The only way to vouchsafe for passing traffic is to know someone in the car.
From the telegraph.co.uk
Chile's predatory snails, and their human predators, will vouchsafe that.
From the economist.com
Monsanto should not have to vouchsafe the safety of biotech food.
From the guardian.co.uk
He loved to talk politics, but there were few politicians whose integrity he would vouchsafe unconditionally.
From the en.wikipedia.org
They purify and store water, influence the weather far away by cooling the atmosphere and seeding clouds, and vouchsafe biodiversity.
From the newscientist.com
Supposedly, this is great for everyone, so the rich will willingly vouchsafe their money upon the middle class in the form of business investments.
From the economist.com
He looked at us, in the first place, with keen and somewhat guarded eyes, as if it were not his practice to vouchsafe any great warmth of greeting, except upon sure ground of observation.
From the theatlantic.com
Vouchsafe, you'll agree they mean we're a nice breed generally, that we like to laugh, reach out, say howdy, lend a hand, touch folks, help push a neighbor's clunker to get it cranked up.
From the newsobserver.com
Following the divine law and the words of wisdom uttered by the sages, may we make a good couple and may God vouchsafe unto us a shining life of virtue and happiness.
From the en.wikipedia.org
More examples
Grant in a condescending manner
To graciously give, to condescendingly grant a right, benefit, outcome, etc.; to deign to acknowledge
(vouchsafed) was gracious enough, or condescended, to give or grant.
(VOUCHSAFED) To allow or permit, to swear or attest.