The green bush in front of the ocotillo is creosote bush.
I have some doubts about this ID but it looks more like Y. constricta than anything else I have ever seen.
Probably this can't be identified without the flower but I thought maybe somebody would have an idea or two.
Hanging out in a tree at the Panther Junction Visitor Center in Big Bend National Park
Dead on the road. In Big Bend National Park, on the Glenn Springs Road by the entrance to the Nugent Mountains. It's possible that this snake is a S. deserticola without the lateral stripe, but the chin and labial scales couldn't be counted due to the specimen's crushed head. S. grahamiae generally lack the lateral line and S. deserticola mostly have it, so it's highly probable that this is the correct identification. Habitat nearby was lechuguilla and creosote bush, so it could support either species.
Saw 3 bucks and a doe around 8am March 10 near Indian Lodge and the park hq.