Intelligent transport systems and logistics information technology
Questions here test whether you understand the ITS architecture stack - sensing, communications, processing, services - and can reason about data quality, integration standards and governance rather than listing acronyms.
Architecture and functions
Advanced traffic management (ATMS) covers signal control (SCOOT, SCATS), incident detection and ramp or lane management; advanced traveller information (ATIS) covers journey-time indication and variable message signs; commercial vehicle operations covers electronic tolling (Autotoll-style tags), weigh-in-motion and fleet telematics. Detector choice matters: inductive loops for presence, radar/microwave for speed, video for classification, Bluetooth/Wi-Fi matching for origin–destination.
Identification and integration
Passive UHF RFID with GS1 keys (GTIN for items, SSCC for logistics units) feeds EPCIS event repositories; TMS and WMS exchange orders, shipments and status through EDI (EDIFACT, ANSI X12) or REST APIs. Event-driven integration beats nightly batch where customer promise dates depend on status.
Worked example
Three RFID checkpoints each read a tag with probability 0.95. End-to-end match probability = 0.95³ = 0.857, so 14.3% of journeys are unmatched and unusable for travel-time estimation. Raising each checkpoint to 0.99 gives 0.970 - still 3% loss. Adding a second antenna per checkpoint so the effective single-point read reaches 1 − 0.05² = 0.9975 gives 0.9925 end-to-end, i.e. under 1% loss. The lesson: redundancy at the weakest point beats marginal gains elsewhere, and the design target should be stated in matched-journey terms.
Time, privacy and cyber
Journey-time calculation needs synchronised clocks and outlier trimming; GPS in dense urban canyons (Central, Mong Kok) degrades, so map-matching is essential. Personal data handling must satisfy the Personal Data (Privacy) Ordinance (Cap 486): lawful purpose, minimum collection, retention limits, security, openness. Operational technology - signals, cranes, terminal control systems - needs segregation from corporate IT.
Traps that cost marks
- Quoting a read rate without defining the matching rule.
- Ignoring clock drift and time synchronisation in travel-time systems.
- Assuming GPS accuracy is uniform across a network.
- Proposing data sharing without a privacy impact assessment or retention policy.