Vehicles and Tires as Evidence Take notes on

Vehicles and Tires as Evidence Take notes on page 108

Anatomy of a Tire � Different characteristics of tires can help identify a specific brand narrow down the suspect pool Ridges – elevated regions of tires (also known as ribs) Grooves – indentations on tires Tire width Unique characteristics: imperfections in tread patterns due to wear and tear, pebbles embedded in grooves ◦ Angle of tread pattern ◦ ◦

Anatomy of a Tire � How many ridges? ◦ 5 � Centered or offcentered? ◦ Centered

Identifying Vehicles � Multiple vehicles could have the same type of tire; track width and wheelbase narrow down the search � Track width – measured from the center of each tire to the center of the opposite tire (need to measure front and rear) � Wheelbase – distance between the center of the front axle and the center of the rear axle

Track Width and Wheelbase � Which letter represents front track width? � Which letter represents rear track width? � Which letter represents wheelbase?

Turning Diameter/Radius �A measure of how tight a circle can be driven by a vehicle � The minimal amount of space required for a car to make a U-turn � During a sharp turn, the front outer tire creates a track because of additional stress � Helps determine size of vehicle (longer turning diameter, longer wheelbase, longer vehicle)

Turning Diameter/Radius � Which vehicle has the most distance between front and rear tires? � What is this distance called? � How does that vehicle’s turning diameter compare to the other vehicles?

Track Width, Wheelbase, Turning Diameter � How do you determine which vehicle was at a crime scene if you can determine track width, wheelbase and turning diameter from skid marks? ◦ Database of automobile statistics by make and model ◦ Look up wheelbase and turning diameter to locate make and model of vehicle

Wear Patterns on Tires � How are these factors going to affect tread patterns on tires? ◦ Under inflated tires ◦ Unbalanced tires ◦ Worn tires ◦ Damaged tires