Drivers who kill could receive life sentences as part of changes coming into force this week.
Judges will be able to hand down life sentences to dangerous drivers who kill and careless drivers who kill while under the influence of drink or drugs.
The current penalty for each crime is a maximum prison sentence of 14 years.
"Those responsible will now face the possibility of life behind bars," Justice Secretary Dominic Raab said.
The changes come into force as part of the Police, Crime, Sentencing and Courts Act.
The new legislation will also create an offence of causing serious injury by careless driving, meaning those who inflict long-term or permanent injuries also face tougher sentences.
The proposed law change was first announced in 2017 and comes into effect on Tuesday.
The increase will apply to offences in England, Scotland and Wales, but not Northern Ireland, which has separate road safety laws.
Mr Raab added: "Too many lives have been lost to reckless behaviour behind the wheel, devastating families."
Steve Gooding, director of the RAC Foundation, said: "Drivers exhibiting the worst behaviour on the roads are a danger to us all.
"Those who behave with disregard to the risk they pose deserve the stiffest penalties when their actions rob others of their lives."
Mr Gooding said he hoped the threat of a life sentence will be enough to cause those who drive recklessly to change their ways, the Sunday Express reported.
"Involuntary manslaughter already carries a maximum penalty of up to life imprisonment so it is hard to argue that killing someone with a car doesn't warrant a possible sanction of similar severity," he said.
The government said it wants to ensure "punishments reflect the severity of crimes and the misery killer drivers leave in their wake".
It said the Crown Prosecution Service will still charge people with murder or manslaughter where there is evidence that a vehicle was used as a weapon to kill or commit grievous bodily harm.