Pedestrian Trajectory Prediction: Forecasting Crossing Behavior & Intent

Pedestrian Trajectory Prediction: Forecasting Crossing Behavior & Intent

In the modern world, transportation systems are developing rapidly, and with them, the complexity of interaction between different traffic participants is increasing. Every year, road traffic incidents result in significant losses, making it crucial to develop effective approaches for analyzing and predicting pedestrian behavior. The ability of systems to predict the actions of traffic participants helps to reduce risks and increase the consistency of actions between people and vehicles.

In this context, methods are being actively researched that enable the tracking of traffic dynamics, identification of typical behavioral patterns, and response to unpredictable situations. The combination of modern data processing algorithms with sensor technologies creates the potential for developing more efficient and safer solutions in the field of transport infrastructure.

Why pedestrian behavior prediction matters in complex, unstructured traffic

In complex and unpredictable road environments, pedestrian traffic is often chaotic, making it difficult to predict their actions. The high diversity of behavior and unpredictable maneuvers poses additional challenges for traffic management and risk assessment systems. Research focused on pedestrian crossing intent, action prediction, and behavior estimation enables the prediction of potentially hazardous situations and enhances the accuracy of risk assessment.

Accurate prediction of pedestrian intentions and actions is particularly important in urban environments with many conflict points and chaotic traffic flows. It ensures the timely response of transportation systems to unpredictable behavior of people, contributing to risk reduction and increased safety of road infrastructure.

State of the art in pedestrian behavior prediction: intention, trajectories, and interactions

Approach / Study

Focus Area

Method / Model

Key Contributions

Strengths

Limitations

Study A

Pedestrian Crossing Intent

Probabilistic / Bayesian Models

Predicts crossing intent based on pedestrian pose and context

Handles uncertainty in intention

Limited to structured crossings

Study B

Trajectory Prediction

LSTM / RNN

Models sequential movement patterns over time

Captures temporal dependencies

Struggles with highly unstructured environments

Study C

Interactions

Social Force / Graph-based Models

Considers interactions among pedestrians and vehicles

Accounts for social behaviors

Computationally intensive

Study D

Intention + Trajectories

CNN + LSTM

Jointly predicts crossing intent and future trajectory

Integrates visual cues and motion

Requires large labeled datasets

Study E

Trajectories + Interactions

Transformer / Attention-based Models

Models complex multi-agent interactions

High accuracy in crowded scenes

High computational cost, needs rich data

Study F

Comprehensive

Multi-modal (LiDAR + Camera + Context)

Combines sensor data for robust behavior estimation and risk assessment

Effective in unstructured traffic

Sensor fusion complexity, expensive deployment

Datasets and gaps: structured vs. unstructured environments and the IDD-PeD contribution

Dataset

Environment Type

Data Modalities

Key Features

Strengths

Limitations / Gaps

IDD-PeD Contribution

ETH

Structured

Video, RGB

Pedestrian trajectories in urban sidewalks

Well-annotated, widely used

Limited to structured urban areas, low traffic complexity

N/A

UCY

Structured

Video, RGB

Pedestrian interactions in small crowds

High-quality trajectory data

Small-scale, lacks complex traffic scenarios

N/A

KITTI

Structured

LiDAR, Camera, GPS

Vehicle-pedestrian interactions on urban roads

Multi-modal, real-world traffic

Sparse pedestrian coverage, mainly structured roads

N/A

nuScenes

Structured

LiDAR, Camera, Radar, GPS

Autonomous driving dataset with annotations

Multi-modal, includes dynamic agents

Mostly structured urban areas, limited pedestrian diversity

N/A

PIE

Semi-structured

Camera, GPS

Pedestrian crossing scenarios

Focus on crossing intent

Limited unstructured traffic, mostly US cities

N/A

IDD-PeD

Unstructured

Camera, LiDAR, GPS

Pedestrians in dense, heterogeneous urban traffic (India)

Captures diverse behaviors, interactions, and unstructured environments

Newer dataset, smaller in size than KITTI/nuScenes

Fills the gap in behavior estimation and risk assessment for unstructured traffic scenarios

Generalization, transferability, and deployment in intelligent transportation systems

Current methods for predicting pedestrian behavior must demonstrate generalization across different road conditions to be effective in the real world. Models trained in structured environments often struggle to transfer to unstructured traffic, where pedestrians exhibit more unpredictable movement patterns.

The problem of transferability for systems integrated into intelligent transportation systems, where it is necessary to predict pedestrian crossing intent, perform action prediction, and conduct behavior estimation in conditions different from the training data, is that of robust knowledge transfer across cities, cultures, and road infrastructure types, increasing the accuracy of risk assessment and enabling systems to make safe and timely decisions.

Effective solutions must combine the prediction of pedestrian intentions and trajectories with risk assessment to improve the safety and efficiency of transportation infrastructure.

Summary

Successful deployment in transportation systems requires algorithms to adapt to different environments, take into account the social and behavioral interactions of pedestrians, and provide timely risk assessments. The combination of prediction of intentions, trajectories, and risk assessment is a key element for improving the safety and efficiency of modern road infrastructure.

FAQ

Why is pedestrian behavior prediction important in complex traffic environments?

Pedestrian behavior prediction is crucial in complex, unstructured traffic because pedestrians display diverse and unpredictable actions. Accurate prediction of pedestrian crossing intent and action improves risk assessment and reduces potential conflicts between vehicles and pedestrians.

What are the main focus areas in pedestrian behavior prediction research?

The main focus areas are predicting pedestrian crossing intent, modeling future trajectories, and understanding social and environmental interactions. Together, these enable more accurate behavior estimation.

How do structured and unstructured datasets differ in this field?

Structured datasets (like KITTI or ETH) represent organized urban traffic with predictable pedestrian behavior, while unstructured datasets (like IDD-PeD) capture dense, heterogeneous, and unpredictable scenarios. Unstructured datasets are essential for robust behavior estimation in real-world conditions.

What is the contribution of IDD-PeD to pedestrian behavior research?

IDD-PeD provides data on pedestrians in highly unstructured traffic, capturing diverse behaviors, interactions, and pedestrian crossing intent. It addresses gaps in risk assessment for complex urban environments.

Which models are commonly used for pedestrian trajectory prediction?

Common models include LSTM/RNN for sequential action prediction, graph-based or social force models for interactions, and Transformer-based models for estimating multi-agent behavior. These models enable accurate forecasting of pedestrian movements.

Why is generalization important for pedestrian behavior models?

Generalization ensures models trained on one dataset perform reliably in different traffic environments. This improves risk assessment and makes pedestrian crossing intent and action prediction applicable to real-world deployments.

What challenges arise when transferring pedestrian behavior models across environments?

Transferability is limited by differences in traffic density, pedestrian culture, and road structure. Models may fail to accurately estimate behavior or predict crossing intent in unfamiliar, unstructured environments.

How do multi-modal datasets enhance pedestrian behavior estimation?

Datasets that combine camera, LiDAR, and GPS data provide a richer context for action prediction and pedestrian crossing intent. Multi-modal information improves risk assessment by capturing both motion and environmental cues.

How do interaction-aware models improve pedestrian behavior prediction?

Interaction-aware models consider social and vehicle-pedestrian interactions to refine behavior estimation. They improve risk assessment by predicting how one pedestrian’s actions influence others in heavy or unstructured traffic.

What are the key considerations for deploying pedestrian behavior models in intelligent transportation systems?

Deployment requires robustness to diverse scenarios, real-time action prediction, and accurate risk assessment. Integrating pedestrian crossing intent and trajectory modeling ensures safer and more effective traffic management.