During planning and design, both the architect and the engineer use the project cost estimate for multiple decisions. Identify all the correct applications of the estimate.

Introduction / Context:
Cost estimates inform technical and planning choices throughout a project. Early in development, they help compare sites, select suitable design strategies, and evaluate alternatives based on life-cycle costs. The estimate acts as a financial compass aligning scope, quality, and budget from concept through detailed design.

Given Data / Assumptions:

• Stakeholders include architects and engineers.
• Decisions involve site, design, and alternative options.
• Estimate quality improves as design matures.

Concept / Approach:

Site selection weighs land cost, site development costs, utilities, logistics, and regulatory impacts. Design development uses estimates to optimize structural systems, MEP choices, and materials. Alternatives analysis compares time, cost, and performance scenarios to maximize value for money while staying within budget constraints.

Step-by-Step Solution:

Verification / Alternative check:

Stage-gate frameworks require updated estimates at each design milestone to confirm affordability and inform decisions.

Why Other Options Are Wrong:

• Any single option ignores other critical uses of estimates.
• 'None of these' contradicts common practice in AEC projects.

Common Pitfalls:

• Relying on outdated unit rates when comparing sites or alternatives.
• Ignoring O&M costs in design decisions, which can reverse rankings.

Final Answer:

All of these