June 3, 2019 12:00 AM, EDT

Intelligent Bridge Analysis Software Enhances Illinois DOT OS/OW Vehicle Permitting System

Courtesy of Illinois Department of Transportation


The Illinois Department of Transportation (IDOT) must find a safe route for trucks traveling in the state of Illinois and issue an oversize/overweight (OS/OW) permit for trucks carrying large loads. With slow, manual permitting processes, IDOT sought to update and automate its permitting system. IDOT implemented the Illinois Transportation Automated Permits (ITAP) system in 2012. The ITAP application auto-issues permits for trucks traveling on roads and highways maintained by the state of Illinois. Individuals submitting the application must enter their truck and load information and then the application searches for a feasible route that would support the weight and size of the truck. To improve this system even further, IDOT decided to integrate Bentley’s SUPERLOAD software to optimize the weights and dimensions of the loads and evaluate the infrastructure on the chosen routes.


Bentley’s SUPERLOAD bridge analysis software was used to provide structural analysis, and the weight limit for auto-issued permits was increased to any load less than 299,999 pounds. When a successful route is found within the ITAP system, all roadway structures on the route are analyzed by SUPERLOAD for the specific truck and load configurations provided. This analysis is important in determining the optimal route for oversize/overweight loads. The ITAP application submitted a list of these structures to the Bentley SUPERLOAD bridge analysis web service, which applies structure ratings to each structure based on the load and the structure’s characteristics. If these structures will not support the weight or are too small for the load’s measurements, another route is determined. If no failed structures are found, a permit is automatically issued.

Courtesy of Illinois Department of Transportation

In the second phase of this project, Illinois DOT implemented Bentley’s SUPERLOAD bridge analysis software. This application analyzes all the roadway structures on the route chosen by the ITAP system to determine if the infrastructure around the route can support the weight and size dimensions of the truck’s load. The software looks at bridge clearances, live-load analyses, and temporary restrictions to determine the feasibility of the route. SUPERLOAD applies structure ratings to each structure based on the load’s characteristics and the structure’s features. If these structures will not support the weight or are too small for the load’s measurements, another route is determined. The state’s bridge engineers were confident with the SUPERLOAD analyses. In both phase II and phase III of this project, SUPERLOAD increased the weight of the load, ultimately landing at 299,999 pounds.


The increase in the weights reduced the number of bridge engineers that had to manually analyze structures for permit requests at a significant savings to the state, which also reduced the time it takes to obtain a permit. By going to the current weight of 299,999 pounds, IDOT saved 54,600 analyses being manually done each year. Throughout each phase of development on this project, the design team was challenged to increase the number of permits auto-issued annually by providing real-time structural analysis for sizable loads. Those seeking permits also received new map layers, providing them with more information about their route, as well as new ways to find a route. After adding Bentley SUPERLOAD software into the ITAP application system, IDOT jumped from 74 percent auto-issuance for oversize/overweight loads to 99.2 percent currently.

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Bentley Systems is a global leader providing engineers, constructors and owner-operators with comprehensive software solutions for advancing the design, construction and operations of transportation infrastructure. Bentley has provided solutions to highway agencies for more than three decades, and its proven and reliable solutions will help you manage your road assets on budget and on schedule. Bentley provides a complete solution for intelligent permitting, routing, and restriction management of oversize/overweight (OS/OW) vehicles. SUPERLOAD automates the permitting and routing of your vehicles, including application processing, route selection and analysis, and permit issuance – all in conformance with state restrictions and road conditions.

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