In a negligence case, how is W's testimony about D1's bad driving treated?

In a negligence case, the treatment of testimony about a defendant's (D1's) behavior, such as bad driving, can impact how a plaintiff (W) supports their claim. The testimony regarding D1's poor driving is relevant to proving D1's negligence directly. Generally, if W's testimony specifically pertains to D1's actions and is based on W's personal observations, it would be admissible as evidence against D1 for failing to uphold the standard of care expected in driving.

However, if there is another defendant (D2), the admissibility of that testimony regarding D1's bad driving changes since it does not directly relate to D2's conduct unless it is being used to show a pattern of behavior that might implicate D2 by association, which would usually require context or further evidence establishing a connection.

In this case, the relevance of W's testimony is primarily tied to D1; hence, it would be admissible to establish D1's negligence while being less relevant to D2 unless there is some additional context showing that D1's actions had a direct bearing or contributory role involving D2. Therefore, the testimony about D1's driving is admissible solely for D1, supporting the view that W