Japan has begun conducting vehicle tailpipe emissions testing in a move that may pave the way for more stringent auto emission standards.

The government has begun testing for nitrogen oxides (NOx), sulphur oxides (SOx), and particulate matter (PM).

In a move that is designed to collate information for the upcoming changes to emission legislation in 2005 vehicle inspections will be conducted on the road.

Currently motor vehicles off the assembly line must comply with emission standards for
NOx, SOx, hydrocarbons (HC), and carbon monoxide (CO), but once registered they only need to meet HC and CO emission standards.

However, the new 'experimental' system may change this as the Tokyo, Nagoya, and Osaka urban areas begin testing.