I wanted to note a key feature of this credit in v4, which was brought to my attention by Dan Ackerstein and Hannah Sokol.
In EBOM 2009, a project only earns points under SSc4 if they achieve (and document) a 10% reduction in conventional commute trips. In LEED v4, any project that simply conducts a LEED-compliant alternative transportation survey can earn a single point, even if they achieve <10% reduction in trips.
This change creates a nice incentive for surveying and establishing a performance baseline, even in buildings that have not been terribly successful with alternative transportation.
This also touches on LEED 2009. USGBC has formally approved a pathway for substituting the v4 credit for the EBOM credit when pursuing EBOM certification; that is, EBOM 2009 projects who complete a LEED-compliant SSc4 survey can now earn 1 point even if they achieve a commute trip reduction of less than 10%. That opportunity is noted here: http://www.usgbc.org/resources/2009-v4-credit-substitution-om.
A survey is a big undertaking, and its great that we now have a mechanism for rewarding that process in and of itself.