In response to the need for introduction of Average Speed Control (ASC) devices for road traffic law enforcement, the Bureau of Standards, Metrology, and Inspection (BSMI) offically published the "Technical Specification for the  Verification and Inspection of Average Speed Control Devices" (hereinafter referred to as the Technical Specification), which will enter into force on 1 January 2021. The implementation of the Technical Specification will reinforce the public confidence by ensuring the accuracy of measurement results of ASC devices.

According to the BSMI, the ASC devices measure the average speed of a vehicle by detecting and recording the time it takes passing through a specific road section. To ensure the accuracy of ASC devices, the BSMI will perform the verification by utilizing calibrated vehicle-mounted time and speed measuring instruments.

On the matter of public concern about the accuracy of ASC devices, the Technical Specification gives explicit rules of maximum permissible error (MPE), i.e. when the average speed of a vehicle is no more than 100 km/h, the positive MPE is 2 km/h and the negative MPE is 4 km/h; when the average speed is greater than 100 km/h, the positive relative MPE is 2%, and the negative relative MPE is 4%.

In addition, in the part of time measuring accuracy, ASC devices are required to have an additional set of time measuring instrument. The two sets of instrument should be compared with each other to ensure accuracy. When the measuring error exceeds 0.2 seconds within 1 minute, an alarm signal should be automatically generated to prevent any false measurement. Meanwhile, ASC devices shall at least perform time calibration once every 5 minutes, and the difference compared to the national standard time shall be no more than 1 second.

The BSMI kindly reminds the public that, while the verification of ASC devices will enhance public confidence and safeguard citizens' interests, citizens shall comply with the requirements of road speed limits to protect safety of themselves and others, with or without the deployment of ASC devices.

BSMI Spokesperson: Deputy Director-General Chen, Ling-Hui

Tel. (O):02-23431709

Email: lh.chen@bsmi.gov.tw

Responsible Unit: Hsia, Chun-Der, Deputy Director of 4th Division 

Tel. (O): 02-23967149 Tel.(M): 0922-952859

Email: Chun.Hsia@bsmi.gov.tw

Press Contact: Lin, Ching-Yen

Tel. (O):02-23431759 Tel.(M):0976-425601

Email: chingyen.lin@bsmi.gov.tw