The following measures to minimize harm and to mitigate impacts to resources were proposed in the report of the Route 710 Meridian Variation Enhancement and Mitigation Advisory Committee (Committee). The following were accepted by Caltrans:

General Recommendations For The Entire Route

• Use of a reduced freeway design from 176 feet width to 142 feet, including reduction of the median strip by 22 feet and use of an intermittent, rather than a continuous 12 feet auxiliary lane.
  
• Elimination of the 110/710 freeway-to-freeway interchange, including all local street connectors in the interchange area.
  
• Use of an intermittent auxiliary lane on the 8-lane (including two HOV lanes) option to help achieve air quality and mobility requirements.
  
• Maximum use of grading contours, retaining walls and other approaches to minimize the freeway footprint in environmentally critical areas.
  
• Construction of 6 cut-and-cover tunnels in the following areas;

  1. Templeton Avenue to Poplar Avenue area in El Sereno.

  2. Sierra Villa Elementary and Short Line Villa Historic District area in El Sereno.

  3. South Pasadena High School/Wynyate area in South Pasadena.

  4. Prospect Circle Historic District area in South Pasadena.

  5. Pasadena Avenue Historic District/ Westridge School area in Pasadena.

  6. Markham Place Historic District area in Pasadena.

• Development of easements or other incentives for properties on cut-and-cover tunnels to encourage ownership of homes.
  
• Work with the local communities on design details to best minimize the anticipated traffic impacts.
• Eliminate long haul trucks from this freeway segment.
  
• Develop a way to permit trucks making local deliveries to utilize the freeway rather than parallel local surface streets.
  
• Planting of the freeway corridor which provides a rich landscaped environment and discourages vandalism and graffiti. Plant shrubs and clinging vines on both sides of the soundwalls.
  
• Other surface treatments for soundwalls may include murals (except in the City of Pasadena) or textured surfaces compatible with the surrounding neighborhood. All non-planted surfaces shall be treated with a graffiti-proof coating.
  
• Arroyo Stone Cobble used for aesthetic treatment (where applicable) of exterior walls, retaining walls, seat walls, bridges, columns, and paving.
  
• Clinker Brick used for aesthetic treatment (where applicable) on exterior walls, retaining walls, seat walls, bridges, columns, pilasters, and paving.
  
• Formed and pre-cast concrete used for aesthetic treatment (where applicable) on bridges and planters.
  
• Constructing a generous landscaped buffer adjacent to the freeway, consisting of a plant material palette consistent with local plant materials - primarily a traditional historic California mixture of shrubs and trees. This plant material should be drought-tolerant and low maintenance.
  
• Use of wrought iron fencing in highly visible areas, where fencing is needed for community safety.
  
• Where chain link fence is used (in non-high visible areas), the chain link will be coated with a black vinyl coating.
  
• Vines will eventually cover chain link fences, except in areas that require visibility.
  
• Relocation of significant mature trees. Where possible these mature trees shall be replanted in selected areas within the 710 corridor.
  
• In historical areas, plant trees that correspond to existing vegetation.
  
• Construction of soundwalls with architectural ornamentation and landscaping adjacent to residential areas. Standard non-ornamental soundwalls should not be utilized.
  
• Plant large specimen trees in the loops formed by the interchange ramps, to provide a mature, visually aesthetic appearance. These trees should be salvaged from disturbed neighborhoods (where possible).
  
• Constructing aesthetically pleasing landscape buffers areas on smaller parcels, not suited for other uses.
  
• Proper grading and use of vegetation to minimize noise propagation.
  
• Use of soundwalls and reasonable alternatives to be developed in a manner consistent with the overall urban design master plan of affected communities.
  
• Consultations with individual property owners or affected individuals by Caltrans to assess the need for noise mitigation measures.
  
• Implementation of the recommendations and procedures contained in the Historic Preservation Subcommittee Report.
  
• Completion of the survey and identification process for the historic properties, as outlined in the Historic Preservation Subcommittee Report.
  
• Use of cut-and-cover tunnels under every National Register eligible historic district and property, unless proven to be infeasible.
  
• Investigation of the feasibility of additional cut-and-cover tunnels and/or shifts in the alignment to avoid or mitigate harm to the South of Mission Historic District, the Grokowsky House, the northern part of the Markham Place Historic District, and any other historic district or property found to be National Register eligible after completion of the survey and identification process.
  
• Replacement of all National Register eligible historic properties and districts back on top of or in proximity to the cut-and-cover tunnels with full rehabilitation of those properties in accordance with relocation guidelines developed in consultation with the SHPO, historic preservation groups, and the Secretary of the Interior’s Standards for Rehabilitation.
  
• For all historic properties that cannot feasibly be replaced on cut-and-cover tunnels, relocation of those properties onto compatible sites within compatible historic districts, based upon relocation criteria designed to maintain National Register eligibility.
  
• Development and implementation of additional mitigation measures for all California Register eligible historic properties, in consultation with the State Historic Preservation Officer (SHPO) and historic preservation groups. The Committee was aware of a new State law effective January 1, 1993, establishing a California Register of Historical Resources. Criteria and regulations for implementation of this new State law had not yet been adopted. The Committee requested Caltrans to comply with all applicable laws. [To date, no eligibility guidelines have been adopted. Consequently, Caltrans continues to rely on the use of National Register criteria when making determinations of eligibility for historic or architectural significance at the State and local level. This approach was approved by the California SHPO in May 1994 as part of the Caltrans Historic Resources Management Plan.
  
• Initiation of an immediate condition assessment of all Caltrans-owned historic properties and performance of needed stabilization measures and repairs.
  
• Use of architecturally-sensitive soundwalls, earth berms, and soundproofing techniques for historic homes affected by noise.
  
• Implementation of the Route 710 Mitigation Monitoring and Enforcement Plan during the construction phase of the project.
  
• Use of an independent oversight Mitigation Monitoring team or independent consultant to monitor and enforce the detailed implementation of the various components of the mitigation program, including the traffic management plan.
  
• Integration of mitigation actions into each project segment to phase funding and provide a clear linkage between the mitigation actions and that phase. This linkage should be part of the Route 710 Mitigation and Monitoring Enforcement Plan