Design justification process
The Federal Highway Administration (FHWA) has established certain controlling criteria under 23 CFR 625, which must be adhered to when designing a roadway project. MassDOT adopted this policy and applies the requirements of 23 CFR 625 to all projects regardless of funding source. In addition, MassDOT established controlling criteria for bicycle and pedestrian facilities, transit provisions and the length of off- and on-ramps, which must also be adhered to on all applicable projects.
Engineering Directive E-20-001 provides additional guidance regarding the Design Justification Process, supplementing information provided in Chapter 2 of the Project Development and Design Guide.
Design justification workbook
The Design Justification Workbook provides designers with a standardized method of identifying and documenting the desirable, minimum and proposed design criteria for each controlling design element, and streamlines MassDOT's design review process. Proposed design criteria that do not meet minimum criteria require documentation and justification in the workbook.
The cover page of the Design Justification Workbook must be stamped and signed by a Professional Engineer registered in Massachusetts and in responsible charge of the work, and contain the following statement:
I have reviewed this document as it relates to the proposed design and have determined the design to be safe for public health and welfare in conformity with accepted engineering standards.
Instructions detailing what supplemental information should be provided with a Design Justification Workbook are included in the workbook template.