Engine always starts up

On a related, one of my Volt-enthusiast friends (and a Volt owner) mentioned that there was some government regulation re: cold start emissions (possibly needing to be down to a certain level?) x # of seconds or minutes after starting. This rule makes sense for regular cars (non-hybrids and non-PHEVs) but didn't make sense for the Volt. He mentioned to me that GM basically got the rule changed during Volt development and that this should benefit others.

Unfortunately, I pinged him for the details/post (asking him to not waste >30 seconds trying to dig it up, if he didn't know where it was). He couldn't find it within the time allotted. Perhaps a Volt enthusiast knows the details.