Why InRoads is First in 3D Road Design

In a previous article I explained why MicroStation dominates State DOTs. Now we are ready to pose a new set of history revealing questions. Why has InRoads, originally developed by Intergraph, emerged as the leading, proven 3D design solution for transportation projects? When was the InRoads 3D decision made? Who influenced the decision? What policy helped sanction the use of 3D over 2D?

How did 3D InRoads win the battle of 2D vs. 3D? Guy Nesin (now deceased) and I joined Intergraph in June of 1981. Guys career with Michigan DOT spanned 20 years and my MDOT career spanned 15 years. Michigans depressed economy forced a leap of faith from our public sector comfort zone to the uncertainty of the private sector.

After six months, Guy and I concluded that MDOT was a well-oiled machine compared to business at Intergraph. MDOT had already implemented and was using in production a robust triangulated Digital Terrain Modeler (DTM) – CARTA TERRA. When we arrived at Intergraph, they were proudly developing a mapping grid terrain model which could not handle discontinuities. We civil engineers clashed with the mappers and ultimately Tom Inzinga, now with Autodesk was assigned to develop a Triangulated Irregular Network (TIN) DTM. Since Intergraph was introducing a 3D version of IGDS, we had to decide – 3D or 2D.

Intergraph formed a steering committee that included the Vermont, New York and Pennsylvania DOTs, plus a number of transportation consultants. As a result in 1986 the decision was made to go 3D along with the use of the metric system to support international clients. Mike Cavanaugh (also an MDOT transplant in 1982) championed the definition and certification of two new Intergraph, VAX-based products; Site Design Package (SDP) and Transportation Design Package (TDP). Even though road design deliverables were 2D, Mike enabled the committees vision of 3D to become a reality. Competing products were 2D cross section databases that automated drafting of cross sections without DTM technology. As UNIX workstations became popular, SDP and TDP were ported and renamed InSite and InRoads, respectively.

During the 1990s, competitors criticized 3D DTMs vs. automated cross sections. InRoads (DTM-based) and GEOPAK (X-section based) were the two primary competitors for State DOT business. Millions of dollars were spent on benchmarks between these two vendors and philosophies. InRoads provided a unique blend of 3D road design modeling superimposed on scanned aerial photos as early as 1990. Combined with Intergraphs ModelView, 3D renderings of before and after dramatically improved communication of proposed designs with non-technical audiences. Previously delayed projects were overcoming stakeholder objections and moving forward using 3D technology.

In 1997, the USDOT, Federal Highway Works Administration published Flexibility in Highway Design which contains the following AASHTO Green Book quote:

Coordination of horizontal alinement and profile should not be left to chance but should begin with preliminary design, during which adjustments can readily be made the designer should study long, continuous stretches of highway in both plan and profile and visualize the whole in three dimensions.

Thanks to the foresight of the InRoads Steering Committee ten years earlier, visualizing in 3D was an easy by product of horizontal and vertical alignment design.

Shortly after this publication was released in 1998, Thinking Beyond the Pavement workshops were created to address the issue of unacceptable project delays caused by community resistance. Evolving from this and several follow up workshops was Context Sensitive Solutions (CSS). Transportation agencies encountered not in my backyard pushback from stakeholders. Using traditional 2D methods, many projects were designed multiple times to no avail. Non-technical audiences rejected engineering drawings because they did not understand them.

Some State DOTs began using InRoads with real scale, 3D renderings superimposed on aerial and oblique photos for conceptual designs. Photomontages enabled stakeholders to understand proposed designs and offer constructive feedback. Engineers discovered that CSS renderings during preliminary engineering fostered approvals from stakeholders before final design plans, specification and estimate (PS&E) were generated. Redesign hours were saved and contractors gained better insight into project scope.

Entering the 2000s , four road design solutions prevailed in State DOTs:

InRoads (3D) most states

GEOPAK (2 D) most seats

CAiCE Visual Roads (3D) CA, GA, WI, WS

Infrasoft/MOSS (3D endorsed by Autodesk) CO, IN, , MA, ME, NH

The Utah DOT selected InRoads for the upgrade of the road network to support the 2002 Winter Olympics. They developed 3D standards which were adopted by the I-15 Design-Build team. The project finished ahead of schedule and within budget. This project became a showcase for demonstrating the value of 3D design. The motto became, If it doesnt fit on the screen, it wont fit in the field.

As seen in the following video this successful use of 3D design was followed by the highly publicized T-REX highway and rail project in Denver, Colorado.


During the early 2000s, Bentley Systems acquired InRoads and GEOPAK. Autodesk acquired CAiCE. Bentley then acquired Infrasoft. Bentley struggled to bring three disparate road design products into a common platform suitable to their respective customer bases. Autodesk decided to invent a new product, Civil3D. By 2010, Bentley had merged the best of breed under the predominately InRoads platform. Autodesk continued to improve Civil3D to compete with InRoads.

Why has InRoads proven to be the leading 3D design solution for transportation projects? InRoads/MicroStation was the platform chosen for the Hong Kong airport, arguably one of the most challenging projects of the 20th century. As we have seen InRoads/MicroStation was the Design-Build project delivery platform for Utah DOTs I-15 and Denvers T-REX project. All of these projects leveraged the power of 3D design and demonstrated its value on these very demanding, high profile projects.

In summary, InRoads was 3D from inception, based on the recommendation of Intergraphs User Group Steering Committee. State DOT policy decisions to embrace a Context Sensitive Solution (CSS) helped sanction the use of 3D over 2D. Finally, the most challenging transportation projects were the proving grounds for 3D design. Today, the transportation design community has embraced 3D and has two excellent products to choose from. Progress has been made, but as you can see it was not done overnight.

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