FINAL DRAFT UGANDA 
STANDARD  
  FDUS 1039  
First Edition  
2013 -mm-dd 
 
 
 Reference number  
FDUS 1039 : 2013 
© UNBS 2013   
  
 
Speedometers, mechanical odometers and chronotachographs 
for motor vehicles — Metrological requirements 
 FDUS 1039: 2013  
ii © UNBS 2013  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2013  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written 
permission from UNBS. 
Requests for permission to reproduce this document should be addressed to 
The Executive Director 
Uganda National Bureau of Standards 
P.O. Box 6329 
Kampala 
Uganda 
Tel: 256 414 505 995 
Fax: 256 414 286 123 
E-mail: unbs@infocom.co.ug  
Web: www.unbs.go.ug  
 
 FDUS 1039: 2013  
© UNBS 2013  – All rights reserved  iii 
 Foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of  Trade and Industry and 
Co-operatives established under Cap 327, of the Laws of Uganda.  UNBS is mandated to co-ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agreements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of representatives of 
consumers, traders, academicians, manufacturers, government and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council. 
This Final Draft Uganda Standard is based on OIML R 55, Speedometers, mechanical odometers and 
chronotachographs for motor vehicles . 
Committee membership 
The following organizations are represented on the Metrology standards Technical Committee (UNBS/TC 9), 
during the development of this standard : 
 Civil Aviation Authority (CAA) 
 Kampala City Traders Association (KACITA) 
 Kyambogo University Kampala 
 Makerere University Kampala 
 Ministry of Defence 
 Ministry of Energy and Mineral Development 
 Ministry of Internal Affairs 
 Ministry of Works and Transport 
 National Environmental Management Authority (NEMA) 
 Uganda National Bureau of Standards 
 UMEME 
 
. 
 UGANDA STANDARD  FDUS 1039 : 2013  
 
© UNBS 2013 – All rights reserved  1 
 Speedometers, mechanical odometers and chronotachographs 
for motor vehicles — Metrological requirements 
1 Scope 
This Final Draft Uganda Standard specifies the requirements for speedometers, mechanical odometers and 
chronotachgraphs for motor vehicles. 
2 Terms and definitions 
For the purposes of this standard, the following terms and definitions shall apply. 
2.1  
chronotachograph 
instrument designed to indicate and record instantaneous vehicle speed, the distance covered by the vehicle, 
and possibly other parameters of the journey (s ee 3.4.2. and 3.5. 1.) 
2.2  
coefficient, w, of the vehic le 
characteristic quantity showing the type (revolutions of the driving shaft or impulses) and number of signals 
emitted by the device provided on the vehicle, for connection to the odometer or chronotachograph, when the 
vehicle covers a distance of 1 km. The coefficient, w, is expressed in the same units as constant, k. The 
coefficient, w, varies according to vehicle load, and the dimensions, pressure and degree of wear of the tyres 
and is be determined under standard test conditions (s ee 5.2.4.). 
2.3  
constant, k, of odometer or chronotachograph  
characteristic quantity showing the type (revolutions of the driving shaft or impulses) and number of signals 
which the odometer or chronotachograph must receive so that the indicated and/or recorded distance 
increases by 1 km. The constant, k, may be expressed in revolutions per kilometre, rev/km, or impulses per 
kilometre, imp/km. 
2.4  
odometer  
instrument designed to indicate the distance covered by the vehicle following a totalisation of vehicle wheel 
revolutio ns 
2.5  
speedometer 
instrument designed to indicate to the driver, the instantaneous speed of his vehicle 
2.6  
speedometer constant 
characteristic quantity showing the type (revolutions of the driving shaft or impulses) and the frequency of 
signals at which the speedometer indicates a speed of 60 km/h. The speedometer constant may be expressed 
in revolutions per minute, rev/min, or in impulses per minute, imp/min. The speedometer constant is 
numerically equal to odometer constant, k, when the same driving. FDUS 1039: 2013  
2 © UNBS 2013 – All rights reserved  
 3 Requirements 
3.1 General 
3.1.1  The speedometer, odometer and chronotachograph shall be manufactured from materials with 
adequate stability and strength, and having electrical and magnetic characteristics capable of ensuring the 
constancy of these instruments, under their normal conditions of use. 
3.1.2  The component elements of the speedometer, odometer and chronotachograph shall be placed inside 
a housing, providing protection against the influence of external factors, such as dust and humidity. 
3.1.4  The speedometer, odometer and chronotachograph shall be so placed in the vehicle, that the driver 
can see the indications of these instruments easily from his normal position. 
3.1.5  The constant, k, of the odometer or chronotachograph, and the coefficient, w, of the vehicle, shall be 
equal within the limits of maximum permissible errors (see Clause 5). If this is not the case, the vehicle shall 
be provided with a device, designated to make constant, k, and coefficient, w, equal with a degree of accuracy 
deter mined by the maximum permissible errors. 
3.1.6  The natural frequency and damping of the measuring mechanism of the speedometer or 
chronotachograph shall be such that the speed indicated and/or recorded can follow within the limits of the 
maximum permissible errors the variation in measured speed, for an acceleration not exceeding 2 m/s2. 
3.2 Speedometer 
3.2.1  The scale interval of the speedometer shall not exceed 10 km/h. 
3.2.2  The scale spacing corresponding to a difference in speed of 10 km/h, shall not be less than 5 mm. 
3.2.3  The scale of the speedometer shall be numbered at least every 20 km/h. 
3.3 Odometer 
3.3.1  The odometer shall comprise at least one totalizer, which cannot be reset to zero, without destroying 
the protective marks. 
3.3.2  The scale interval of the odometer totalizer shall be either 1 km or 0.1 km. Where the scale division is 
0.1 km, the figures indicating hectometres shall be clearly distinguishable from those indicating integral 
number of kilometres, for example by the use of a comma as a decimal point, or by the use of a comma as a 
decimal point and a different colour. 
3.3.3  The measurement range of the odometer totalizer shall be at least 99 999 km. 
3.3.4  The figures of the odometer totalizer shall be clearly readable, with an apparent height of at least 4 
mm. 
3.4 Chronotachograph 
3.4.1  The chronotachograph shall indicate and record instantaneous speed, and the distance covered by 
the vehicle. 
3.4.2  The chronotachograph can also record: 
a) running time and stopping time, 
b) working time for the driver or drivers, and FDUS 1039: 2013 
© UNBS 2013 – All rights reserved  3 
 c) other driving parameters.  
3.4.3 . Recordings shall be made in form of diagrams on a record chart (strip or disc). The chart shall be of a 
quality such that the operation of the instrument is normal, and the recordings are indelible, clearly legible, and 
identifiable. 
3.4.5. The mechanism driving the record chart, shall ensure that the latter is driven with no slip with respect 
to the control system, and can be correctly inserted and extracted freely. 
3.4.6  In any chronotachograph, a marker or any other appropriate device shall be provided, ensuring 
correct positioning of the chart, so as to obtain correspondence between the time indicated by the 
chronotachograph or actual time where there is no time indicator, and time marking on the chart. 
3.4.7  The minimum recording capacity of the charts, irrespective of their form, shall be 24 h. Lower 
recording capacities can be used on special purpose vehicles. 
3.4.8  The speed recorder stylus shall have a rectilinear movement, perpendicular to the direction of 
displacement of the record chart. 
3.4.9  The speed scale of the speed diagram shall be numbered at least every 20 km/h. This scale can start 
at 0 km/h. Maximum values of the measurement ranges, indicated and recorded, shall be the same. 
3.4.10 Each variation in speed of 10 km/h, shall be represented on the speed diagram by a distance of at 
least  1.5 mm for measurement range with upper limit not exceeding 125 km/h and 1.2 mm for measurement 
range with upper limit exceeding 125 km/h. 
3.4.11 Every kilometre of distance travelled shall be represented on the distance diagram by a distance of at 
least 1 mm. 
3.4.12 The scale interval of the time scale on the record chart shall not exceed 5 min, and time values shall 
be indicated at least every hou r. 
3.4.13 . The housing containing the record chart and time reset control device, shall be fitted with a lock. Any 
opening of this housing shall be recorded automatically on the sheet. 
3.5 Supplementary devices 
3.5.1  The following supplementary devices can be used: 
a) time indicator (clock), on speedometers, odometers and chronotachographs; 
b) partial distance totalizer with possibility for zero reset, on odometers and chronotachographs; 
c) alarm device indicating overrange of a preset speed, on speedometers and chronotachographs; and 
d) devices indicating other parameters of the journey. 
3.5.2  The measurement range of the partial distance totalizer with possibility for zero reset shall be at least 
equal to 999 km. 
4 Marking  
4.1 The unit of measurement of speed, km/h, shall be marked on the speedometer dial and on the 
chronotachograph dial in the vicinity of the speed scale. The unit of measurement of distance, km, shall be 
marked on the odometer dial and on the chronotachograph dial in the vicinity of the distance totalizer. Where 
the speedometer and odometer share a common dial, it is sufficient to indicate one of the preceding units 
only, of speed or of distance . FDUS 1039: 2013  
4 © UNBS 2013 – All rights reserved  
 4.2. The following indications shall appear on the speedometer, odometer or chronotachograph dial, or on 
their housing or data plate: 
a) manufacturer's name or mark; 
b) production serial number; 
c) pattern mark ; and  
d) value of constant k. 
4.3. The chronotachograph record chart shall bear the following indications: 
a) manufacturer's name or mark; 
b) pattern mark of chronotachograph in which it can be used; and 
c) upper limit of speed measurement range of chronotachograph, in km/h. 
5 Maximum permissible errors  
5.1 The maximum permissible errors for speedometers, odometers and chronotachographs, on verification 
before installation on a vehicle, for a temperature range of (+ 20 ± 10) °C, are as follows: 
a) the maximum permissible error, positive or negative, for the indication or recording of the distance 
covered is equal to the larger of the two following values: 1 % of the true distance 10 m ; 
b) every indicated or recorded value of the speed shall be within an interval not exceeding the larger of 
the two following values: 6 % of the true speed 6 km/h. National regulations will indicate whether the 
distribution of the maximum permissible errors, with respect to the true value, shall be symmetrical or 
non-symmetrical; and 
c) the maximum permissible error, positive or negative, for the indication or recording of time is equal to : 
2 min in 24 h or 10 min in seven days, when clock operating time following reset is not less than this 
period or 0.5 %  of the record chart capacity, for a time less than 24 h. 
5.2 The maximum permissible errors for speedometers, odometers and chronotachographs, on 
verification after installation on a vehicle, for a temperature range of (+ 20 ± 10) °C, are as follows: 
a) the maximum permissible error, positive or negative, for the indication or recording of the  distance 
covered is equal to the larger of the two following values :  2 % of the true distance  20 m ; 
b) every indicated o r recorded value of the speed shall be within an interval not exceeding the  larger of 
the two following values :  8 % of the true speed  8 km/h.  National regulations will indicate whether the 
distribution of the maximum permissible errors,  with respect to th e true value, shall be symmetrical or 
non-symmetrical ; 
c) the maximum permissible error for the indication or recording of time is that fixed in 5.1(c); and  
d) the maximum permissible errors defined above, are determined under the following conditions, which 
should be considered as standard test conditions : 
i. vehicle empty, with only one driver, 
ii. tyre pressures in accordance with manufacturer's recommendations, 
iii. tyre wear within limits permitted by current requirements, FDUS 1039: 2013 
© UNBS 2013 – All rights reserved  5 
 iv. no slip between wheels and road surface, 
v. vehic le running in a straight line under its own motive power, on a flat surface and at a speed of  
(50 ± 5) km/h. Verification can also be carried out using appropriate equipment approved by  
national regulations,  and 
vi.  position of the instruments in accordance with manufacturer's recommendations 
6 Controls  
6.1 If speedometers, odometers and chronotachographs are subject, in a given country, to mandatory 
national metrological control, this control shall include at least the verification indicated in 6.2 and 6.3. 
Supplementary verification can be imposed by national regulations. 
6.2 The speedometers, odometers and chronotachographs are subject to pattern approval, initial 
verification, before and after installation on a vehicle, and verification after each repair under the conditions in 
Clause 5. 
6.3 In addition to the verification indicated in 6.2. the chronotachographs are subject to periodic control 
carried out at least once every two years. 
6.4 The maximum permissible errors in service, applying to instruments installed on vehicles, will be fixed 
by national regulations FDUS 1039: 2013  
6 © UNBS 2013 – All rights reserved  
 Bibliography 
 OIML R 55 Edition 1981 (E), Speedometers, mechanical odometers and chronotachographs for motor 
vehicles  (Measuring instruments for road traffic , was sanctioned by the International Co nference of 
Legal  Metrology in 1980)  
 
. FDUS 1039: 2013 
© UNBS 2013 – All rights reserved  7 
 Certification marking 
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. T he 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 FDUS 1039 : 2013   
 
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© UNBS 2013 – All rights reserved