No, they are not
In fact the college of policing list section 163 stops under 'Powers akin to stop and search'.
You can stop a vehicle on a whim, but that won't stand up in court under examination. Any lawyer will tell you that the first question a judge is going to ask is 'why did you stop this vehicle', if the answer is 'because it was there' the rest of the hearing will go very poorly for the police, notwithstanding section 163 powers (which incidentally officers are told very clearly not to use in their training materials).
They're also reminded as follows:-
HM Inspectorate of Constabulary recommendation 6:
The College of Policing should make sure that the relevant authorised professional practice include instruction and guidance about how officers should use the Road Traffic Act 1988 power to stop motor vehicles and the Police Reform Act 2002 powers to search for and seize alcohol and tobacco from young people in a way that is effective and fair.
HMIC (2015) Stop and search powers 2: are the police using them effectively and fairly?
Which is a big red flag in policing terms.
Vehicle stops under section 163 of the Road Traffic Act 1988
Section 163 RTA states that a person driving a mechanically propelled vehicle on a road must stop if required to do so by a constable. Not to do so is an offence. There are no procedural requirements for the stop and there is no associated search power.
The officer can ask the driver for their licence and ask the driver and passengers questions, in effect a stop and account. The officer may only search the vehicle or persons in it if one of the stop and search powers applies in the circumstances, eg, if there is intelligence giving reasonable grounds to suspect that drugs or a weapon are being carried in the vehicle. If no power applies, no search can take place.
Although the officer does not need to have any particular reason to stop the vehicle and there is no obligation to explain why the vehicle has been stopped, explaining why the officer decided to stop the vehicle – in line with a procedural justice approach – is likely to improve the quality of the encounter and how it is perceived by the person stopped4.
In addition, officers are subject to the public sector equality duty under section 149 of the Equality Act 2010. In the exercise of their functions, the officer must have due regard to the need to eliminate unlawful discrimination, harassment and victimisation. They are therefore not permitted to stop a vehicle solely based on relevant protected characteristics, including the race, age or religious dress of the driver or passengers.