What we know as dashboards, not the one on your computer, in cars- are evolved from the early dashes in horse carriages and buggys. The dash board was the boards or material dropcloth that kept the horses back feet from splashing mud and muck onto the driver and carriage... the carriages became motorized and the dashboards were the best place for the first gauges, so the dashboards became the instrument panels
from the above splash guard behind the horse, to
Sparked by an article http://tywkiwdbi.blogspot.com/2011/02/why-is-it-called-dashboard.html