Metric to U.S. FAQ
Q1: What is the schedule in the Transition Plan for reverting back to the U.S. Customary (English) system of units?
A: The following is a simplified version of the transition schedule. For a more expanded version, please see Appendix C of the Metric to U.S. Customary Transition Plan.
Transition Schedule
Milestone
Duration
Date
Transition Plan Approved (Begin Transition)
Release Interim U.S. Customary Guidelines, English resource files for MicroStation and CAiCE English Parameter files
All projects initiated (i.e. entering the PID phase) after March 1, 2005 that also PS&E after March 1, 2007 must use English units unless an exception is approved by the Chief, Office of Geometric Design Standards .
Release U.S. Customary Version of Standard Plans, Standard Specifications & Special Provisions
Release U.S. Customary Version of Manuals & Guidance Documents Begin delivery of U. S. Customary PS&E Packages to HQOE End Metric Projects
(No on-going or shelved projects may bid in Metric)
Q2. What is the current status of the Department’s Transition back to English units?
A: On May 1, 2006 the Department released the 2006 Standard Plans, Specifications, and Special Provisions in U.S. Customary (English) units. The Sixth Edition of the Highway Design Manual will be in English units and is scheduled for release on the Design website on September 1, 2006. Interim design guidance in English units is currently available on the Design website and many other Department manuals and publications are also available or are nearing completion in English units.
Q3: Should my project be designed using the English system of units?
A: All newly initiated projects must be in English units if their PS&E submittal to DES is after June 30, 2007, unless an exception is granted.
Q4: I have a project in the design phase of development that will not bid until after June 30, 2007. Should I switch to designing in English units now to prevent unnecessary resource expenditures to convert later?
A: The decision to convert projects should be made on a case-by-case basis by the District in order to minimize disruption to schedules and resources until such time that Metric projects are no longer allowed without an exception from HQ. A transition period to deliver the majority of the Metric projects currently in the project delivery process will follow the release of manuals and standards documents. Projects will be phased out from predominately using the Metric System to using U.S. customary units. Again surveyed mapping is a key item as discussed in Question 2, but if the project is not surveyed in Metric, you may want to consider converting the layouts and design information to avoid the potential for a costly conversion should the project eventually PS&E after the department has decided to disallow Metric projects.
Q5: How do I design an English project until all the Department manuals and the other guidance necessary to plan and design projects are in English units?
A: The Division of Design released Metric to U.S. Customary Interim Guidelines in March 2005. These Interim Guidelines are available on this website and cover the more commonly used Highway Design Manual design standards. A Primer for conversions and CADD drafting standards are also available so that projects may begin using English units.
Q6: Huh? What’s the difference between “hard” and “soft” conversion?
A: A soft conversion is the U.S. Customary equivalent to the corresponding metric number.
Soft Conversion Example:
The width of a standard traffic lane is 3.6 meters. Calculation: 3.6 m x 3.281 ft/m = 11.8 feet.
A hard conversion is a new rounded, or rationalized U.S. Customary number that is different from its corresponding metric number. The decision to use a hard number varies from application to application.
Hard Conversion Example:
The Department has determined that the standard width for a new traffic lane will be 12 feet.
The General Primer attached to the Metric to English Transition Plan has a detailed explanation of this item.
Q7: Does all this apply to locally funded and permit projects?
A: Yes. All projects affecting transportation facilities within the State Highway rights of way are affected by the Metric to English transition. If a locally funded project is not within the State Highway right of way, then it is not affected. Contact the Headquarters Design Coordinator for your district for assistance, as needed, on a project-by-project basis.
Q8: Is an exception required for projects to bid in English units prior to June 30, 2007?
A: No. Projects on the State Highway System may now be developed, advertised, and awarded in English units.
Q9: I work for Caltrans. How should I charge my extra time related to this effort that would not have been required had the Department remained Metric?
A: Use the EA number you would normally use for that task or project, but include Special Designation 6ENGLISH. By billing to Special Designation 6ENGLISH, the department can track all expenditures related to this effort and be able to break it down by project and department/district. Do not charge to an overhead EA if the task is project related or part of your regular scope of work.
Q10: What happens after the decision is made to deliver my project in English?
A: A memorandum to the Project History File must be prepared documenting the supporting factors (engineering, economic, project delivery, etc.) that led to the decision. This decision must also be recorded on the CLAS screen in the Project Management Control System (PMCS) database by entering a “1” in the “W flag” field.
Q11: What happens after the decision is made to continue to deliver my project in Metric?
A: A memorandum to the Project History File must be prepared documenting the supporting factors (engineering, economic, project delivery, etc.) that led to the decision. This decision must also be recorded on the CLAS screen in the Project Management Control System (PMCS) database by entering a “2” in the “W flag” field. An “Exception Request to Continue the Use of Metric Units” (attached below) must be completed and signed by Region/District Design Management.
This page last updated July 21, 2006