The United States of America and its surrounding areas use 9 standard time zones. Also, these abbreviations can be the same as those used in other parts of the world for different time zones. The shorter abbreviations we often use are just for convenience and are not official. The official names of the time zones are what's used in laws and official documents. Before this, they were based on the solar time at different longitudes west of Greenwich, UK. Since August 9, 2007, these time zones are defined by how many hours they are ahead of or behind Coordinated Universal Time (UTC). The Secretary of Transportation has the power to decide which time zones different regions will use and whether they'll follow daylight saving time. This law decides when daylight saving time starts and ends, if it's used. In the United States, standard time zones and the rules for daylight saving time are set by federal law (15 USC §260). United States Maps in our Store - Order High Resolution Vector and Raster Files It is the mix of the time zone and DST rules, along with the timekeeping services, which calculate the legal civil time for any United States location at any moment. The clocks managed by these services are kept in synchronization with each other as well as with those of other internationally recognized timekeeping organizations. Official and extremely precise timekeeping services (clocks) are presented by 2 federal agencies: NIST (the National Institute of Standards and Technology) (an agency of the Department of Commerce) and UNSO (the United States Naval Observatory). The time zone boundaries and daylight saving time observance are organized by the Department of Transportation. ![]() observing DST (daylight saving time) for generally the spring, summer, and fall months. Explore the dataĬurious about America’s time zones? The National Transportation Atlas Database provides a digital representation of the geographic boundaries for the nine time zones that cover United States and its territories.Explore US time zone map, Time in the United States of America, by law, is divided into 9 standard time zones covering the American states, territories and other U.S. National Council of State Legislatures map shows States with legislative activity to adopt year-round DST. Some States have enacted legislation to adopt DST as their permanent setting, pending federal approval. States can opt-out from DST, but such an exemption must apply to the entire portion of that State that lies in a given time zone (some states, like North Dakota, straddle two different zones). Currently, DST begins the second Sunday in March and ends the first Sunday in November. Congress has amended time change laws several times since then. ![]() The Standard Time Act of 1918, “an Act to save daylight and to provide standard time for the United States,” authorized the nation’s first “Daylight Saving Time” to begin on the last Sunday of March and conclude on the last Sunday of October. time zones as recorded in the National Transportation Atlas Database Daylight Saving Time rules begin in 1918 but have changed through the years Department of Transportation to change their time zone.Ĭurrent U.S. The early maps had today’s four time zones for the coterminous states, but the boundaries were very different from today. Time zone map of the United States from 1913, as published in the Chicago Daily News Almanac and Yearbook. British railroads were the first to adopt standard time in 1840, and railroads in the US and Canada adopted standard time zones in 1883. Thank the railroads for our standard time zonesīefore time zones were created, each locality set its own clocks to noon at the time of day when the sun was at its highest position. Virgin Islands) don’t practice the spring and autumn time change. territories (American Samoa, Guam, Northern Mariana Islands, Puerto Rico, and the U.S. Some states (Hawaii, Arizona-except for the Navajo Nation within the state) and U.S. Last weekend, millions of Americans turned back their clocks one hour to mark the return from Daylight Saving Time to Standard Time. Advisory Council on Transportation Statistics.National Transportation Knowledge Network. ![]() National Transportation Library Main - Library. ![]() Vehicle Inventory and Use Survey (VIUS).Transportation Statistics Annual Reports.Local Area Transportation Characteristics (LATCH dataset).Government Transportation Financial Statistics.Freight Logistics Optimization Works (FLOW).Electric Vehicle Inventory and Use Survey (eVIUS).Statistical Products and Data Main - Statistical 1.Transportation Maps and Geospatial Data.Introduction to Transportation Statistics.
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