While a vehicle's stopping distance is relatively easy to test under controlled circumstances, it can be harder to judge objectively when behind the wheel. External factors ranging from road conditions to tire wear can greatly affect your car's ability to stop, creating some day-to-day variation. However, more significant changes in braking performance are often far more noticeable and distressing.

If you're noticing a reduction in braking performance, the solution is straightforward: have a competent shop investigate as soon as possible. Still, you're probably interested in knowing why your brakes aren't performing as well as you might expect. While there are many potential causes for reduced braking performance, here are three of the most common.

1. Severely Worn Brake Pads

Normal wear and tear on your brake pads shouldn't reduce their performance. The wear indicator will make contact with metal (creating the loud squealing you hear when your brakes require replacement) while plenty of "meat" remains on your pads. Although it's still important to change your brake pads soon, they will continue to provide solid performance for a while longer.

However, ignoring this warning sign can allow your brakes to wear down to the backing plate. You may hear a grinding noise at this point, and your braking performance can suffer severely. This condition may also damage your rotors, reducing brake performance further and creating vibrations or other symptoms.

2. Stuck Calipers

Your car's calipers compress your brake pads against your rotors, creating the friction necessary to stop your vehicle. A stuck caliper will prevent the pads from extending or retracting. This situation can leave the pads stuck in contact with the rotors or prevent them from gripping down, although the former failure mode is more common.

A stuck caliper usually indicates another issue with your braking system, such as a collapsing brake hose. If you have a stuck caliper, you might notice excessive brake dust or one wheel or feel your car pulling in one direction while braking. Stuck calipers are serious problems that can make your car's braking unreliable and unpredictable, so it's critical not to ignore these warning signs.

3. Brake Fluid Issues

Your car relies on adequate hydraulic pressure to compress your brakes and bring your car to a smooth and safe stop. Issues with your car's brake fluid, including low fluid levels, burnt or contaminated fluid, and collapsed brake hoses, can substantially impact braking performance. In many cases, the most noticeable symptom will be a change in brake pedal feel.

If your brake pedal feels soft or immediately goes to the floor, your car is unsafe to drive, and you'll need to call for a tow to a brake repair shop.