News & Media

Electronic Brake Performance Monitoring (EBPM) - What it does and how it works

The cutting-edge telematics system from BPW-idem typically incorporates electronic brake performance monitoring (EBPM) as standard. It has been designed by BPW engineers in the UK, in collaboration with the BPW Mechatronics Department in Germany and the multiple award-winning telematics company, idem.* This innovative function audits the brake performance of a trailer and reports it to the operator via the idem telematics system. All braking events are monitored. However, only those that fit certain criteria, making them suitable for reliable analysis, are used to report on braking performance. 


EBPM makes use of data taken from the trailer’s electronic braking system (EBS) during a braking manoeuvre. It combines this with data from the telematics system in order to calculate the change in speed over distance and time and determine a deceleration rate for that manoeuvre. The data is then transmitted to the idem servers via General Packet Radio Service (GPRS). Once processed, it becomes available to the report-writing system. 


Traditionally, trailer brakes are tested annually at the MOT on a roller brake tester. This provides a performance figure for the trailer in a static condition; i.e., the vehicle combination is not moving, so the brakes are operating without modulation from the tractor unit and at a slow speed only simulated by the brake rollers. For a tri-axle semi-trailer, there is a testing condition which allows the trailer to be presented for the test in the unladen condition and where wheel locks are relied upon in order to pass the test. In recent times, there has been a move towards testing trailer brakes four times a year, one of which must be carried out at MOT time. Continuous monitoring of trailer brakes is an alternative. This is a very cost-effective and accurate method for monitoring braking performance. EBPM provides for this, and the vehicle will only require a roller brake test annually at MOT time.


Because EBPM continually monitors the trailer brakes, there are other advantages:

  • The brake efficiency is calculated each time the brakes are applied, and therefore, the trailer is tested with varying load conditions.
  • The trailer brake performance is given at normal highway speeds and not just at slow speeds on the brake roller tester.
  • The foundation braking system is being tested whilst running at its correct working temperature.
  • Any faults that affect the performance of the brakes will become evident before the next scheduled brake roller test.
  • Reports can be generated for the user at various intervals to satisfy either the statutory requirements or those demanded by the business for planning service intervals or service operations.


When EBPM gathers the brake efficiency data, it does so for the entire combination, i.e., the tractor and the trailer together as a single unit. This means that the figures are not directly compatible with those from a brake roller tester. The system’s software allows for this, as well as the impacts of external variables, in order to create data for the customer that is comparable to data from the brake roller tester. In order for this system to work correctly, it is essential that the trailer brake calculations are accurate. An important part of the installation of EBPM is to ensure that the brake calculations are checked and that changes are made where necessary. It is also important that the braking compatibility between the tractor and the trailer is accurately set; otherwise, the quoted braking efficiency may not be correctly stated for the trailer when compared to the figures gained from a roller brake test. 


It is crucial to understand that the results of an unladen brake roller test for a trailer cannot be compared to the results for braking efficiency given by EBPM. This is because the figures from an unladen test will only record the retardation indicated at the point of wheel locking, whereas under normal loading conditions at highway speeds the performance may be higher. Trailers loaded to at least 60% of the maximum bogie load will yield more accurate results. However, allowances will need to be made for testing with cold brakes at low roller speeds. 


It is natural to assume that in cases of reported poor brake performance, the trailer is in need of attention, but the problem could equally be an issue with the tractor braking system. It must be remembered that the figures sensed by EBPM are for the combination. The first step when investigating poor (or excessive) braking performance is to carry out a laden graduated brake roller test. 


The reports that are generated by the system can be for various periods. However, 90 days will give a very good overall picture of how the brakes are performing, and a weekly view will give an early warning of any problems.





















Looking at the diagram on the previous page, which shows a ‘typical 90-day report for a tri-axle semi-trailer’, it can be seen that the vehicle is performing at 0.56g (the minimum acceptable for an MOT pass on a semi-trailer is 0.45g). The histogram represents the space shown in the brake calculations for the semi-trailer. The light blue bars on the left-hand side would represent low-performance braking and the light blue bars on the right-hand side would represent high-performance braking. It is normal to see a small percentage of brake events in both of these areas. The dark blue bars show braking in the acceptable range. For example, the dark blue bar in column 13 shows that 171 brake applications out of 1127 fall into this band, so this trailer is performing very well against the predictions from the brake calculations.

















The section highlighted in grey is the area in which the laden brake performance curve has to be located in order for the trailer to comply with the brake calculations for the vehicle to meet UK-type approval regulations. In the previous diagram, the nine vertical bands coloured in dark blue are positioned inside the grey area of the diagram above. This serves to show the relationship between the EBPM reports and the braking regulations. 


Alongside the electronic brake performance monitoring (EBPM) function offered by idem, there is also the option to add tyre pressure monitoring (TPM), temperature control monitoring (TCM), and door sensing.


*About idem telematics GmbH – Connecting all road transport 


As Europe’s leading telematics partner, idem telematics supports forwarders, fleet operators and shippers in using data to continuously improve their core business, and thus to increase their profitability, customer satisfaction and competitiveness. Its systems are uncomplicated, independent, cross-fleet and cross-manufacturer, and adaptable to any company size and business model. The service: individual on-site process consulting – combined with the Europe-wide market-leading all-in-one cargofleet telematics platform for trucks, trailers, freight, and logistics. Consolidating and summarising the data sets of vehicles, drivers and freight, idem telematics provides a complete system for increasing the transparency and economy of the entire logistics process. Benefits include unique customer proximity and flexibility for individual telematics requirements based on more than 20 years of telematics, transport and logistics expertise. idem telematics is a subsidiary of the BPW Group.




11th January 2023


For further press information, contact Rebecca Wesley or Emma Makings-Hone at BPW Limited:

Telephone: 0116 281 6100 | Email: [email protected] | 

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