Guidance

Electronic braking performance monitoring system (EBPMS): industry standard specification

Updated 10 September 2024

Background and scope

Vehicle operators and drivers have a legal obligation to ensure their vehicles are roadworthy at all times when operating on public highways. The Driver and Vehicle Standards Agency (DVSA) produces the Guide to maintaining roadworthiness. It outlines best practice for the maintenance of commercial vehicles, including a recommended preventative inspection regime for commercial vehicle brakes on vehicles and trailers.

The guide states that “It is strongly advised that a calibrated roller brake tester (RBT) is used at each safety inspection” and “Where possible brake testing should be undertaken with the vehicle or trailer in a laden condition”.

The specification defined within this document describes a system that overcomes many of the difficulties and limitations of the current service brake guidance in Great Britain.

Confirmation of the capability an electronic brake performance monitoring system (EBPMS) can detect an underperforming braking system shall be established against the requirements defined within this specification by a competent person or body.

In providing a system defined within this document as an EBPMS, it is recommended that appropriate elements should, where possible, employ at least the same, similar or equivalent methodologies as those described in ISO 21069.

The requirements specified within this document have been developed based on existing known technologies. It may be necessary to review the content to take into consideration further developments or in the light of experience gained.

1. Definitions

For the purposes of this specification, the following definitions shall apply.

Electronic braking performance monitoring system (EBPMS)

This is a system that enables the braking performance of a commercial vehicle to be monitored and recorded during everyday operation under a variety of operating conditions. EBPMS autonomously collects braking event data during every braking event and analyses the data over time to produce a braking performance value.

Braking event

This is a period of time during which the service braking system generates a retarding force in response to a driver demand and ends when the driver demand is reduced or a minimum speed has been reached.

Braking event data

This is a series of readings taken before, during or after a braking event including but not limited to change in vehicle speed, demand pressure, axle/bogie Load, time/date stamp and road gradient/angle.

Braking performance value

This is a value, based upon continuous sampling of data whilst the vehicle is in operation, indicative of the service braking performance of the vehicle and expressed as a braking rate relative to the maximum static axle/bogie load for a given demand pressure.

Demand pressure

This is the pressure related to the level of service braking required by a driver actuating the braking system. In the case of a pneumatically braked trailer this is the signal transmitted to the coupling head either electronically or pneumatically.

Axle/bogie load

This is the vertical static reaction (force) of the road surface in the contact area on the wheels of the axles derived from suspension characteristics.

Time/date stamp

This is the time and date associated with at least the braking event data.

Road gradient/angle

This is the angle of the road relative to horizontal in the direction of travel.

Braking performance report

This is a report which shall include:

• a means of identifying the vehicle it relates to
• the braking performance value (expressed as a percentage)
• the date range to which the braking performance value applies
• a graphical report of the brake performance value over the period of the report illustrating any trend occurring

The braking performance report shall also indicate if the data does not enable a valid braking performance value to be produced.

95% confidence level

This is the probability that a braking performance value will fall between an upper and lower bound of the confidence interval. For example, the braking performance value has a 95% probability of encompassing the actual braking performance.

Margin of error

This is the maximum expected difference (within the confidence interval) between the braking performance of the vehicle and the reported braking performance value. It can be considered the margin of error is half the width of the confidence interval and thus there is a probability of 95% that the vehicle’s braking performance is within the margin of error.

Vehicle operator

This is the person legally responsible for the operation of the vehicle, as defined by operator licensing.

2. Requirements specification

An electronic braking performance monitoring system shall provide a braking performance value for a given time period using braking event data and a plurality of braking events.

The braking performance value shall be derived using a repeatable algorithm and the results shall:

• be reported with a statistical 95% confidence interval
• have a margin of error of less than 3%
• utilise braking event data in a manner that minimises the effect of braking events, which includes braking event data that could have a negative influence on the validity of the braking performance value
• compensate for the effect of gravity on the braking event data when a braking event occurs on an incline

The braking performance value shall not:

• utilise inappropriate braking event data, including but not limited to that generated during ABS cycling, or which includes inappropriate demand pressures or speeds or changes in speed
• indicate a value where the demand pressure required to achieve said value cannot be supplied by the towing vehicle

The electronic braking performance monitoring system shall include the following functionality:

• to alert the vehicle operator by an appropriate means (for example email or SMS) when a vehicle appears to be braking at a rate below its minimum prescribed in service braking performance
• to alert the vehicle operator by an appropriate means(for example email or SMS) when the ABS/EBS system reports a fault
• identify a singular defective brake where data is available
• to provide the vehicle operator with the ability to produce a braking performance report
• report if there is insufficient data to provide a brake performance value
• to provide the vehicle operator with access to a system that allows historical braking performance reports to be viewed for up to 36 months in the past and shall be verifiable as a true record
• produce a braking performance report for use during preventative maintenance inspections by the maintenance provider providing a brake performance value for the inspection period and a performance trend graph
• the braking performance report shall include supporting information indicating how the above requirements are fulfilled

Any change to the electronic braking performance monitoring system that impacts on the performance of the system relative to this specification shall be declared.

3. Confirmation of fulfilment of the requirements

To gain acceptance of the electronic braking performance monitoring system, an information document shall be made available which will include at least the following.

General

The document will include:

• the name of the manufacturer
• the system name
• identification of units
• system variants
• the software version
• an explanation of the basic function and/or philosophy of the system to achieve the requirements of section 2 above

Applications

The document will include:

• a list of vehicle types on which the brake performance monitoring system may be installed
• any limitations in application or installation

Environmental protection

The manufacturer shall define what measures have been taken to ensure the electronic braking performance monitoring system is compatible with the environment to which it will be subject during normal operation of the vehicle.

Verification of function

The information document shall include confirmation of the capability an EBPMS can detect an underperforming braking system in compliance with the requirements defined within this specification by a competent person or body. It must identifying the testing organisation and the capability of the system.