Complex sentence: The M4 bus lane is a bus lane on the eastbound (London-bound) carriageway of the M4 motorway between Heathrow Airport and central London from junction 3 (A312) to the start of the elevated 2-lane section near Brentford.
Split into simpler sentences: The M4 bus lane is a bus lane on the eastbound (London-bound) carriageway of the M4 motorway between Heathrow Airport and central London. It operates between junction 3 (A312) to the start of the elevated 2-lane section near Brentford.