Crash Investigations Class 315 Practice Test 2026 - Free Crash Investigations Practice Questions and Study Guide

Downstream describes the traffic moving away in the direction of travel after a point of reference, such as a crash site. It refers to vehicles that have passed the point and are continuing in the same direction, which is why departing traffic is the best fit. In contrast, approaching or upstream traffic is moving toward the point of reference, such as vehicles coming toward the scene. On-ramp traffic isn’t defined by its relation to the crash point, and stopped traffic isn’t inherently downstream—the term emphasizes movement in the direction of travel, specifically those leaving the scene or moving past it.