The Measuring Instruments Directive

Beer Glasses, Petrol Pumps, Aquila T2 and T-Tiny Taximeters...

Aquila T2 and T-Tiny Taximeters are both certified to the Measuring Instruments Directive.

On 30th April 2004, the European Union published the Measuring Instruments Directive, a wide-ranging change to the certification of equipment used in the field of Legal Metrology. Included in this our specialist subject – taximeters!

You can find the Directive here

The Law In Summary

This new law began its introduction in October 2006 and there is a 10 year transition period for products which were already approved before then. In the case of taximeters, this means that all new meters must comply with the new rules one way or another:

In the case of taximeters:

A taximeter product first put on sale after October 2006 must carry a legal “M” (for MID) marking, meaning it complies with the MID. We’ll explain how this marking works later, but this is an example of one (from an Aquila T-Tiny):

A meter put on sale before this date must comply with the “Applicable National Approval” in force previously. The UK has decided that this is the London Public Carriage Office approval (known to some as “BSI/PCO” or similar).

… so, in the UK, if it wasn’t PCO approved before October 2006, or correctly “M” marked after then, it can’t be sold and fitted to a taxi. That’s what the law says.

Measuring Instruments - Background

It is clearly very important that we as consumers can rely on the accuracy of the devices used to make measurements, particularly where the payment of money is involved. This is why our beer glasses, petrol pumps, weighing machines and many other instruments are subject to legal controls.

Taximeters clearly also fall into this category, ie the measurements they make decide how much money is paid for the service of providing transport in a taxi.


Before the MID, each state in Europe had its own local rules for Measuring Instruments. Here in the UK, we had “Weights and Measures” requirements for our beer glasses and petrol pumps, and we had local regulations for Taximeters, including the London based Public Carriage Office approval.

The MID, like other European rules, is designed to create a certification system which applies equally across all of the EU states, so this meant that the National Standards needed to be replaced by standards which applied throughout the EC.

This is why you will see “M” marks on “Measuring Instruments” all over Europe, including on its Taximeters.

The MID actually replaces these National Standards, making, for example, PCO Approval unnecessary for areas outside London.

What does the MID Say About Taximeters?

The Measuring Instrument Directive tells us the important features of Taxi Meters including how they work, how accurate they need to be, and how reliable they need to be. It also tells us how we must ensure that the products we supply (as manufacturers) are up to this standard. The result of following these rules is the “M” mark on the meter, which gives the authorities, taxi operators, and the public the assurance that the meter complies with the law and can be relied upon.

.. but how do you know that the mark is legal and correct?

Understanding The M Mark on a Taximeter

Every MID compliant taximeter (ie: every taximeter type put on sale after October 2006) must:

.. be supplied with a Declaration of Conformity, which shows how a particular Taxi Meter complies with the MID and also any other Directives applying to it

.. Have an ‘M’ mark, with the detail including the year of affiation and the number of the Notified Body associated with it.

The CE Mark, decalares that the meter complies with all relevant “New Approach” European Directives. To find out which ones, there will be a Declaration of Conformity from the Manufacturer.

Many products sold in Europe have this mark, not just Measuring Instruments - so it is only meaningful if read in conjunction with the Declaration of Conformity.

Routes to Compliance

There are several ways for a manufacturer to achieve compliance to the MID. Aquila has chosen to invite a Notified Body to approve its Quality Management Systems to ensure that they comply with ISO9001 and the additional rules for the MID. This route is covered by “Annex D” of the Directive, and Aquila has achieved approval to this.

The route to Compliance should always be given on the product’s Declaration of Conformity.


If, as a taxi operator, taxi meter installer, enforcement authority, or even a user of taxis, you would like further information or details, please get in touch and we will try to help. Equally, if you see any inaccuracy or ways we could improve this information, it would be great to hear from you.