Atourniquet is a band that is placed over a major artery to constrict the flow of blood. would you expect a tourniquet over the radial artery (near the elbow) to increase the blood pressure on the proximal side of the band (closer to the center of the body) or the distal side of the band (closer to the fingers)? why?

You should expect a tourniquet near the elbow, closer to the center of the body. This is to prevent the further loss of blood from the radial artery. This is major artery responsible for the blood supply of the arms. Tourniquets are one of the major first aid materials found in a first aid kit.

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.