Traffic Diagrams

Back in the day (in other words BC -Before Computers) in police work, officers used to have to draw collision scenes by hand. After a 40 hour class in investigation you were supposed to know how to draw a single two lane scene.

When I became a traffic investigator I and my partner were assigned to handle the serious or fatal collision. I always volunteered to do the diagram for a challenging scene and my partner would gladly handle the written investigation (anywhere from 10 to 50 pages) because he thought the scene was daunting. The diagram was the only document in police reports that were allowed to be in pencil.

click on image to enlarge

So the scene had to be recreated almost to scale by using tape measures and stroll-meters to plot location of evidence and the scene. I would grab a rookie and tell him to measure from a certain point to another point while I filled page after page with measurements and rough sketches. Everything pertinent had to be described and plotted for court or reconstruction purposes.

This case, a car drove off the road and flew over the edge hitting a tree about 40 feet below. The license plate was embedded into the tree and of course I loved showing that! The family believe the driver swerved to avoid another car but the tire track and lack of skids pointed to the more likely possibility of him falling asleep at the wheel.

Now the lucky cops have computers to do all this.