Exhibit 6.4 Environmental Issues and Strategies Used to Address Them for International Transportation PPP Projects

Issues

Strategies

Widespread public opposition to project due to broad array of environmental and community concerns

Held regular meetings with local community groups during both construction and implementation phases to identify and mitigate construction-related impacts and operational impacts once opened.

Negotiated agreement with major opposition groups that included conditions requested to be included in the concession agreement, such as the use of noise-reducing asphalt.

Used comprehensive environmental studies prior to plan development that included extensive public outreach and stakeholder communications over a 4 to 8-year timeframe that resulted in adjustments to the original facility locations.

Used public outreach during the environmental planning process to convert a planned toll project to a non-tolled facility paid through shadow tolls.

Integrated new facility into the local geography, added landscaping, and built high embankments to hide toll plazas.

Constructed by-pass routes for trucks accessing the construction site during project development.

Integrated environmental mitigation and improvement mechanisms early in preliminary design process.