Why Traffic Signal Inspections Should Be an Essential Part of Your Municipality’s Maintenance Program

When you think about the moving parts of a town or city, traffic signals may not be the first thing that comes to mind. They hang above intersections, doing their job day in and day out, mostly without notice, until something goes wrong. A dark signal on a busy road can snarl traffic, confuse drivers, and even put lives at risk. That’s why routine traffic signal inspections should never be treated as an afterthought; they’re a critical piece of a municipality’s overall maintenance program.

Who is Responsible?

The Manual on Uniform Traffic Control Devices (MUTCD), the federal rulebook for traffic control, makes it clear that the public agency with jurisdiction over the roadway is responsible for ensuring proper maintenance of traffic control devices, which includes traffic signals. While the MUTCD does not prescribe a specific inspection frequency, it does state that agencies must provide qualified personnel and maintain spare equipment so signals remain operational and effective at all times [MUTCD, Part 4D.02].

In other words, the buck stops with the municipality (or county, or state highway agency, depending on the road). Outsourcing may be an option, but the legal and practical responsibility still sits squarely on the public agency’s shoulders.

Who Should Perform the Inspections?

Here’s where the difference between a light bulb changer and a trained signal professional matters. Changing out a burned-out lamp is one thing; diagnosing controller cabinet issues, wiring faults, or improper signal phasing is another story entirely. A trained signal technician can spot developing issues like worn connectors, compromised grounding, outdated software, or poorly calibrated detection systems; problems that may never occur to someone whose experience is limited to swapping bulbs.

Think of it this way: would you rather have your car inspected by a mechanic who understands the whole engine system or by someone who only knows how to replace windshield wipers? The same logic applies to signals. A certified traffic signal professional can educate your team on every potential fault, whereas a casual maintenance worker may not even know what to look for.

How Often Should Inspections Occur?

While the MUTCD does not set an interval, industry best practices do. A commonly referenced guideline recommends comprehensive signal inspections at least once every two years [CTI, 2017]. Some agencies choose to perform them annually, especially in high-volume urban corridors where signals are mission-critical.

During these inspections, technicians don’t just check the lights. They’ll review:

• The physical condition of signal heads and supports.

• Controller cabinet wiring, grounding, and cleanliness.

• Detection systems (inductive loops, cameras, radar).

• Timing and phasing accuracy.

• Visibility, lens condition, and reflectivity.

Preventive inspections are like regular medical checkups: they help catch small issues before they turn into expensive emergencies.

What Happens If You Don’t Inspect?

Failing to inspect your traffic signals is a gamble with high stakes. At best, the outcome is reduced efficiency - longer queues at intersections, wasted fuel, frustrated drivers. At worst, it’s liability exposure. If a crash occurs at a poorly maintained signal, plaintiffs’ attorneys will almost certainly ask for your inspection and maintenance records. If you don’t have a defensible record showing that inspections were performed, your municipality could face costly litigation and damaged public trust.

Consider too the hidden costs of letting things slide. A $200 fix for a loose wire today can become a $20,000 replacement of an entire cabinet tomorrow. Preventive inspections extend equipment life, save money, and reduce emergency callouts.

Why This Should Be Essential

Traffic signals are more than just blinking lights; they’re public safety devices. Treating inspections as optional is like skipping maintenance on your smoke alarms. By making inspections an essential part of your maintenance program, you:

• Protect residents and road users.

• Reduce liability and risk exposure.

• Stretch your budget through preventive care.

• Keep your operations smooth and predictable.

The MUTCD tells you that it’s your responsibility to maintain signals, but it doesn’t hand you a calendar. That’s where common sense and industry guidance step in. Schedule inspections regularly - every year if possible, no less than every other year - and have them performed by trained signal professionals. Your future self (and your community) will thank you when those signals keep clicking along reliably for decades.

Citations:

MUTCD, Part 4D.02, Maintenance of Traffic Control Signals, Federal Highway Administration.

Connecticut Transportation Institute (CTI), Preventative Maintenance of Traffic Signals (2017). PDF file

If you're concerned about your lack of defensible records - or your department's recordkeeping in general, look at Roadwurx - an asset managment system created specifically for highway departments. Roadwurx allows you to easily maintain records of your traffic signals and every maintenace event.