Fighting Traffic

Across the country, electrical contractors currently are or will be garnering contracts to upgrade traffic signals—replacing the incandescent bulbs with light-emitting diode (LED) lamps. Take a few tips from one company that has successfully completed a major project of this type.

In May 2010, Aldridge Electric Inc., a 60-year-old, family-owned company with corporate headquarters in Libertyville, Ill., began a two-year, $7.4 million contract for the Chicago Department of Transportation (CDOT) to replace incandescent-bulb traffic signal heads with LED versions at 850 intersections in the city. The company was later awarded with change orders—amounting to 149 percent of the original contract—for an additional 450 intersections.

According to the City of Chicago’s website, the project—funded by the Department of Energy’s Energy Efficiency and Conservation Block Grant and Illinois matching funds—will lead to an estimated $1.8 million annual savings in electrical costs and a reduction in almost 15,000 metric tons of carbon dioxide (CO2).

What can we learn from Aldridge’s experience?

Tip No.1: Do a survey of existing conditions
Aldridge’s strategy involved extensive preplanning during an almost four-month period. The first phase of the project surveyed the conditions at 850 intersections in Chicago, using a valuable in-house resource: six participants in the company’s paid intern program. (The 10-year-old program is set up for college students who work for three to four months.) The interns did a detailed survey of each intersection, denoting the existing conditions—the number of mast head mounts, any missing mast arms, whether signal heads had been previously replaced by the city, access restrictions, etc.—with accompanying photographs, drawings or schematics, and a map of each intersection. This information was included in a database and in a binder used by both the project management and the field teams. The data was then retained as an as-built of the existing conditions and was submitted to CDOT.

“With the information the interns gathered, we knew exactly what we were getting into at each intersection before we went there,” said John Wendel, Aldridge Transportation division manager. “That allowed us to preplan and proactively predict what we were going to run into … and that changed how many and what type of LED we ordered. Plans called for 1,000 of one item, and our survey found that only 800 were needed. Some line items weren’t accounted for, so we had to add [them].

“We knew because of the survey what material was needed on each intersection. On some, the signal heads were stacked. On others, they were mounted in the old style of those built 50 years ago. Our process eliminated the guess work and pop-up issues,” Wendel said. “The city appreciated it, too. The preplanning put everyone on the same playing field. Our message was: ‘Here’s what we’ve got out there, and here’s what it will take to replace it.’ It was a good starting place for everyone.”

Tip No. 2: Have a distributor preassemble the signal heads and LED lamps
Another decision that made the project go smoothly was the arrangement Aldridge made with Brown Traffic, a distributor headquartered in Davenport, Iowa, with offices in the Midwest. Brown preassembled the LEDs in the signal heads. LED lamps for traffic signals are a round globe with a self-contained section that fits within a plastic signal-head housing. Two lead wires run off the housing and terminate in a terminal strip. Products used included Dialight LEDs and a Siemens signal housing. Brown also attached one bracket arm to the signal head and supplied Aldridge with another bracket that could be attached in the field. The latter could be adapted and used for several of the custom mounts, some of which dropped the lights down 18 inches, others 2 feet off the mounting structures.

“The prefabrication process sped up the installation process and was very cost-effective,” Wendel said. “A conscious contractor will look at what can be prefabricated to make things easier and quicker for a field installation. It facilitates the whole process rather than having two guys out in the field trying to assemble something before they actually install it. There is quite a lot of safety liability to working out in live traffic, and you don’t want guys out there longer than they have to be.”

Tip No. 3: Use a movable trailer for materials
Once the field conditions were clarified, Aldridge brainstormed ideas for different methods of material delivery. An initial plan was to rent bucket trucks for materials storage that would be restocked daily for each of the crews; another was to have drop boxes or pods—approximately 10-feet-by-20-feet—loaded with materials that could be picked up by crews or delivered to specific work locations. However, those plans were abandoned in favor of movable stocked trailers for each crew. They were parked at the intersections being worked on that day. Then, warehouse crews restocked the trailers based on a field crew’s production from the previous day, providing them with three days’ worth of supplies including three-section bracket mounts, three-section mast arm mounts, four- and five-section heads, and pedestrian crosswalk signals (which were stored in front for easy access).

“It was the best choice because we could easily move the truck and pull-behind trailer, park it on intersections in the morning and stage it in the intersection while we did the installations. Having the ability to move the material to and from each location efficiently was very important,” Wendel said.

Tip No. 4: Do trial runs of traffic management
During the field aspect of the project, Aldridge employed traffic management practices in accordance with the Manual on Uniform Traffic Control Devices (MUTCD) and CDOT standards with the placement of traffic control devices and “men working” signs. But prior to sending out the eight crews, Aldridge took another preplanning step. A range of “easy to difficult” intersections were chosen, and two of their crews did trial installations at the intersections in order to uncover unforeseen issues, test best practice installation procedures, and determine the most effective means, methods and tooling on a small sample of work, Wendel said.

“Preplanning is so important,” he said. “If you can build something conceptually, and nail down 95 percent of the details and variables, while building best practice methods with your team prior to actual construction, it will make you 10 times more productive when you mobilize to perform the project. You will have proactively eliminated many of the obstacles, instead of trying to figure those things out on the fly while making changes under pressures, time restraints or project deadlines.”

Tip No. 5: Preplan routes to minimize driving time
Since Aldridge wasn’t doing every corner in the city, and only portions of some corners, the company planned routes so their crews could do a loop, said Matt Wysocki, Aldridge project manager.
“Basically we laid the job out so the guys weren’t driving from one end of the city to the other,” he said.

Tip No. 6: Simplify fieldwork
Due to the aforementioned steps, Aldridge was able to reduce the amount of time its crews might normally have spent working in the field. In terms of actual installation, on most intersections, crews cut the old signal heads off the poles and used stainless steel banding to attach the new polycarbonate signal heads onto the poles.

“Other cases called only for light replacement; LEDs were a one-for-one swap,” Wykowski said. “We replaced incandescent signal heads that were 8 inches in diameter with LED module signal heads that are 12 inches in diameter. If an LED did malfunction during the project, our crews would open up the housing, pull out the LED section, replace it and close the housing without having to replace the signal head.

“Also during the project, there were a number of signal heads that had to be optically programmed due to the configuration of the intersections and the drivers’ line of site to the signal head,” Wysocki said. “As opposed to the prior practice of taping off beam, we programmed by computer so that lights would be visible to a specific direction of traffic while invisible to other adjacent lanes. In most of those cases, primarily based on the age of the existing head and funding amounts to complete the work, the optically programmed incandescent heads were swapped out one-for-one with more efficient LED ones,” Wykowski said.

Field challenges were reduced to solving problems related to atypical mounting installations.

“In certain applications, the city didn’t have a standard of how things were mounted in the past,” Wysocki said. “For example, there were places where the lights had been mounted on viaducts or to the elevated [railway] Chicago Transit Authority structures, so they would be in the viewing area of the driver. We had to fabricate or modify aluminum drop-down brackets that we could use to mount to the existing traffic signal poles.”

Thinking about going after a traffic signal replacement project in your city? Take a few tips from Aldridge Electric, and good luck in getting a green light on a project for your company.

CASEY, author of “Kids Inventing! A Handbook for Young Inventors” and “Women Invent! Two Centuries of Discoveries that have Changed Our World,” can be reached at and

About the Author

Susan Casey

Freelance Writer
Susan Casey, author of "Women Heroes of the American Revolution," "Kids Inventing! A Handbook for Young Inventors," and "Women Invent! Two Centuries of Discoveries that have Changed Our World," can be reached at or www.susancaseybooks...

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