Basic requirements for good racks include:

• Simple and obvious in function—no moving parts*
• Design should provide stability—two points of contact with the frame in a horizontal plane to prevent the bike from falling
• Rack allowing frame and wheels to be locked using either standard type of locking device (U-lock or cable lock)
• Easy access—bikes roll in without tangling with street furniture, other bikes and without lifting over rack elements
• Low or modest cost to manufacture and install
• Suitable for the site and able to meet demand—well-designed racks will allow for a maximum number of bikes to be stored in a small area
• Racks permanently anchored with tamper-proof bolts
• Racks should be compact and attractive as street furniture and coated to minimize damage

Don't choose a rack that:

• Cannot ensure security of the bicycle
• Assumes a specific locking device to be effective
• May damage bike components or tangles bikes at capacity
• Supports the bike by the wheels rather than the frame
• Balances the bike frame on a single upright
• Is too big or too small for the location or expected demand
• Uses more space than needed for a given number of bikes