This is a Copperhead (Latin name, stepponus, bite-your-footus) I could have stepped on had someone not smashed it with a vehicle. In the "dark" picture, it is illuminated with a Energizer Brand Penlight. A terrific buy at your local AutoZone for about $6.00 or $7.00! The inferior picture was taken with a Motorola Razor cellphone, for the record.
I went back and took another picture when the sun came up, opossums or racoons had their way with the carcass so there wasn't much to look at it after that but does show the stunningly beautiful coloration that a Copperhead has.
And, this is a pretty big Copperhead, too. The ones I have run into in the past have never been much more than 14 inches long.