Final answer:
The timing of 2/3rds of deer collisions relates to periods of high deer activity such as mating season or migration, often occurring in fall and early winter, and typically during times of low visibility like dusk and dawn.
Step-by-step explanation:
The question of when 2/3rds of deer collisions occur is related to wildlife activity patterns and driver behavior, rather than specific statistics on traffic collisions or vehicle physics. Hence, the exact time of year when the majority of deer collisions happen is not provided within the provided references.
Typically, deer collisions are more frequent during certain times of the year when deer are more active, such as mating season or when they are migrating to new habitats. This often corresponds to the fall and early winter months. Additionally, driving conditions and visibility may also play a role, as collisions are more likely to happen during dusk or dawn when visibility is lower, and deer are more active.
It is important to remain alert, especially during these high-risk times, to prevent traffic collisions with deer.