Variable Message Signs: How to Optimize Preventative Maintenance Visits

 Variable Message Signs like most ITS equipment needs to be maintained to guarantee reliable operation. There are two types of maintenance visits:

• Preventative maintenance
• Corrective maintenance

Why Is Preventative Variable Message Sign Maintenance Important?

Preventative maintenance is performed on a semi annual or annual basis to ensure proper operation and reliability for years to come.Electrical components and electronic devices are rated and designed to be used in this type of environment, and need to be inspected / verified periodically. Variable Message Signs are installed in all types of environmental conditions and are subjected to severe storms, varying temperatures, dust and roadway debris. 

They are installed on overhead or side of the roadway structures which vibrate and can create issues within the VMS.

Newer LED technology is much more robust than previous generations of DMS for example: fiber optic signs and flip disk technology.

Preventative maintenance is recommended by most DMS manufacturers, some key elements must be followed to ensure an efficient preventative maintenance visit. The purpose of such visit is to ensure the variable message sign housing and all electronic components inside are protected and operating effectively. 

Proper preventative maintenance will increase the life of your variable message signs while decreasing corrective maintenance visits.

Preventative Maintenance Tips:

Tip #1 - Prepare For Your Maintenance Inspection

Always be prepared with a preventative maintenance checklist or procedure.  This will ensure technicians are efficient and no inspection steps or checks are overlooked.

 Tip #2 - Don't Forget to Check the Basics
Because of vibrations, corrosion, dirt and dust, wiring and electrical connections should be inspected, tightened and cleaned to ensure safe operation. 

Tip #3 - Start with the Variable Message Sign Controller and Traffic Cabinet

Starting in the DMS controller cabinet can be key to your teams preventative maintenance visit.  Diagnosing your DMS before hand for pixel, and or power supply issues will ensure your team is properly equipped with spare parts before closing lanes and accessing your DMS housing. Inspecting electrical connections and cabling condition will ensure proper and safe operation of your DMS.

Tip #4 - Upload the Last Versions of Firmware and Software

DMS controllers, display boards and other components often run on proprietary software. The DMS manufacturer may from time to time update software and firmware for better system performance. Like your phone needs to be updated, we recommend to make sure you contact your DMS manufacturer and update firmware during preventative maintenance inspections. With the SESA embedded web server, this is very easy to do, explained in our article "9 benefits of using an embedded web server".  

Tip #5 - Check Mechanical Aspects of the Controller Cabinet and Variable Message Signs
It is important not to only focus on electrical connections and software. Inspecting the mechanical aspect of the DMS, access doors, water / dust intrusion gaskets, cable entry points, etc... Make sure there are no signs of water intrusion as well as verifying locks, hinges and any other equipment for any damage. 

Tip #6 - Verify Communication With the Control Center

When on site, contact the control center and ask the operators to post specific messages. Verify the correct feed back and verify the VMS is displaying correctly. By doing so you will make sure that the operators see what is currently displayed. 

Tip #7 - Perform Security Checks

VMS have unique features, and should behave appropriately when some events occur like loss of power or loss of communication. You want to make sure that the message displayed is correct. For example, if the communication was lost for more than a pre-defined time, the DMS should blank or display a certain message.

Tip #8 - Verify power, power supplies, voltages

With a voltmeter, verify that the power being supplied to the DMS is within tolerances and verify that DC power supplies are delivering the correct voltages to specialized equipment. If the voltage values are not in tolerance you may be able to diagnose an issue before it negatively effecting the VMS.

Financial benefits of Preventative Maintenance

Preventative maintenance is not a cost but an investment. It will guarantee your VMS will last longer and will operate properly. If potential failures are discovered in advance, they can be fixed at a lower cost. We recommend a preventative maintenance visit semi annually.  If budget constraints play a factor to this time frame you can extend visits to 9-12 months. Please bear in mind that most checks can be done from the controller cabinet which is easier to access and usually does not require lane closures.  

You can find more about maintenance tips in this article: The benefits of embedded web server in DMS controller Maintaining a old legacy sign may be difficult and can become expensive if parts are obsolete. The solution is to Retrofit and Upgrade it to the newest technology: