Why is MicroStation the De Facto State DOT CAD standard?

Frequently I have been asked why MicroStation is the default CAD standard within the U.S. departments of transportation – DOTs in spite of AutoCADs popularity. Where did the initiative start? When did the market penetration reach dominance? Who enabled this success? What are the lessons learned in this historical success story?

How did MicroStation become the CAD standard in all but three State Departments of Transportation (DOTs)? Actually, the road to dominance began before Autodesk and Bentley Systems Inc. existed. In the 1970s, Intergraph Corporation (then M & S Computing) developed IGDS (Interactive Graphics Design System) on PDP mini-computers. Thus, .DGN preceded AutoCAD .DWG by over a decade.

Texas DOT was the first state to use .DGN for digital mapping. When Michigan DOT became the second implementation of IGDS in 1976, the product was not productive in producing engineering drawings. However, Intergraph tailored IGDS to meet MDOTs need. Fate delivered a critical project request from the legislature that could not be delivered on time using traditional design squads. In spite of internal skepticism for this new technology, management decided to rely on the new tool. A centralized, three shift drafting operation was set up to compress the schedule. Project deadlines were met and skeptics were silenced.

Word spread and MDOT became a showcase for visits by a whos who in the transportation private sector community. By the end of the 70s, six DOTs were using IGDS.

Entering the 1980s, CAD vendors, Bentley and Autodesk did not exist. Prevailing CAD vendors did not focus on State DOTs. IGDS used very compact, double precision integer .DGN files. Unique firmware in a dedicated File Processor keyed on the compact data structure yielding superior performance with large CAD files. Drawing elements were written immediately to the .DGN file, immunizing workers from losing data when systems went down, a common event with mini-computers.

Like today, State DOTs were challenged to Do More With Less because of downsizing budgets. CAD automation potential begged the question Who else is using CAD? Highway Engineering Exchange Program (HEEP) conference meetings provided the social media for learning and sharing with others.

Do More With Less meant in-house software development was no longer an affordable option. A joint development cooperative, formed by AASHTO, hired a consultant, C.W. Beilfuss and Associates, to develop and distribute the FHWA funded Roadway Design System (RDS). Direction of RDS was governed by a Steering Committee of users. These RDS users funded the development of Interactive Graphics Road Design System (IGRDS), marrying engineering and IGDS. RDS/IGRDS site licenses enabled states to justify acquisition of Intergraph Systems which included IGDS licenses at no additional cost. Adding new users was easy. By late 1980s, thirty eight states had standardized on IGDS. Intergraph supported IGRDS meetings by loaning mini-computers for demonstrations by the consultant.

Bentley Systems Inc. founded in 1984, developed MicroStation on UNIX and PC platforms. Using Intergraphs published IGDS format, Bentley create File Processor emulators, negating the need for an expensive VAX computer from Intergraph. This emulator honored .DGN files created by IGDS. By the end of the decade, Intergraph acquired 50% ownership of Bentley and marketed MicroStation.


As State DOTs migrated from IGDS to MicroStation, they were pleased with the bi-directional fidelity. Revived projects could be retrieved from the archives and started immediately without translation. They soon discovered the previously free IGDS was replaced with an expensive MicroStation license that they had not budgeted for. AASHTO joint development presented the dilemma to Intergraph. What evolved was an AASHTO discount on all licenses to all State DOTs, regardless of size. The smallest state paid the same license fee per seat as the largest state. This Public Private Partnership (P3) cemented the relationship and continued the growth of Microstation in the DOT community.

Autodesk, founded in 1982, could not overcome the head start of Intergraph/Bentley in the battle for these CAD seats. However, State DOTs of 1990s became concerned about being locked into one vendor. This enabled solutions not dependent on MicroStation to emerge:

CEAL with translators to CAD

CAiCE founded by a CEAL developer with translators to CAD

Infrasoft MOSS with translators to CAD

State DOTs could now hedge their dependence on the Intergraph/Bentley joint adventure. However, translations were unreliable. Also, road design application running inside CAD was more efficient in making design changes.

Adventure it was! Intergraph started developing a Microsoft compatible CAD platform while de-emphasizing MicroStation. During the ensuing feud between Intergraph and Bentley, Autodesk released R13 of AutoCAD, arguably the worst version ever. The Intergraph and Bentley feuding prevented domination of the civil/transportation CAD platform. Intergraph Civil Engineering, with no loyal CAD supplier, developed a CAD-neutral, patented solution to run on top of either platform with a common Windows look and feel.

Autodesk rejected an opportunity to declare Intergraphs InRoads as their road design solution. Instead they standardized on Infrasoft/MOSS. When that failed, they acquired CAiCE used by CALTRANS and a couple other states. When that failed, they decided to develop Civil 3D and model it after InRoads.

What an adventure! How could Bentley deem feuding with Intergraph more important that capturing market share from Autodesk? How could Autodesk reject the best road design solution, InRoads, already used by over half the state DOTs then copy it a decade later. Why did it take Bentley several years of owning InRoads before deciding it was the best platform for road design?

In summary, you now have insight who, what, where, when, why and how CAD evolved in State DOTs. Some pearls of wisdom from this adventure include:

DOTs are constantly having to Do More With Less and need proven solutions

DOTs social media at HEEP and AASHTO meetings guide the easy path to progress

Vendors should view DOT business as the crown jewel of clients

Public Private Partnerships (P3) require long term, trust relationships

As always hindsight is 20/20. Up next is an article on the History of 3D InRoads.

About the Author

Guest Contributors

Guest Contributors ... Articles from Experts in the LiDAR community
Contact Contributor Article List Below