Drivers who cause death by dangerous or careless driving could get life in prison under new government proposals.
Ministers want to bring the offence, which has a maximum sentence of 14 years, in line with manslaughter.
Motorists who cause death by speeding, street racing or while on a mobile phone are among those who could face longer sentences.
Road safety charity Brake welcomed the plans, but is worried the lesser charge of "careless" driving could remain.
Offenders convicted while under the influence of drink or drugs could also be given life sentences.
In 2015, the average custodial sentence for causing death by careless or dangerous driving was just under four years.
Dawn Brown-Lartey's son, Joseph, was killed instantly when a motorist who was racing crashed into him and split his car in two.
The driver, who had no insurance and only a provisional licence, was sentenced to six years.
"Our life is changed beyond recognition," she told BBC Breakfast.
Claiming he travelled from Leeds to Manchester in 11 minutes, the motorist posted pictures on Snapchat of his speedometer reaching 140mph on a motorway and running a red light at 82mph in a 30mph zone.
"The police were saying that this was the most severe crash that they'd gone to on an urban road and this boy, you know he's a boy, is only going to serve three years in a young offenders [institute]," she added.
Janice Ward's daughter, Rachael, was killed by a driver who was racing while high on drugs. He received a seven-year jail term.
She told BBC Radio 5 live victims' families and friends felt let down by sentences.
"It's just not reflecting the seriousness of the crime. When a car's driven like that it's a lethal weapon and it should be classed the same as using any other lethal weapon. It should mean a life sentence."
Stephen Oldham, a solicitor who specialises in representing motorists accused of offences, said there should be different levels of culpability to fit different types of driving behaviour.
Speaking to Breakfast, he said life sentences were generally reserved for people who have "gone out of their way" to commit these serious offences and have displayed intentional recklessness to kill or to cause serious injury.
"That's often the element that's missing with the driving case," he added.
Justice Minister Sam Gyimah said it was "impossible to compensate for the death of a loved one", but he was determined to make sure the punishment fitted the crime.
"Killer drivers ruin lives. Their actions cause immeasurable pain to families, who must endure tragic, unnecessary losses," he added.
Gary Rae, campaigns director for Brake, hailed the "vindication" of its efforts calling for change, but said the offence of careless driving should also be scrapped.
"Some of the strongest feedback we have received from the families we work with is that there is nothing careless about taking someone else's life," he said.
The charity is also seeking clarification on whether the current automatic 50% discount - which means convicted drivers serve only half their term in jail - would still apply.
Under separate plans announced earlier this year, the Department of Transport is set to double the punishment for using a mobile phone while driving. Fines will rise from £100 to £200 and penalty points will go up from three to six.