Definition
DSM (Driver State Monitoring) uses in-vehicle infrared or visible light cameras with AI algorithms (face detection, eye movement analysis, head posture, etc.) to identify driver fatigue, distraction, smoking, phone calls, unfastened seatbelt, and other statuses, issuing timely audio-visual alerts to ensure driving safety. DSM is a mandatory or recommended feature for commercial vehicles, ride-hailing cars, two-passenger-one-dangerous cargo scenarios, and together with ADAS constitutes an active safety system.
DSM is usually integrated into DVRs or standalone modules, and reports alarm data and captured images to the FMS through the T-Box. The EU AEBS regulations require commercial vehicles to be equipped with DSM, and some provinces and cities in China have similar requirements for passenger buses, dangerous goods vehicles, and ride-hailing cars. IoT SIM cards provide connectivity for DSM alarm reporting, remote configuration, and OTA upgrades.
Technical Features
DSM uses computer vision and deep learning to recognize fatigue features such as PERCLOS (eyelid closure), gaze deviation, and yawning. It supports local warnings and cloud analysis, and alarm data can be used for fleet safety management, insurance claims, and accident liability determination. When integrated with a DVR, it can trigger video uploads when an alarm occurs.
Use Cases
DSM is applied in commercial vehicles, logistics vehicles, buses, ride-hailing cars, taxis, and passenger and dangerous goods vehicles. Typical scenarios include fatigue driving warnings, distraction warnings, driving behavior analysis, fleet safety management, and insurance UBI. SimtoLink provides IoT SIM cards, dedicated APNs, data plans, and connected vehicle solutions for DSM in-vehicle systems.
A failed upload must not turn off the local warning
In driver status monitoring the IoT SIM carries alarms, snapshots, and parameter changes to the fleet platform. It does not sound the warning in front of the driver. The in-cab algorithm does that locally. If the picture did not upload, the fatigue warning still has to sound. If a warning-policy download fails, the vehicle should keep the last policy that was already in effect. It must not become “no policy, so no monitoring.” A SIM outage may delay what management can see. It must not delay the safety action. If the system treats a cloud acknowledgement as the switch for the local alarm, fatigue inside a tunnel is not warned, and a photo caught up after the tunnel does not help the driving that already happened.
The in-cab clock has to be reliable. Alarm records carry speed, position, and time, and snapshots can wait in a local queue until cellular returns. The queue limits picture size and count and keeps higher-severity events first, so one high-resolution image does not block every later alarm. Parameter download needs a version and a confirmation. A driver or someone on site must not be able to turn the function off with no record. Bind the SIM to the vehicle and the terminal serial number. When the vehicle or the terminal changes, alarm ownership changes with it. Night infrared and daytime visible-light policies differ. A failed remote switch must not disable the camera. On privacy, state which pictures leave the vehicle, how long they are kept, and who may retrieve them. Diagnostic logs should not also carry continuous video that has nothing to do with the alarm.
A common error is to judge whether the device is working by the alarm count on the platform. That count depends on coverage. The local sound-and-light count is what shows whether monitoring is on. Another error is an algorithm upgrade that erases the old model first. The download fails and the device has neither the new model nor the old one. Putting DSM pictures and driving video into one unlimited catch-up has the same effect: someone plays video back and the fatigue snapshot is delayed until the shift ends. A covered camera can still show communications online. With no cover event, the platform assumes the driver has been fine. Acceptance should trigger one repeatable alarm locally, shield cellular at the same time, confirm the sound and light still happen, and after recovery see one platform record whose time is the trigger time. How the alarm lines up with video is described under ADAS and DVR integrated upload. The recorder is described under DVR.
List local warning count and platform receipt count separately. When they disagree, look at the queue and coverage first. Do not mark the driver as “device not enabled.” Camera cover, infrared failure, and algorithm off are separate events. Communications online does not cancel them. Write the policy version on each alarm, so it is possible to explain why the same action sometimes warns and sometimes does not. If an upgrade package fails to download, roll back to the last model that can run. Do not show online with an empty model. Cap the picture queue. Past the cap, drop lower severity and record the drop. Do not drop a local event that has not yet warned, because the local warning does not depend on the queue in the first place. Separate retrieval rights and retention by how the vehicle is used. Continuous pictures for diagnosis stay off the upload by default. When the vehicle or the terminal changes, export unsent alarms to the new device or mark them as remaining on the old terminal, so the new SIM does not keep reporting the old vehicle’s fatigue records. At night, check the warning once with no network. Sound, light, and the local record should all be there. The platform record may arrive late, but its time must be the time of the event.
While a cover event continues, do not wait for a successful picture upload before showing it on the platform. If the vehicle already knows the camera is blocked, send that state first, or at least keep a flag that it is waiting to be sent. If a policy-off command comes from remote, the command itself needs an acknowledgement. With no acknowledgement, treat it as not off, and the vehicle keeps warning under the original policy. When the driver changes and the vehicle does not, the alarm still belongs to the vehicle. Do not rewrite the previous driver’s unsent records onto the new name.