Troubleshooting

Optimizing Volume Count Accuracy

The most common reasons for vehicle count discrepancies are:

• Zone boundaries overlap or are too close - When this occurs, vehicles in one zone are shown as being in an adjacent zone. This is referred to as "splashing". In this case, changing the zone by increasing or decreasing the boundary can eliminate splashing.
• Improper sensor aiming - When this occurs vehicle counts are below what is expected. If the sensor is aimed too low or high, or is not perpendicular to the zone, vehicles may not be detected.
• Obstruction between the sensor and zone - An obstruction, such as concrete lane divider may cause smaller vehicles to be missed.
• Occlusion - This is when a vehicle is hidden from view by another vehicle or object. A large truck can occlude (hide) the detection of a small car hidden behind.

For additional information, see:

• Optimizing Counts: Over/Under Count in Adjacent Zone
• Optimizing Counts: Under Count in Near Zone
• Optimizing Counts: Under Count in Far Zone
• Optimizing Counts: Under Count in Several Zones
• Optimizing Counts: Over Count in Several Zones
• Optimizing Counts: Under Count in First Zones Past a Barrier

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