[tak-uh-graf, -grahf]
A tachograph is a device that combines the functions of a clock and a speedometer. Fitted to a motor vehicle, a tachograph records the vehicle's speed and the length of time that it is moving or stationary. The mechanical tachograph writes on a round piece of paper which constantly turns throughout the work day. The marker moves nearer to or further from the center according to the driving speed. An entire rotation encompasses 24 hours.

Analogue tachographs record the driver’s periods of duty on a waxed paper disc. However, these are vulnerable to tampering, and so are being replaced by digital tachographs which record data on smart cards.

Tachographs are also used to improve road safety and ensure fair competition. They are also used in the maritime world. Rules for this are made by the Central Commission for Navigation on the Rhine.


For reasons of public safety, many jurisdictions have limits on the working hours of drivers of certain vehicles, such as buses and trucks. A tachograph can be used to monitor this and ensure that appropriate breaks are taken.

In Germany

The Verkehrs-Sicherungs-Gesetz (German Traffic Safety Law) of December 19 1952, made tachographs mandatory in Germany for all commercial vehicles weighing over 7.5 tons. Since March 23rd and December 23rd 1953, all new commercial vehicles and buses must be equipped with the device per law StVZO § 57a.

Tachographs are mandatory for vehicles allowed to carry a total weight of over 3.5 tons and vehicles built to carry at least 9 passengers, if the vehicle is used for commercial purposes. They are used to review the driving and rest time of drivers during reviews by traffic standards organizations or accident investigation. A driver must carry the tachograph records with him for all days of the current week and the last day of the previous week that he drove. Companies must keep the records for 1 year. In Germany, § 16 of the work time regulations lengthens this time to 2 years if the records will be used as proof of work time.


EEC regulation 3821/85 from December 20 1985 made tachographs mandatory throughout the EEC as of September 29 1986. A "European arrangement in regard to the work of driving personnel engaged in international traffic" (AETR) became effective on July 31 1985.


Tachographs can be tampered with in various ways, such as slightly twisting the marker, blocking the path of the arm with a piece of rubber or foam, and short-circuiting the unit for short periods. Replacing the (older analogue) tachographs power supply voltage with a blown fuse to stop operation completely thus recording no information whatsoever. Also the old "forgetting to insert" when beginning the drive and unauthorized changing of the discs are known throughout Europe.

Ghosting is another common trick when false driver information is entered onto a second chart to give the appearance that there is a second driver present in the cab for long distance runs that cannot be completed within a single driver's daily driving period.

Accident investigation

Apart from enforcing regulations, tachographs are often used in Germany to investigate and punish speeding. This practice was approved by the German high regional court in the 1990s. Also, after an accident, the discs are often examined with a microscope to discover the events that took place at a collision site.

Digital tachograph

Digital tachographs make tampering much more difficult through, for example, the vehicle sending signals in an encrypted manner. EU regulation 1360/2002 makes digital tachographs mandatory for all vehicles described in the above section Regulations and made after August 1, 2005. Digital tachographs would be required as of May 1, 2006 for all new vehicles for which EWG regulation VO(EWG)3820/85 applies, as is published in the official newsletter of the European Union L102 from April 11, 2006. But this law was dismissed and converted to a national law. The EU regulation is as of March 29, 2006, and is still in negotiation and has not yet been announced. Only after its announcement will it go into effect in Europe.

Digital tachographs have been implemented in Mexico since 1994, but this is not a federal regulation. The last implementations developed in Mexico have GPS capabilities such as mapping, altitude and location-activated video triggering.


The tachograph was originally introduced for the railroads so that companies could better document irregularities. The inventor was Max Maria von Weber, an administrative official, engineer and author. The Hasler Event recorder was introduced in the 1920s.


Tachographs are being phased out in favour of electronic log books which record data digitally on a smart card.

The case against tachographs

When the use of tachographs was imposed by the European Union on its member states in the 1980s, governments and operating companies were opposed on the grounds that tachographs were expensive and unnecessary, and contributed nothing to road safety. Domestic hours regulations were replaced by European regulations which were complicated. It was doubtful whether strict enforcement of these regulations would reduce driver fatigue since they were not based on scientific evidence.

Drivers and their trade unions initially opposed the use of tachographs because they feared that employers would examine the records and reduce the driver's pay for any time stopped, even if the stop was for a good reason, such as checking the vehicle or going to the toilet. This would encourage tired drivers to continue driving rather than rest, and encourage drivers to exceed speed limits in order to reach their destination within the required time.

In some countries, fines to foreign drivers are imposed on the spot, and the drivers may not leave until the fine is paid. In other countries, the driver is required to pay within a time limit. Since collection of fines does not work over the borders, a foreign driver can throw away the demand documents, making the tachograph system less meaningful. The EU is negotiating a system where fines received in an EU country are payable in the home country.

The case for tachographs

Today operators see tachographs as levellers -- devices which prevent unfair competition from companies who force their drivers to work excessive hours. Trade unions and drivers also now favour tachographs for this reason and records are often used in tribunals as proof when claiming for unpaid work.

Tachographs are also useful after an accident to help establish the cause and corroborate eye witness accounts. Trade unions take a dim view of anyone who exceeds speed limits or permitted hours.

Fears that it is easy to falsify readings by tampering with tachographs have been allayed, since it is relatively easy to spot such attempts.

See also


External links

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