With fewer people dying on the roads than at any time since records began in 1926, it may be difficult to understand why the Government is taking a harder line with those who speed or drive carelessly.

The answer may be that the measures proposed yesterday were mooted by the Department for Transport in 2004, when road deaths appeared stuck at about 3,400 a year. Since then the toll has declined to just under 3,000 in 2007 and is on course to fall below 2,700 this year.

The trend is clearly in the right direction but ministers appear determined to make more improvements and have discussed privately a target for 2020 of fewer than 2,000 deaths.

Several studies have shown that a 1 per cent reduction in average speed produces a 3 to 6 per cent fall in collisions.

The existing penalty-point system is only partly successful at making drivers slow down. Drivers who already have one three-point penalty are no less likely to be caught speeding than drivers with clean licences. But drivers with six points appear to change their ways and are only half as likely to be caught again.

The DfT says that a six-point fixed penalty for those caught at least 15mph over the limit “will effectively target excessive speeders and move them more quickly to the 6-9 point threshold, where the evidence shows they will slow down”.

The question remains whether campaigning against speeding is the best way to reduce crashes.

Jim Fitzpatrick, the Road Safety Minister, said yesterday that speed was a factor in 29 per cent of fatal crashes last year, or 727 deaths.

But a closer look at the official figures reveals that fewer than 350 of those deaths involved a breach of the speed limit. The others were caused by motorists driving within the limit but too fast for the conditions.

Such drivers will not be caught by speed cameras, only by traffic officers. The Government's proposal to make careless driving punishable by a fixed penalty may be much more effective at saving lives than issuing more points for speeding.

On the question of reducing the drink-driving limit, the Government claimed yesterday to have a “completely open mind”. But last year ministers said that they were minded to reduce the limit from 80mg to 50mg, which would have put drivers at risk of prosecution after just one drink.

A study by University College London has found that a lower limit would save 60 lives a year. The DfT's road safety advertising campaigns say that motorists should not drink at all before driving. Yet the Government appears reluctant to give that message legal reinforcement.