Traffic Control Products that are used to slow down, stop and/or prevent structural damage on vehicles are called Speed Bumps and Clearance Bars.
You are maybe more familiar to speed bumps than clearance bars. This is because speed bumps can be seen in almost every street and parking lots. This bumps are used to enforce minimum speed especially on potentially hazardous driveways and streets. This also works as a protective stopper on sloped streets and parking areas. Speed bumps are made with highly durable polyethylene materials, which can hold extreme weight and everyday outdoor exposure. These bumps are usually painted with bright yellow or black and yellow stripes for maximum visibility.
Clearance bars on the other hand, serve as low clearance warning for drivers. These are use in buildings and other structures that have low vertical clearance or ceiling. If you see these bars, it means that vehicles that higher than the clearance bar are not allowed to enter the premises. This is to prevent vehicle and structural damages.