More and more state departments of transportation are relying on computer-aided design and drafting (CADD) systems to help them prepare and produce their roadway designs. The procurement and implementation of such systems do not usually occur at one time throughout all departments. Consequently, state DOTs may acquire a variety of systems over time, or they may wish to continue to take advantage of new technologies as they evolve. State DOTs also contract design work to consultants who may or may not have compatible systems. This array of possible situations highlights the potential problem of exchanging graphic and design data among various systems. Inadequate capability for such exchanges hinders productivity, limits competition, and inhibits the advantageous use of new developments in hardware and software.
The primary objective of this research was to design a standard file for the exchange of computerized roadway design and graphics data. A standard file, if adopted and maintained, would have the potential of facilitating the transfer of data between existing, but different, systems and for providing a target for future software program developments. Based on a thorough investigation of DOT needs, systems used, and interchange formats, a specification was defined for a standard file format, the Common Data Interchange File (CDIF), that could accommodate interrelated roadway design and graphics data. Prototype software for data-interchange processes was also developed for the more commonly used state DOT systems to demonstrate the utility of the interface.
Research is complete and the main text of the final report has been published as NCHRP Report 326, "Development of a Roadway Design/Graphics Interface System." The appendixes to the agency's final report were not published, but copies of that report, entitled "Development of a Design/Graphic Interface System---Appendixes A--E," were transmitted to all state DOTs addressed specifically to the membership of the AASHTO Administrative Subcommittee on Information Systems. The appendixes are titled as follows: Appendix A, Guidelines for Entry of Data to be Transferred; Appendix B, Common Data Interchange File Specification; Appendix C, Information for DIP Usage; Appendix D, Programmer Information for DIP Enhancement/New Development; and Appendix E, Test Data.
The research agency also demonstrated, to a limited extent, the actual exchange of information. The computer programs employed for this purpose were made available for use and further development. All of the software was developed in FORTRAN for a DEC VAX environment. The descriptions are written using DEC VAX terminology and descriptive notations. The FORTRAN source code, executables, and test data were available for DEC VAX computer systems on a single magnetic tape (9 track, 1600 BPI, 1200 foot reel).