Cross-Modal Reconstruction Pretraining for Ramp Flow Prediction at Highway Interchanges
Yongchao Li, Jun Chen, Zhuoxuan Li, Chao Gao, Yang Li, Chu Zhang, Changyin Dong
TL;DR
Ramp flow prediction at highway interchanges is hindered by missing ramp detectors and data silos. The authors propose STDAE, a two-stage cross-modal pretraining framework that reconstructs ramp flows from mainline data using decoupled spatial and temporal autoencoders, then augments a downstream predictor (GWNet) with learned STDAE representations. Across three real interchanges and multiple sampling intervals, STDAE-GWNET outperforms 13 baselines and approaches the performance of models that have access to historical ramp data, demonstrating robustness to missing inputs and strong generalization. The approach is plug-and-play across predictors and remains effective under data loss, highlighting practical deployment potential for refined highway traffic management. Limitations include lack of weather/incidents data and potential computational costs for real-time network-scale deployment, with future work aimed at broader validation and efficiency improvements.
Abstract
Interchanges are crucial nodes for vehicle transfers between highways, yet the lack of real-time ramp detectors creates blind spots in traffic prediction. To address this, we propose a Spatio-Temporal Decoupled Autoencoder (STDAE), a two-stage framework that leverages cross-modal reconstruction pretraining. In the first stage, STDAE reconstructs historical ramp flows from mainline data, forcing the model to capture intrinsic spatio-temporal relations. Its decoupled architecture with parallel spatial and temporal autoencoders efficiently extracts heterogeneous features. In the prediction stage, the learned representations are integrated with models such as GWNet to enhance accuracy. Experiments on three real-world interchange datasets show that STDAE-GWNET consistently outperforms thirteen state-of-the-art baselines and achieves performance comparable to models using historical ramp data. This demonstrates its effectiveness in overcoming detector scarcity and its plug-and-play potential for diverse forecasting pipelines.
