Officers installed special monitoring equipment on Fakenham's Norwich Street between August 16 and 29.
The device was set up to monitor drivers' speeds after complaints from a trader that the 20mph limit was not being observed.
Police say 22,421 vehicles' speed was measured during the two weeks when the device was operational.
Of these, 22,105 were driving within the limit of 24mph - a compliance level of 98.6pc.
Norfolk police said: 'We consider 90pc to be an acceptable level of compliance so this is a very low proportion of drivers to be over the limit.'
Some 316 vehicles were over the 'compliance limit' (24mph), while nine of these drivers were doing over 31mph.
Average speeds per hour during the course of a day ranged from 19.2 to 23mph.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here