Street light inventories and networked controls before an LED retrofit

Reference article · 7 min read

An LED retrofit looks like a fixture purchase. It is mostly a records project. Before an agency can scope, price, or finance a conversion, it has to answer three questions that many jurisdictions cannot answer on demand: how many street lights exist, who owns each pole and each luminaire, and what rate the agency pays for the energy. Projects that move ahead without those answers end up specifying fixtures for poles the agency does not control, or paying for lights that were removed years ago.

The work is unglamorous and it pays for itself. Ownership determines who can touch the asset. The tariff determines what the savings actually are. The inventory determines whether the savings are real or arithmetic. Do this part first, and the rest of the project becomes a normal procurement.

Who owns the pole, the fixture, and the circuit

Ownership is rarely uniform across a jurisdiction. A single city can have all of the following, sometimes on the same street:

• Utility-owned and utility-maintained. The agency pays a bundled rate covering energy, fixture, and maintenance. The agency generally cannot change the fixture on its own, and conversion happens on the utility's schedule and terms.
• Agency-owned and agency-maintained. The agency pays for energy only, often unmetered, and carries all maintenance cost and liability.
• Mixed. The agency owns the luminaire on a utility-owned pole, or owns poles on arterials inherited from a state or county road transfer while the utility owns residential lights.

Ownership of the pole, the luminaire, the mast arm, and the underground or overhead circuit can each sit with a different party. Ask the utility for its pole and light records in a machine-readable export rather than a PDF, and ask specifically whether joint-use agreements or historical transfer documents affect any segments. Where records conflict, the field survey is the tiebreaker, and the discrepancy should be documented before it becomes a dispute during construction.

The tariff and the unmetered billing count

Most street lighting is billed unmetered. The utility applies an assumed wattage and assumed burn hours per fixture type, multiplied by a count on file. That count is a billing record, not an inventory. It drifts as lights are added by developers, removed after crashes, or annexed in.

Request the billing detail behind the street lighting account: fixture type, wattage class, rate schedule, and count per location or per circuit. Compare it line by line against the field survey. Expect to find lights being billed that no longer exist, and lights in service that are not being billed. Both matter, and both should be corrected before the conversion, so that post-project savings are measured against a clean baseline.

Street lighting tariffs are filed with the state utility commission, and the process for adding an LED wattage class, changing a fixture code, or converting to a new schedule varies by state and utility. Timelines can be long. Confirm with the utility and, where a tariff change or a purchase of utility-owned assets is contemplated, with agency counsel, early enough that the tariff work runs in parallel with design rather than after it.

Building the inventory in GIS

Collect the inventory as geospatial data the agency owns, not as a consultant's spreadsheet. Useful minimum fields include pole identifier, utility pole tag as painted or stamped in the field, luminaire type and nominal wattage, mounting height and arm length, photocontrol receptacle type, circuit or service point, owner, maintenance responsibility, condition, and a photograph. Capture coordinates at the pole, not at the curb.

Quality control matters more than collection speed. Check for duplicate points, poles recorded on the wrong side of the street, and records that fail to join to either the billing file or the utility's export. The inventory should reconcile to three sources: what crews see, what the utility bills, and what the agency's own asset or work order system already holds.

Node-level controls and what they monitor

Networked controls put a communicating node on each fixture, usually in the photocontrol receptacle. The energy savings come from the LED. The operational value comes from the node: per-fixture fault and outage alarms, burn hours, measured or estimated consumption for verification, remote schedule changes, and group control by corridor or district.

Controls also create a long-term dependency, so evaluate them as a system:

• Communications. Mesh, cellular, or a mix. Each has different coverage behavior, recurring cost, and failure modes in tree canopy or valleys.
• Interoperability. Confirm the dimming receptacle and node conform to the applicable ANSI C136 standards, and ask whether the management system supports an open interface such as the TALQ specification, so a future node vendor is possible.
• Data. The agency should own the telemetry, be able to export it in bulk, and have a defined path to retrieve it if the subscription ends.
• Lifecycle. Node service life and warranty are often shorter than fixture life. Budget for node replacement separately.

Dimming and color temperature with the public in mind

Correlated color temperature is the decision residents notice. Higher CCT sources read as harsh and draw complaints about glare and light trespass into bedrooms. Guidance from lighting and dark-sky organizations has generally moved toward warmer sources and better shielding, and many agencies now standardize on a lower CCT for residential streets while treating major intersections separately. Confirm current recommendations with the relevant standards body rather than relying on an older specification sheet.

Run demonstration blocks before the standard is locked, publish the locations, and collect reactions. Where adaptive dimming after late-night hours is under consideration, design to recognized roadway lighting criteria and involve the traffic engineer and the police department in setting the schedule. Keep a written record of the design basis, because complaints and liability questions both arrive later.

Outage reporting from residents and from the network

Residents will keep calling. Give them something to report with: a legible pole identifier visible from the sidewalk, and one intake path through 311 or the agency web form regardless of who owns the light. Behind that intake, route the ticket by ownership, and track utility-owned repairs against whatever response commitment the tariff or franchise agreement provides.

Network alarms do not replace resident reports. They surface fixtures on unwalked streets, but they also generate false positives from communication failures rather than lamp failures. Reconcile both streams against the same asset identifier so that a single light does not become three open work orders.

What to ask vendors and require in the contract

• Warranty terms in writing, separately, for fixture, driver, and node, including whether labor and travel are covered or parts only, and how a claim is proven.
• Warranty tracking data. Require install date, serial number, and firmware version delivered per asset in the GIS record, not in a vendor portal the agency cannot export.
• Parts availability for the stated warranty period, with part numbers and a discontinuation notice obligation.
• Data ownership, export format, and API access, plus priced options to continue or terminate the management subscription.
• A defined acceptance period with burn-in, aiming verification, and a punch list tied to payment.
• Clear allocation of tariff work, including who prepares the utility notification of converted fixtures and who bears cost if the billing count is not updated.

Confirm any grant, domestic preference, or financing condition with the funding agency before award, as those requirements change.

HQT works with state and local agencies on asset inventory, GIS data, and systems integration supporting infrastructure programs of this kind.

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