Unlike most of Emperor Norton's eccentric ideas, his decree to build a bridge had wide public and political appeal. Yet the task was too much of an engineering and economic challenge, since the bay was too wide and too deep there. In 1921, over forty years after Norton's death, a tube was considered, but it became clear that one would be inadequate for vehicular traffic. Support for a trans-bay crossing finally grew in the 1920s with the increasing popularity and availability of the automobile.