Parking blocks prevent the forward movement of cars and other vehicle by acting like a "curb." Unfortunately, for elderly persons or others with poor vision, they are sometimes difficult to "see" as they project only four to eight inches off the ground. An ASTM stan- dard recommends that parking blocks not be used in parking lots and parking garages. On the other hand, the Americans for Disabilities Act (ADA) shows the use of parking blocks in the design of parking spaces for persons with disabilities. What are the advantages and disadvantages of parking blocks? What is your opinion as to whether the utility out- weighs the risk of harm of using parking blocks? Are there certain places where parking blocks should not be used? Are there parking garages that do not use parking blocks?