Mark Loughlin, 50, drove into the back of a Range Rover while attempting to connect to his Bluetooth hands-free kit.
Loughlin failed to notice the car ahead had stopped and was indicating to turn right when he hit it on the A370 in East Brent, Somerset in September last year.
His Citroen Relay van hit the Range Rover which led to the driver, a woman in her 60s, being cut free from the vehicle before being taken to hospital for treatment. Loughlin was unhurt.
He admitted driving without due care and attention when he appeared at Bath Magistrates’ Court on October 1 and was fined £482, Avon and Somerset Police said.
Loughlin, from Yate, South Gloucestershire, also received nine points on his driving licence and was ordered to pay £110 costs and a £48 victim surcharge.
Pc Owen Davies, who led the investigation, said: “The shocking footage of this incident clearly illustrates the dangers of driving whilst distracted.
“An innocent motorist suffered significant injuries – we are fortunate not to be talking fatalities.
“Driver distraction is one of the ‘fatal five’ main causes of serious injuries and death on the roads.
“Research shows that drivers using a phone – handheld or hands-free – are four times more likely to be involved in a collision and their driving is impaired to a degree similar to that of a drink-driver.”