BAD manners are a bigger cause of road rage than bad driving, according to research among motorists carried out by a professor of psychology.

Being tailgated or cut up by road hogs were the kind of experiences most likely to provoke anger in other drivers - more so than traffic jams or encountering the police.

The findings come from ''audio diaries'' provided by 100 drivers who were issued with cassette recorders by Professor Geoffrey Underwood, a psychologist at Nottingham University, who said that if drivers adopted better manners, road rage could be eradicated.

Ranging from verbal or gesticulatory abuse to dangerous driving which forces others to pull over and leave the road, rage is a common phenomenon on British roads.

A 1995 survey by the AA found that 90% of motorists questioned had experienced road rage incidents in the previous year.

Mr Underwood and his colleagues - backed by the Economic and Social Research Council - examined audio diaries compiled over two weeks by drivers aged between 17 and 42, and almost equally divided between male and female.

Each was also assessed on a driver anger scale, which listed six potentially anger-provoking driving situations.

Top of the list was discourtesy, followed by hostile gestures, slow driving, illegal driving, and traffic obstructions, with police presence the least anger-provoking of the six.

Drivers also completed a driver behaviour questionnaire to discover how often they admitted to committing driving slips, mistakes, and violations - and a social motivation scale, which asked questions about attitudes to mild cheating.

The drivers reported 292 near accidents and 385 occasions when they experienced anger. Where anger was directly associated with a ''near miss'', in 109 out of 110 cases anger followed as a direct result, rather than prior to the incident.

Specific types of near accident were more likely to provoke anger than others, in particular where the reporting driver considered themselves not at fault. Anger levels also rose with traffic levels.

''Perhaps drivers need to be made more aware of the potential impact on other roads users of discourteous behaviour, such as driving on other people's bumpers or cutting in on other drivers,'' said Mr Underwood. ''Campaigns aimed at more courteous driving practice could make a significant difference.''