VTC Regions Guide

This guide will show you how to configure regions in order to classify turns/link movements (left, right, through). There are two main concepts:

  1. The “Region of Interest” (ROI): This outline should include the area of video that contains traffic, and nothing else. The purpose of the ROI is to ignore non-traffic movement in the video.

  2. Approach and Exit regions: Each pair of approach/exit regions (for example, Approach 1 and Exit 1) originates from one road. The Approach and Exit numbering is based on a 4-way intersection; the approaches are numbered in counterclockwise order. A typical 4-way intersection will have four Approaches and four Exits. The purpose of the Approaches and Exits is to determine which road a vehicle appeared and exited on. This is used to classify the movement.

VTC can be configured for junctions other than 4-way intersections. To configure a two-way road without any junction, set one direction as Approach1/Exit1 and the opposite direction as Approach3/Exit3. Selecting Approach2/Exit2 and Approach4/Exit4 would yield the same result.

Drawing a Region Shape

VTC determines which road a vehicle entered from by comparing the vehicle’s first location to the nearest Approach/Exit region. Vehicles inside a region will be assigned to that region. Vehicles outside a region will be assigned to the nearest region.