Brake testing at safety inspections. Proved on paper.

A safety inspection sheet with every brake component ticked and no brake test attached is one of the quickest ways to an unsatisfactory finding. Looking at linings, drums and pipes tells you the parts are there. It does not tell you the vehicle stops. DVSA expects proof of brake performance at every safety inspection, and it expects to find that proof on the vehicle file.

The rule

The legal duty is in regulation 18 of the Road Vehicles (Construction and Use) Regulations 1986: every part of every braking system, and the means of operating it, must be maintained in good and efficient working order and properly adjusted. The Guide to maintaining roadworthiness turns that into practice. Section 5.3 says there is an expectation that every safety inspection will include a brake performance assessment, using one of:

• a roller brake test
• a suitable electronic braking performance monitoring system, known as EBPMS
• a decelerometer test with brake temperature readings

The operator has to be satisfied that whatever method it uses is enough to meet regulation 18. The guide also points out that fit and serviceable can go beyond the annual test standard, and uses brakes as the example: a vehicle can pass its MOT with minor brake defects as long as the minimum performance is met, but that is not the standard the operator licence holds you to.

What the guide says for buses and coaches

Section 5.3 has a part specifically for passenger carrying vehicles. In short:

• An unladen roller brake test is expected at every safety inspection.
• If the operator has assessed the risks and decides decelerometer tests are appropriate, there must still be at least four roller brake tests a year, spread evenly, and the annual test can count as one of them.
• Where a roller brake test is not done at an inspection, a decelerometer test with temperature readings is an acceptable way to assess performance.
• Where a decelerometer test is used, a risk assessment must be completed and kept on file. If the vehicle’s use and condition will not change over twelve months, one risk assessment can cover that period. Any change needs a new one.

The unladen wording matches how PSVs are tested at annual test. The PSV inspection manual says PSVs are presented unladen and tested as presented, and the way efficiency is worked out depends on how many wheels lock during the test.

Laden testing

The general part of section 5.3 still applies. It says a laden test on a calibrated roller brake tester is the most effective way to measure both individual and overall braking performance, and that a plate brake tester may also be suitable depending on its design. Where a laden test is not done, a competent person who understands braking systems must complete a risk assessment, and it must be looked at again at every inspection that does not include a laden test. Risk assessments are kept with the vehicle’s maintenance documents for 15 months.

The examiner’s own question set, in the maintenance investigation questions at question 4b, lists three ways to check brake performance at a safety inspection: a laden roller brake test, with a recommended minimum of three a year as well as the MOT, a decelerometer with brake temperature measurement for rigid vehicles, or an EBPMS assessment. It says plainly that a road test is not enough.

Roller brake testers

A roller brake tester measures the braking force at each wheel, which is why DVSA prefers it. A decelerometer gives one overall figure for the vehicle and, as the guide says, may not pick up a problem at an individual brake. When you read an RBT printout, the overall efficiency is only part of the story. The PSV inspection manual treats these as defects on a roller brake test:

• a binding brake on any wheel
• a brake that is slow to respond, shown by an abnormal time lag before the reading rises
• on a steered axle, a reading that rises and falls with each turn of the wheel by more than 70% between highest and lowest, which points to an oval drum
• very little or no braking effort at a wheel
• any wheel giving less than 70% of the effort of the other wheel on the same axle, or less than 50% on a steered axle
• the specified efficiency not being met

The efficiency figures

The manual sets these minimum efficiencies, depending on when the vehicle was first used:

How the secondary brake is assessed depends on which system is designated as the secondary brake on that vehicle, so make sure the inspector knows the arrangement on each of your vehicle types.

Testing up to 14 days early

The guide lets you put a vehicle on the rollers up to 14 days before the safety inspection, so you can catch it laden during normal work without loading it specially. The RBT report then has to be given to the person doing the inspection, and a copy kept on the vehicle file.

Decelerometer tests

The guide accepts an approved and calibrated decelerometer for measuring overall brake performance on vehicles without trailers, or vehicles that cannot be tested on rollers. For buses and coaches, the passenger vehicle rules above still apply. The guide says take brake temperatures before and after the test. The final readings should be clearly higher than the starting readings and reasonably even for each brake across an axle. The point of the temperatures is to show each brake is actually working. If you cannot get satisfactory results, use another method.

Recording the result

The paperwork matters as much as the test. The guide says:

• a signed printout from the roller tester, plate tester or decelerometer should be attached to the safety inspection record
• if the equipment cannot print, the inspector must write the results on the inspection report, including temperatures where they were taken
• the record should show the date of the brake assessment, how it was done and whether the vehicle was laden
• brake test reports should be read and understood, then kept with the record

Question 4b of the maintenance investigation adds that the inspector must record how braking performance was tested, and that the operator must hold documents relevant to each inspection, giving brake test reports as the example. An inspection with no brake evidence is an incomplete record.

PSVault lets the technician enter brake figures, with pass and fail guidance based on DVSA’s published efficiencies, or attach the roller tester printout as a PDF or photo. Before the sheet is signed, it flags a missing brake result or printout, no record of who did the test, and brake work with no brake test after it. More on the safety inspections page.

What examiners look for

In a maintenance investigation the examiner samples vehicle files. On brakes they want to see a performance assessment for every inspection in the sample, a printout or written results attached, the method recorded, whether it was laden, roller tests at the frequency the guide expects, risk assessments where laden tests were not done, and a brake test after any brake repair. The same investigation also looks at your annual test history and your prohibitions. Under OCRS, a brake defect on a roadside prohibition carries twice the points of a defect outside tyres, brakes and steering on the same kind of prohibition, so a gap here shows up in more than one place. See the DVSA maintenance investigation and OCRS explained.

Common mistakes

• No printout. The test was done but nothing is on the file, or the printout is loose and not matched to an inspection.
• Unsigned printout, or no record of who did the test.
• Method not recorded, so nobody can tell whether the figure came from rollers, a decelerometer or a guess.
• Laden or unladen not stated.
• Decelerometer without temperatures, or temperatures that barely rise and were not questioned.
• Road test written down as the brake test. DVSA says that is not enough.
• Reading only the overall efficiency and missing an imbalance or a binding brake on one wheel.
• Too few roller tests across the year where decelerometers are used at most inspections.
• No risk assessment, or one written years ago for a vehicle now doing different work.
• No test after brake work before the vehicle went back into service.
• RBT done more than 14 days before the inspection and counted as part of it.

Brake testing checklist

1. Decide the brake test method for each vehicle and write it into your maintenance procedure.
2. Where you do not test laden, complete and date a risk assessment by a competent person and review it at each inspection.
3. If you rely on decelerometers, plan at least four roller tests a year per vehicle, spread evenly, as the Guide to maintaining roadworthiness asks for PSVs.
4. Make sure your inspection facility, or your contractor’s, has access to brake test equipment and, where relevant to your fleet, a brake temperature gauge.
5. Attach a signed printout, or written results with temperatures, to every inspection sheet.
6. Record the date of the test, the method, who did it and whether the vehicle was laden.
7. Read every printout for imbalance, binding and fluctuation, not just the overall figure.
8. Brake test after any brake repair before the vehicle goes back out, laden where performance has been a problem.
9. Check a sample of files each month for missing or incomplete brake evidence.

For how often inspections should happen in the first place, see safety inspection intervals.