Thank you for the…

Thank you for the opportunity to provide comments re. amendment to OPSS 510 specification. We believe that, Implementation of 3D milling technology is a very important technical step, that would not only benefit the road industry, but our society in general for providing safety, the comfort and minimizing CO2. Per our understanding following discussions with several dealers, 3D milling is a technological process that allows milling a road according to a 3D model. This 3D model is prepared in advance in the office, all the problems of the construction are solved and the model is approved. Then there are no unpleasant surprises for the workers on the construction site. The quality of the milling is primarily determined by the quality of this 3D digital design model (DDM), and the quality of the DDM is limited primarily by the quality of the Road Surface Survey. We have attached comments summarizing our understanding of the 510 proposal, including comments, questions, and general feedback bothering on definition of the tolerances of the accuracy of each step and the inspection procedure, as well as instructions to designers.
Summarily, we believe that, what kind of software is used for 3D modeling of DDM or what hardware (AGM -Automated Machine Guidance) is mounted on the milling machines for 3D milling control is not the most important thing. What is crucial is the accuracy of the input data => the road surface survey before milling. Bad inputs mean bad results. This is also the conclusion of the U.S. Department of Transportation study, "UTILIZING 3D DIGITAL DESIGN DATA IN HIGHWAY CONSTRUCTION - CASE STUDIES", which concludes on Page 178:
"It was surprising to find that the issues with design data-such as inconsistency with the design intent in the plans-took time to resolve, but had a minor impact on construction outcomes. The construction issues were a result of the unreliable original ground survey that the design was based on."

We encourage the Ministry to take at least a cursory look at this study, while considering the detailed comments and concerns and questions we have provided, thank you.

https://www.fhwa.dot.gov/construction/3d/hif17027.pdf.