Traffic4Cast 2022 - TSE

Solution of team TSE to NeurIPS2022-Traffic4cast Challenge

• Traffic4Cast 2022 - TSE
  • Installation
  • Usage
  • Checkpoints
  • Feature Engineering
    • Prerequisites
    • Static network features
    • Loop counts features
    • Speed features
    • KNN label features
    • Feature combination
  • Report
  • Citation
  • Acknowledgements

Installation

Necessary packages needed for running the scripts are included in requirements.txt. In addition, the official t4c package have to be installed in advance.

pip install -r requirements.txt

Usage

The scripts used for data imputation, data preparation, feature extraction and model training & prediction are included in run.sh. Before running the scripts, please configure the paths in config.json.

sh run.sh

Checkpoints

The model checkpoints are included in the folder processed/checkpoints.

Checkpoints	Description
lgb_1+nr2_model_london.pkl	London model with Mahattan and normed Euclidean distance
lgb_1+nr2_model_madrid.pkl	Madrid model with Mahattan and normed Euclidean distance
lgb_1+nr2_model_melbourne.pkl	Melbourne model with Mahattan and normed Euclidean distance
lgb_1+p2_model_london.pkl	London model with Mahattan and Euclidean distance
lgb_1+p2_model_madrid.pkl	Madrid model with Mahattan and Euclidean distance
lgb_1+p2_model_melbourne.pkl	Melbourne model with Mahattan and Euclidean distance
lgb_full_missing_model_london.pkl	London model for samples with high missing rate

Feature Engineering

Prerequisites

The codes of feature engineering are included in the folder src/feature_extraction. Please note that, before running the codes within this folder to extract features, the scripts within the src/preparation folder should be run first to prepare all required inputs. Those scripts should be run as follows.

• prepare_train_test_arrays.py: restructure the raw loop dataset, the imputed loop dataset, and the y labels in the eta task.
• extract_missing_index.py: calculate the missing rate of loop data for each observation (time step).
• missing_data_split.py: construct the support set and train set for the observations with high missing rate in loop data in London specifically.
• speed_processing.py: processing the speed data, which will be used for extracting speed-based features.

Static network features

See static_features.py.

• Number of nodes involved in the supersegment (SG)
• Length of SG
• Number of oneway edges in the SG
• Statistics of the speed limits of edges in the SG: mean, std, 25, 50, 75 percentiles, min, max
• Haversine distance between SG OD
• For SG $i$: Shortest/design travel time = $\sum_{j \in SG_i} \frac{\text{length}_j}{\text{MaxSpeed}_j}$
• Statistics of the $y$ values of all samples under consideration (all nn)
• Percentage of $(- \infty, 1800]$, $(1800, 2400]$ and $(2400, \infty)$ in the y query set for each SG

Loop counts features

See loop_features_fully_missing.py.

• Sum, mean, std of loop counts (at nodes) within SG
• Number of loops with values (at each interval)

Speed features

See speed_features_fully.py. Free flow speed and median speed of a SG is defined as the mean free flow speed and mean median speed of the edges involved. $k \in [1,2,5,10,50]$ below.

• Mean, std of the free flow speed, median speed of $k$ nearest neighbors
• Mean, std of the edge volume classes percentage/distribution of $k$ nearest neighbors

KNN label features

See knn_features_eng.py and knn_features_manipulate.py. $k \in [2,5,10,30,50,100]$ below.

• Statistics of $y$ values of the $k$ nearest neighbors: mean, std, 25, 50, 75 percentiles, min, max

Feature combination

We also combine (difference, addition, quotient) multiple aforementioned features together to construct more powerful features. This step is carried on in the model training script.

Report

The accompanying technique report can be found in Traffic4cast_2022_TSE.pdf.

Citation

@misc{tse-t4c22,
  title     = {Similarity-based Feature Extraction for Large-scale Sparse Traffic Forecasting},
  author    = {Wu, Xinhua and Lyu, Cheng and Lu, Qing-Long and Mahajan Vishal},
  year      = 2022,
  month     = {Oct},
  url       = {https://github.com/c-lyu/Traffic4Cast2022-TSE},
  language  = {en}
}

Acknowledgements

This repository is based on the official repository of the competition NeurIPS2022-traffic4cast.