In the southern european plains, a species of flower comes in two colors, purple and pink. when pink flowers are most common in a field, bees visit and pollinate the purple flowers more often, and vice versa. this switching of pollinator preference will result in

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.