Smart Motorway gantry sign
A gantry structure spanning the motorway with electronic signals, blue signs showing the left two lanes exiting and the other two continuing ahead, and the following text.
Left-hand two lanes destinations: M4w SOUTH WALES [Hollow square diversion symbol]; Chepstow (M48) .
Right-hand two lanes destinations: London; Bristol (M32) M4e .
Change Route: M4 SOUTH WALES or M4 London
Three lanes divide into two sliproads, one for the east and one for the west. Where will you go?