This photo show a Fruit Fly Roadblock on the border at Wodonga (where I live) of New South Wales (NSW) and Victoria. The border is defined by the Murray River.
In Queensland (further north) there is a pesky fly that lays its eggs in fruit, particularly tomatoes, citrus etc. When the eggs "hatch" the maggots begin eating the flesh inside the fruit. Trust me when I say it is disgusting to cut into an apparently okay looking tomatoe to find it riddled with horrible little white maggots.
In an attempt to prevent the spread of this pest from the northern state of Queensland to Victoria, the Victorian Government set up these road blocks on the main highways and no fruit of any type, no matter where it originally came from, was allowed in.
Each car was stopped by the officers and asked if they had fruit to declare. If you said "No Officer" and you looked honest and maybe not the type to have fruit on board, then you were waived through. Or they may just decide to search the vehicle anyway, particularly if you were a family.
If you said "yes officer" and handed over fruit, they may waive you through or decide to search your vehicle further anyway.
It was quite common to see families parked there with everyone devouring fruit rather than hand it over, where is was just destroyed.
Even if we brought some fruit with us when we left home to go on a day trip to NSW, and then return, we had to declare any uneaten fruit and hand it over. The theory was those sneaky Queensland Fruit Fly my have flown in through our car window and laid eggs in our previously pure Victorian fruit.
Unfortunately those clever Queensland Fruit Fly spread further south into NSW and on reaching the Murray River at the border to Victoria, realised they could just keep flying and enter Victoria wherever they liked, thus making the road blocks somewhat useless.
Now the fruit fly are a permanent menace here and the reason I stopped growing tomatoes.
I do not know the make of any of the cars in the photo.