21 jun. 2011

Pedestrian Crossings

A pedestrian crossing or crosswalk is a designated point on a road at which some means are employed to assist pedestrians wishing to cross. They are designed to keep pedestrians together where they can be seen by motorists, and where they can cross most safely across the flow of vehicular traffic. Pedestrian crossings are often found at intersections, but may also be at other points on busy roads that would otherwise be too unsafe to cross without assistance due to vehicle numbers, speed or road widths. They are generally also installed common where large numbers of pedestrians are attempting to cross (such as in shopping areas) or where vulnerable road users (such as school children) regularly cross.

The term pedestrian crossing includes a wide range of crossing provisions, both those that give priority to pedestrians, and those that assist pedestrians, but legally still prioritise road vehicles. Signalised pedestrian crossings meanwhile clearly separate when each type of traffic (pedestrians or road vehicles) can use the crossing. They, especially when combined with other features like pedestrian priority or raised surfaces, can be used as a traffic calming technique.
Pedestrian refuges or small islands in the middle of a street may be added when a street is very wide, as these crossings can be too long for some individuals to cross in one cycle. In places where there is very high pedestrian traffic, pedestrian scrambles (also known as Barnes Dances) may be used, which stop vehicular traffic in all directions at the same time. Another relatively widespread variation is the Curb (or kerb) extension (also known as a bulb-out) which narrows the width of the street and is used in combination with crosswalk markings.

Reports suggest that many walk buttons in some areas such as New York City are actually placebo buttons designed to give pedestrians an illusion of control while the crossing signal continues its operation as programmed. This can also be witnessed at Anniesland Cross, a large road junction in Glasgow, Scotland. While each pedestrian crossing has a push button, all roads and pedestrian crossing run on a cycle and the pedestrian crossing will change only at the correct point of the cycle, whether the buttons are pushed or not. 

In the United States, crosswalks are sometimes marked with white stripes, though many municipalities have slightly different methods, styles, or patterns for doing so, and the styles may vary over time as intersections are built and reconstructed. There are two main methods for road markings in the United States. Most frequently, they are marked with two thick white lines running from one side of the road to the other.

The designs used vary widely between jurisdictions, and often vary even between a city and its county (or local equivalents). Where a road forms part of a city limit or other such political boundary—thus making the intersection shared between the two—there may be more than one design used on different sides, depending upon which government painted it.
At crossings controlled by signals, the most common variety is arranged like this: At each end of a crosswalk, the poles which hold the traffic lights also have white "walk" and Portland Orange "don't walk" signs. These particular colors are used in North America to provide conspicuity against the backdrop of red, yellow, and green traffic lights. Modern signals generally use pictograms of an red hand and a green pedestrian rather than words. As a warning, the "don't walk" or hand signals begin to blink when the transition to "don't walk" is imminent. This normally occurs several seconds before the light turns yellow, usually going solid orange when the traffic light turns yellow. A black baffle is customarily placed in front of the lights to shield them from the sun and increase their visibility, as well as protect them from damage.

Crosswalks have also been adapted for the blind by adding accessible pedestrian signals [APS] that include two small distinct speakers at the actuator for each crossing location. The current accepted APS units have a continuous audible chirp that is easy to detect from a close distance but is not so loud as to be intrusive to neighboring properties.
In some countries, instead of "don't walk", a depiction of a red man or hand indicating when not to cross, the drawing of the person crossing appears with an "X" drawn over it.

As we can see in this article, the pedestrian crossings have been, in the last few decades, not also a form of controlling the traffic circulation but a form of art expresion about all the world.
Some countries around the Baltic sea in Scandinavia duplicate the red light. Instead of one red light, there are two which both illuminate at the same time.
In many parts of eastern Germany, the design of the crossing man (Ampelmännchen) has a hat.
In Mexico City, the walking man moves his feet.
In Taiwan there is generally no crossing manner. The majority of crossings cannot be controlled by pedestrians, although there are exceptions in Taipei. 
In the United States, there are many inconsistencies, although the variations are usually minor. There are several distinct types in the United Kingdom, each with their own name, usually animal names are  used to distinguish these several types:
  • Zebra crossing: wide longitudinal stripes on road, often with belisha beacons; pedestrians may cross at any time; drivers must give way to pedestrians who demonstrate intent to cross.
  • Pelican crossing: traffic lights for pedestrians and vehicles; button-operated.
  • Puffin crossing: pedestrian lights on near side of road; button-operated with curb-side detector.
  • Toucan crossing: for bicycles as well as pedestrians.
  • Pegasus crossing: an equestrian crossing.
Belisha beacons are found at zebra crossings. The other types of crossing use coloured pictogram lights, depending on the intended users of the crossing this will be a man, a bicycle or a horse.

In Australia, pictograms are standard on all traffic light controlled crossings. Like some other countries, a flashing red sequence is used prior to steady red to clear pedestrians. Moments after, a flashing yellow sequence begins for the motorist who can proceed through the crossing if safe to do so.

3 comentarios:

  1. muy chulos jeje, el de don limpio mola :P. por ahí he visto alguna imagen de uno de pac-man jaja, ya te lo pasaré :)

  2. El del Pac-man lo tengo, ya lo pondré en el blog =oD, gracias Jorge =o)