended ATMA/AIPV deployment strategies will be delivered. Quarterly reports, and a final report will be prepared to document all the major findings and work from this project. Presentations and research papers will be produced and made publicly available. 

The benefits of this project are threefold: 1) Help DOT gain a fundamental understanding on the impacts of such autonomous system to traffic operation and roadway safety, which unfortunately existing literature, standards or federal policy fail to touch base upon. 2) Support DOT in developing recommended ATMA/AIPV deployment strategies including the roadway maintenance sequence, staffing plan and needed resource, potential impacts to the traffic network and any suggested traffic management plan to ensure a smooth and safe traffic flow while effectively maintaining the roadway facilities. 3) Develop and deliver an open source practical software tool to benefit DOT and other stakeholders in the community.