H.R.6278: To amend title 49, United States Code, to prohibit the transportation of horses in interstate transportation in a motor vehicle containing 2 or more levels stacked on top of one another.

Horse Transportation Safety Act of 2008 - Amends federal transportation law to prohibit a person from transporting a horse in interstate commerce in a motor vehicle containing two or more levels stacked on top of one another. Sets forth civil penalties for persons who knowingly violate such prohibition.