Extreme care must be exercised. In other words, if the expert loses the item or alters it in any way by testing, neither that item nor your expert's testimony regarding his opinions as to its relevancy to the accident will be allowed. If you allow someone to remove, test or hold evidence, make sure they understand it must not be altered or destroyed until the other litigants have had a chance to examine it in its original state. Once you have the evidence in hand, you must consider the best way to present it to a jury. There are dozens of ways to present evidence.
Some types are simple and convey the message quickly and clearly.
Others are more involved and may be needed where complex issues or situations have to be presented. Still others, although simple in appearance, are difficult to produce and can be expensive. In any instance, it is imperative the attorney is aware of the different types of trial exhibits, the advantages and disadvantages of each and the cost of production for each type. For traffic accidents, the most common exhibit is the scale diagram. Prepared by an accident reconstructionist, these are simple in appearance but the amount of data required to prepare one can be tremendous.