(1)Where a constable is for the time being engaged in the regulation of traffic in a road, a person driving or propelling a vehicle who neglects or refuses—
(a)to stop the vehicle, or
(b)to make it proceed in, or keep to, a particular line of traffic,
when directed to do so by the constable in the execution of his duty is guilty of an offence.
(2)Where—
(a)a traffic survey of any description is being carried out on or in the vicinity of a road, and
(b)a constable gives to a person driving or propelling a vehicle a direction—
(i)to stop the vehicle,
(ii)to make it proceed in, or keep to, a particular line of traffic, or
(iii)to proceed to a particular point on or near the road on which the vehicle is being driven or propelled,
being a direction given for the purposes of the survey (but not a direction requiring any person to provide any information for the purposes of a traffic survey),
the person is guilty of an offence if he neglects or refuses to comply with the direction.
(3)The power to give such a direction as is referred to in subsection (2) above for the purposes of a traffic survey shall be so exercised as not to cause any unreasonable delay to a person who indicates that he is unwilling to provide any information for the purposes of the survey.