MassDOT Variable Message Sign Replacement and Upgrade

The Massachusetts Department of Transportation (MassDOT) has led a successful, multi-year Intelligent Transportation System (ITS) Program. As ITS manufacturer technology advanced, the existing variable message sign (VMS) equipment reached the end of its life cycle and was no longer supported by the manufacturers. Replacing and upgrading the VMS allowed MassDOT to effectively manage traffic and reduce congestion along key corridors using improved infrastructure technology.

VMS technologies are imperative for safe and efficient traffic management. They enhance communication by providing real-time information to motorists, significantly improving transportation safety and awareness and helping minimize travel times, especially along busy interstates with high traffic flow. GFT provided engineering and construction phase services on this intensive project. The team prepared the design and construction support for removing and replacing 22 non-functioning overhead VMSs along I-90, I-93, I-95/Route-128, and State Routes 2, 3, and 24. In addition, the team added one new VMS along Route 2.

With improved safety and efficiency at the forefront of the project’s design, GFT:

• Conducted structural inspections of the existing overhead sign structures.
• Prepared systems engineering documentation.
• Conducted structural analysis of the infrastructure.
• Coordinated with utility service providers and other external stakeholders.
• Developed preliminary and final design plans, specifications, and cost estimates.
• Provided construction engineering support services.

GFT made sure the design addressed MassDOT’s and other stakeholders’ concerns by adhering to the systems engineering (SE) process throughout design and construction. The team developed two critical documents during the SE process: a concept of operations (ConOps) and a systems requirements specification. These two documents work together to establish project objectives aligning with stakeholder needs and develop a functional approach to meet the project goals. GFT’s adherence to SE procedures allowed stakeholders to trace requirements back to the initial project objectives, enhancing the collaborative nature of this endeavor.

The team comprehensively assessed existing sign supports for the VMS installation. They inspected each overhead structure for deficiencies and compared the existing and proposed VMS loads to assess support capacity. Additionally, they performed fatigue analyses on representative sign structure types following the latest version of the American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals. The analysis revealed that natural wind gusts produced the highest fatigue stresses, exceeding fatigue design criteria.

The team used AASHTO methods to predict the fatigue life of elements on the structures and determine an appropriate course of action, which was to retain the existing structures and implement a specific inspection program to place added focus on the fatigue-prone structural members. Compared to the conservative approach of removing and replacing the support structures, this innovative approach to analyzing structural integrity resulted in significant cost savings for the Commonwealth of Massachusetts. A typical overhead truss sign structure costs approximately $400,000 to $500,000. GFT’s innovative approach resulted in total cost savings of approximately $10 million.

The VMS replacement project demonstrates that innovative thinking and analytical techniques can offer safe, cost-effective solutions that reduce inconvenience to the public. The project introduced modern, technologically advanced signs that help improve communications and awareness, making Massachusetts’ roads safer and motorists more informed.