This month I spoke with Leslie Tracey, a traffic engineer with the City of Durham’s Department of Transportation.
Q What is the Department of Transportation all about?
A We deal with all transportation services in the city, including traffic signals, paint markings (on the pavement), signs, speed bumps, and traffic calming. And we develop where and how to put in bike lanes.
Our department also does transportation planning: The planners study and project the traffic flow and volumes (number of vehicles) over a period of 20 to 30 years. That’s so we can know which corridors are the ones to watch. We’ll be able to adjust the traffic signals and widen streets as needed. The state and the city have to work together because most of the main roads in Durham are state roads.
Our bus system, DATA—it’s Go Triangle now—is part of the Department of Transportation and Go Triangle (which used to be Triangle Transit).
Q What do you do as a traffic engineer, and are you the only one on the staff?
A I’m one of five traffic engineers, and we all have different duties. I’m concerned with traffic flow, so I keep track of all of the city’s traffic signals and signs, and I also take care of traffic-signal designs and pavement markings.
Q What do you mean by traffic-signal design?
A If we decide that an intersection needs a traffic signal, I study the traffic flow and how the intersection’s laid out. Then I determine where the posts go and decide which type of traffic signal is needed: for example, whether a left-turn arrow is needed (we call that “protected”). I’m out in the field, taking measurements and check signal timing at least once a week.
[Click here for a list of all of the streets that are maintained by the City of Durham. Call 919-560-4326 or click here for the staff directory of the Public Works Department.]
Q Seems to me that if you’re at an intersection with a big, busy street and a smaller side street, the busy street gets a longer green light. Am I right?
A You’re right. So in these types of intersections, the side streets, like Riddle Road, have detectors. Their sensor wires, which are embedded in the pavement, create a magnetic field. When something with lots of metal—like a car—comes along and disrupts the magnetic field, the traffic signals change, and the vehicles on Riddle Road get to cross Highway 55. But the green light is just long enough to clear traffic. That traffic light on Highway 55 will stay green until the detectors sense vehicles on the side streets. Other cities have microwave or infrared detection, but that’s the system we use. And the traffic signals on certain downtown streets, like Main Street, have longer green times during peak hours (morning and afternoon commutes).
Q So what do you do when an intersection needs some type of traffic signal?
A We do a study and determine which “warrants” pertain to the particular intersection (all laid out in a nationwide manual—all cities use the same rules). For a volume warrant, we count all of the vehicles that approach the intersection in a 24-hour period. We can look at the numbers for the peak hours or the entire day, and then check the volume of traffic on the main road and the side roads. There are also accident warrants for those intersections that have a high number of accidents. There are pedestrian warrants; in fact, there are 13 warrants in total for us to choose from.
Q What do you like best about being a traffic engineer?
A My day’s not predictable. I can’t always know what’s going to happen—something always comes up. There are signal malfunctions and I might have to adjust the time of some signals when there are road closures and detours. All of the signals are available online and I can make adjustments right here in the office. And we do hear from citizens when something’s not right—they might not know why there’s a problem, but they know when something’s off. We appreciate hearing from them; they can call Durham One-Call [call 919-560-1200 or fill out an online form].
A I can’t say when, exactly. It’s really frustrating because there are so many unexpected expenses. It costs so much more to bring a building up to code while it’s being designated an historic building. You have to follow the rules about the changes that you make inside and out. Some of these unforeseen issues might call for additional funding. We’re still working it out.
Q You must get up early. What time do you start your day?
A Around 4am! I have to do my paperwork some time, and I’m a morning person. So my workday is from 4 to 4. Supplies have to be picked up, so sometimes I’ll get them on the way in. I also schedule deliveries of Larry’s Coffee, desserts (from Party Kakes and Favor Desserts), soft drinks, and I have to figure out what we need for special events. And we get as much as we can locally—our eggs are from Hillsborough, and we like to buy local produce and poultry products.
Q What are your hours now? And can you still use your space for parties on the weekend?
A Our official hours are weekdays from 8am to 4pm. But we can use our space seven days a week for birthday and retirement parties, receptions and reunions, seminars, and annual corporate meetings. We recently had an event with 180 people from the Community Health Coalition.
Q How do you choose your specials—and what lunchtime specials are you running this week?
A A lot of times we choose customer favorites for our specials—one different special each day. This week our specials are barbecue ribs, Salisbury steak, we always have fish on Fridays … lots of soul food like cornbread, homestyle baked chicken, and don’t forget our veggie plates.
Q I thought it was strange that Blue Coffee Café ended up at NC Mutual, but now I understand.
A NC Mutual has been our saving grace! Tell everybody to come see us—we’re here and we have the same good food and same good prices.
City Hall (1 City Hall Plaza)
Department of Transportation, 4th floor