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News Release
September 8, 2010




Minnesota Department of Transportation
Rochester District 6
2900 48th Street
Rochester, MN 55901


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New MnDOT traffic signals minimize delays, improve safety
Biggest change in traffic signal design in 40 years


ROCHESTER, Minn. — Motorists in Woodbury are among the first in the nation to encounter a new traffic signal design that minimizes unnecessary waiting for motorists and improves safety.

The new signals feature a flashing yellow arrow, in addition to the standard red, yellow and green arrows. When illuminated, the flashing yellow arrow allows waiting motorists to make a left-hand turn after yielding to oncoming traffic. Otherwise, the new traffic signals work the same as traditional signals.

The new signals, located at the Interstate 94 and Highway 95 interchange in Woodbury, represent a major change in traffic signal operation, according to the Minnesota Department of Transportation.


“This is the biggest change in traffic signal design and operation in the past 40 years,” said Jerry Kotzenmacher, MnDOT senior engineering specialist. “We have shop tested these signals for many months and are confident the signals will improve safety and reduce congestion.”


In December 2009, after extensive testing, the Federal Highway Administration authorized use of flashing yellow arrows nationwide. Some Minnesota cities and counties have already installed the new signals on city and county roadways. MnDOT expects to install several systems by the end of 2010.


A study conducted by the National Cooperative Highway Research Program determined that drivers had fewer crashes with flashing yellow left-turn arrows than with traditional yield-on-green signal configurations.


MnDOT installed a flashing yellow arrow signal at Highway 110 and Highway 149 in Mendota Heights in 2006 as a federally approved pilot project. MnDOT’s goal with this pilot was to test how the new signal worked with existing signal controllers and components. The information obtained from the pilot will help streamline future installations. The pilot signal operated for three years and no problems or crashes were attributed to its use.


The flashing yellow arrow is now part of MnDOT’s official design of traffic signals. MnDOT plans to install the new flashing yellow arrow systems on most future traffic signal construction projects. Retrofitting existing signals to include flashing yellow arrows can be costly and will only be done on a limited basis, when necessary.


 “The new signals will give us a great deal of flexibility in adjusting the operation of left-turn signal timing to keep traffic moving most efficiently and safely,” said Kotzenmacher. “We can control and adjust signal timing and operation from our offices which enables us to make adjustments very quickly if needed.”


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