2010 News Archive 

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Traffic signal retiming yields time, fuel, dollar savings

Retiming of traffic signals along two of Johns Creek's more heavily traveled corridors is saving motorists who pass through the locations an estimated 51,000 hours and 30,600 gallons of fuel a year, adding up to almost $811,000 in annual savings, city transportation officials report.

Traffic Services Manager Tom Udell told the Mayor and City Council at their Jan. 11 work session that the $35,000 retiming project has resulted in significant improvements along Abbotts Bridge, Jones Bridge and State Bridge roads.

The city began working with Wolverton & Associates in October to retime and interconnect three signals on State Bridge Road between the Chattahoochee River and Medlock Bridge Road and retime five signals near the intersection of Abbotts Bridge Road and Jones Bridge Road (north of Abbotts).

Udell said the city chose those two systems for the project because:

• The signals on State Bridge operated independently and resulted in poor traffic progression, due in part to a lack of communications between signals. Installation of fiber optic communication in late 2008 helped remedy that situation.
• The signals at Abbotts Bridge and Jones Bridge were timed after construction of the roads was completed and that timing had been the source of numerous complaints to the traffic division.

Because of these efforts, Udell reported that the average delay for getting vehicles from the Gwinnett County line to the intersection of State Bridge and Medlock Bridge Road was reduced from 63 seconds to 23 seconds, and average travel time along that section of road went from 58 seconds to 43.

At the Abbotts Bridge/Jones Bridge intersection, the average delay dropped from 19 seconds down to six and the average travel time along that section declined from 58 to 43 seconds as well.

"The time savings may not seem like much at first, but when you carry it out over the thousands of vehicles that pass through these corridors, it is actually quite substantial," Udell said.

The traffic services manager said the cost and fuel savings estimates were based on "a conservative" calculation that assumed a fuel price of $2.50 a gallon, vehicle occupancy of 1.2 people per vehicle and an average income of $12 per hour per person.