What
Start with the payroll side, because that is where the symptom shows up first. Pull your overtime hours for a fixed period, say the last quarter, and put them next to the time-on-site totals your fleet tracking system recorded for the same drivers over the same weeks. If payroll shows more paid hours than the system can account for at customer locations, you are not looking at a driver effort problem yet. You are looking at a reporting gap, and delayed geofence alerts are one of the most common places that gap hides. Overtime is often a symptom of poor route planning and unchecked driver behavior rather than pure workload, which is why the numbers rarely match up neatly on the first pass.Next, measure the delay itself. Pick the stops where drivers commonly arrive right at the edge of a service window. For each one, compare the physical arrival or departure time, recorded by the driver, a customer sign-in sheet, or a yard log, against the timestamp on the geofence alert. Do this across fifty stops or so, and you will get an average delay figure. Multiply that delay by your daily stop volume per driver. Ten minutes per stop sounds harmless on paper, but across multiple territories and dozens of vehicles it turns into a real financial leak, and it quietly pushes completed work past the eight-hour mark.A controlled test sharpens the picture. Choose one route and record arrival and departure times independently for a week, then compare them against the geofence alerts in your system. If the variance is consistent and one-directional, the problem is systematic rather than random. If it only appears in specific areas, you are probably dealing with coverage rather than configuration.Now isolate the cause. Three things usually explain unreliable geofence alerts: ignition detection settings on the device, weak cellular coverage in the affected zones, and geofence radius or debounce settings that are too tight or too loose. Check each in that order. A geofence drawn too small will trigger late as the vehicle crosses the boundary, while an overly sensitive one fires early and logs the wrong arrival time.Then tune before you buy anything. Widen or reshape the geofence radius, adjust dwell time thresholds so brief pass-throughs do not register as stops, and add signal filtering to smooth out the jitter that shows up in tunnels and dense urban corridors. Watch your time-on-site variance for two to three weeks after each change. Change one setting at a time, or you will never know which adjustment actually helped.After tuning, reconfigure your route parameters. Shift the priority from pure distance to time windows, so dispatch is working from planned schedules instead of manually patching around stale location data. Route optimization uses vehicle telematics to calculate the most efficient sequence of stops, minimizing miles driven and idle time, and that logic falls apart when the underlying arrival data is late. If dispatchers cannot see where a vehicle actually is, they assume the schedule is holding, and the day ends with mandatory overtime to finish the remaining work. Inaccurate time tracking caused by delayed geofence alerts is a well-documented driver of unpaid or disputed overtime, so closing that loop matters for compliance as much as for cost.Set a decision boundary and stick to it. If geofence entry alerts are still unreliable after you have tuned the parameters and reconfigured the route logic, internal fixes have hit their ceiling. Poor cellular coverage and software that cannot handle complex multi-stop routes in real time are limits you cannot configure your way out of. At that point, compare the overtime leakage still on your books against the cost of replacement hardware or a different platform. When the monthly bleed exceeds the replacement cost, the decision makes itself. Until then, measure first, tune second, and replace only when the data says you have run out of room.