Multi-Horizon Explainable Queue Forecasting and Resource-Aware Decision Support for Intelligent Border Control Using LightGBM
Organizations: Department of Electronic Engineering, Hellenic Mediterranean University · School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece
Abstract
Border crossing points are stochastic service systems in which traffic demand, traveler categories, registration status, inspection requirements, staffing, and lane availability interact on multiple time scales. This paper extends an earlier multimodal queue-management framework by introducing an implementation-oriented, multi-horizon forecasting and decision-support architecture based on Light Gradient Boosting Machine (LightGBM) models. In contrast to a single forecasting block, the proposed approach constructs horizon-specific regressors for 15, 30, 60, and 120 min forecasts and jointly estimates future waiting time and queue lengths. The models operate on temporally lagged traffic, service, density, and queue features, while an operational layer incorporates lane compatibility, officer availability, possibly degraded resources, traveler category, preregistration information, and human-approval constraints. Quantile LightGBM models provide 95% prediction intervals for waiting-time forecasts. Beyond prediction, the framework produces machine-readable recommendations, alerts, aggregate key performance indicators, confidence information, and integration outputs suitable for border resource-management and decision-support systems. The results establish a reproducible synthetic-data baseline and a practical interface for subsequent validation with operational border-crossing data.
Figures & tables
| Sampling interval | 5 min |
|---|---|
| Total duration | 35 days |
| Queue streams | 5 |
| Total observations | 50,400 |
| Training period | First 28 days |
| Training observations | 40,320 |
| Test period | Subsequent 7 days |
| Horizon | Waiting Time | Queue Length | ||||
|---|---|---|---|---|---|---|
| (min) | MAE (min) | RMSE (min) | MAE (veh.) | RMSE (veh.) | ||
| 15 | 5.007 | 10.186 | 0.9870 | 0.784 | 1.182 | 0.9995 |
| 30 | 5.705 | 11.435 | 0.9836 | 1.108 | 1.704 | 0.9990 |
| 60 | 6.588 | 13.074 | 0.9785 | 1.609 | 2.557 | 0.9977 |
| 120 | 8.472 | 16.729 | 0.9648 | 2.468 | 3.926 | 0.9946 |
| Overall | 6.438 | 13.079 | 0.9785 | 1.490 | 2.558 | 0.9977 |
| Configuration | Waiting Time | Queue Length | ||||
|---|---|---|---|---|---|---|
| MAE (min) | RMSE (min) | MAE (veh.) | RMSE (veh.) | |||
| Full model | 6.438 | 13.079 | 0.9785 | 1.490 | 2.558 | 0.9977 |
| Without lagged history | 6.436 | 13.078 | 0.9785 | 1.511 | 2.599 | 0.9976 |
| Without demand/context | 6.414 | 13.048 | 0.9786 | 1.504 | 2.573 | 0.9977 |
| Without service rate | 6.582 | 13.407 | 0.9774 | 1.510 | 2.576 | 0.9977 |
| Without temporal encoding | 7.284 | 14.542 | 0.9734 | 2.102 | 3.937 | 0.9946 |
| Study | Application | Models/approach | Forecast setting | Reported result | Relation to present work |
|---|---|---|---|---|---|
| Zhang and Haghani [ 4 ] | Freeway travel time | Gradient boosting regression trees; ensemble/statistical baselines | Multi-step ahead | GBM reported advantageous prediction accuracy and interpretability | Establishes gradient boosting as a suitable nonlinear, interpretable travel-time predictor. |
| Berliotti et al. [ 15 ] | Road traffic flow, 14 sensors | LightGBM, XGBoost, CatBoost, Random Forest | Hourly traffic; two unseen one-week periods | First test week: LightGBM MAE 0.0679; XGBoost 0.0649; CatBoost 0.0637 (normalized task scale) | Demonstrates that no boosting method is universally dominant and motivates same-data model comparison. |
| Wang et al. [ 3 ] | 209 urban signalized intersections | Dynamically Weighted LightGBM versus LightGBM, XGBoost, LSTM, GRU, RF, SVM, KNN | Hourly traffic-volume forecasting | DW-LGBM RMSE 5.54, ; standard LightGBM RMSE 118.13, | Supports temporal weighting/encoding and shows the importance of feature architecture around LightGBM. |
| Hari et al. [ 16 ] | Multi-location pedestrian/crowd demand | LightGBM, CatBoost, LSTM and other models | Multiple prediction windows | Best model changes with location and horizon; reported ranges from negative values at difficult low-volume sites to at busier sites | Reinforces horizon- and location-dependent evaluation rather than reliance on one aggregate metric. |
| Present work | Border queue waiting time and queue length | Horizon-specific LightGBM + quantile LightGBM + resource-aware decision layer | 15/30/60/120 min; strict 28-day train/7-day unseen test | Wait: MAE 6.438 min, RMSE 13.079 min, ; Queue: MAE 1.490 veh., RMSE 2.558 veh., | Adds border-specific segmentation, service/resource constraints, uncertainty intervals, JSON interoperability, and operational recommendations. |
Time Series Forecasting
Time series forecasting predicts future values from ordered observations using statistical, neural, and probabilistic models to support decisions under uncertainty.
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