Projects

Design Criteria for Engineering

banner design3Seven required Engineering Design Criteria have been developed to address the unique characteristics of the I-70 Mountain Corridor. These criteria are intended to influence the alignment of the transportation facilities and are an essential component of engineering design.

The Engineering Design Criteria have been developed and adopted by the Colorado Department of Transportation (CDOT) because they represent an approach that enhances safety, mobility, and sustainability while reducing maintenance through design and engineering.

Design Criteria Categories
The following Design Criteria categories direct the development of both I-70 and the Advanced Guideway Systems (AGS)*:

  • Design speed
  • Alignment
  • Slope cut and fill
  • Disturbance
  • Rock cut
  • Bridge structures
  • Sound attenuation

*As the AGS for the I-70 Mountain Corridor is further defined, developed, and refined, the criteria may be updated to match the chosen technology.

Application of Design Criteria
All of the design criteria must be met in Life Cycle Phase 2: Project Planning. Alternatives may be refined in Life Cycle Phase 3: Project Design, when the designer is able to determine which criteria may require an exception and why. The one exception for this requirement is in Areas of Special Attention, where a design exception may be considered in Phase 2 due to the complexity of the issues involved.

Federal, state, and local agencies will neither officially review nor grant design exceptions until Life Cycle Phase 3: Project Design.

Project Leadership Team Role
The Project Leadership Team (PLT) must be apprised of the criteria being used on its I-70 Mountain Corridor project.

Justification for any criteria that would not be met as determined during design must be presented, discussed, and agreed upon by the PLT. Consideration will be given to the I-70 Mountain Corridor Core Values; safety; operation; compatibility with the overall network; character of traffic; cost implications; and impacts to scenic, historic, and environmental features. Other variables to consider include the amount of change to the criteria, its effect on other criteria, and any additional impacts that one change may make.

Design Exception Process
Due to challenges presented within the I-70 Mountain Corridor, a situation may arise in which the existing design criteria cannot be met, or in which the impact of meeting the criteria would be too great. Should this be the case, a design exception must be requested. Design exceptions may assist a designer in finding a transportation solution that balances impacts to scenic, historic, and culturally or environmentally sensitive areas while still providing for safety and mobility. Designers should think innovatively, consider the Core Values, and take into account the flexibility available to them when designing a transportation solution for the I-70 Mountain Corridor.

Design exceptions may be granted for the following justifications:

  • Complementing surrounding physical characteristics
  • Enhancing safety
  • Increasing capacity
  • Reducing costs
  • Protecting the environment
  • Preserving historic and scenic elements
  • Interfacing with multiple modes of transportation
  • Utilizing new technology or innovative approaches
  • Doing the right thing

Colorado: The Official State Web Portal