Additional survey, SUE and geotechnical studies may be needed to commence final design activities. Most field data collection will have occurred during preliminary engineering. However, as a large project develops, it is common for the designer to determine that existing data may be insufficient or need updating.

Additional field survey, including survey needed for performing final hydraulic studies, is begun as soon as the final ROW footprint is set (see ), if possible. Additional SUE tasks are initiated after potential utility conflicts have been determined.

Similarly, additional geotechnical cores for bridge and/or retaining walls and sound walls are identified and initiated after locations are set during preliminary engineering. Geotechnical investigations also include obtaining data for designing high mast illumination, signals, and overhead sign structures.