Using a mobile phone should also be thought an "aggravating factor" leading to stiff minimum sentences, courts have been told.
The Sentencing Advisory Panel, which advises judges in England and Wales, said judges should consider imprisoning every motorist who causes death by dangerous driving.
Falling asleep at the wheel - which until now has been considered a mitigating factor - should actually make the crime worse and lead to a longer sentence, the panel said.
2-5 YEAR JAIL SENTENCE RECOMMENDED FOR DRIVERS WHO KILL WHEN THEY
Panel chairman Professor Martin Wasik said: "Drivers do not normally fall asleep without warning.
"The proper course of action for a motorist who feels drowsy is to stop driving and rest.
"It should be regarded as an aggravating factor and we recommend should be sentenced with two to five years imprisonment."
Motorists who kill should face a short spell in jail for even a "momentary error of judgment" or a short period of bad driving, said the report.
THE SELBY TRAGEDY
The sentence should rise to between two and five years if there was an aggravating factor such as alcohol, drugs, racing, showing off, excessive speed, disregarding warnings from fellow passengers, falling asleep or being distracted by a mobile, it added.
If there were three or more aggravating features the sentence should rise to between five and 10 years.
At present there is no clear starting point for sentencing this offence, said Professor Wasik.
In the year 2000, about 15% of drivers convicted of causing death by dangerous driving actually escaped jail.
"This offence causes particular difficulty for sentencers," he said.
"On the one hand, an offence involving a person's death is always serious, and understandably leads to calls for severe sentences.
"On the other hand, an offender convicted of this offence did not deliberately cause death or serious injury.
"The standard of the offender's driving at the time of the offence should be the primary factor in determining the seriousness of an offence."
2000 STATISICS
But motoring groups questioned whether mandatory minimum sentences would make any difference.
"The UK legal system relies on the judiciary, when passing sentence, to take account of all factors relating to the offence, the consequences and the offender," said the RAC Foundation.
"In most cases of causing death by dangerous driving, this already leads to a custodial sentence."
The RAC Foundations called instead for a new offence of causing death by careless driving, which it said should solve any sentencing problems.