The sub-car of Qin Dynasty. How to write?

After Qin Shihuang unified China (22 1 year ago), he implemented the policy of "the same language in words, the same rail in cars", and the policy of unified measurement was in the charge of Prime Minister Li Si. On the basis of the original big seal script used by Qin, he simplified it, canceled the variant characters of other six countries, and created Xiao seal script as a unified text.