Reference number  
DRS 407-1: 2019 
© RSB 2019 
 
 
 RWANDA 
STANDARD  DRS 
407-1 
 
First edition  
2019 -mm-dd 
 
Emission limits  — Specification  
Part 1: 
Road vehicles  
  DRS 407-1: 2019  
©RSB 2019  - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2019 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw   
ePortal: www.portal.rsb.gov.rw   DRS 407-1: 2019  
iii                ©RSB 2019  - All rights reserved  
 Contents  Page 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative  references  ................................ ................................ ................................ ..................  1 
3 Terms and defi nitions  ................................ ................................ ................................ ..................  1 
4 Requirements  ................................ ................................ ................................ ................................  3 
4.1 General requirements  ................................ ................................ ................................ ..................  3 
4.2 Specific requirements  ................................ ................................ ................................ ..................  4 
5 Test methods  ................................ ................................ ................................ ................................  7 
Annex  A (informative)  Vehicle categories  ................................ ................................ .............................  8 
Annex  B (normative)  Emissions inspection schedule  ................................ ................................ .........  9 
Annex  C (normative)  Test methods  ................................ ................................ ................................ ...... 10 
C.1 New vehicles (locally manufactured/assembled or imported new)  ................................ . 10 
C.2 Imported used and in -use gasoline and lpg powered vehicles  ................................ .............  10 
C.3 Types of test  ................................ ................................ ................................ ...............................  10 
C.4 Imported used and in -use diesel powered vehicles  ................................ ...............................  12 
 
 
 
 
 
  DRS 407-1: 2019  
©RSB 2019  - All rights reserved                  iv 
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adopted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS  407-1 was prepared by a Joint Technical Committee RSB/TC 41, Environmental protection  and RSB/TC  
23, Road vehicles . 
DRS 407 consists of the following parts, under the general title Emission limits — Specification : 
 Part 1: Road vehicle s  
 Part 2: Non-road mobile machinery  
 Part 3:Thermal power plant s 
Committee membership  
The following organizations were represented on the  Joint  Technical Committee on Environmental protection  
(RSB/TC 41) and RSB/TC 23 on road vehicles in the preparation of this standard.  
Akagera Motors  
Energy Development Corporation Ltd (EDCL)  
Integrated Polytechnic Regional College (IPRC) Kigali  
Metropole Motors  
Ministry of Environment (MoE)  
Ministry of Infrastructure (MININFRA)  
Ministry of Trade and Industry (MINICOM)  
PurePro® Ltd  
Real Contractors Ltd  DRS 407-1: 2019  
v                ©RSB 2019  - All rights reserved  
 Rwanda Environment Management Company (RWEMACO)  
Rwanda Garages Association (RGA)  
Rwanda National Police (RNP)  
Rwanda Transport Development Agency (RTDA)  
Rwanda Utility Regulatory Agency (RURA)  
SAR Motors  
Standards for Sustainability (SfS)  
Sulfo Industries Rwanda  
TUMECO Garage  
University of Rwanda - College of Science and Technology (UR - CST)  
Rwanda Standards Board (RSB) – Secretariat  
 DRS 407-1: 2019  
1                ©RSB 2019  - All rights reserved  
 Emission limits  — Specification — Part 1  — Road vehicles  
1 Scope  
This Draft Rwanda Standard specifies  requirements  for emission limits and test methods for road vehicles.  
This Standard is applicable to all vehicles designed for road circulation: motor vehicles, towed vehicles, 
combinations of vehicles, moped s and  moto rcycles.  
This Standa rd does not cover  vehicles such as agricultural tractors.  
2 Normative  references  
The provisions of this Rwanda Standard have been adopted or adapted from the following referenced 
documents. For dated references, only the edition cited applies. For undated references,  the latest edition of 
the reference document including amendments applies.  
RS ISO 3833, Road vehicles — Types — Terms and definitions  
ISO 16183 , Heavy duty engines  — Measurement of gaseous emissions from raw exhaust gas and  of particulate 
emiss ions using partial flow dilution systems under transient test conditions  
ISO 6460 -2, Motorcycles  — Measurement method for gaseous exhaust emissions and fuel consumption — Part 
2: Test cycles and specific test conditions  
RS ISO 3929, Road Vehicles — Measurement methods for exhaust gas emissions during inspection or 
maintenance  
3 Terms and definitions  
For the purposes of this Standard, the terms and definitions given in RS ISO 3833, and the following apply.  
3.1 
new vehicle  
any manufactured motor vehicle, motor cycle or motor tricycle whose legal title has not been issues to an 
ultimate purchaser and whose only documentation is the manufacturer’s statement of origin  
3.2 
used vehicle  
any motor vehicle, motor cycle or motor tricyc le which has previously been owned or registered in Rwanda or 
in any other jurisdiction   
©RSB 2019  - All rights reserved                  2 
 3.3 
in-use vehicle  
any motor vehicle, motor cycle or motor tricycle that is registered in Rwanda is ope rating on Rwandan public 
roads  
3.4 
motor tricycle  
motor  vehicle,  other  than a motorcycle  or a tractor,  that has three  wheels  and that is designed  to be driven  by means  
of the type of controls  usually  fitted  to a motorcycle  
3.5 
initial inspection  
inspection which a new motor vehicle, motor cycle or motor tricycle  must re ceive when it is newly operated  
3.6 
periodic inspection  
inspection which a motor vehicle motor cycle or motor tricycle  must receive when it is to be operated continually 
on Rwandan public roads after the term of validity of its  ins pection certificate has expired  
3.7 
modification inspection  
inspection which a motor vehicle motor cycle or motor tricycle  must receive when there are changes in the 
length, height, width, maximum payload and other major specificati ons 
3.8 
on-road random inspection  
an inspection which a motor vehicle, motorcycles and moto tricycles must receive when it is picked up at random 
on the  road by the relevant authority  
3.9 
towed vehicle  
non powered drive road vehicle which on account of its design and appointments , is used to transport persons 
or goods and is intended to be  towed by a motor vehicle  
3.10 DRS 407-1: 2019  
3                ©RSB 2019  - All rights reserved  
 combination of vehicles  
motor vehicle coupled with one or more towed vehicle(s)  
3.11 
moped vehicles  
two wheeled or three wheeled moto driven while with a maximum design speed not exceeding 50km/h  
3.12 
motorcycles  
two wheeled motor driven vehicle or three wheeled moto driven vehicle whose unla den weights does not exceed 
400 kg 
3.12 
emission  
discharge  of substances from a road vehicle  into the atmosphere  
3.13 
emission limit value  
permissible quantity of a substance contained in the waste gases from a road vehicle  which may be discharged 
into the air during a given period  
4 Requirements  
4.1 General requireme nts 
4.1 All motor vehicles, motor cycles and motor tricycles to be used on Rwandan public roads shall be 
inspected and tested for compliance with exhaust emissions limits in accordance with the relevan t provisions of 
this Draft Rwanda standard.  
4.2 No motor vehicle, motor cycle or motor tricycle shall be registered for the first time without a certificate of 
compliance with exhaust emission limits in addition to any other requirements on roadworthiness.  
4.3 Imported motor vehicles, motor cycles and m otor tricycles shall be accompanied by a certificate of 
compliance with exhaust emission limits issued by a duly approved agency in the exporting country in 
accordance with releva nt provisions of this Draft Rwanda S tandard and Rwandan law .  
©RSB 2019  - All rights reserved                  4 
 4.4 Motor vehicl es, motor cycles and motor tricycles shall be inspected and tested in inspection centres  
approved by relevant authority.  
4.5 Emissions  inspection and testing  shall be according to the schedule laid out in Annex B.  
4.2 Specific requirements  
4.2.1  Exhaust emission limits 
The following exhaust emission limits shall apply to the different types and categories of vehicl es as outlined in 
Tables 1 – 6. 
Table 1 — Type approval/certification maximum emission limits for new diesel powered vehicles 
(compression ignition engines) (locally manufactured/assembled or imported new), g/kwh  
Vehicle Category  CO  HC+ NOx  NOx  PM Test m ethod  
Light duty Passenger Cars  
Class  M 
 0.50 0.30 0.25 0.025  WLTP*  
 
Light Duty Commercial Vehicles (LDV Class 1, 2 & 3)  
LDV Class 1 (RM ≤ 1 305 kg)  0.50 0.30 0.25 0.025   
 
WLTP  LDV      Class 2  
(1305 kg < RM ≤ 1 760 kg)  0.63 
 0.39 0.33 0.04 
LDV Class 3 (RM > 1  760 kg)  0.74 0.46 
 0.39 0.06 
 
Medium Duty Vehicles (MDV)  
(2700 ≤ GVW < 3500 kg)  0.74 0.46 0.39 0.06 WLTP  
 
Heavy Duty Vehicles (N 2, N3, O) 
N2 (GVW  > 3 500 kg <  12 000 kg)  1.50 0.46 3.5 0.02  
ISO 
16183:2002  N3 (GVW  > 12 000 kg)  1.50 0.46 3.5 0.02 
 
O (Trailers including  semi -trailers)  1.50 0.46 3.5 0.02 
*Worldwide Harmonized Light Vehicle Test Procedure  
  DRS 407-1: 2019  
5                ©RSB 2019  - All rights reserved  
 Table 2 — Type approval/certification maximum emission limits for new gasoline and LPG powered 
vehicles (spark ignition engines) (locally manu factured/assembled or imported new), g/km  
Vehicle Category  CO  HC NOx  Test m ethod  
Passenger Cars Class M  
 1.00 0.10 0.08 WLTP*  
 
Light Duty Commercial Vehicles (LDV Class 1, 2 & 3)  
LDV Class 1 (RM ≤ 1  305 kg)  1.00 0.10 0.08  
 
WLTP  LDV Class 2  
(1305 kg < RM ≤ 1  760 kg)  1.81 0.13 
 0.10 
LDV Class 3 (RM > 1  760 kg)  2.27 0.16 
 0.11 
 
Motor Cycles (Class I & II)  
Class I (<150 cc displacement)  
 5.50 1.20 0.30 ISO 6460 -2 
 
Class II (150 cc displacement)  5.50 1.0  0.30 
 
Tricycles  
All Gasoline  7.0 1.50 0.40 ISO 6460 -2 
 
*Worldwide Harmonized Light Vehicle Test Procedure  
Table 3 — Emission standard for imported used diesel powered vehicles (compression ignition 
engine)  
Vehicle category  Maximum s moke density  Test method  
 
 
All Categories  
 Light absorption coefficient = 1.5 M-1  
 Metered smoke test  
 
  
©RSB 2019  - All rights reserved                  6 
 Table 4 — Maximum mission limits for imported used gasoline and LPG powered vehicles 
(compression ignition engine)  
Vehicle Category  CO 
(% volume)  HC (pa rts per 
million)  Test  method  
Motor Vehicles  
 
All categories  1.00 400 Basic emission test  
 
NOTE  Under the provisions of Aricle  6 of the Ministerial Order No. 02/2018 (official gazette no. 39bis of 
24/09/2018), all motorcycles imported into Rwanda must be brand new. Hence, the limits in table 4 above do 
not apply to motor cycles and motor tricycles. All imported motor cycles and t ricycles are subject to the limits in 
Table 2, except where an exemption is granted pursuant to Article 6 of the Ministerial Order or a ny other written 
law of Rwanda.  
Table 5 — Maximum emission limits for in -use diesel powered vehicles (compression ignition engine)  
Vehicle Category  Date of 
manufacture  
(Y/M)  Maximum smoke density  Test method  
 
 
 
All Categories  2005/01 
upwards  Light absorption coefficient = 
1.5 M-1 Metered smoke test  
From 1992/07 -  
2004/12  Light absorption coefficient = 
2.5 M-1 Metered smoke test  
Before 1992/07  - Visual Inspection  
 
Table 6 — Maximum emission limits for in -use gasoline and LPG vehicles (spark ignition engines)  
Vehicle Category  Date of manufacture  
(Y/M)  CO 
(% volume)  HC (Parts 
per million)  Test method  
Motor Vehicles  
 
All categories  From 2005/01 upwards  1.00 400  
Basic emission test  Before 2005/01  3.0 500  
Before 1992/07  4.5 600  Non-catalytic test  
Motor cycles*  
 After 31/3/ 2000 (4 stroke)  3.5  4 500 Basic emission test  
After 31/3/ 2000 (2 stroke)  3.5  6 000 
on or before 31/3/2000 (2/4 
stroke)  4.5  9 000 
Motor tricycles  DRS 407-1: 2019  
7                ©RSB 2019  - All rights reserved  
 All  All 3.5  4 500 Basic emission test  
5 Test methods  
Emissions inspection and testing for all vehicles subject to this standard shall be carried out in accordance with 
the Te st Methods outlined in Annex C.  
 
 
 
 
  
©RSB 2019  - All rights reserved                  8 
 Annex  A 
(informative)  
 
Vehicle c ategories  
Category  Description  
Passenger cars (M)  
M Motor  vehicles  with at least  four wheels  designed  and constructed  for the carriage of passengers.  
M1 Vehicles  designed  and constructed  for the carriage  of passengers  and comprising no more than 
eight seats in addition to the driver’s  seat 
 
M2 Vehicles designed and constructed for the carriage of passengers, comprising more  than eight  
seats  in addition  to the driver’s  seat,  and having  a maximum  mass (“technically permissible 
maximum laden mass”) not exceeding 5,000 kg.  
 
M3 Vehicles designed and constructed for the carriage of passengers, comprising more  than eight  
seats  in addition  to the driver’s  seat,  and having  a maximum  mass exceeding 5,000kg.  
Light Commercial Vehicles (N)  
N Motor  vehicles  with at least  four wheels  designed  and constructed  for the carriage of goods.  
N1 Vehicles designed and constructed for the carriage of goods and having a maximum mass not exceeding 3 500 
kg. Light commercial vehicles Classes for N1 are further divided into three Weight classes and two categories 
based on GVWR and the Reference Mass (RM), defined as the mass of the vehicle in running order less the 
uniform mass of the driver of 75 kg, a nd increased by a uniform mass of 100  kg. 
N1 Weight Classes  
Class I  RM ≤ 1  305 kg  
Class II  1 305 kg < RM ≤ 1  760 kg  
Class III  RM>1  760 kg  
Heavy Duty Vehicles  
N2 Vehicles  designed  and constructed  for the carriage  of goods  and having  a maximum  mass  
exceeding  3,500 kg  but not exceeding  12,000 kg.  
N3 Vehicles  designed  and constructed  for the carriage  of goods  and having  a maximum mass 
exceeding 12,000 kg.  
O Trailers (including semi -trailers)  
Motor c ycles  
Class I  
 Two-wheeled motor -driven vehicle whose unladen weight does not exceed 400 kg, with <150 cc 
displacement  
Class II  Two-wheeled motor -driven vehicle whose unladen weight does not exceed 400 kg, with 150 cc 
displacement  
Motor tricycles  
Motor tricycle  Three -wheeled motor -driven vehicle whose unladen weight does not exceed 400 kg  
  DRS 407-1: 2019  
9                ©RSB 2019  - All rights reserved  
 Annex  B 
(normative)  
 
Emission s inspection s chedule  
Vehicle category  Initial  Inspection  Periodic  Inspection  
(frequency)  Modification  
Inspection  On-road 
Random  
Inspection  
Passenger cars 
Class M1, Motor 
cycles and  
Tricycles  All  12 Months  Yes  Yes  
All other 
categories  All 
 6 Months  
 Yes 
 Yes  
 
  
©RSB 2019  - All rights reserved                  10 
 Annex  C 
(normative)  
 
Test methods  
C.1 New vehicles (locally manufactured/assembled or imported new)  
C.1.1  Worldwide Harmonized Light Vehicle Test Procedure (WLTP)  
For type approval and certification of all categories of light duty and medium duty vehicles, whether locally 
manufactured/assembled or imported. The WLTP defines a global harmonized standard for determining the 
levels of pollutants a nd CO 2 emissions, fuel efficiency, and electric range from light -duty vehicles (passenger 
cars and light commercial vehicles),  and was developed under the guidance of UNECE World Forum for 
Harmonization of Vehicle Regulations . 
C.1.2  World Harmonized Stationary Cycle (WHSC)  
For type approval and certification of all categories of heavy duty vehicles, whether locally 
manufactured/assembled or imported. The WHSC test is a steady -state engine dynamometer schedule defined 
by the Global Technical Regulation (GTR) No. 4 developed under the guidance of UNECE World Forum for 
Harmonization of Vehicle Regulations. The GTR is covers a world -wide harmonized heavy -duty certification 
(WHDC) procedure for engine exhaust emissions.  
C.1.3  World Motorcycle Test Cycle  (WMTC)  
For type appr oval and certification of all categories of motorcycles and motor tricycles, whether locally 
manufactured/assembled or imported. The WMTC  is a system of  driving cycles used to measure fuel 
consumption and emissions in motorcycles and motor trycles. The met hods are stipulated as part of the Global 
Technical Regulation established under  the guidance of UNECE World Forum for Harmonization of Vehicle 
Regulations . 
C.2 Imported used and in -use gasoline and lpg powered vehicles  
C.2.1  Vehicles to be tested  
In-use exhaust emi ssions testing are applied to all petrol and LPG -powered motor vehicles, motor cycles and 
motor tricycles.  
C.3 Types of test  
The emissions test to which a vehicle is subject will depend upon its date of manufacture as follows:  DRS 407-1: 2019  
11                ©RSB 2019  - All rights reserved  
 C.3.1  Non-catalyst test  
For all petrol  and LPG -powered vehicles first used before 1st July 1992, the non -catalyst test procedure will 
apply. This is used for petrol and LPG -fuelled vehicles which are not equipped with advance emission control 
systems such as catalytic converters.  
C.3.1.1  Checks on the  vehicle before the test  
Before carrying out the test, the Examiner will confirm that the engine is at its normal operating temperature 
which, in most cases, will require the use of an oil temperature probe inserted into the dipstick tube. Before 
proceedin g, the Examiner will also check that the engine has sufficient oil and fuel to complete the test. For 
vehicles with manual transmission the test will be carried out with the gear lever in the 'neutral' position and with 
the clutch engaged. For vehicles wit h automatic transmission the gear selector will be in either the 'neutral' or 
'park' position.  
C.3.1.2  Test p rocedure  
C.3.1.2.1  Visual inspection (all vehicles)  
Once the preliminary checks have been completed , the Examiner will raise the engine speed to around 2500rpm 
or half the maximum engine speed if this is lower. The engine speed will be held steady for approximately 20 
seconds after which the engine will be allowed to return to its natural idle speed. On ce the emissions have 
stabilized the Examiner will assess the smoke emitted from the tailpipe. If the exhaust is emitting dense blue or 
clearly visible black smoke then the vehicle will fail the test. In exceptional cases, especially on certain vehicles 
manufactured before 1960 where emissions of smoke are unavoidable due to the engine design, these vehicles 
will not fail the test.  
C.3.1.2.2  Standard emissions test  
Emissions will also be checked using an approved analyzer. After completing the visual test, the Examin er will 
use the analyzer to assess the concentration of carbon monoxide (CO) and hydrocarbons (HC) in the exhaust 
gases by inserting a sample probe into the exhaust tailpipe. The test is carried out with the engine at its normal 
idling speed and the analyz er displays the results continuously. Once a stabilized figure is achieved the tester 
will record the result. The vehicle must comply with the appropriate emissions limits set out in Table 6 of the 
standard.  
C.3.1.3  Basic Emissions Test (BET)  
The basic emissions test (also known as the ‘catalyst test’) will be applied to all petrol and LPG fuelled vehicles 
first used on or after 1st July 1992. This test is primarily aimed at identifying, and assessing emissions from 
vehicles with advanced emissions control systems  such as three -way catalytic converters. As the procedure is 
more complicated than the non -catalyst test, the emissions analyzers include computer software aimed at 
guiding the examiner through the test sequence.  The test consists of checking the emission s at ‘fast -idle speed’ 
which involves running the engine at a speed of 2500 - 3000 rpm. During this test the emissions of CO and HC 
will be checked. The emissions limits to be met are specified in Table 6. Where these limits are not met, a check 
will be ma de to identify vehicles (e.g. those without a catalyst) which should only be required to meet the non -
catalyst emissions check requirements.   
©RSB 2019  - All rights reserved                  12 
 C.4  Imported used and in -use diesel powered vehicles  
C.4.1  Vehicles to be tested  
This inspection applies to all imported us ed and in -use diesel engine vehicles with four or more wheels.  
C.4.2  Checks on the vehicle before the test  
Wherever possible, vehicles should arrive at the inspection centre with the engine at its normal operating 
temperature (e.g. after a drive of approximately  5 kilometers). Before carrying out the test, the Examiner must 
confirm that the engine is at its normal operating temperature. In most cases this will require the use of an oil 
temperature probe inserted into the dipstick tube. The Examiner will also chec k that the engine has adequate 
oil and fuel to complete the test before proceeding. In addition the Tester will check the condition of the camshaft 
drive belt (where visible) and the fuel injection pump (governor) anti -tampering seals. For vehicles with ma nual 
transmission the test will be carried out with the gear lever in the 'neutral' position and with the clutch engaged. 
For vehicles with automatic transmission the gear selector will be in either the 'neutral' or 'park' position.  
C.4.3  Test p rocedure  
C.4.3.1  Visual i nspection  
For all diesel powered vehicles first used before 1st July 1992, a visual test will be carried out. The  Examiner 
will check the smoke emissions by raising the engine speed to around  2500 rpm or half the maximum engine 
speed if this is lower. This  speed will be  maintained for 30 seconds to ensure that the inlet and exhaust system 
has been fully  purged. The Examiner will then allow the engine to return to idle. Once the engine has  stabilized 
at this speed, the emissions from the exhaust tailpipe will be assessed. If  the exhaust is emitting dense blue or 
clearly visible black smoke for a period of 5  seconds or more the vehicle will fail the test.  The Examiner will then 
rapidly increase the engine speed to around 2500 rpm or half the maximum engine speed if this is lower and 
assess whether the smoke emitted from  the exhaust is likely to obscure the vision of other road users. If it is 
likely to do so, in  the Examiner’s opinion, the vehicle will fail the test.  However, vehicles manufactured before 
1960 will not be failed if  the smoke is unavoidable due to the engine design.  
C.4.3.2  Metered smoke t est 
For all diesel powered vehicles used on or after 1st July 1992, a metered smoke test will be carried out. Before 
checking the smoke emissions, the Examiner will firstly ensure that the engine inlet and exhaust system is fully 
purged, and the engine speed governor, where applicable, is functioning correctly. The engine speed will then 
be raised to around 2500 rpm or half the maximum engine speed if this is lower. Upon reaching this speed, the 
Examiner will hold the engine speed steady for 30 seconds to purge the inlet and exhaust systems, then the 
engine speed will be sl owly increased to maximum to check the operation of the fuel pump governor. Where 
the engine speed stabilizes at its maximum speed indicating that the governor is working, the engine will then 
be returned to idle speed. Where it is clear that the governor is not working, the engine will be returned to idle 
speed and stopped, the smoke test will not be carried out and the Examiner will be unable to pass the vehicle. 
Provided the preliminary checks are completed satisfactorily, the Examiner will prepare the s moke meter and 
insert the sampling probe into the exhaust tailpipe. Having restarted the engine the Examiner will start the smoke 
test as follows:  
a) Diesel Fast Pass  DRS 407-1: 2019  
13                ©RSB 2019  - All rights reserved  
 The smoke meter will indicate to the Examiner to accelerate the engine. The accelerator ped al will be depressed 
quickly and continuously but not violently, to reach the full fuel position in less than 1 second. After the release 
prompt is given, the Examiner will immediately release the throttle. The meter will calculate the maximum smoke 
emissi on during the acceleration and display the result. If, after the first acceleration, the meter reading is at or 
below the limits specified in Table 5, the vehicle will pass the meter test and a pass result will be displayed on 
the meter; if it exceeds, the  vehicle will fail the test and a fail result will be displayed on the meter.  
b) Standard diesel t est 
If the smoke level reading is greater than the limits in Table 5, a further two accelerations will be requested by 
the meter. Provided the average of the 3 t ests is at or below the appropriate limit in Table 5, the vehicle will 
have passed the test. The Examiner will stop the engine and remove the smoke meter probe from the tailpipe. 
Where the average smoke emission at the end of the third acceleration exceeds  the limit in Table 5, the meter 
will request further tests. This will continue until either the average of the three preceding accelerations is at or 
below the limit in the Table 5, or a maximum of six accelerations have been completed. Once the vehicle h as 
either passed the test or a maximum of six accelerations have been completed the Examiner will stop the test 
and remove the smoke meter probe from the exhaust tailpipe. As a final check the Examiner will assess visually 
whether the smoke emitted from th e exhaust, regardless of measured smoke density, is likely to obscure the 
vision of other road users. If it is likely to do so the vehicle will fail the test.  
 DRS 407-1: 2019  
ICS 13.040.50  
 
 
©RSB 2019  - All right s reserved