Harsh Driving Event Setup
Written by Matthew Clark-Massera
Updated at March 12th, 2025
Table of Contents
Digital Matter hard-wired devices can log the below accelerometer based harsh driving events:
- Harsh Acceleration
- Harsh Braking
- Harsh Cornering
Installation and Auto-Orientation
Devices can be mounted in any orientation. The device will automatically figure out which way is forward/back, left/right, and up/down.
Mount the device such that it does not experience excessive vibration or rattle during driving - i.e. don't loosely cable tie the device under the dash so that it shakes about.
Once powered, the device will begin to continuously self-calibrate. It begins from an uncalibrated state, in which the harsh driving detection is disabled, and the accident detection is in a basic mode that ignores orientation. Once the vehicle begins a trip, each time it accelerates, brakes, or turns, the unit can compare the acceleration to the GPS velocity to determine its orientation. Each maneuver increases the accuracy of the orientation, and when the accuracy is high enough, harsh driving and advanced accident detection are enabled. This typically takes 10 to 15 minutes of normal driving.
System Parameters
Each device has slightly different configuration:
- Bolt2
- 1 x acceleration, 1 x braking, and 1 x cornering threshold and duration (time over threshold) can be defined
- The device will log an event when a threshold is exceeded
- A Log Backoff Time
- Dart3 + G70 series
- As per Bolt2 above
- Additionally, a number of beeps per threshold can be defined - to provide in cab feedback to the driver they have breached a threshold
- G120 & G150
- As per Dart3 + G70, but two threshold are available.
Bolt2
For each event type (Acceleration, Braking, Cornering) there are the following parameters:
- Log Threshold
- Log Duration
By default, the log thresholds are:
- Harsh Acceleration + Braking = 4.4m/s^2
- Harsh Cornering = 5.5m/s^2
Duration is 0. This means an 'instantaneous' event (as detected by the accelerometer, which runs at 100Hz) that exceeds the threshold is logged.
A duration can be added such that brief events can be filtered out. However we find most partners get on fine with the defaults. It should be noted adding a lengthy duration can potentially prevent any events from being logged.
An event will be logged if the acceleration exceeds the threshold for at least the configured Log Duration Threshold (seconds). A second event is logged if the acceleration drops below the threshold for the configured Log Duration Threshold (seconds) and then exceeds the threshold again for the configured Log Duration Threshold (seconds).
The Lock Backoff Time can be thought of as a ‘debounce’ where if a harsh event occurs, subsequent events are not logged until the Backoff Time elapses. This can be used to avoid
Dart3 & G70
For each event type (Acceleration, Braking, Cornering) there are the following parameters:
- Log Threshold
- Log Duration
- Beep Number
By default, the log thresholds are:
- Harsh Acceleration + Braking = 4.4m/s^2
- Harsh Cornering = 5.5m/s^2
Duration is 0. This means an 'instantaneous' event (as detected by the accelerometer, which runs at 100Hz) that exceeds the threshold is logged.
A duration can be added such that brief events can be filtered out. However we find most partners get on fine with the defaults. It should be noted adding a lengthy duration can potentially prevent any events from being logged.
An event will be logged if the acceleration exceeds the threshold for at least the configured Log Duration Threshold (seconds). A second event is logged if the acceleration drops below the threshold for the configured Log Duration Threshold (seconds) and then exceeds the threshold again for the configured Log Duration Threshold (seconds).
Beep Number
If an external buzzer is configured setting these parameters will sound the buzzer when an event is logged, provide the driver in-cab feedback that they have exceeded the threshold so that they can adjust their driving.
G120 & G150
The Harsh Driving parameter is added from Parameters -> Edit System Parameters -> Add Parameter -> Harsh Driving.
The G120 & G150 have two Harsh event Thresholds marked "A" and "B" in the parameter tab. This allows for the following operation
- Threshold A set at a certain level. The device will beep to provide in-cab feedback to the driver that they have breached a threshold.
- Threshold B can then be set at a higher level, where the device will log this event as well.
- Threshold A provides a warning to the driver, threshold B is logged for reports in TG or another platform - and action can be taken to rectify these drivers behaviour.
- The above is just the intended application - yet we can use only 1 threshold, or both, beep and log on both etc.
The Duration on both thresholds are disabled by default. This means that any instantaneous event (as detected by the accelerometer, which runs at 100Hz) that exceeds the threshold will be logged. A duration can be added such that brief events can be filtered out.
We find most partners get on fine with the defaults. It is important to keep in mind that adding a lengthy duration can potentially prevent any events from being logged, so it would be best to test these settings before rollout.
An event will be logged if the acceleration exceeds the threshold for at least the configured Log Duration Threshold (seconds). A second event is logged if the acceleration drops below the threshold for the configured Log Duration Threshold (seconds) and then exceeds the threshold again for the configured Log Duration Threshold (seconds).
Beep Number
Configuring the beep numbers will sound the internal buzzer on the G120 or G150 (or any external buzzers connected) when an event is logged and provide the driver in-cab feedback that they have exceeded the threshold so that they can adjust their driving.
Setting Thresholds
The defaults work well for most, but not all vehicles, however here are some notes on setting the right level if they need adjustment.
- Defaults: acceleration and braking thresholds are 4.4m/s^2, and Cornering is 5.5m/s^2. These are set reasonably high to log a minimum number of events on most vehicles.
- Testing: Set the thresholds artificially low to generate events. Acceleration and braking can be configured to 3.0m/s^2 and Cornering to 3.5m/s^2
- In practice: Choose levels between the defaults and the testing levels (i.e. start low, and slowly bump up until you're no longer getting excessive events)
Harsh Events on Telematics Guru
For TG users, Harsh Event Logging must also be configured in TG to log these events in Harsh Driving Reports. See Harsh Driving On Telematics Guru.
Excessive Alerts
Different vehicles require different thresholds for triggering events, therefore it is important to test and adjust the thresholds. A large truck and a motorcycle will require very different thresholds.