Police in West Sussex are appealing for information after the lorry failed to stop following the incident on the A27 at Fishbourne, near Chichester, on Thursday morning.
The woman's four-month-old baby, who was riding in the front passenger seat, was uninjured.
The woman, from Bognor Regis, was driving towards Hampshire in an Audi A4 when wood fell from a skip carried by the lorry and hit the windscreen of her car.
The lorry failed to stop and continued west-bound towards Hampshire.
Failing to stop after a road traffic incident to hand over your insurance and driver details is a criminal offence, which can incur a maximum prison sentence of six months, a £5,000 fine, 10 penalty points and the possibility of disqualification from driving, which is decided at the discretion of a judge or magistrates.
Anyone with information should call 0845 60 70 999, quoting serial 596 of December 3.
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