Why aren’t some downtown Wilmington traffic signals put in flashing operation mode late at night?
In a word, “safety,” said Denys Vielkanowitz, city signal systems management engineer.
The topic has been the subject of much research by the N.C. Department of Transportation, Vielkanowitz said.
“Studies have shown that collisions may increase at locations where traffic signals operate in late-night flash (mode). With today’s modern traffic control signal equipment, wait times at sparsely traveled roadways late at night should be minimal,” he said.
The N.C. DOT has criteria to evaluate if a traffic signal may safely operate in late-night flash mode, Vielkanowitz said.
“If the traffic signal meets this criteria, it is monitored on a regular basis to make sure crashes do not increase during the late-night flash,” he said.
Based on safety data, the local Division 3 N.C. DOT office made the decision to remove late-night flashing operation from all traffic signals within its jurisdiction, Vielkanowitz said.
Vielkanowitz said a traffic signal operating in normal mode is understood and obeyed “at a much higher rate than a traffic signal in flashing operation.”
“Flashing operation can be perceived as a malfunctioning traffic signal. Therefore, some drivers do not obey the proper driving procedure when approaching the intersection, which increases the potential for an incident,” he said.
Here’s a link to questions frequently posed to the N.C. DOT about traffic signals: http://www.ncdot.gov/doh/preconstruct/traffic/faq.html
Here’s a link to the N.C. Division of Motor Vehicles Driver’s Handbook: http://www.ncdot.org/dmv/driver_services/drivershandbook/download/NCDL_English.pdf
Chapter 5 describes Traffic Signals, Signs, and Markings. Page 87 refers to procedure for flashing traffic signals.
Date posted: February 24, 2011
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