After 1927 and 1929, in which no highways were added to the system, the legislature authorized the construction of 23 new routes in 1931, which were numbered from 72 to 80 when not forming extensions of existing routes. Two years later, another 213 sections of highway were added, almost doubling the total length of state highways to about ; the last-assigned route number jumped from 80 to 202. Many of these new routes, as well as a number of existing routes, were incorporated into the initial system of state sign routes in 1934, also posted by the auto clubs.