Short-term traffic speed prediction models for highways using UAV-based trajectory data and artificial intelligence
摘要
This study presents a spatiotemporal traffic speed prediction framework using high-resolution unmanned aerial vehicles (UAV)-based trajectory data under heterogeneous, lane-free traffic conditions on Indian highways. Two 300 m highway sections (one curved, one straight) were divided into six 50 m regions across each lane and analyzed at one-minute intervals to capture lane-wise speed dynamics. A tailored spatiotemporal matrix transformation was developed to structure historical speed data from adjacent upstream regions and time steps into 3D arrays, enabling sequential learning. A comparative evaluation of five models, random forest (RF), convolutional neural network (CNN), recurrent neural network (RNN), long short-term memory (LSTM), along with the statistical autoregressive integrated moving average (ARIMA) was conducted. A detailed spatiotemporal window selection process, supported by variable importance analysis and error surface evaluation, established a 20 min temporal and three-region spatial look-back as optimal. Performance was assessed using RMSE, MAE, and MAPE. Among the models, RF demonstrated superior accuracy, with MAE ranging from 2.45 to 3.95, RMSE from 2.99 to 3.65, and MAPE from 5.0 to 6.80% encompass both spatial and temporal predictions across the curved and straight highway sections. The LSTM model followed as the next best-performing technique. Model accuracy slightly declined for shoulder lanes due to higher speed variance caused by frequent vehicle entries/exits. Generalization was assessed on a third independent site, where RF maintained strong predictive accuracy. The proposed framework offers actionable value for real-time speed control, congestion mitigation, and proactive traffic safety in mixed-traffic environments where traditional sensor networks are sparse or ineffective.