I suppose the best place to go for such research is among university students, and that is just what Brunel University have done. Although the sample group tested was unusually small, the results were remarkably uniform. A poor night’s sleep, low blood sugar and dehydration all markedly affect the ability to drive safely even if someone is within the drink-drive limit, the study found.

Eleven students were tested on a driving simulator while sober and again while suffering a hangover, though within the legal limit of alcohol in the blood. The two tests were compared and it was found that, on average, hungover drivers drove almost 10mph faster, left their lane four times as often and committed double the number of traffic violations like ignoring red lights or stop signs. The average speed for the sober test was 32.6mph which rose to 41.7mph while hungover. Sober drivers travelled 6.3% of the five-mile trip above the speed limit which rose to 26% while hungover. Traffic violations rose from an average of 3.9 for sober drivers to 8.5 for hungover drivers. Several representatives of the motoring press, including the Telegraph and Independent, replicated the tests and their results were universally similar to the test group. The Mail’s Sharon Marshall found the results “horribly real. It’s clear I am in no fit state to drive The terrifying thing is I would have passed a breathalyser test.”

The research was sponsored by insurers RSA. Their spokesman, Graham Johnston, said “What surprised us was that people were driving faster. The fact they were driving more erratically we’d expect. Not taking care, going through red lights, that’s more alarming.” He added “You may be legal, but be aware that anything that makes the driver less alert will make them a worse driver.” The message comes through loud and clear; driving the morning after is not a good thing to do.

That is a shame, because the outcome of the debate is quite literally a matter of life and death, particularly as the government has decided against reducing the legal limit for alcohol in a driver’s blood. This is despite suggestions it could save 65 lives a year. The government had previously planned to cut the limit from 80 to 50 milligrams of alcohol per 100 millilitres of blood. Cutting the limit to 50 milligrams – equivalent to about half a pint of beer – would put drivers at risk of prosecution after just one drink, and bring them in line with Europe. But Road Safety Minister Jim Fitzpatrick has now said that the consultation document on plans to reduce drink-driving, to be published this month, will not recommend the reduction. According to ‘The Times’, he said “we are not convinced that dropping to 50 is the right answer. Drivers who are between 50 and 80mg are not the ones we’re most worried about. It’s the ones above 100.” He said his focus would now be on better enforcing the existing limit. Police could be given new powers to stop and test drivers at random rather than needing to suspect an offence is being committed.

Road safety campaigners have accused the Government of backtracking. The proposed reduction had been supported by the Association of Chief Police Officers and the Royal Society for the Prevention of Accidents. Andrew Howard, head of road safety at the AA, said that the motoring organisation used to oppose any lowering of the limit but had changed its position recently. The BMA’s Head of Science and Ethics, Dr Vivienne Nathanson, told BBC News that the BMA believed a reduction in the drink-drive limit would prevent deaths and reduce the number of lives ruined by drinking drivers. “There is clear evidence of the link between rising blood alcohol concentrations and dangerous driving behaviour,” and she added that a new impetus was needed to reduce the toll of injury and death.

Ben Webster, writing in ‘The Times’, suggests that “by leaving the alcohol limit unchanged, the Government will avoid the awkward question of whether to introduce a lower penalty for registering just over 50mg. At present, anyone caught drink-driving serves a minimum ban of 12 months. Most countries that have lower limits only fine drivers and give them penalty points for minor breaches.”

Causing death by careless, or inconsiderate, driving
A person who causes the death of another person by driving a mechanically propelled vehicle on a road or other public place without due care and attention, or without reasonable consideration for other persons using the road or place, is guilty of an offence.

Enabling Provision: s.2B Road Traffic Act 1988, inserted by s.20 Road Safety Act 2006
Triable Status: Either way
Max. Sentence on Indictment: 5 years or a fine or both
Max. Sentence Summary: 12 months or statutory maximum fine or both
Both ways: Obligatory disqualification; obligatory endorsement; 3-11 penalty points.

Causing death by driving: unlicensed, disqualified or uninsured drivers
A person is guilty of an offence under this section if he causes the death of another person by driving a motor vehicle on a road and, at the time when he is driving, the circumstances are such that he is committing an offence under—
(a) section 87(1) of this Act (driving otherwise than in accordance with a licence),
(b) section 103(1)(b) of this Act (driving while disqualified), or
(c) section 143 of this Act (using motor vehicle while uninsured or unsecured against third party risks).

Enabling Provision: s.3ZB Road Traffic Act 1988, inserted by s.21 Road Safety Act 2006
Triable Status: Either way
Max. Sentence on Indictment: 2 years or a fine or both
Max. Sentence Summary: 12 months or statutory maximum fine or both
Both ways: Obligatory disqualification; obligatory endorsement; 3-11 penalty points.

(See Criminal Offences Handbook, 4th edition, pp 329/330 (available from Anya Designs Ltd))