ICR-DS: In-Cabin Radar Driver State Dataset

ICR-DS (In-Cabin Radar Driver State) is a multimodal naturalistic driving dataset for driver vigilance and physiological state monitoring. The dataset was collected from 28 participants during approximately 50 minutes of real-world urban and highway driving using synchronised wearable physiological sensing, radar, and an in-cabin RGB camera.

To provide an objective measure of vigilance, each participant completed a Psychomotor Vigilance Test (PVT) before and after each drive. The dataset therefore supports longitudinal analysis of behavioural and physiological driver-state measurements, as well as future development of non-contact physiological monitoring using in-cabin radar sensing.

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Overview

Each recording session is stored as a single HDF5 file. The file contains:

• raw signals retained at native resolution
• processed metrics computed from windowed aggregation
• session-level attributes describing the participant, timestamps, sensor configuration, and modality availability
• PVT summaries collected before and after the drive

The dataset includes synchronised recordings from:

• a 60 GHz FMCW radar sensor
• a BioHarness 3 chest strap
• an in-cabin RGB camera
• session-level PVT outcomes

OpenFace was applied to the video stream to derive eye and head-behaviour measurements.

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Session Attributes

Each HDF5 file contains the following session attributes:

Attribute	Example	Description
session_id	"s027_2026-05-08"	Session identifier
subject_id	"s027"	Subject identifier
start_time_iso	"2026-05-08T11:27:21Z"	Session start time in UTC ISO-8601 format
end_time_iso	"2026-05-08T11:28:32Z"	Session end time in UTC ISO-8601 format
frame_period_s	0.09	Radar frame period in seconds
carrier_freq_hz	60000000000	Radar carrier frequency
wavelength_m	0.005	Radar wavelength
range_resolution_m	0.0843	Radar range resolution
has_radar	"present"	Radar availability flag
has_vision	"present"	Vision availability flag
has_bioharness	"present"	BioHarness availability flag
has_gps	"present"	GPS availability flag
has_pvt	"present"	PVT availability flag

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HDF5 File Structure

Each session file follows this structure:

/
├── raw/
│   ├── radar/
│   │   └── beamformed_cube
│   ├── physiology/
│   │   ├── hr_1hz
│   │   ├── br_1hz
│   │   ├── ibi
│   │   └── ibi_ts
│   ├── vision/
│   │   ├── landmarks_raw
│   │   ├── gaze_xy
│   │   ├── pose_rxyz
│   │   ├── eye_open
│   │   └── confidence
│   └── labels/
│       ├── motion_flag
│       ├── predrive
│       └── postdrive
└── processed/
    ├── physiology/
    │   ├── mean_hr
    │   ├── mean_br
    │   ├── rmssd
    │   ├── sdnn
    │   ├── pnn50
    │   └── hf
    └── vision/
        ├── blink_rate
        ├── perclos
        ├── blink_duration
        ├── gaze_speed
        ├── gaze_x_std
        ├── gaze_y_std
        ├── head_speed
        ├── head_yaw_std
        ├── head_pitch_std
        └── head_roll_std

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Radar Data

Each radar sample is stored as a beamformed complex IQ tensor with shape:

(Window, IQ, Doppler, Direction, Range) = (200, 2, 5, 63, 7)

Radar tensor dimensions

Dimension	Size	Description
Window	200	Consecutive radar frames sampled every 90 ms, giving approximately 18 seconds of observation
IQ	2	Real and imaginary components of the beamformed signal
Doppler	5	Low-velocity Doppler bins centred on zero Doppler
Direction	63	Beamformed look directions (9 azimuth × 7 elevation)
Range	7	Selected range bins corresponding to the driver region

The raw radar stream is retained at native resolution and stored in raw/radar/beamformed_cube.

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Physiological Signals

The BioHarness 3 chest strap provided:

• heart rate at 1 Hz
• breathing rate at 1 Hz
• R-R intervals as event-based measurements

Raw physiology is stored in:

• raw/physiology/hr_1hz
• raw/physiology/br_1hz
• raw/physiology/ibi
• raw/physiology/ibi_ts

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Vision Signals

The in-cabin RGB camera was mounted next to the radar and focused on the driver's head and face. OpenFace was applied to the video stream to derive eye and head-behaviour measurements.

Raw vision features are stored in:

• raw/vision/landmarks_raw
• raw/vision/gaze_xy
• raw/vision/pose_rxyz
• raw/vision/eye_open
• raw/vision/confidence

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PVT Labels

To provide objective vigilance measurements, participants completed a Psychomotor Vigilance Test before and after each drive.

The following outcomes were extracted:

• mean_rt_ms
• median_rt_ms
• reciprocal_rt_1_per_s
• lapse_rate
• commission_rate

These are stored in:

• raw/labels/predrive
• raw/labels/postdrive

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Motion Flag

A motion flag is stored in:

• raw/labels/motion_flag

This signal is generated from aligned vehicle and body motion sources and stored as a session-aligned derived label signal.

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Temporal Alignment

Each modality had its own time stream and was synchronised using the latest common start time, with the earliest end time defining the shared analysis interval.

Raw signals were retained at their native resolution. Feature extraction begins after a 5-minute offset to enable reliable HRV estimation and maintain alignment across modalities.

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Processed Features

Processed features were computed from the raw signals using fixed temporal aggregation windows.

Physiology Metrics

Physiological features were computed every minute using a 5-minute rolling window.

Metric	Unit	Description
Heart rate	bpm	Mean heart rate
Breathing rate	breaths/min	Mean breathing rate
RMSSD	ms	Root mean square of successive R–R interval differences
SDNN	ms	Standard deviation of normal-to-normal intervals
HF power	ms²	High-frequency HRV power
pNN50	%	Percentage of successive R–R intervals differing by more than 50 ms

Stored in:

• processed/physiology/*

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Vision Metrics

Blink-based measures were computed over non-overlapping 1-minute windows. Gaze and head-pose features were computed over non-overlapping 10-second windows to capture short-term changes in visual scanning behaviour.

Blink Metrics

Metric	Unit	Description
Blink rate	blinks/min	Number of blink events per minute
Blink duration	s	Mean duration of detected blinks
PERCLOS	%	Percentage of time the eyes are closed

Stored in:

• processed/vision/*

Gaze Metrics

Metric	Unit	Description
Gaze x std	rad	Variability of horizontal gaze angle
Gaze y std	rad	Variability of vertical gaze angle
Gaze speed	rad/s	Mean rate of gaze-angle change

Head Pose Metrics

Metric	Unit	Description
Yaw std	rad	Variability of yaw angle
Pitch std	rad	Variability of pitch angle
Roll std	rad	Variability of roll angle
Head speed	rad/s	Mean rate of head-pose change

Stored in:

• processed/vision/*

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Loading the Dataset

Each HDF5 file corresponds to a single driving session.

A session can be loaded using h5py:

import h5py

with h5py.File("s027_2026-05-08_session.h5", "r") as f:
    radar = f["raw/radar/beamformed_cube"]
    physiology = f["raw/physiology"]
    vision = f["raw/vision"]

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Intended Use

This dataset is intended for research on:

• driver vigilance estimation
• physiological state monitoring
• multimodal learning
• radar-based non-contact sensing
• joint behavioural and physiological analysis
• longitudinal comparison of pre-drive and post-drive vigilance outcomes

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Citation

If you use this dataset in your research, please cite the associated publication (citation to be added).

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License

This dataset is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license.

For the full license text, see: https://creativecommons.org/licenses/by/4.0/