Home > Ramp meter
A ramp meter is a device, usually a basic traffic light, that regulates traffic entering freeways according to current traffic conditions. They have several aims. One is to break up platoons entering freeways, ensuring that traffic can merge easily. A second is to ensure that total flow on the freeway does not exceed capacity at downstream bottlenecks. Some metered ramps have bypass lanes for high occupancy vehicles, allowing carpoolers and vehicles like buses to skip the queue and get directly on the highway. Meters often only operate in rush hour periods.1 Ramp metering in North America
In the Los Angeles and Minneapolis-St. Paul metropolitan areas they are commonplace, and they are found in more than two dozen smaller metropolitan areas.
Ramp metering was first implemented in 1963 on the Eisenhower Expressway ( Interstate 290) in Chicago, Illinois. This first application involved a police officer who would stop traffic on an entrance ramp and release vehicles one at a time at a predetermined rate, so that the objectives of safer and smoother merging onto the freeway traffic was easier without disrupting the mainline flows. Since then ramp-meters have been systematically deployed in many urban areas including Los Angeles, California, Minneapolis-St. Paul, Minnesota, Seattle, Washington, Denver, Colorado, Phoenix, Arizona, Portland, OregonPortland is the largest city in Oregon, and county seat of Multnomah County. It is a major Pacific seaport located about sixty miles from the west coast of the United States, situated on both sides of the Willamette River, just south of its confluence wit, and Toronto, OntarioFor alternate meanings of Toronto, see Toronto (disambiguation). City of Toronto, Ontario, Canada (in detail) (in detail) Motto: Diversity Our Strength Area: 641 sq. Distance East to West: 43 km. Distance East to West: 21 km. Population Total (2001) Cdn.. Ramp meters have been withdrawn after initial introduction in several cities, including Austin, TexasAustin is the capital of the state of Texas, within the United States of America. As of Census 2000, the population of 656,562 people (metro area population of over 1 million people) made Austin the fourth-largest city in Texas (behind Houston, Dallas, an, Dallas, TexasDallas redirects here. For other uses see Dallas (disambiguation Dallas is one of the ten largest cities in the United States and the heart of the largest metropolitan area in Texas. It is the county seat of Dallas County and small portions of the city al, and San Antonio, TexasThe Alamo in San Antonio San Antonio is a city in the U. state of Texas. As of the 2000 census, the city had a resident population of 1,144,646. It is the county seat of Bexar County 6. Originally founded by Canary Islanders in 1731 (although a small Indi and Columbus, OhioColumbus is the capital of the state of Ohio in the United States of America. The city is the largest in the state (when measured by city borders), with a population of 711,470 as of the 2000 census. According to recent U. census estimates, in Ohio only t. Disused metering signals can still be found, forgotten along some parkways surrounding New York, New York.
In 2000, an experiment was conducted involving shutting off all 433 ramp meters in the Minneapolis-St. Paul area for eight weeks to test their effects. In general, ramp meters were shown to reduce accidents and marginally reduce total travel time compared with the unmetered case. However, they remained controversial, and the Minnesota state Department of Transportation has developed new, less onerous ramp control strategies. Fewer meters are activated during the course of a normal day than what had happened prior to 2000, and timing has been altered.
