I have a 10 week puppy who has been in the car four times (not counting the journey home).  She travels in a crate on the back seat and the last three journeys has toileted in the crate.  She has never pooed in the house and she has just got the hang of going out to wee.  (We have had 3 days with only one accident on the way to the back door!)  She was given ample time outside before setting off today, I put a filled kong in the crate and it was a very short journey.

I know she is young but I have never had a puppy that toileted in the crate or car before.  I have never really had any problems with travelling. Is it just a matter of waiting till she is older?  Is there anything to be done in the meantime?  I would welcome any suggestions.  It does cause problems with socialisation as she is too heavy to carry far and it means we are unable to get out at all.  I am travelling on my own so cannot sit with her in the back.

May be stress, try putting her in the car in the crate but dont go anywhere. get her out after a few minutes or even seconds. Build up the time and start the engine, then begin to go on very short jouneys.
Sit with her and get someong else to drive, so you can see what happens.
It may be the motion or the smell of the car thats making her go so get her used to it very graduly.
Remenber the first time she was in a car she was taken away from her mother and siblings.
What are you putting on the botton of the crate? If you put newspaper she may of had newspaper to toilet on before you had her. Therefore she will use it. Try putting her bed in the crate.

I am putting her bed in the bottom of the crate with a towel on top.  I will try taking it a bit more slowly thanks.

> he travels in a crate on the back seat

Just as another thought is the crate secure or does it move when you're driving? If not totally secure then i'd do this, better still pop the crate into the boot area to make it more secure.
Can the pup see out of the window?

Just a thought.  Would it be a good idea to put my adult dog in the car with the puppy?  She is an excellent traveller.  Only trouble is that it would make it difficult to reach the puppy and clean up without taking the other dog out.

It is the smallest size crate and has two seatbelts through it to anchor it at the back.  She can see through the window easily.  Not sure if it would fit in the boot as it is a smallish car.  Shall I cover the crate?

You've nothing to loose by trying with the older dog in the car, I can see that it could cause you a bit of hassle but her travelling well may help the little one.

Wouldnt put the pup in the boot, thats the place that swings round the most. Place the pup as near to the centre of the car as possible. Personly I dont like dogs in the boot in case someone runs into the back of the car.

Definitely sounds stress related.

I'd put the crate up front on the front seat if it fits, or buy a smaller crate to fit the seat, maybe strap it in with the seat belt, this way your pup will be able to see you and the surroundings. And if you have passengers make them sit in the back, until pup is used to the car and stops toileting in it.

Thanks everyone for your replies.  A bus ran into the back of my previous car with my dog in the boot.  Fortunately she was ok as we were going very slowly but the car was badly dented.  So I am reluctant to use the boot again.

My latest puppy was dirty in the car for the first few journeys.  Even the 1/2 mile or so to the vet for innoculations she managed it both there and back!!!
She was crated in the boot - I think the boot is more stable than a passenger seat, especially if they move around. 
Slowly, she got better - every trip I made I was prepared - plenty of clean newspaper, towels, baby wipes and air freshner plus carrier bags for rubbish etc.  Once she'd had her first 'clean' trip, she has never done it again - touch wood.
Keep patient with her, try taking a passenger with you to reassure her while you are driving.  She will get better I'm sure.

my puppy was dirty in the car, so put her in a smaller crate, and also strapped the crate in to the seat so it did not move and i also covered her, it was not just poo,but vomit every where, started putting her in the crate and not move any where take her out and praise her, then we progressed to turning the engine on and not moving, and then taking her out and going for a walk, then we progressed to moving the car two mins and back into space and then take her out, it did take a while and patience is the key, and now for the last 3 months she has not been sick or poo in her cage, she cannot travel in the back with the big dogs as the motion makes her vomit and poo so she stops in her own cage at the moment hope this helps