HGV’s – Roller Brake Testing


HGV Roller Brake testing


In November 2018, the DVSA issued the latest version of the Guide to Maintaining Roadworthiness.  This document has amended the advice on brake testing.


The Guide states that every safety inspection (PMI) must assess the braking performance of the vehicle or trailer.  It goes on to ‘strongly’ advise that a calibrated roller brake test is used at each safety inspection.  However, it does say that it is acceptable to use an approved and properly calibrated decelerometer for vehicles without trailers.


What is also important is that vehicles or trailers are brake tested in a laden condition.  Otherwise the brakes could lock up.  A laden condition is deemed to be at least 65% of the vehicle design axle weight. Operators are also advised to obtain the printout and attach it to their PMI sheet.


The guidance now says that the rolling road brake test can be carried out at any time within the week that the PMI takes place.


Most operators will simply look for the word ‘Pass’ at the bottom of the sheet and file the sheet away.  However, the brake test printout should be properly analysed, with inconsistent brake readings across an axle investigated. A locked wheel doesn’t always mean a good brake! It’s important for all wheels to be able to meet the required standard.


Imbalance on axle readings could be caused by insufficient loading of the vehicle for test or it could indicate a fault on the vehicle’s braking system, such as a damaged diaphragm.


Operators should also be looking for low brake values i.e. the brakes have locked up at a lower force than should be expected.  This could be due to insufficient weight on the vehicle or an issue with the maintenance of the rolling road brake equipment itself.


Currently there is limited assistance to be drawn from the Guide to Maintaining Roadworthiness to advise you as to what investigations should take place, or to advise you what pitfalls to look out for on a brake test print out.  However, Traffic Commissioners expect Operators to apply an ‘inquisitive mind’ to the rolling road brake test print out.  It is understood that further guidance could be issued this year.



Important checklist for Operators

  1. Rolling road brake test at each PMI
  2. Always carry out laden
  3. Obtain the printout
  4. Analyse the printout information


For advice on Operator Licensing, contact Jared Dunbar on 01829 773 105 or jid@dynesolicitors.co.uk