Trailer Drive (TDRV)
See how the trailer behaves on the road
A trailer is not simply following the truck.
While driving, its braking system, pneumatic supply and stability functions are continuously responding to the vehicle combination and road conditions.
The Trailer Drive Parameter Group provides live information about trailer speed, braking activity, pneumatic pressure, emergency braking and stability interventions.
It gives fleet applications insight into how the trailer is actually operating while on the road.
Specifications
Name: Trailer Drive
Header: $TRAILERDRIVE1
Subscription: Yes
Solution: Trailer Box
Trigger: Every 10 seconds and on event
Buffer: Yes, default
Server header: Time and location
Changes in important operational parameters, including gear requests and braking status, can generate an immediate event.
For multi-trailer combinations, an individual message is generated for each trailer. The trailer number is reflected in the message header, supporting trailers 1 through 5.
Key Parameters
Trailer Speed
Provides the actual speed measured by the trailer.
This gives the application an independent indication of trailer movement and provides useful context for braking and stability events.
Pneumatic Supply Pressure
Monitors the pneumatic pressure supplied to the trailer.
Adequate air pressure is essential for correct operation of the trailer braking system. Monitoring the available supply pressure provides valuable information about the operating condition of the pneumatic system.
Brake Activity
Provides information about active braking conditions, including:
- Brake switch status
- External brake request
- Emergency braking status
These parameters allow an application to recognise when the trailer braking system is being actively controlled and distinguish normal braking from specific externally requested or emergency braking events.
Individual Brake Cylinder Pressure
The actual brake cylinder pressure can be monitored separately for the left and right sides of the first three axles.
Available information includes:
- Axle 1 – left and right
- Axle 2 – left and right
- Axle 3 – left and right
This provides detailed insight into how braking force is being applied across the trailer.
ABS & Stability Control Activity
Trailer Drive includes counters for:
- ABS interventions
- VDC interventions
These counters provide insight into how frequently the trailer’s electronic braking and stability systems have intervened.
A high number of interventions may provide useful information for later analysis of vehicle operation, route conditions or driving circumstances.
Gear & Manoeuvring Status
Where supported, the PG provides:
- Reverse gear request
- Neutral gear request
- Neutral gear status
These parameters provide additional operational context, particularly during manoeuvring and specialised trailer applications.
Trailer Electrical Supply
Indicates whether the trailer’s electrical supply is sufficient.
This provides a simple but important indication that the trailer electronics have the power required for correct operation.
The complete Parameter Group and parameter definitions are available to Squarell partners.
ISO 11992 & Squarell Checker Box
ISO 11992 is a point-to-point communication network between truck and trailer. The Squarell Trailer Box therefore reads the active communication non-intrusively through CANcliQ, without interfering with the truck-to-trailer connection.
When the trailer is disconnected, the Squarell Checker Box can communicate actively with the trailer to retrieve additional information that may not be available during normal operation.
Together, these technologies allow Squarell to obtain both live and additional trailer information while respecting the special architecture of the ISO 11992 network.
From driving data to trailer behaviour
The real value of Trailer Drive comes from combining parameters.
For example:
Trailer Speed + Brake Activity + Brake Cylinder Pressure
shows how the trailer braking system responds while driving.
Emergency Braking + ABS/VDC Activity
provides valuable context around a significant braking event.
Pneumatic Supply Pressure + Brake Cylinder Pressure
provides insight into the operation of the pneumatic braking system.
ABS/VDC Interventions + Location + Time
can help identify where and under what circumstances stability interventions frequently occur.
These combinations turn individual technical parameters into meaningful information about trailer behaviour on the road.
Typical Applications
Trailer Drive can support applications such as:
- Live trailer monitoring
- Braking behaviour analysis
- Emergency braking detection
- ABS activity monitoring
- Stability control analysis
- Pneumatic system monitoring
- Brake pressure analysis
- Road condition analysis
- Driver and vehicle combination analysis
- Multi-trailer monitoring
- Incident analysis
Business Value
The Trailer Drive Parameter Group helps fleet operators to:
- Understand how trailers behave while driving
- Monitor trailer braking activity
- Detect emergency braking events
- Monitor pneumatic supply pressure
- Analyse ABS and stability interventions
- Compare braking behaviour between axles
- Identify unusual operating conditions
- Support technical investigations
- Improve trailer safety
- Gain better insight into demanding routes or operations
Why Squarell?
Much of the information exchanged between truck and trailer is only relevant for fractions of a second while the combination is driving.
Squarell’s Trailer Box continuously monitors the ISO 11992 communication and converts the available information into a harmonised Trailer Drive Parameter Group.
Fleet applications therefore gain access to meaningful trailer operating information without having to understand the underlying ISO 11992 communication.
Related Product
Trailer Box
The Squarell Trailer Box provides non-intrusive access to the ISO 11992 communication between truck and trailer.
With onboard processing, modem communication, GNSS and harmonised Parameter Groups, important trailer driving events can be captured and transmitted to the back office.
Trailer Drive — See what happens behind the truck while it is happening.
