AECOM Software Engineer Case Interview: Designing a City-Scale Digital Twin for Water Infrastructure

What this covers: A realistic, consulting-style system design and stakeholder case reflecting AECOM’s work across water, environment, and transportation. You will act as a Software Engineer on a cross‑disciplinary team (planners, civil/water engineers, GIS, PMs) building a secure, scalable digital platform to monitor a midsize U.S. city’s water network, predict leaks, and report KPIs to public‑sector clients. Focus areas mirror AECOM’s culture of client impact, safety, sustainability, and equity. Case prompt: The city wants a cloud-based digital twin integrating GIS/BIM data (e.g., ArcGIS, IFC/REVIT exports), IoT/SCADA sensor streams (flow/pressure), work orders, and field inspections. The MVP must: (1) ingest and validate real‑time and batch data; (2) provide a web dashboard and APIs for internal teams and client stakeholders; (3) support offline-capable mobile inspections; (4) include role-based access controls and auditability for public-sector compliance; (5) surface leak/anomaly alerts; (6) target an initial pilot district within 6 months while meeting budget and sustainability goals. What you’ll do: 1) Clarify requirements and constraints (public-sector procurement, data residency, cybersecurity, accessibility, privacy). 2) Propose an end‑to‑end architecture: ingestion (IoT gateway/stream processing), storage (time‑series + spatial DB), services (REST/GraphQL), analytics (rules + optional ML), and front end. 3) Show how you’ll integrate GIS/BIM standards and OGC/IFC data, and handle data quality and metadata. 4) Address security (RBAC, secrets, encryption), compliance (e.g., ISO 27001 controls), accessibility (WCAG), and sustainability (cost/energy trade‑offs). 5) Outline CI/CD, infrastructure‑as‑code, observability, testing strategy, and a phased rollout plan with risk/mitigation. 6) Communicate how you’d collaborate with non‑software disciplines and manage change with client PMs. Timing (approx.): 70 minutes total — 5 intro; 10 prompt + context; 10 clarifying Q&A; 20 architecture/diagramming; 10 deep dives (data model/API/security); 10 client/consulting scenarios + trade‑offs; 5 wrap‑up. Evaluation rubric (aligned to AECOM): Client orientation and clarity; cross‑disciplinary collaboration; pragmatic engineering trade‑offs; security, safety, and governance; sustainability/ESG considerations; code and delivery excellence (testing, CI/CD, observability); communication and structured thinking. Deliverables in-session: verbal walkthrough, sketched architecture, brief API/data model outline, risks/assumptions, and a phased plan.