Safety first
Safety first
If a tyre fails and the car can still be driven safely, get it off the road into a side road, a lay-by or a car park. A lay-by on a fast road is a place to stop safely, not somewhere we can work; we come to the car once it is on a side street or in a car park. On a busy road or dual carriageway, do not try to change the wheel yourself; call your breakdown cover, or 999 if the car is somewhere dangerous. We never work on the carriageway of a motorway or main road, on a hard shoulder, in a smart motorway emergency area or on a slip road.
None of the road has a hard shoulder, from Finchley Road, Hendon Way and Watford Way in London, through the Watford, Kings Langley, Hemel Hempstead, Berkhamsted, Tring and Aston Clinton bypasses, to the single carriageway from Aylesbury to Bicester.
Transport for London runs Finchley Road, Hendon Way and Watford Way as red routes with no stopping on the carriageway, and Edgware Way through Stanmore has clearway restrictions. Outside London the county highway authorities look after the road. We cannot stop or work on a red route; the car needs to be on a side street or private ground first.
The road's junction list and the full Highway Code steps are on its main page, under Related pages below.