Dog hyperactive with the car (separation anxiety)

We have a Mini Wire Dachshund who is increasingly becoming uncontrollable. She is just 2 years and for the past year becoming increasingly problematic when either I or the OH heads for the front door to go to the car. She begins to scream to get out and scratches frantically at the door. We have tried putting her in another room, in a cage, nothing works. If you pick her up she screams even higher.
Once in the car, she rips everything in sight even in a car cage, pulling in the cover, ripping the plastic floor, salivating some much that the cage is swimming in it, on 1 occasion she managed to rip a 2 kilo bag of dog biscuits but most of the biscuits were in her cage!!. Once the OH or I are in the car she settles till we leave the car then she starts off again, screaming ripping and salivating.
If we leave her in the house and one of us goes out, we have to either cage her, leave her to run frantically around the house totally demented. We can not leave her in the house as she would scream too much, and taking her in the car is becoming too bad that we have to return every 5 minutes to calm her.
We have changed her diet to Burns, tried doggie sedation treatments and nothing has an effect.
We have another 10 daxies which are becoming affected by her anxieties.
We are at the point when we now do not go out together, either I am at home with her or the OH is. When we DO go out ie away in the caravan to the Dog Shows I have her up front on my lap.
The odd thing is if we are away in the caravan she is okay if we go out in the evening and sleeps of a night in the car. Same cage, same covers.She is ruining our life.
Apart from that, she is a loving, sweet little dog.
Any suggestions gratefully received.

PS Of note most of the litter have hyperactivity of some sort. The breeder of our girl has kept one of the litter and they have problems with a ball, which she bounces off the walls all night (literally)

has something happened to increase this level of anxiety? Sounds like she is just permanently stressed so may need to enforce a strict routine with her to see if you can eliminate the root cause. If you have 10 other dogs though then maybe she's just trying it on for attention?

I'm sure one of the more experienced Dogwebbers will have more to add - good luck though.

PS - have you tried giving her B12 vitamins? Can be useful in long term management of stress - for humans and dogs!

Yes been on B12 for months

To be honest I think it has reached the stage where you need to get some professional, hands-on advice. Ask your vet to refer you to a behaviour consultant. Might be expensive but worth it if it gives your dog some relief from her obviously serious stress.