The M2 starts west of Strood, Kent at Three Crutches, diverging southeastwards from the A2 road that heads ESE from Central London, one of five roads of dual carriageway width or greater reaching into the southern half of Greater London. From Junction 1 it has four lanes each way that slope into the Medway Valley south of Rochester. On the west bank of the River Medway is Junction 2 intersecting the A228 between Strood and West Malling, a junction where the master exit roundabout passes under the HS1 track and which retains, by footbridge and tunnel, the North Downs Way (a public footpath).