Push Crash Data

Introduction

The transfer of data collected by the DriveKit SDK during a collision and the crash insights are a common need for DriveQuant platform users. Crash data can be shared to:

• An assistance platform in order to alert an operator, who may decide to call in a tow truck or the emergency services.

• An insurance platform to open a claims report and use the data to accelerate decision-making and processing.

This is why DriveQuant offers the possibility to retrieve all the data collected by the mobile SDKs during a collision as well as all the crash indicators that result from our analyses. This is the purpose of the Crash Data Push service.

Principle

The crash data push service sends the crash analysis results right after it is completed and analysed.

The accident detection and confirmation cycle is described below.

• Crash detection is active only while a trip is being recorded. Trip recording is automatically triggered by the DriveKit SDK, which can detect a vehicle's displacement.

• The SDK constantly analyses the data collected by the phone's sensors during the trip. In case of a collision, the DriveKit SDK sends a portion of data to the DriveQuant platform for analysis.

• The DriveQuant platform performs signal processing on the raw data to extract sensitive indicators. These indicators are analysed by an algorithm trained to identify accidents by similarity with a confirmed accident database.

• As soon as the analysis is complete, the data is transmitted to your platform through the crash data push service.

Collision detection on the smartphone is instantaneous. Then, 20 seconds are required to record the post-collision data before sending the data to the DriveQuant platform. Crash confirmation on our platform takes less than a second. As soon as the crash is confirmed, the data is pushed. Overall, it takes less than 30 seconds from the time of collision to get accident data on your platform.

Configuration and Automatic retry

Crash data is sent as a POST request to a client URL. The URL must be provided to DriveQuant in order to set up and activate the crash data push service.

The body of the request is a JSON object with a set of fields that contain the raw data and crash indicators.

It is mandatory to configure a adequate response code: if the push request is accepted, we expect a 200 (OK) http status code. Any other code will be considered as a failure, and the service will attempt to send the crash data again every minute for 30 minutes. If the request still fails after 30 attempts, the crash will be sent once a day until receiving a valid answer, or until the crash expires.

If the service returns a 200 http code, while the data has not been accepted by your server, then there will be no further attempt to send the data.

The expiration period of a crash whose probability is lower than 20% is at most 90 days. Therefore, if your push services are configured to receive both confirmed and unconfirmed crashes, any crash with a probability lower than 20% will be deleted after 90 days, even if it could not be sent to your platform.

Security

See Security in parent section.

Sample Message

The crash data push API specification can be downloaded here in OpenAPI YAML format.

Sample message (click to expand)

{
    "crashId": "676300727dba71011b728ddf",
    "customerId": "------------------",
    "driverId": "------------------",
    "userId": "------------------",
    "state": "CONFIRMED",
    "probability": 78,
    "predictionVersion": "1.3.0",
    "parameter": {
	"localTripId": "1b17c96284d3e7faf275d7c30142a89a0444b819fa75ead7601f15dd01deff26_1734540967.843855",
	"date": "2024-12-18T17:03:26.570+0000",
        "tripStartDate": "2024-12-18T16:56:07.844+0000",
        "gpsWindowNeg": 20,
        "gpsWindowPos": 20,
        "imuWindowNeg": 5,
        "imuWindowPos": 10,
        "imuFrequency": 100,
        "installationId": "9cc02aaa-92b4-cbd2-73fb-3dda6243dddf"
    },
    "gps": {
        "timestamp": [
            0,
            0.98,
            2.01,
            "//... 37.98",
            38.98
        ],
        "latitude": [
            41.912932,
            41.912858,
            41.912822,
            "//... 41.910656",
            41.910656
        ],
        "longitude": [
            12.454223,
            12.454248,
            12.454268,
            "//... 12.454856",
            12.454856
        ],
        "velocity": [
            18.21,
            18.22,
            18.06,
            "//... 0",
            0
        ],
        "heading": [
            166.283,
            166.268,
            169.471,
            "//... 170.671",
            170.671
        ],
        "accuracy": [
            24,
            24,
            24,
            "//... 12",
            12,
            12
        ],
        "elevation": [
            70.5,
            70.3,
            68.4,
            "//... 70",
            70.1
        ]
    },
    "movements": {
        "timestamp": [
            0,
            9,
            20,
            "//... 14969",
            14980
        ],
        "accelerationX": [
            504,
            687,
            726,
            "//... 197//",
            192
        ],
        "accelerationY": [
            985,
            862,
            934,
            "//... 985//",
            981
        ],
        "accelerationZ": [
            20,
            230,
            314,
            "//... 57//",
            65
        ]
    },
   "gpsFeatures": {
    "index": 20,
    "time": 20,
    "latitude": 43.677391,
    "longitude": 1.532724,
    "crashType": 1,
    "stopTime": 35,
    "stopDuration": 15,
    "stopDistance": 20,
    "velocity": 22.94,
    "velocityMin": 0,
    "velocityMax": 41,
    "velocityClass": 2,
    "velocityPreNear": 29.31,
    "velocityPreFar": 37.41,
    "velocityPostNear": 18.36,
    "velocityPostFar": 0.52,
    "velocityOffsetNear": 10.95,
    "velocityOffsetFar": 28.79,
    "acceleration": -0.609,
    "accelerationMin": -1.653,
    "accelerationMax": 0.195,
    "heading": 0.44,
    "yawRate": 0.0609,
    "yawRateMin": -0.6862,
    "yawRateMax": 0.6683,
    "available": true
  },
  "movementFeatures": {
    "index": 503,
    "module": 11.21,
    "time": 5.03,
    "energy": 24.39,
    "power": 1.62,
    "energyNear": 5.01,
    "energyFar": 0.87,
    "powerNear": 8.35,
    "powerFar": 1.47,
    "stdModuleNear": 1.91,
    "stdModuleFar": 0.03,
    "stdModuleOffset": 1.88,
    "entropyNear": -1.45,
    "entropyFar": -0.27,
    "entropyOffset": -1.18,
    "meanModuleNear": 2.15,
    "meanModuleFar": 1.2,
    "meanModuleOffset": 0.95
  },
    "userLocationUrl": "https://sharedtrip.drivequant.com/v1/CQD5hLox7"
}

Definitions

The content of the crash body request is described in the following section.

Crash identification and status

Name	Description
crashId	Unique crash identifier
userId	Unique user identifier
state	Crash state Allowed values: CONFIRMED, UNCONFIRMED
probability	Crash probability
userLocationUrl	URL link that directs to a map displaying the user's location after a confirmed accident

Crash recording configuration (parameter)

Name	Unit	Description
localTripId	-	Unique trip identifier
date	-	Crash date
tripStartDate	-	Trip start date
gpsWindowNeg	s	Recording duration of GPS data before detection Default value: 20 s
gpsWindowPos	s	Recording duration of GPS data after detection Default value: 20 s
imuWindowNeg	s	Recording duration of accelerometer data before detection Default value: 5 s
imuWindowPos	s	Recording duration of accelerometer data after detection Default value: 10 s
imuFrequency	Hz	Accelerometer signal recording frequency Default value: 100 Hz
installationId	-	Unique identifier of an installation

GPS data recorded during the crash (gps)

Name	Unit	Description
timestamp	s	Time in seconds
latitude	deg	Latitude
longitude	deg	Longitude
velocity	km/h	Velocity
heading	deg	Heading
accuracy	m	GPS accuracy
elevation	m	Elevation

Acceleration data recorded during the crash (movements)

Name	Unit	Description
timestamp	ms	Time in millisecond
accelerationX	mG	Acceleration component along the East axis in the Earth reference frame
accelerationY	mG	Acceleration component along the North axis in the Earth reference frame
accelerationZ	mG	Acceleration in the vertical direction, perpendicular to the Earth's surface

Schematic representation of the data

Sample of crash data: velocity (top) and acceleration signal magnitude vector (SMV, bottom).

How to use crash data in an assistance context?

The push crash data service is designed to automatically make an emergency call to an assistance operator. The data shared by this service in meant to help the operator take the right decision in assisting the driver, depending on the severity of the accident. For example:

• Call the driver to obtain confirmation of the accident.

• Send a towing vehicle in the case of mechanical damage.

• Send the emergency services if there is a severe accident.

Assessing the situation and the severity of the accident is critical and can be facilitated by the following indicators:

• The probability of an accident, expressed as a percentage.

• The velocity at the time of collision. At high speeds, a vehicle stores more kinetic energy, which will cause more damage the force of the collision.

• The force of the impact measured by the smartphone. The severity of the accident increases with the force measured.

• The location of the user after the time of collision.

In addition to the characteristics and location of the accident, the DriveKit SDK also measures and shares the smartphone's live location after the accident. Therefore, the operator can easily determine whether the driver is continuing his route or has stopped near the place of the accident, which can help evaluating the severity of the accident.

The most relevant informations is displayed on a web page, which can be accessed from a unique URL provided in the userLocationUrl field of the push crash request's body (see above), and in a callback of the DriveKit SDK crash events listener (see android or iOS references):

• The web page displays the crash data and the smartphone's live location, updated every 10 seconds until the trip recording ends.

• The data displayed on the web page is limited to the trip during which the accident was detected and confirmed.

• The URL expires after 24 hours by default, or can be revoked anytime using the dedicated DriveKit admin API.

Display of a user's location during a trip: (a) the green pinpoint indicates the collision location; (b) the blue circles represent the user's location before and after the detected collision (by default, ± 20 s); (c) the blue dots represent the user's locations after the collision (refreshed every 10 s).