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Travelers information stations (TIS), also called highway advisory radio stations (HAR) by the United States Department of Transportation, are licensed low-power AM radio stations operated by departments of transportation, airports, local government, colleges, parks, events and destinations. The stations provide information to motorists regarding travel, situations of imminent danger and emergencies. ==TIS operation in the United States== These systems are licensed by the Federal Communications Commission (FCC) in the United States. The TIS station class was originally created by the FCC by the Report and Order in Docket 20509.〔http://fjallfoss.fcc.gov/edocs_public/attachmatch/FCC-77-414A1.pdf〕〔(【引用サイトリンク】url=http://www.fcc.gov/encyclopedia/travelers-information-stations-search )〕 TIS stations are limited to a maximum signal of 2 mV/m at 1.5 km (0.93 mi) using a power of up to 10 watts to achieve this limit in the case of vertical antenna systems (the most common type). Up to 50 watts in the case of the radiating cable antenna systems may be used to achieve a maximum of 2 mV/m at 60 m (200 ft) from the radiating cable. Radiating cable systems are limited to a continuous antenna length of 1.9 km (1.2 mi).〔(【引用サイトリンク】url=http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=405d9709a1c35621ce5ad1df005e7720&rgn=div5&view=text&node=47:5.0.1.1.3&idno=47#47:5.0.1.1.3.9.111.8 )〕 Cable systems are used for situations such as Dulles International Airport with very long limited-access approach roads where multiple systems can be placed in 1.9 km segments. Critical evacuation systems, such as those in the Florida Keys and near chemical and nuclear facilities, have been granted exceptional power waivers for emergency operations. These systems will typically operate under the normal power level, but have permission to exceed that limit, typically to 100 W, in the face of a critical emergency evacuation situation. The former American Airlines TIS stations at Dallas-Fort Worth International Airport on 1640 and 1680 kHz (before the AM band expanded above 1600 kHz) ran 60 watts power out under special exemption. The station audio is required to be passed through an audio low-pass filter which rolls off frequencies above 3 kHz, to prevent music from being played as a low power AM station. There have been discussions by the FCC about whether to remove this requirement as it has been found that it is not effective in reducing interference to non-TIS stations (the original reasoning for the rule) and it degrades the intelligibility of the station audio.〔(【引用サイトリンク】url=http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-13-98A1.pdf )〕 TIS station content is defined by the FCC as FCC in 2013 clarified in its Report and Order (13-98) regarding TIS stations. The Report and Order was issued as a result of a petition for clarification of the rules by the (American Association of Information Radio Operators ) (AAIRO). (Formed in 2008, AAIRO is a nonprofit organization of operators and licensees from public agencies who manage information radio stations across the country to inform and protect motorists.) In May 2014, a Compliance Guide (DA-14-651) was issued by the FCC to summarize the Report & Order and to make it more accessible for licensees. The Report and Order and the Guide made it clear that TIS stations can be linked in "ribbons" as long as content relates to the motorist at each point in the ribbon. They also clarified that stations' content must relate to travel, emergencies or situations of imminent danger to the public - and that it is at the discretion of the station operator, based on his knowledge of his area and its population, what situations present an imminent danger to the public locally. In the United States, only government entities may have licenses for TIS/HAR stations, with some exceptions granted for quasi-governmental agencies and authorities as well as health and emergency service providers working in conjunction with governmental entities. The FCC formerly reserved the bottom and top channels (530 and 1610) on the AM band for these stations, before the AM expanded band (1610 to 1700) was introduced in North America. Systems may currently be licensed on any frequency from 530–1700 kHz. (Most radios tune to 1710; however, this frequency has only been licensed by FCC in one instance, by (Information Station Specialists ) for Hudson County, New Jersey, due to the potential for an evacuation from New York City.) Stations for U.S. national parks and other units under the U.S. federal government are licensed by the NTIA rather than the FCC. A no-cost newsletter "The Source" which details rule and technology changes and use examples is published regularly by Information Station Specialists at www.theradiosource.com. The newsletter is provided at no charge to members of the American Association of Information Radio Operators www.AAIRO.org and others who subscribe. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Travelers' information station」の詳細全文を読む スポンサード リンク
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