The three new baton types, made from synthetic materials, are 26, 24 and 20 inches (65, 60 and 50cm) long, compared with the standard 15-inch (37.5cm) hardwood truncheon currently in use.
In each of the four police divisions taking part in the trials, 50 male and female officers have been chosen to be extensively trained to use the batons.
The officer in charge of the trials, Detective Superintendent Bill Grahamslaw, said the training emphasised the defensive use of the baton, with officers taught to heighten their awareness and to recognise threatening and aggressive situations earlier. He said the police force would consider the views of the public before a final decision was made.
The batons on trial are an aluminium and polycarbonate model which extends from 12 to 24 inches; a 26-inch rubber-covered rattan baton, similar to that favoured by some Eastern forces; and a 20-inch solid polycarbonate baton already used by Dorset police.
Last year, Kenneth Clarke, then Home Secretary, said the 24-inch US side-handled baton, as used in the Rodney King assault in Los Angeles, was not in keeping with the image of the British police and angered police by halting trials.
But his successor, Michael Howard, has given authority for laboratory tests to be conducted on an expandable version of the side-handled baton, which extends from 13 to 24 inches. If approved, it is also likely to be given operational trials.