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Effectiveness of On-Ramp Signals

On-ramp signals were first introduced in Illinois in 1963 on Chicago's Eisenhower Expressway. Several other states – including California, Minnesota, Washington, Arizona and Nevada – use them to effectively keep freeway traffic moving. They also are used extensively throughout Europe – most notably in England, France, Belgium, Germany and the Netherlands.

The following table shows data from other U.S. cities that use on-ramp signals (data based on 2013 studies).

​Performance Measure​Location and Result
​Travel timeAtlanta – 10 percent decrease in peak period
Houston – 22 percent decrease in peak period
Arlington – 10 percent decrease in peak period
​Travel speed ​Milwaukee – 35 percent increase in peak period
Portland – 155 percent increase in peak period
Detroit – 8 percent increase
​Crash rate Phoenix – 16 percent decrease during metered hours
Milwaukee – 15 percent decrease in peak period
​Crash frequency​Portland – 43 percent decrease
Sacramento – 50 percent decrease
Los Angeles – 20 percent decrease
​Driver hours​Sacramento – 50 percent decrease
Vehicle volumeMilwaukee – 22 percent increase in peak period
Sacramento – 5 percent increase in peak period
Detroit – 14 percent increase in volume
​Gallons of fuel saved ​Portland – 700 gallons per weekday
​Emissions reduction Minneapolis – 1,160 tons annually
​Benefit-cost ratio ​Atlanta – benefits were four times greater than the cost after one year and 20 times greater after five years

4/16/2018 4:29 PM

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