As traffic on your street or road moves along much faster than you think it should, you request a speed reduction along this stretch of the roadway. However, there is a good chance authorities will deny the request. What you may not know is that all traffic control devices, which are signs, signals, markings or other devices used to regulate, warn or guide traffic, are controlled by the Federal Highway Administration under the national standard in accordance with Title 23, U.S. Code of Federal Regulations.
The Manual on Uniform Traffic Control Devices is recognized as the national standard for all traffic control devices installed on any street, highway, bikeway, or private road open to public travel. It is the "Bible" for governing the safe and efficient movement of all traffic, including bicycles and pedestrians.
The need for uniform standards was recognized as far back as 1927 when the American Association of State Highway Officials, now known as the American Association of State Highway and Transportation Officials, published a manual for rural highways. Now, under the MUTCD, signs, signals, pavement markings and other devices used to control the safe and smooth flow of traffic are uniform throughout the nation.
Traffic control devices notify road users of regulations and provide warning and guidance needed for the uniform and efficient operation of all elements of the traffic stream in a manner intended to minimize the occurrences of crashes. The proper use of traffic control devices should provide the reasonable and prudent road user with the information necessary to efficiently and lawfully use the streets, highways, pedestrian facilities, and bikeways.
Design of traffic control devices, their placement and operation, maintenance, uniformity, and authority for placement is all mandated by the MUTCD. Placement of traffic control devices generally must meet warrants spelled out in the manual as determined by engineering studies and engineering judgment before decisions to install control devices, such as speed signs, are made. In simple terms, you just don't go out and install a speed zone without justifying it according to the MUTCD.
Some examples of uniform traffic controls for pavement markings include:
Longitudinal white pavement lines are used to separate lanes of traffic moving in the same direction, or along the right edge of the road (fog line).
Yellow longitudinal lines separate traffic moving in opposite directions, are used to designate "two way left turn" lanes, and the left hand edge of roadways of divided highways.
Purple pavement markings shall supplement lane line or edge line markings for toll plaza approach lanes that are restricted to use only by vehicles with registered electronic toll collection accounts (i.e. E-Z Pass lanes on the Thruway).
Even the width, length, and spacing of broken lines for passing are spelled out in the MUTCD.
So you can see that there are defined regulations for all traffic control devices. They are not placed haphazardly, but rather under strict controls and with a defined purpose.