It seems the reason Zone exceptions don't trigger sometimes is because of a GPS record not being recorded during the time the vehicle travelled through the zone. For now what you can do is increase the size of zones you notice aren't triggering so there is a longer period of the vehicle being in the zone to capture a GPS record. I have brought this issue up Geotab to investigate if a new feature can be developed to address this.
Example issue - 66971 (Geo ticket 386826):
Database: tolko, Server: my137.geotab.com
Customer is reporting that many Rules are not being triggered at times. Specifically in this case:
Date/time: 01/09/2017 16:10 Vehicle: 1532_Timbertech - G71620DBF51E Rule: Inside Gate (Condition - inside Zone Type Gate)
The Rule triggered 3 other times that day. The following Trips History shows the trip in which the vehicle passed through zone Gate-WattE which is zone type Gate at 16:10 that day but no exception is triggered:
There don't seem to be any Engine Faults that would cause a loss in data at that time (See attached). I checked the Audit Log already as well and there is no record of events, rules or zones being edited or removed for that day.
Wentao Xu (2018-02-01 16:56:36)
Thanks for contacting Geotab Support.
The exception is not triggered as there are no valid GPS logs been recorded when the vehicle driving in the zone during that time. Let's take a look at the examples of exception been triggered and the exception not been triggered for comparison.
1. exception triggered
As we can see from 16:46:58 ET to 16:48:28, the vehicle is driving inside the zone. And from the back end logs, we can see there are logs been recorded at that time, so this exception has been triggered.
From the trip history the vehicle is inside the zone from 19:10:06 to 19:11:06 ET, however, as we can see from the back end log there is no valid logs been recorded at this minute, which we have log at 19:09:42 and log at 19:11:21, and no logs been recorded in between. So this exception has not been triggered.