Inspect your tires: Worn-down tires make it hard to stop, even if your brakes are in good order. Try the coin test on your tires: Insert a quarter into several grooves across each tire. If part of Washington's head is always covered, you still have 4/32 inch of tread left and can probably drive safely. If you have less tread, it's time to think about replacements. (A definite danger signal comes when you slip a penny into a groove and the tread does not reach Lincoln's head.)
Even if your tire tread are OK, make sure you keep them inflated to the pressure listed on the placard visible when the driver's door is open. You can boost your gas mileage by 3% or more and make the car safer as well. To get an accurate reading, check the pressure of tires when they are cold, not when you have been driving.