Pup is an 15 week old JRT; had since 8 weeks, carried everywhere to get used to noises and sights and sounds etc. He is an absolute angel in the house, is pretty much housetrained now, clean and dry overnight, recall is fab, with the aid of a clicker and liver treats, and he walks brilliantly on the lead... Apart from whenever a car, bus, motor bike etc. goes past, when he freezes to the spot then tries to run away! I'm currently trying to distract him with treats which works to a point, but he's just petrified of anything noisy and fast moving. Any tips?
Other issue I'm having is him growling/barking at random stationary objects such as litter bins, trees, push bikes and the like. Again, I'm distracting him, making myself exciting, turning the other way etc., but is there anything else I should be doing? I know he's only a baby and he may well just get used to things, but I don't want him getting into the habit of barking at everything. I also appreciate that JRT's do tend to be of the you variety, so a lot of it may be nature not nurture!
For dealing with traffic I would find somewhere to sit near to but not too close to a road (far enough away that he is not scared) and just sit there with your dog, letting him look at the traffic. Each time a car goes past give your dog a treat. When you think he is ready move a bit closer and repeat. Slowly. Don't rush it and be aware that it could take weeks.
As for stationary objects do you let him investigate them? My dog will sometimes react to things, so we go look at them and he deems them not scary and pretends it never happened. The method for dealing with traffic will also work for objects.