U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

California Division

Home / About / Field Offices / California Division / Systems Engineering Guidebook for ITS

Home What's New Systems Engineering Guidebook Views Search Glossary Resources Feedback Site Map

4.2.1 The Basic Waterfall Development Model

The waterfall shows the sequence of steps from system requirements through operations and maintenance as a cascade of steps where each step feeds the next and provides feedback to the previous step.  The steps are system requirements, software requirements, preliminary design, detailed design, code and debug, test and pre-operations, and operations and maintenance.

Figure 4‑1 Waterfall Development Model [Royce 1969]

Highlights of the waterfall development model:

  • Initial development model for software systems development
  • All requirements are known up-front
  • Form follows function philosophy: “What to do? “[Function] before “How to do it?” [Form]
  • Still used for certain types of systems:
  • systems with low complexity, and systems that cannot evolve
  • Relationships between the early phases of the project to the end results are not illustrated
  • Stakeholder involvement is not recognized beyond the initial requirements
  • Control gates not always obvious


Return to top
Page last modified on September 20, 2016
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000

All Federal Highway Administration (FHWA) information technology systems will be unavailable, Friday, December 2, at 10:00 p.m. to Sunday, December 04, at 11:59 p.m., EDT, while work is being performed on the network. During that time, users will not be able to access any FHWA systems.

If you have any questions or problems, please contact the 5-Help Service Center @ (866) 466-5221 or 5-HelpServiceCenter@dot.gov.