Handbook 44 – 2022 5.54. Taximeters

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Table of Contents

Page

Section 5.54. Taximeters........................................................................................................ 5-27

A. Application .................................................................................................................................................. 5-27

A.1. General................................................................................................................................................5-27

A.2. Exceptions...........................................................................................................................................5-27

A.3. Additional Code Requirements...........................................................................................................5-27

S. Specifications............................................................................................................................................... 5-27

S.1. Design of Indicating and Recording Elements....................................................................................5-27

S.1.1. General..................................................................................................................................5-27

S.1.2. Advancement of Indicating Elements. ..................................................................................5-27

S.1.3. Visibility of Indications. .......................................................................................................5-28

S.1.4. Actuation of Fare-Indicating Mechanism. ............................................................................5-29

S.1.5. Operating Condition. ............................................................................................................5-29

S.1.6. Fare Identification.................................................................................................................5-29

S.1.7. Extras. ...................................................................................................................................5-29

S.1.8. Protection of Indications.......................................................................................................5-29

S.1.9. Recorded Representation......................................................................................................5-29

S.1.10. Non-fare Information............................................................................................................5-30

S.2. Basis of Fare Calculations. .................................................................................................................5-30

S.2.1. Initial Time and Distance Intervals.......................................................................................5-31

S.3. Design of Operating Control...............................................................................................................5-31

S.3.1. Positions of Control. .............................................................................................................5-31

S.3.2. Control for Extras Mechanism..............................................................................................5-31

S.4. Interference. ........................................................................................................................................5-31

S.5. Provision for Security Seals................................................................................................................5-31

S.5.1. Taximeter Connected to Networked Systems. ......................................................................5-33

S.5.2. Taximeters Calibrated to Specific Vehicles..........................................................................5-33

S.6. Power Interruption, Electronic Taximeters. ........................................................................................5-33

S.7. Measurement Signal Loss...................................................................................................................5-33

S.7.1. Intermittent Trip Data Loss...................................................................................................5-33

S.7.2. Significant Trip Data Loss....................................................................................................5-33

S.8. Anti-Fraud Provisions, Electronic Taximeters....................................................................................5-34

N. Notes............................................................................................................................................................. 5-34

N.1. Distance Tests.....................................................................................................................................5-34

N.1.1. Test Methods.........................................................................................................................5-34

N.1.2. Test Procedures.....................................................................................................................5-34

N.1.3. Test Conditions.....................................................................................................................5-35

N.2. Time Test. ...........................................................................................................................................5-36

N.3. Interference Test. ................................................................................................................................5-36

T. Tolerances.................................................................................................................................................... 5-36

T.1. Tolerance Values. ...............................................................................................................................5-36

T.1.1. On Distance Tests. ................................................................................................................5-36

T.1.2. On Time Tests.......................................................................................................................5-36

T.1.3. On Interference Tests............................................................................................................5-36

T.2. Tests Using Transfer Standards. .........................................................................................................5-37
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UR. User Requirements ..................................................................................................................................... 5-37

UR.1. Inflation of Vehicle Tires....................................................................................................................5-37

UR.2. Position and Illumination of Taximeter. .............................................................................................5-37

UR.3. Statement of Rates. .............................................................................................................................5-37
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Section 5.54. Taximeters

A. Application

A.1. General. – This code applies to taximeters; that is, to devices that automatically calculate at a predetermined 

rate or rates and indicate the charge for hire of a vehicle.

A.2. Exceptions. – This code does not apply to the following:

(a) odometers on vehicles that are rented on a distance basis. (Also see Section 5.53. Code for Odometers.)

(b) devices that only display a flat rate or negotiated rate; or

(c) Transportation Network Measurement Systems. (Also see Section 5.60. Transportation Network 

Measurement Systems.)

(Amended 1977, 2016, and 2017)

A.3. Additional Code Requirements. – In addition to the requirements of this code, Taximeters shall meet the 

requirements of Section 1.10. General Code.

S. Specifications

S.1. Design of Indicating and Recording Elements.

S.1.1. General. – A taximeter shall be equipped with a primary indicating element.

(Amended 1988 and 2015)

S.1.1.1. Recording Elements. – A receipt providing information as required in S.1.9. Recorded 

Representations shall be available from a taximeter or taximeter system through an integral or separate 

recording element for all transactions conducted.

[Nonretroactive January 1, 2016]

(Added 2015)

S.1.2. Advancement of Indicating Elements. – Except when a taximeter is being cleared, the primary 

indicating and recording elements shall be susceptible of advancement only by the movement of the vehicle or 

by the time mechanism.

At the conclusion of a transaction (e.g., following the totalizing of all accrued charges and having a customer 

receipt made available), no other advancement of fare, extras, or other charges shall occur until the taximeter 

has been cleared.

[Nonretroactive as of January 1, 2017]

Where permitted, a flat rate or negotiated rate shall be displayed in the “fare” indicating mechanism, provided 

that once a flat rate or negotiated rate is entered the fare may no longer be advanced by movement of the vehicle 

or the time mechanism.

(Amended 1988 and 2016)
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S.1.2.1. Time Mechanism. – Means shall be provided on all taximeters designed to calculate fares based 

on a combination of time elapsed and distance traveled, to enable the vehicle operator to render the time 

mechanism either operative or inoperative with respect to the fare-indicating mechanism.

(Added 2017)

S.1.2.2. Distance Mechanism. – Means shall be provided on all taximeters designed to calculate fare 

based on a combination of time elapsed and/or distance traveled to enable the vehicle operator to render the 

distance mechanism either operative or inoperative with respect to the fare-indicating mechanism.

[Nonretroactive as of January 1, 2020]

(Added 2017) (Amended 2018)

S.1.3. Visibility of Indications.

S.1.3.1. Taximeter Indications. – The indications of fare, including extras, and the mode of operation, 

such as “time” or “hired,” shall be constantly displayed whenever the meter is in operation. All indications 

of passenger interest shall be easily read from a distance of 1.2 m (4 ft) under any condition of normal 

operation. This includes any necessary lighting, shading, or other means necessary to make displayed 

indications clearly visible to operator and passenger.

(Amended 1977, 1986, 1988, and 2017)

S.1.3.2. Minimum Height of Figures, Words, and Symbols. – The minimum height of the figures used 

to indicate the fare shall be 10 mm and for extras, 8 mm. The minimum height of the figures, words, or 

symbols used for other indications, including those used to identify or define, shall be 3.5 mm.

(Added 1986)

S.1.3.3. Passenger’s Indications. – A supplementary indicating element installed in a taxi to provide 

information regarding the taxi service to the passenger (i.e., Passenger Information Monitor or PIM), shall 

clearly display the current total of all charges incurred for the transaction. The accruing total of all charges 

must remain clearly visible on the passenger’s display (unless disabled by the passenger) at all times during 

the transaction.

[Nonretroactive as of January 1, 2016]

(Added 2015) (Amended 2017)

S.1.3.3.1. Additional Information. – Additional information shall be displayed or made available 

through a passenger’s indicating element (as described in S.1.3.3. Passenger’s Indications) and shall 

be current and reflect any charges that have accrued. This additional information shall include:

(a) an itemized account of all charges incurred including fare, extras, and other additional 

charges; and

(b) the rate(s) in use at which any fare is calculated.

Any additional information made available must not obscure the accruing total of charges for the taxi 

service. This additional information may be made accessible through clearly identified operational 

controls (e.g., keypad, button, menu, touch-screen).

[Nonretroactive as of January 1, 2016]

(Added 2015)

S.1.3.3.2. Fare and Extras Charges. – The indication of fare and extras charges on a passenger’s 

indicating element shall agree with similar indications displayed on all other indicating elements in the 

system.

[Nonretroactive as of January 1, 2016]

(Added 2015)
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S.1.4. Actuation of Fare-Indicating Mechanism. – When a taximeter designed to calculate fares upon the 

basis of a combination of distance traveled and time elapsed, but not both time and distance used concurrently to 

calculate fare, is operative with respect to fare indication, the fare-indicating mechanism shall be actuated by the 

distance mechanism whenever the vehicle is in motion at such a speed that the rate of distance revenue equals or 

exceeds the time rate, and may be actuated by the time mechanism whenever the vehicle speed is less than this 

and when the vehicle is not in motion. 

(Amended 1977 and 2017)

S.1.5. Operating Condition.

S.1.5.1. General. – When a taximeter is cleared, the indication “Not Registering,” “Vacant,” or an 

equivalent expression shall be shown. Whenever a taximeter is set to register charges, it shall indicate 

“Registering,” “Hired,” or an equivalent expression and the rate at which it is set shall be automatically 

indicated (Rate 1 or Rate A, for example).

(Amended 1988)

S.1.5.2. Time not Recording. – When a taximeter is set for fare registration with the time mechanism 

inoperative, it shall indicate “Time Not Recording” or an equivalent expression.

(Amended 1988)

S.1.5.3. Distance Not Recording. – When a taximeter is set for fare registration with the distance 

mechanism inoperative, it shall indicate “Distance Not Recording” or an equivalent expression.

[Nonretroactive as of January 1, 2020]

(Added 2017) (Amended 2018)

S.1.6. Fare Identification. – Fare indications shall be identified by the word “Fare” or by an equivalent 

expression. Values shall be defined by suitable words or monetary signs.

S.1.7. Extras. – Extras shall be indicated as a separate item and shall not be included in the fare indication. 

They shall be identified by the word “Extras” or by an equivalent expression. Values shall be defined by suitable 

words or monetary signs. Means may be provided to totalize the fare and extras if the totalized amount returns 

to separate indications of fare and extras within 5 seconds or less.

(Amended 1988)

S.1.7.1. Nonuse of Extras. – If and when taximeter extras are prohibited by legal authority or are 

discontinued by a vehicle operator, the extras mechanisms shall be rendered inoperable or the extras 

indications shall be effectively obscured by permanent means.

S.1.8. Protection of Indications. – All indications of fare and extras shall be protected from unauthorized 

alteration or manipulation.

(Amended 2015)

S.1.9. Recorded Representation. – A printed or electronic receipt issued from a taximeter, whether through an 

integral or separate recording element, shall include as a minimum, the following information when processed 

through the taximeter system:

(a) date;

(b) unique vehicle identification number, such as the medallion number, taxi number, vehicle identification 

number (VIN), permit number, or other identifying information as specified by the statutory authority;*

(c) start and end time of the trip;*

(d) distance traveled, maximum increment of 0.1 km (0.1 mi);*
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(e) fare in $;

(f) each rate at which the fare was computed and the associated fare at that rate;*

(g) additional charges (in $) where permitted such as extras, any surcharges, telecommunication charges, 

and taxes shall be identified and itemized;*

(h) total charge for service in $ (inclusive of fare, extras, and all additional charges);*

(i) trip number, if available;** 

(j) telephone number (or other contract information) for customer assistance;**and

(k) a statement of chargeable time and chargeable distance for taximeters that calculate fare using time and 

distance concurrently.***

Note: When processed through the taximeter or taximeter system, any adjustments (in $) to the total charge for service 

including discounts, credits, and tips shall also be included on the receipt.**

[Nonretroactive as of January 1, 1989] 

*[Nonretroactive as of January 1, 2000]

**[Nonretroactive as of January 1, 2016]

***[Nonretroactive as of January 1, 2018]

(Added 1988) (Amended 1999, 2015, and 2017)

S.1.9.1. Multiple Recorded Representations - Duplicate Receipts. – A recording element may produce a 

duplicate receipt for the previous transaction provided the information printed is identical to the original 

with the exception of time issued. The duplicate receipt shall include the words “duplicate” or “copy.” The 

feature to print a duplicate receipt shall be deactivated at the time the meter is hired for the next fare.

[Nonretroactive as of January 1, 2000]

(Added 1999)

S.1.10. Non-fare Information. – The fare and extras displays may be used to display auxiliary information 

provided the meter is in the vacant condition and such information is only displayed for10 seconds, or less. If the 

information consists of a list of information, the list may be displayed one item after another, provided that each 

item is displayed for 10 seconds, or less.

[Nonretroactive as of January 1, 2002]

(Added 2000)

S.2. Basis of Fare Calculations. – A taximeter shall calculate fares only upon the basis of:

(a) distance traveled;

(b) time elapsed; or

(c) a combination of distance traveled and time elapsed.

A taximeter may utilize more than one rate to calculate the fare during a trip. Any change in the applied rate must 

occur at the completion of the current interval.

(Amended 1977 and 2016)
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S.2.1. Initial Time and Distance Intervals. – The time and distance intervals of a taximeter that does not 

calculate fares based on distance traveled and time elapsed used concurrently shall be directly proportional as 

expressed in the following formula:

Distance per Non Initial Mileage Interval

Distance of Initial Mileage Interval

Seconds per Non Initial Time Interval

Seconds of Initial Time Interval

− = −

(Added 1990) (Amended 2017)

S.3. Design of Operating Control.

S.3.1. Positions of Control. – The several positions of the operating controls shall be clearly defined and shall 

be so constructed that accidental or inadvertent changing of the operating condition of the taximeter is improbable. 

Movement of the operating controls to an operating position immediately following movement to the cleared 

position shall be delayed enough to permit the taximeter to come to a complete rest in the cleared position.

(Amended 1988)

S.3.2. Control for Extras Mechanism. – The knob, handle, or other means provided to actuate the extras 

mechanism shall be inoperable whenever the taximeter is cleared.

S.4. Interference. – The design of a taximeter shall be such that when a fare is calculated by using time and/or by 

using distance (but not used concurrently) there will be no interference between the time and the distance portions of 

the mechanism device at any speed of operation.

(Amended 1977, 1988, and 2017)

S.5. Provision for Security Seals. – Adequate provision shall be made for an approved means of security (e.g., 

data change audit trail) or physically applying security seals in such a manner that requires the security seal to be 

broken before an adjustment or interchange can be made of: 

(a) any metrological parameter affecting the metrological integrity of the taximeter and associated equipment; 

or

(b) any metrological parameter controlled by software residing in the taximeter or an associated external 

computer network.

When applicable, the adjusting mechanism shall be readily accessible for purposes of affixing a security seal.

(Audit trails shall use the format set forth in Table S.5. Categories of Device and Methods of Sealing)

(Amended 1988, 2000, and 2017)
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Table S.5. 

Categories of Device and Methods of Sealing

Categories of Device Methods of Sealing

Category 1: No remote configuration capability. Seal by physical seal or, for components that may be 

removed from the vehicle, a combination of physical seals 

and a physical or electronic link as described in 

S.5.2. Taximeters Calibrated to Specific Vehicles.

Category 2: Remote configuration capability, but access 

is controlled by physical hardware.

The device shall clearly indicate that it is in the remote 

configuration mode and record such message if capable of 

printing in this mode. The device shall not operate as 

normal when in the remote configuration mode.

The hardware enabling access for remote access to 

calibration functions must be at the device and sealed 

using a physical seal and the device shall include an event 

logger. 

An event logger must be used to record changes to 

configuration parameters made through remote access.

The event logger must include event counters (000 to 999 

with a minimum count of 1000 events), the parameter ID, 

the date and time of the change, and the new value of the 

parameter. A printed or electronic copy of the information 

must be available through the device. The event logger

shall have a capacity to retain records equal to 10 times 

the number of sealable parameters in the device, but not 

more than 1000 records are required.

(Note: Does not require 1000 changes to be stored for 

each parameter.

Category 3: Remote configuration capability access may 

be unlimited or controlled through a software switch (e.g., 

password).

The device shall clearly indicate that it is in the remote 

configuration mode and record such message if capable of 

printing in this mode. The device shall not operate as 

normal when in the remote configuration mode.

An event logger must be used to record changes to 

adjustable parameters that are made through remote 

access and which is accessible only by authorized persons 

(using an Internet web browser or other such secure 

software.

The event logger shall include event counters, the date and 

time of the change, the parameter ID, and the new value 

of the parameter. A printed or electronic copy of the 

information must be available through the device. The 

event loggers shall have a capacity to retain records equal 

to 10 times the number of sealable parameters in the 

device, but not more than 1000 records are required.

(Note: Does not require 1000 change to be stored for each 

parameter.)

The device shall become inoperable when access to the 

system’s metrological parameters is made through 

unapproved or unauthorized means. The device shall 

remain inoperable until cleared by the official having 

statutory authority.

[Nonretroactive as of January 1, 2018] 

(Added 2017)
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S.5.1. Taximeter Connected to Networked Systems. – Metrological features that are not located on the 

taximeter device installed in the vehicle (i.e., accessed through a computer network, server, or “cloud”) shall be 

secured by means that will:

(a) protect the integrity of metrological data and algorithms used to compute fares from such data against 

unauthorized modifications; and

(b) use software-based access controls or equivalent technological protections that limit access to 

metrological data and algorithms used to compute fares from such data only to authorized persons.

(Added 2017)

S.5.2. Taximeters Calibrated to Specific Vehicles. – In the case of taximeters where the proper performance 

and calibration of the device has been verified when used in a specific vehicle and which may be removed from

the vehicle (e.g., slide mounting the taximeter), means shall be provided through a physical seal or electronic link 

between components affecting accuracy or indications of the device to ensure that its performance is not affected 

and operation is permitted only with those components having the same unique properties.

(Added 2017)

S.6. Power Interruption, Electronic Taximeters.

(a) After a power interruption of three seconds or less, the fare and extras indications shall return to the 

previously displayed indications and may be susceptible to advancement without the taximeter being cleared.

(b) After a power interruption exceeding three seconds, the fare and extras indications shall return to the 

previously displayed indications and shall not be susceptible to advancement until the taximeter is cleared.

After restoration of power following an interruption exceeding three seconds, the previously displayed fare shall be 

displayed for a maximum of one minute at which time the fare shall automatically clear and the taximeter shall return 

to the vacant condition.*

[*Nonretroactive as of January 1, 2002]

(Added 1988) (Amended 1989, 1990, and 2000)

S.7. Measurement Signal Loss. – If the measurement signal is interrupted, the taximeter shall be capable of 

determining any information needed to complete a transaction in progress at the time of signal loss/interruption.

Note: If the meter ceases to increment fare based on distance, the taximeter may continue to increment fare based on elapsed 

time provided the time mechanism is not affected by signal loss.

(Added 2017)

S.7.1. Intermittent Trip Data Loss. – When the measurement signal is lost intermittently during a trip (e.g., 

traveling through a tunnel), but recovered prior to the end of the trip, the taximeter shall be capable of calculating 

an accurate fare in accordance with T.1. Tolerance Values.

(Added 2017)

S.7.2. Significant Trip Data Loss. – When the signal is lost for a significant portion of the trip, the taximeter 

shall calculate the total charge utilizing recorded time and distance measurements and other charges (e.g., tolls 

and airport fees), and may also include other means in accordance with the terms of service (or other agreement) 

the passenger has agreed to.

Note: Significant trip data loss refers to instances when the measurement signal is lost to the extent that the taximeter cannot 

perform an accurate measurement or when the signal is not regained by the end of the trip.

(Added 2017)
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S.8. Anti-Fraud Provisions, Electronic Taximeters. – An electronic taximeter may have provisions to detect and 

eliminate distance input that is inconsistent with the taximeter’s source(s) of distance measurement data. When a 

taximeter equipped with this feature detects input inconsistent with the distance measurement data source(s):

(a) the meter shall either filter out the inconsistent distance input signals or cease to increment fare based on 

distance until the distance input signal is restored to normal operation. If the meter ceases to increment fare 

based on distance, the taximeter may continue to increment fare based on elapsed time when (1) permitted 

by the statutory authority; and (2) the time mechanism is not affected by inconsistent signals;

(b) the taximeter shall provide a visible or audible signal that inconsistent input signals are being detected; and

(c) the taximeter shall record the occurrence in an event logger. The event logger shall include an event counter, 

the date, and the time of at least the last 1000 occurrences.

(Added 2001) (Amended 2017)

N. Notes

N.1. Distance Tests.

N.1.1. Test Methods. – To determine compliance with distance tolerances, a distance test of a taximeter shall 

be conducted utilizing one or more of the following test methods:

(a) Road Test. – A road test consists of driving the vehicle over a precisely measured road course.

(b) Fifth-Wheel Test. – A fifth-wheel test consists of driving the vehicle over any reasonable road course 

and determining the distance actually traveled through the use of a mechanism known as a “fifth wheel” 

that is attached to the vehicle and independently measures and indicates the distance.

(c) Simulated-Road Test.* – A simulated road test consists of determining the distance traveled by use of 

a roller device, or by computation from rolling circumference and wheel-turn data.

*Simulated-road testing is not appropriate for taximeters using measurement data from sources other than 

signal(s) generated by rotation of the wheels of the vehicle.

(Amended 1977 and 2017)

N.1.2. Test Procedures. – The distance test of a taximeter, whether a road test, a simulated-road test, or a 

fifth-wheel test, shall include at least duplicate runs of sufficient length to cover at least the third money drop or 

1 mi, whichever is greater, and shall be at a speed approximating the average speed traveled by the vehicle in 

normal service. In the case of metric-calibrated taximeters, the test should cover at least the third money drop or 

2 km, whichever is greater.

(Amended 1977)

N.1.2.1. Taximeters Using Measurement Data Sources from Other Than Rotation of the Wheels.

N.1.2.1.1. Testing, General. – Testing of taximeters with metrologically significant parameters that 

do not completely reside within the taximeter device shall include tests performed under variable 

conditions to verify that any non-compliant issue is generated from a network system rather than a single 

taximeter device. The variability tests shall include a minimum of three consecutive tests of varying 

lengths, locations, and/or environment conditions.

(Added 2017)

N.1.2.1.2. Repeatability Testing, Taximeters Using Measurement Data Sources From Other 

Than Rotation of the Wheels. – Repeatability testing shall be conducted if, during testing, a taximeter 

registers a distance measurement that does not comply with the tolerance values in T.1.1. Distance Tests. 
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A minimum of three additional tests shall be conducted at the same location and where all test variables 

are reduced to the greatest extent practicable to verify the system’s ability to repeat transaction 

indications. Repeatability testing performed in excess of these three additional tests is done at the 

discretion of the official with statutory authority.

(Added 2017)

N.1.3. Test Conditions.

N.1.3.1. Measurement Data Based on the Rotation of the Vehicle’s Wheels. – For taximeters that 

receive input of measurement data generated (directly or indirectly) from rotation of the vehicle’s wheels, 

the test of the taximeter shall be performed under the following conditions.

(Added 2017)

N.1.3.1.1. Vehicle Lading. – During the distance test of a taximeter, the vehicle shall carry two 

persons, or in the case of a simulated-road test, 70 kg or 150 lb of test weights may be substituted in lieu 

of the second person.

N.1.3.1.2. Tire Pressure. – At the completion of test run or runs, the tires of the vehicle under test 

shall be checked to determine that the tire pressure is that operating tire pressure posted in the vehicle. 

If not, the tire pressure should be adjusted to the posted tire pressure and further tests may be conducted 

to determine the operating characteristics of the taximeter.

(Amended 1977)

N.1.3.2. Taximeters Using Other Measurement Data Sources. – Except during type evaluation, all tests 

shall be performed under conditions that are considered usual and customary for the location(s) where the 

system is normally operated and as deemed necessary by the statutory authority.

(Added 2017)

N.1.3.2.1. Testing for Environmental Influences. – During type evaluation, the distance test may 

be performed on a route traveled by the vehicle that exposes the system to conditions possibly 

contributing to the loss of, or interference with, the signal(s) providing measurement data. This may 

include:

(a) objects that may obstruct or reflect signals such as tall buildings/structures, forestation, 

tunnels, etc.;

(b) routes that do not follow a straight-line path;

(c) significant changes in altitude; and

(d) any other relevant environmental conditions.

(Added 2017)

N.1.3.2.2. Testing for Environmental Influences. – During type evaluation, the distance test may 

be performed on a route traveled by the vehicle that exposes the system to conditions possibly 

contributing to the loss of, or interference with, the signal(s) providing measurement data. This may

include:

(a) objects that may obstruct or reflect signals such as tall buildings/structures, forestation, tunnels, 

etc.;

(b) routes that do not follow a straight-line path;

(c) significant changes in altitude; and

(d) any other relevant environmental conditions.

(Added 2017)
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N.2. Time Test. – If a taximeter is equipped with a timing device through which charges are made for time intervals, 

the timer shall be tested at the initial interval, four separate subsequent intervals, and an average time test of at least 

four consecutive subsequent time intervals.

(Amended 1988)

N.3. Interference Test. – For taximeters that calculate fares based on time and/or distance but not simultaneously,

a test shall be conducted to determine whether there is interference between the time and distance elements. During 

the interference test, the vehicle’s operating speed shall be 3 km/h or 4 km/h (2 mi/h or 3 mi/h) faster, and then 3 km/h 

or 4 km/h (2 mi/h or 3 mi/h) slower than the speed at which the basic distance rate equals the basic time rate. The 

basic rate per hour divided by the basic rate per mile is the speed (km/h or mi/h) at which the basic time rate and basic 

distance rate are equal.

Note: Performance of the interference test may not be considered appropriate as a field test while travelling in a vehicle equipped 

with a taximeter. This test may be performed during type evaluation under controlled conditions for practicality and for safety 

concerns.

(Amended 1988 and 2017)

T. Tolerances

T.1. Tolerance Values.

T.1.1. On Distance Tests. – Maintenance and acceptance tolerances for taximeters shall be as follows:

(a) On Overregistration: 1 % of the interval under test.

(b) On Underregistration: 4 % of the interval under test, with an added tolerance of 30 m or 100 ft whenever 

the initial interval is included in the interval under test.

T.1.2. On Time Tests.

T.1.2.1. On Individual Time Intervals. – Maintenance and acceptance tolerances on individual time 

intervals shall be as follows:

(a) On Overregistration: 3 seconds per minute (5 %).

(b) On Underregistration: 9 seconds per minute (15 %) on the initial interval, and 6 seconds per minute 

(10 %) on subsequent intervals.

T.1.2.2. On Average Time Interval Computed After the Initial Interval. – Except for the initial 

interval, maintenance and acceptance tolerances on the average time interval shall be as follows:

(a) On Overregistration: 0.2 second per minute (0.33 %).

(b) On Underregistration: 3 seconds per minute (5 %).

(Amended 1991)

T.1.3. On Interference Tests. – For taximeters designed to calculate fares upon the basis of a combination of 

distance traveled and time elapsed (but not using both simultaneously), the distance registration of a taximeter 

in the “time on” position shall agree within 1 % of its distance registration in the “time off” position.

(Added 1988) (Amended 2017)
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T.2. Tests Using Transfer Standards. – To the basic tolerance values that would otherwise be applied, there 

shall be added an amount equal to two times the standard deviation of the applicable transfer standard (i.e., fifthwheel) when compared to the basic reference standard.

(Added 2017)

UR. User Requirements

UR.1. Inflation of Vehicle Tires. – For taximeters that receive input of measurement data generated (directly or 

indirectly) from rotation of the vehicle’s wheels, the operational tire pressure of passenger vehicles and truck tires 

shall be posted in the vehicle and shall be maintained at the posted pressure.

(Amended 1977 and 2017)

UR.2. Position and Illumination of Taximeter. – A taximeter shall be so positioned and illuminated that its 

indications, operational markings, and controls of passenger interest can be conveniently read by a passenger seated

in a position of up to 1.2 m (4 ft) away from the taximeter under any condition of normal operation.

(Amended 1985, 1986, and 2017)

UR.3. Statement of Rates. – The distance and time rates for which a taximeter is set, including the initial distance 

interval and the initial time interval, the local tax rate, and the schedule of extras when an extras indication is provided

shall be conspicuously displayed inside the front and rear passenger compartments. The words “Rate,” “Rates,” or 

“Rates of Fare” shall precede the rate statement. The rate statement shall be fully informative, self-explanatory, and 

readily understandable by the ordinary passenger, and shall either be of a permanent character or be protected by glass 

or other suitable transparent material.

(Amended 1977, 1988, 1990, and 1999)
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