How to train when out and about

[Mumma301]

DS almost 3 has been potty trained for a couple of months now... but only at home. He happily goes off to the potty himself and takes his pants off at home, but the second we go out anywhere he wets himself.

I’ve tried limiting drinks and making him go to the loo before we go out. But even if it’s just driving to the shops by the time he’s gotten out of the car he has wet himself. We’re using pull ups for this reason but have tried without too and he still sets himself. He doesn’t even seem to notice, it’s obly when I see a wet patch that I realise he’s done it!

Does anyone have any advice? He’s starting pre school in 2 months and for his own sake I really want him to be potty trained!