Could you tell me, .. is there any version with SI unit (NOT in U.S. customary units only) ? We would like to use SI units. Thank you for your help!

An SI version of the HCM 2010 was not developed. You can find guidance on applying the HCM 2010 with metric units in a document posted at the following site: http://sites.kittelson.com/hcqs-userliaison/Downloads

By the way, was there a reason not to produce a SI version? We all kmow HCM is now widely used worldwode. In Brazil, for instance, most private highway concessionaires, which take care of toll highways and freeways, must do HCM analysis to the state agency, as defined by their contract. To return to be an US customary only publication just seems to make little sense.

At the time the HCM 2000 was being produced, there was a federal requirement in the U.S. for the states to transition to metric design for roadways. As a result, there was a U.S. market for a metric/SI edition. That requirement was later recinded and the vast majority of U.S. transportation agencies have gone back to designing in U.S. customary units. Therefore, a decision was made for the HCM 2010 to only produce a U.S. customary units version.