CA SB1174

Exempts truck tractor semitrailer combinations used exclusively or primarily for motorsports from standard length limitations, allowing trailers up to 56 feet long and kingpin-to-rearmost-axle measurements up to 46 feet, effective until January 1, 2016.

Permits authorized motorsports vehicles to operate on the National Network, transition routes, and other routes approved by the Department of Transportation in consultation with the California Highway Patrol.

Requires the Department of Transportation to conduct a field test evaluating the performance of 56-foot motorsports trailers on various highway segments and submit a report to the Legislature by January 1, 2014 with recommendations on reauthorization.

Defines "motorsports" as events and related activities (administration, testing, practice, promotion, merchandising) sanctioned under the Automobile Competition Committee for the United States.

Establishes the motorsports vehicle exemption as temporary legislation that automatically repeals on January 1, 2016 unless extended by subsequent legislation enacted before that date.