The implementation of design flexibility through nomenclature changes to the Highway Design Manual (HDM) and the Project Development Procedures Manual (PDPM) have been published online, effective July 2, 2018.
- The changes were in response to a Value Analysis regarding the Design Guidance Process Improvement Study to implement the following recommendations:
- Emphasize design flexibility and innovation
- Review HDM standards and re-evaluate the classification of mandatory and advisory guidance
- Update and streamline where possible the Fact Sheet format contained in the PDPM
- No geometric design guidance changes were included, just nomenclature
- Nomenclature changes replaced the following wording throughout both manuals:
Mandatory standard to bold face standard
Advisory standard to underlined standard, and
Design exception fact sheet with design standard decision document
The previous hierarchy of standards have been replaced such that both the bold face and underlined standards are weighed equally, allowing greater flexibility in exercising the appropriate design decisions based on roadway context, need, and scope on a project-by-project basis.
For more information, refer to the following websites:
http://www.dot.ca.gov/design/manuals/hdm.html
http://www.dot.ca.gov/design/manuals/pdpm.html