Signals can be two way, whereby they control entry to the block on either side of the signal. Trains can pass through these signals from either direction, providing the next block is empty. Note: Two-way signals can be prone to gridlocking, especially at single entry/exit locations like stations, or on single pieces of track.
One-way traffic (or uni-directional traffic) is traffic that moves in a single direction. A one-way street is a street either facilitating only one-way traffic, or designed to direct vehicles to move in one direction. One-way streets typically result in higher traffic flow as drivers may avoid encountering oncoming traffic or turns through oncoming traffic. Residents may dislike one-way streets due to the circuitous route required to get to a specific destination, and the potential for higher speeds adversely affecting pedestrian safety. Some studies even challenge the original motivation for one-way streets, in that the circuitous routes negate the claimed higher speeds.[1]
- 1Signage
Signage[edit]
General signs[edit]
Signs are posted showing which direction the vehicles can move in: commonly an upward arrow, or on a T junction where the main road is one-way, an arrow to the left or right.[2] At the end of the street through which vehicles may not enter, a prohibitory traffic sign 'Do Not Enter', 'Wrong Way', or 'No Entry' sign is posted, e.g. with that text, or a round red sign with a white horizontal bar. Sometimes one portion of a street is one-way, another portion two-way. An advantage of one-way streets is that drivers do not have to watch for vehicles coming in the opposite direction on this type of street.
No entry signs[edit]
The abstract 'No Entry' sign was officially adopted for standardization at the League of Nations convention in Geneva in 1931. The sign was adapted from Swiss usage, derived from the practice of former European states that marked their boundaries with their formal shield symbols. Restrictions on entry were indicated by tying a blood-red ribbon horizontally around the shield.[3] The sign is also known as C1, from its definition in the Vienna Convention on Road Signs and Signals.
The European 'No Entry' sign was adopted into North American uniform signage in the late 1960s / 1970s, replacing a previous white square sign bearing only the English text in black 'Do Not Enter'. In addition to the standardized graphic symbol, the US version still retains the wording 'Do Not Enter', while the European and Canadian versions typically have no text.
Since Unicode 5.2, the Miscellaneous Symbols block contains the glyph ⛔ (U+26D4 NO ENTRY), representable in HTML as ⛔
or ⛔
.
One-way sign used in South Africa, Botswana, Swaziland, Namibia, Lesotho, and Tanzania
The contemporary Australian one way sign is vertically oriented, but older signs similar to those used in North America are still common.
One-way road sign used in Russia
Sign used in Russia to indicate end of one-way traffic
'No entry' signs are often placed at the exit ends of one-way streets
A Swedish one-way sign used on T junctions
Some countries, like Germany, show text on one-way signs (Einbahnstraße means 'one-way street')
Applications[edit]
One-way streets may be part of a one-way system, which facilitates a smoother flow of motor traffic through, for example, a city center grid; as in the case of Bangalore, India. This is achieved by arranging one-way streets that cross in such a fashion as to eliminate right turns (for driving on left) or left turns (for driving on right). Traffic light systems at such junctions may be simpler and may be coordinated to produce a green wave.
Some of the reasons one-way traffic is specified:
- The street is too narrow for movement in both directions and the road users unable to coordinate easily[4]
- Prevent drivers from cutting through residential streets to bypass traffic lights or other requirements to stop (a so-called 'rat run')
- Discourage drivers from cruising through a residential neighborhood (e.g. by having mostly one-way streets pointing outwards, with relatively few vehicular entrances)
- Part of a one-way pair of two parallel one-way streets in opposite directions (such as a divided highway)
- For a proper functioning of a system of paid parking[5] or other restricted vehicular access (these may also use one-way treadles which puncture tires if traversed in the forbidden direction)
- To calm traffic, especially in historic city centers
- Eliminate turns that involve crossing in front of oncoming traffic
- Increase traffic flow and potentially reduce traffic congestion[6]
- Eliminate the need for a center turn lane that can instead be used for travel
- Better traffic flow in densely built-up areas where road widening may not be feasible
- Simplify pedestrian crossing of the street due to walkers only needing to look for oncoming traffic in one direction
- Eliminate cars' driver-side doors opening into the travel lane in parallel parking spaces for parking lanes located on the left (right-hand drive) or right (left-hand drive) side of a street
- Locate a one-way bike lane on the opposite side of the street from parallel parking spaces to prevent dooring
- Limited-access highway entrance and exit ramps.
Left turn on red[edit]
In the United States, 37 states and Puerto Rico allow left turns on red only if both the origin and destination streets are one way. See South Carolina law[7] Section 56-5-970 C3, for example. Five other states – Alaska, Idaho, Michigan, Oregon, and Washington – also allow left turns on red into a one-way street from a two-way street.[8][9][10][11]
History[edit]
An attempt was apparently made in 1617 to introduce one-way streets in alleys near the River Thames in London by The Worshipful Company of Carmen who were commissioned by the King to regulate traffic in the square mile of the City of London.[12][13] The next one-way street in London was Albemarle Street in Mayfair, the location of the Royal Institution. It was so designated in 1800 because the public science lectures were so popular there.[14] The first one-way streets in Paris were the Place Charles de Gaulle around the Arc de Triomphe,[15] the Rue de Mogador and the Rue de la Chaussée-d'Antin, created on 13 December 1909.[16]
According to the folklore of Eugene, Oregon, the use of one-way streets in the United States started in Eugene itself. In 1941 6th Ave was converted into a one-way avenue by the Highway Department.[17] Other sources claim the fad arose in relation to the disaster of the SS Morro Castle. On 9 September 1934, the on-fire SS Morro Castle was towed to the New Jersey shoreline near the Asbury Park Convention Center and the sightseeing traffic was enormous. The Asbury Park Police Chief decided to make the Ocean Avenue one-way going north and the street one block over (Kingsley) in one-way going south, creating a circular route. By the 1950s this 'cruising the circuit' became a draw to the area in itself since teens would drive around it looking to hook up with other teens. The circuit was in place until the streets went back to two way in 2007 due to new housing and retail development.[18]
One-way traffic of pedestrians[edit]
Sometimes one-way walking is specified for smooth pedestrian traffic flow, or in the case of entrance checks (such as ticket checks) and exit checks (e.g. the check-out in a shop). They may be outdoors (e.g. an extra exit of a zoo), or in a building, or in a vehicle (e.g. a tram). In addition to signs, there may be various forms and levels of enforcement, such as:
- personnel; sometimes a 'soft' traffic control system is supported by vigilant staff monitoring
- a turnstile; however, turnstile jumping is possible
- a High Entrance/Exit Turnstile (HEET)
- a one-way revolving door
- an escalator; however, the escalator can be traversed in opposite direction, by walking up or down the stairs faster than it moves
- an elevator that can only be called from one floor; this is common in IKEA stores.
- Two-way elevators: passengers enter from the front on one floor and exit from the back in another floor.
- a door or gate that can only be opened from one side (a manual or electric lock, or simply a door that is pushed open and has no doorknob on the other side), or which automatically opens from one side. (However, with help from someone on the other side, it may often be bypassed in the reverse direction.)
- entrance of a shop
- an emergency exit, which may activate an alarm
- Airports - (e.g. passport control, customs, baggage security)
Sometimes a door or gate can be opened freely from one side, and only with a key or by inserting a coin from the other side (house door, door with a coin slot, e.g. giving entrance to a pay toilet). The latter can be passed without paying when somebody else leaves, and by multiple persons if only one pays (as opposed to a coin-operated turnstile).
References[edit]
- ^Jaffe, Eric. 'The Case Against One-Way Streets'. The Atlantic Cities. Atlantic Media Company. Retrieved 31 January 2013.
- ^'Traffic Signs Manual Chapter 3'(PDF). The Stationery Office. 2008. pp. 25–26. Retrieved 28 December 2018.
- ^Lay, M.G. (1992). A History of the World's Roads and of the Vehicles That Used Them. Rutgers University Press. p. 190. ISBN9780813526911. Retrieved 28 December 2018.
- ^'One way streets'. Bath and NE Somerset Council. Retrieved 28 December 2018.
- ^'One Way Signs: Helping Improve Traffic Flow With Single Direction Traffic'. Seton - A Brady Corporation Company. 8 May 2013. Retrieved 28 December 2018.
- ^Matchett, Conor (5 October 2018). 'Calls for one-way traffic trial after roadworks improve traffic flow'. Archant Community Media Ltd. Retrieved 28 December 2018.
- ^scstatehouse.govArchived November 5, 2011, at the Wayback Machine
- ^'13 AAC 02.010. Traffic-control signal legend'. touchngo.com.
- ^'legislature.idaho.gov'.
- ^'Michigan Legislature - Section 257.612'. legislature.mi.gov.
- ^'RCW 46.61.055: Traffic control signal legend'. apps.leg.wa.gov.
- ^Homer, Trevor (2006). The Book of Origins. London: Portrait. pp. 283–4. ISBN978-0-7499-5110-8.
- ^Penguin Pocket On This Day. Penguin Reference Library. 2006. ISBN978-0-14-102715-9.
- ^Singh, Simon. 'Stars In Whose Eyes?'. Retrieved 2013-08-10.
- ^Higonnet, Patrice L. (2009). Paris: Capital of the World. Harvard University Press. p. 187. ISBN9780674038646. Retrieved 28 December 2018.
- ^Eno, William Phelps (1939). The story of highway traffic control, 1899-1939. The Eno foundation for highway traffic control, inc. p. 243. Retrieved 28 December 2018.
- ^https://www.eugene-or.gov/DocumentCenter/Home/View/24803
- ^Friedman, Alexi (6 September 2009). '75-year-old film footage shows aftermath of fire aboard luxury liner in Asbury Park'. Advance Local Media LLC. Retrieved 28 December 2018.
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TV signal splitters and combiners are not the flashiest electronics components on the market, but they are very important for home and office use. Because of this, special attention must be paid to the features and capabilities of these components. It is often necessary to split a television signal that is coming from a single cable outlet on a wall so that multiple televisions can receive the signal. This is far more practical and much less expensive than calling an electrician to install an entirely new outlet. There are other cases where a user may want to combine different television signals to connect them to a single television, which is something that combiners enable a user to do. The devices themselves appear very simple, but there are some features that buyers should be familiar with before making a purchase. This guide will detail the basics of using TV signal splitters and combiners, including an explanation of how they work, the different types of splitters and combiners that are available, and their common uses.
How Do TV Signal Splitters and Combiners Work?
![Signal Signal](http://www.mashinky.com/screens/7.jpg)
TV signal splitters and combiners either split or combine television signals, depending on the preferences and needs of the user. Quite often, the same device can either divide a signal multiple ways or it can combine multiple signals for transmission through a single cable. This section will describe how the device performs both of these operations.
Splitters
A TV signal splitter has one input where the signal enters the splitter and at least two outputs where the signal leaves the splitter to go to multiple devices. Because multiple devices are using the splitter, the signal for each device will be weaker than if the signal went straight to a single device without running through the splitter. The more times the signal is split, the weaker it will become. It is possible to increase a signal's strength before splitting it, and this will be discussed later in the guide.
Most splitter manufacturers will indicate somewhere on the splitter the strength that the signal will be when it leaves the outputs. Those that are using a splitter to divide a high definition television signal for viewing on multiple screens will want to pay attention to this number, as they may find that the split signal from some splitters is insufficient for this use. It is also important not to use more than one splitter on a signal. If a signal needs to be routed to four different televisions, a 4- way splitter should be used rather than three 2- way splitters.
Combiners
A TV signal combiner looks like a TV signal splitter, and in most cases it is actually the same device. Instead of taking one signal and dividing it into multiple signals, a signal combiner takes two or more signals and produces a single signal from them. This does not necessarily make for one stronger signal, though. Rather, it is used to run two different types of TV signals through a single cable to the input on a television receiver. The following sections discuss a few common situations whereby a combiner can be used to merge multiple TV signals.
Types of TV Signal Splitters and Combiners and Their Uses
This section will describe a few different types of TV signal splitters and combiners. It will also point out a few common uses for each type, helping readers to decide which kinds of signal splitters and combiners they need.
Regular Splitters
Regular splitters simply divide a signal with no additional processing. This results in the loss of signal strength for each device that uses the same signal. A two-way splitter, for example, results in the signal strength being half of what it would be if it went straight to a single device. Signal strength is measured in decibels, so if the signal strength has higher decibels to begin with, the loss in strength may not be noticeable on the televisions using it.
High Bandwidth
High bandwidth splitters are designed to divide dense signals, such as those used for high definition television. Most cable television signals are have a frequency of 1000 megahertz (MHz), so a high bandwidth splitter should be capable of handling this frequency to avoid attenuation of the signal. High bandwidth splitters are usually a little more expensive than regular splitters are, but the cost should be worth it to avoid what could be a large loss in signal quality.
Signal Amplifiers
The primary role of a signal amplifier is to increase the strength of a signal without distorting it. Some signal amplifiers come with multiple outputs, so that they can split the signal after amplifying it. Many signal amplifiers also allow users to control how much they want to strengthen the signal before it is split. These devices are a great solution for signals that become too weak after an ordinary splitter has divided them. A signal amplifier may also be used in conjunction with a splitter if the signal amplifier does not divide the signal as many times as the user desires.
Diplexers
Diplexers are another name for signal combiners. These can also receive one signal and divide it a few times, meaning that they function as splitters as well. Diplexers are especially useful for combining a cable television signal with an antenna signal and running it through the same coaxial cable to a television's receiver. Local television stations are now available in high definition through an antenna, so a cable television subscriber can use a diplexer to watch those high definition local stations on the same television to which the non-HD cable signal is connected.
Combining a satellite and an antenna signal is a bit more complicated. Most antenna signals are passed through an RC-59 coaxial cable, while satellite signals typically run through RC-6 cable. Some satellite signals can pass through an RC-59 cable though, so it is best to consult the owner's manual for a satellite system before trying to run a satellite signal through a diplexer.
Where to Buy TV Signal Splitters and Combiners
There are many retailers with brick and mortar stores and with online shops that specialize in electronics components, and these are generally good sources from which to buy TV signal splitters and combiners. Brick and mortar stores with electronics components usually carry all of the different types of splitters and combiners that have been detailed in this guide, and store employees are often helpful when it comes to advising customers on which splitters and combiners they need. Stores that sell TV signal splitters and combiners are usually also geographically convenient, even in small towns.
Shopping for splitters and combiners is even more convenient online. Electronics components retailers operating online make their large stocks of splitters and combiners available for purchase around the clock and from anywhere a customer can connect to the Internet. Although there are usually no employees to advise customers during their online shopping experiences, online retailers generally post thorough product descriptions for the splitters and couplers that they sell. This is often all that customers need to make the right buying decision on their own.
How to Buy TV Signal Splitters and Combiners
If you are looking to shop online for TV signal splitters and combiners, you will find a large stock of these items on eBay. It is easy to sort through this stock to find the splitters and combiners that you need. eBay also makes it easy to find sellers of these items that offer free shipping, helping you to save money.
Finding TV Signal Splitters and Combiners on eBay
You can start your search for TV signal splitters and combiners on eBay's homepage. Next, select TV, Audio & Surveillance from the Electronics menu. On the following page, click on All Categories and choose Splitters & Combiners under the TV, Video & Audio Accessories heading on the menu that appears. This will list all of the splitters and combiners that are for sale on eBay.
From here, you can search for most of the types of splitters and combiners that have been described in this article. If you are looking for a diplexer, type 'diplexer' in the search bar and click Search. For a high bandwidth splitter, search for the amount of megahertz that the splitter should be capable of handling, such as 1000 MHz. Signal amplifiers can be found under the same TV, Video and Audio Accessories heading on the pop-up menu. You just need to make sure that they have multiple outputs if you plan to split the signal after amplifying it. It is also possible to sort splitters by the amount of outputs they have, such as 2, 3, 4, 6, and 8, by choosing one of these options from the Connection Split/Duplication menu.
Free Shipping
eBay helps you to identify sellers that are offering free shipping on splitters and combiners, which can save you some money on your purchase. If you are looking for free shipping on a two-way splitter, pull results for these items by following the directions in the previous section, and then choose Free shipping from the Show only menu. These sellers all offer free shipping on splitters, which lets you save some money for buying other electrical components.
Conclusion
Although TV signal splitters and combiners are not the most exciting electrical components, they do play an important role in many homes and offices. The need to split a signal among multiple televisions is a common one, and more and more people are finding couplers useful for being able to watch on the same television standard cable and high definition local stations received via antenna. Although splitters and couplers may appear similar to one another, there are some differences in their features and uses. This guide has described the most important of these features and uses, including basic explanations for how splitters and combiners work. Readers can use this information to make informed decisions about the TV signal splitters and combiners that they purchase, which will help them to get the most out of their televisions.