The Dart3 can log the below accelerometer based harsh driving events:

• Harsh Acceleration
• Harsh Braking
• Harsh Cornering

Installation and Auto-Orientation

The Dart3 can be mounted in any orientation. The device will automatically figure out which way is forward/back, left/right, and up/down. The Dart3 should not experience excessive vibration or rattle during driving. 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

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, or a DM RFID reader is used, 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.

Configuring Thresholds

The defaults work well for most vehicle, 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. There is no 'magic' setting per vehicle or asset type. Instead the best way to get the thresholds correct is simply some trial and error. 

If you are getting excessive alerts, just bump up the values.