Deviations are stand-alone documents. There should be enough information and description of the project, the deviation and the justifications so that the approving authority will have all the information necessary to approve it.
Project Overview
- Project Description (type, purpose, major work items
- Highway classification
- Design matrix
- Funding sources
Existing Conditions
- Location
- Lane configuration
- Vertical alignment (vertical curve, profile grade)
- Posted speed and design speed
- Present and 20 year projected ADT
- Truck percent
- Rural, urban or developing
- Route development plan
- Environmental issues
- Right of Way issues
Deviation Description
- Design standard that will be deviated
- Reference in the Design Manual that established the standard
- Station and/or milepost of the deviation
- Previously approved deviations at same location
Alternatives
- Description
- Cost estimate
- B/C ratio
- Advantages/disadvantages
- Reasons for rejections
Justification
The deviation must include these two explanations:
- Give reasons why design standard will not be met
- Provide support to justify the proposed design
Accident history of potential
Benefit/Cost analysis
Cost to build to standards
Cultural impacts
Engineering judgment
Environmental issues
Existing conditions
Geotechnical feasibility
Guidelines from AASHTO, MUTCD, Local Agency Guidelines (LAG), FHWA publications and other recognized technical sources
Insufficient Right-of-Way
Memos from specialists (Traffic, Hydraulics, Materials, etc.) concurring with proposed design
Predictions from ROADSIDE Safety program
Relationship to future improvements
Route Continuity
Truck Turning Diagrams
Deviations must be supported by at least two of these (Design Manual 330.04(4))
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Mitigation (If applicable)
Summarize the deviation mitigation options used to mitigate the deviation to an improved condition but still not providing for Design Manual standards
For additional information see Deviation Mitigation for Designers (92KB PDF).
Recommendation
Summarize the deviation and list the two required justifications the recommendation is based on
Attachments
Vicinity map
Plan sheets
Photos
Charts – use to compare options, design elements, costs, etc.
Design Manual Figure or Section that shows Design Standard
Deviation requests should be submitted as early as possible in the design process. They should be submitted as a separate document before the Design Documentation Package is submitted. The approved deviation is to be included in the design documentation package.
For devation examples see Design Deviation Examples.