For night time use or low-light situations traffic cones are usually fitted with a retroreflective sleeve to increase visibility. On occasion, traffic cones may also be fitted with flashing lights for the same reason. In the US, cones are required by the US Federal Highway Administration's Manual on Uniform Traffic Control Devices (MUTCD) to be fitted with reflective white bands to increase night-time visibility. Reflective collars, white strips made from white reflective plastic, slip over cones snugly, and tape or adhesive can be used to permanently attach the collars to the cones. Traffic cones are designed to be highly visible and easily movable. Various sizes are used, commonly ranging from around to a little over . Traffic cones come in many different colors, with orange, yellow, pink and red being the most common colors due to their brightness. Others come in green and blue, and may also have a retroreflective strip (commonly known as "flash tape") to increase their visibility. Types and sizes Typical traffic cones are fluorescent "safety" orange or lime green, but in some countries a range of other colors are used depending on context. Traffic cones also commonly come with reflective striping around them, to increase visibility. In the United States, they come in such sizes as: , – for indoor/outdoor applications , – for outdoor applications such as free-way line painting , , (also called Metro cones for their use in cities) – for Non-highway applications e.g. Local street, , – for free-way/high-way applications (With reflective stripes) , – for free-way/high-way applications (With reflective stripes) In New Zealand, they are compliant in two sizes for use on all roads; these are: 35 in (900mm), up to 16.5 lb (7 kg) - for all activities on all roads. (with two reflective stripes) 17.7 in (450mm), up to 16.5 lb (7 kg) - for the protection of wet road markings only. (with one reflective stripe) Other forms Cones are easy to move or remove. Where sturdier (and larger) markers are needed, construction sites use traffic barrels (plastic orange barrels with reflective stripes, normally about the same size as a drum). When a lane closure must also be a physical barrier against cars accidentally crossing it, a Jersey barrier is preferred. See also Fitch Barrier. In many countries such as Australia or American states such as California, traffic barrels are rarely seen. Devices called bollards are used instead of