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Fleet Management Technology Terms: FMS vs Telematics vs ELD vs VER vs ADAS vs CAS vs DMS

While researching and developing business strategies to manage your fleet, you’ve probably encountered a bunch of acronyms for the various tools and systems on offer. Just when you feel like you’re getting a grasp on them, ten more pop into the lexicon with the emergence of new technologies.

While everyone in the industry probably has some sense of what these terms mean, it can be easy to lose track of where their definitions diverge or overlap. So we put together this simple guide to help you keep straight where one concept ends and the other starts.

Fleet Management System (FMS)

We’ll start with FMSs because they can incorporate many of the other technologies. The idea is to have a database of all the information you need to manage your fleet. An FMS is software that usually runs on a central server and focuses on metrics including:

- Vehicle and driver schedules

- Maintenance schedules and costs

- Fuel costs

The typical use of an FMS has a fleet manager signing in to see a dashboard listing which vehicles are available, which are unavailable, and which need some sort of service. The manager can then line up the list of available vehicles with a list of work orders and a list of available drivers. The system may even have features that allow you to plan the optimal route for the delivery.


The term telematics comes from combining telecommunications with informatics. Vehicle telematics refers to the transmission of data about performance and location from the vehicle to some far-off office where it can be accessed by a fleet manager. What types of information are transmitted?

- GPS location

- Vehicle performance

- RPM for the wheels

- Real time fuel efficiency

Essentially, an FMS is the database and interface used by the fleet manager to plan hauls, while telematics is the real-time data sent from the truck to the office where the manager can track the haul’s progress. Data from the telematics system is usually also saved in the FMS to facilitate the planning of future hauls as well. So, in the most advanced setups, these two technologies complement each other.

Electronic Logging Device (ELD)

Since late 2019, most commercial vehicles have been required to have an ELD installed in them. This is how fleets, and regulators, make sure drivers are complying with government rules. ELDs include hardware attached to the engine that tracks when it’s running, whether the vehicle is moving, how far it’s moved, and how long it’s been moving.

Much of this information overlaps with what telematics systems track, but the main purpose of ELDs is to ensure drivers are adhering to the Federal Motor Carrier Safety Administration’s hours of service rules. These rules are meant to minimize risks posed by fatigued drivers, and they require that breaks be taken after the number of hours on the road reaches certain limits. The FMCSA allows data from ELDs to be transmitted through a telematics system, so the two technologies, along with FMSs, are often used together.

Video Event Recorder (VER)

If one of your drivers is in an accident, you could rely on the testimony of everyone involved to learn what really happened. Or, if you had cameras on the truck recording the whole thing, you could simply review the footage. As so-called nuclear verdicts (those costing fleets $10 million or more) are becoming more prevalent, many trucking companies are turning to cameras and recorders to protect themselves from fraudulent cases—or to let them know they should settle a case out of court.

A VER can also catch incidents of theft or collision while the truck is parked—even when no driver is around to activate it. Many cameras and recording devices have triggers that activate them when a door is opened or something comes in contact with part of the vehicle.

VERs are also used in training and coaching. This can be done through analyzing an incident after it has occurred to evaluate the driver’s performance. Or it can take the form of ongoing tracking, as cameras and AI monitor the driver and report behaviors like checking phones or failing to buckle safety belts. (Here, there’s overlap with Driver Monitoring Systems—see below.)

Cameras and recorders are often integrated with telematics to give fleet managers a more comprehensive view of what’s going on with their trucks at any given time.

Advanced Driver Assistance System (ADAS)

This is a general term that encompasses the next two categories below (and several others not included in this list). ADASs include sensors, indicators, and sometimes automated driving technologies. Some of the most common applications are adaptive cruise control and antilock brakes.

On the passive end of the spectrum, there are sensors and indicators to warn drivers when there’s an object in their path. More active features include automated parking, lane assist, and automatic braking. Technologies that rely on communication between vehicles, or between the vehicle and various elements of infrastructure, are also advancing rapidly. Full vehicle autonomy, though not available yet, will likewise fall under the category of ADAS.

Collision Avoidance System (CAS)

CASs are rapidly becoming standard for all new vehicles. Here you have the first technology on the list that doesn’t necessarily save or transmit data from the vehicle—though many fleets integrate their CAS with their telematics system to gain greater insight into trends and driver behaviors. The main purpose is instead for sensors and indicators to alert drivers to potential hazards in the road.

An advanced CAS might include sensors on the rear of the vehicle that sound an audio alert when the driver is about to back into something. Many vehicles have sensors that monitor the blind spot, beeping and flashing a light on the side mirror when there’s another vehicle traveling there. And there are also front-facing sensors that pick up everything from other vehicles and pedestrians to lane markings and traffic signs.

Again, integrating a CAS with telematics can give fleet managers an idea of which drivers have a habit of following too close or swerving between lanes. The frequency of the sensors’ activation can also help to identify stretches of road where drivers should expect delays and difficult traffic conditions.

Driver Monitoring System (DMS)

These systems rely on in-cab cameras that are directed at drivers. It’s not quite true that DMSs are used to spy on drivers, though, since the cameras usually aren’t recording anything, and when they’re triggered the alert may not go anywhere but to the drivers themselves (depending on how the systems are configured). But they are powerful tools for both driver training and for improving safety records, meaning they’re a good way to potentially reduce the cost of insurance.

DMSs often incorporate artificial intelligence, which enables them to recognize various behaviors—heading nodding that signals fatigue, eyes turned away from the road for prolonged intervals—while differentiating them from other similar behaviors. Is the driver scratching her ear or answering her phone? A machine-learning program can easily be trained distinguish between the two.


Now that we’ve gone through all the terms, it’s important to note that fleets often use two or more of these technologies in tandem, and providers will often use different terms to mean the same thing. What’s important isn’t that you use one term vs another but that you understand the role each tool plays in helping you to manage your fleet successfully.

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