Clear Signals : Lights Direct the Stop and Go, but How They Work, Few Know
Quick now, how many bulbs are in the traffic lights at a common Southland intersection?
Your time is up. The answer is 36. One bulb for red, one for yellow, one for green--on each pole. Facing him, a motorist has lights to the left, lights on a mast arm over the street, and lights to the right. Therefore, nine lights for each of the four approaches.
Traffic signals--something we all take for granted. Leonard Nicholas, however, doesn’t. What he does instead, and does every working day for a living, is see to the care and feeding of traffic lights.
This translates into cleaning each and every signal lens on his route (two other city workers do the same), and then replacing the bulbs inside.
“No, I don’t do windows,” Nicholas quipped. “But I am very good at changing light bulbs in my home.”
Although the subject may not exactly dominate at cocktail parties, Angelenos were reminded of the traffic lights that regulate their comings and goings by the recent announcement of a $9.6-million synchronized traffic signal system designed to ease congestion on downtown streets. City officials said they have added 212 signaled intersections to the Automated Traffic Surveillance and Control System (ATSAC).
According to transportation department general manager Ed Rowe, it will be the mid-1990s before the high-tech system is citywide. After all, we are talking about 3,910 traffic signals (each one, as the paranoid will attest, programmed to deliberately turn red just as you approach). Of the approximately 38,000 intersections in the city, only about 10% have lights--the rest are either controlled by signs or are uncontrolled.
And though it may not always seem so, assistant general manager Guy L.Quinn Jr. said the city is always making a sincere effort at synchronization--the object being to help you avoid stopping at every corner.
Quinn explained why this doesn’t always work:
“If we had all traffic signals spaced at quarter-mile intervals, and if everyone drove at 30 m.p.h., and if all traffic lights were on 60-second cycles, a platoon of cars (any grouping that proceeds through each set of signals) could continue throughout the city and hit nothing but green lights.”
--In the downtown area, signals are at every block, not every quarter mile.
--Just about nowhere in Los Angeles does traffic flow uniformly at 30 m.p.h.
--Because of heavier traffic on certain streets, and at certain times, those streets may be programmed for longer green lights, the result being longer waits for intersecting traffic.
Trailblazing Signals in 1914
We wouldn’t be talking about any of this, of course, had not Cleveland, Ohio, in 1914, installed electric cross arms at one of its intersections. Not only did these trailblazing signals have red and green lights, but they had buzzers--two long buzzes permitted Euclid Avenue traffic to proceed, one buzz allowed the same for 105th Street.
The concept caught on. And while the public complains of traffic on the one hand, it also seems to like the idea of more lights, judging from the 2,200 or so requests for new ones that the department receives annually.
“We authorize about 25 new signals a year,” Quinn disclosed, adding that sometimes the result isn’t totally positive. “Any time you do it, you introduce a delay factor. And sometimes the accident pattern changes--sometimes accidents actually increase. The rear-end type may increase.”
However, Quinn added, “generally, a traffic signal will prevent accidents when the right of way needs to be assigned.”
“For a couple of years we have been trying a few ‘rest-in-red signals,’ ” Rowe said. “We have put them in areas known for speeding. If you go slowly, the light will change to green. If it detects you speeding, it will stay on red and force you to stop.”
Sounds great, right? “But the problem,” Rowe sighed, “is that the same residents who had been complaining of the speeding, now are complaining of the noise from the brakes.”
One thing that does work without question, particularly in gridlock, is something the transportation department calls a flush:
Explained Rowe: “Somebody in the field downtown may call ATSAC and say: ‘Everything is at a standstill. Throw in a flush!’
“Then we may, for instance, put Broadway on green for two solid minutes. If we need three minutes, we call it a royal flush. After Broadway is cleared, the side streets can proceed, and the gridlock is broken. We use this a lot during the holidays.”
The department used to have another term, morning sickness, which referred to the unfortunate propensity of some street lights not to change from red early in the morning. Some lightly traveled roads used to have treadles in the pavement (now, embedded wire loops have replaced most of them). With the treadles, lights hopefully changed after vehicles passed over those pressure pads. But under certain weather conditions, particularly in the hours after sunrise, moisture interfered with their efficiency--and the motorist waited forever for a green light. Thus the designation of morning sickness.
And power outages no longer have the impact they once did. Rowe, who joined the department in 1958, recalled that until the installation in the late ‘60s of master controllers, whenever power went out, even momentarily, so did traffic light synchronization--and not just momentarily. “When power was restored,” Rowe said, “the lights would fire at screwy times. Sometimes this would be discovered only when a crew happened to be in that area.”
In many parts of the city, he explained, there are different signal synchronization schedules for different time periods--perhaps one set for the morning and evening rush hours, another for less busy hours. “Such a little thing as a relay (switch) that sticks may, for instance, result in a synchronization more appropriate to midnight than to 8 a.m. ATSAC identifies such malfunctions immediately, but until the system is citywide, we only find out (in other areas) when routine maintenance is being performed.”
As for where motorists have a good chance of an unimpeded drive, Quinn said that generally the West Valley has good spacing of signals, and a motorist often has a good chance of hitting a progressive flow.
As new signals are needed anywhere in Los Angeles (all solid state now, no more electric motors), they are constructed by the city, in a yard on Exposition Boulevard, and then installed. The cost, Quinn said, would be more than the $48,000 apiece if done privately. Some of the older versions, scattered in various parts of town, have lasted 20 years or so, he said.
How good is your memory? All light poles used to be yellow, and they needed to be painted from time to time. The current models are galvanized, which requires no painting, and the heads are black plastic.
Some of those heads, incidentally, are a type known as “programmed visibility"--intentionally designed to be seen in only one lane--such as the left turn lane, so a driver won’t be confused by seeing more than the light which pertains to him.
Regardless of the type, on Leonard Nicholas’ route, they are all his babies. And they all need to be cleaned and changed.
“With a typical 60-second cycle,” Quinn explained, “the breakdown is 27 seconds of green, three of yellow, 30 of red.”
No more than one of the bulbs during this silent sequence is on at the same time. And it had occurred to city officials for a time that, given the brief marquee billing of the yellow, they could skip changing that bulb on every other visit to an intersection.
The saving was more trouble than it was worth, though. The bulbs at a given intersection are changed about once a year, and invariably, an ignored yellow one would give out and require a special trip. So now everything is changed at once, including those for the pedestrian signals at more than 90% of the intersections.
The 56-year-old Nicholas works by himself (as do the city’s other two re-lampers) usually arriving at the first of his seven daily intersections shortly after 6:30 a.m.
Never worry about him being a bulb-snatcher. “I carry about 400 of them in my truck,” he boasted.
Electric Bill Went Down
According to Quinn, the bulbs themselves are of a design meant to be used in a horizontal position and to withstand the vibrations from traffic. “For our mast arm indications, we had been using 150-watt bulbs, but during one of the energy crises, we switched to 133 watts. We discovered that not only did they provide adequate illumination, but our electric bill went down.”
Traffic trivia: The city uses 105,000 of these long-life, clear bulbs a year.
Before reaching for one of his, Nicholas deploys traffic cones around his truck, hoists himself up about 20 feet in a bucket lift to each set of signals, opens the lens, sprays on a solution and towels each one clean of grime. Then he screws in a fresh bulb.
He applied for the “re-lamping” job about 12 years ago, Nicholas said, after having spent years in the city shop. He says he likes being outdoors.
And occasionally communing with nature. Such as bird nests. From time to time, Nicholas will find a collection of eggs, sometimes chicks, and will remove them for humane disposition.
As mentioned by Quinn, nesting birds recognize the protection provided by the signal hoods and the heat thrown off by the lights.
Besides, in Southern California, everybody wants affordable housing.