Mid-level interview questionAsked at Uber · interview write-up
Design a ride-hailing ETA system, covering labels, features, model choice, low-latency serving, delayed ground truth and drift.
Model answer
Label: actual trip time. Start from a routing engine's ETA over the road graph, then learn a residual correction from time of day, live traffic, region, weather and trip type, as DeeprETA does. Serve a compact model with cached features.
Ground truth lands when the trip ends, so track error by segment as labels arrive, watch feature drift meanwhile, and retrain regularly. Pick the loss by business cost, asymmetric if lateness hurts more.
Practise the rest
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