Rear-end collision diagram: a worked example

The scenario

V2 is stopped at a signal (or slowing in queue). V1 approaches in the same lane and strikes V2 from behind. Impact point X1 sits between V1's front and V2's rear. So far, any sketch shows this. Now the parts that matter:

The three details that make it useful

• ▸Braking evidence: draw the skid mark as a line behind V1 and measure it. Skid length can provide useful context in a rear-end case, depending on the circumstances.
• ▸The lead vehicle's state: stopped at a light? Note the signal in the diagram and say 'stopped' in the narrative. Moving slowly? The arrow lengths can suggest relative speeds, and the narrative should state them.
• ▸Impact alignment: dead-center, or offset toward a corner? An offset impact often means a late lane change or an attempted swerve — draw the vehicles with the true overlap.

Multi-vehicle chains

For a chain (V1 pushes V2 into V3), number the vehicles from the rear-most striking car forward and mark each impact point separately (X1, X2). The narrative should state the order of impacts if known — the diagram alone cannot prove sequence.

Draw it

Use the one-way road or highway template, place V2 (and V3) in the lane, place V1 behind with a skid line and a measurement, add the signal if there was one, mark the impact points and export.