In the UK parking enforcement is usually by lines and signs displayed in streets.
Why do I stress lines and signs? It's because you can not have indications which implement a parking restriction without lines suggesting which part of the street the parking limitations affect. This may maybe appear simplified but if you think of let us say a no waiting sign the indication will define the times or days or in some cases month of the year - however how do drivers determine to what span of the road the prohibition applies?
A single yellow line suggests that there is a parking restriction but that is not developed for 24/7. As an outcome so regarding understand exactly what the actual restriction is there need to be indications showing the times and days that the restriction applies. These indications, frequently referred to as repeater signs, need to be sited every 60 metres along the length of the pavement (pathway in the U.S.A) for the extent of the single yellow line constraint to which it applies. As you can appreciate there are locations where a single continuous yellow line would stretch for a considerable range so there is a lawful dispensation under which those indications are not required.
This concession allows a regional authority not to have repeater indications if there are indications, called Controlled Parking Zone indications, at the access to each street going into the zone where single yellow lines are painted. Such regulated parking zone indications should particularly specify the restriction that applies to all single yellow lines in the zone.
Likewise the restrictions on packing need to be accompanied by a sign and in this case kerb markings. These kerb markings are periodically called chevrons otherwise "blips". A single yellow kerb mark suggests that there is a loading restriction but it does not in alone designate the days and times of that limitation only that it will not use 24/7. For that reason it needs to be accompanied by a sign offering the details connecting to the limitation.
Double kerb marks kerb marks specify that there is no packing 24/7 and in spite of the truth that this is an overall restriction an indication showing that restriction is obligatory to be placed beside the kerb marking.
A double yellow line in a street indicates that there is a total 24/7 restriction on parking (technically it's waiting instead of parking however everyone understands and uses the word parking). In this circumstances there is no requirement to have car park barriers an indication revealing that there is a 24/7 constraint.
So to summarize for all with the exception of double yellow lines there need to be signs so the law remains in these scenarios is: sign however no lines your parking ticket is not enforceable - lines however no indications your parking ticket is ticket can not be enforced.
Along with yellow lines parking bays have restrictions - they are either exclusively planned for citizens to park or for the general public at large and even in some cases a multi-purpose bay which can be used by both citizens and any driver Equally there are parking bays which are restricted to specific drivers - e.g. for handicapped motorists or are restricted for particular purposes - for instance filling only.
The universal feature of all these bays is that they must have an indication to indicate the sort of constraint e.g. is it for citizens, handicapped drivers or filling just. In addition such indications are needed to show the times and days that their use is limited. When again the law is if there are lines specifying the parking bay then there has to be a sign showing the nature of the prohibitions. Therefore if there is no sign any parking ticket chauffeurs collect can not be imposed and you should appeal.