Solution

Numerous states and provinces have chosen Strieter-Lite reflectors and drastically cut down on night time deer-vehicle collisions. Here is how they work.

Here is the corresponding action sequence:

A deer approaches the road at
dusk, dawn or night.
Car headlights shine on the
reflectors. The deer sees the
reflected light, is startled, and
 waits or runs away.
The deer has safely crossed the
road after the car has passed.

Here are the results as reported by highway officials in states and provinces that have installed the reflectors.