A row of parked cars may look like a quiet edge of the road, yet a door can swing into a cyclist’s path. The space to think about is therefore wider than the car body itself: it includes the area an open door would occupy. Cycling UK advises riding at least a door’s width away from parked vehicles, rather than close to their sides.
As you approach, first check behind to make sure moving farther from the kerb is safe. Then choose a steady line that other road users can understand. Repeatedly moving into every gap between parked cars and out again creates extra sideways manoeuvres. If there is not enough room to pass with a useful gap, slowing down and waiting for a better opportunity may be the safer choice.
A vehicle that has just parked, an interior light or a person visible inside may give clues, but none guarantees that a door will remain closed. Drivers and passengers have a part to play too: they should look back before opening a door. The Dutch Reach uses the hand farther from the door to open it, encouraging the body to turn and the eyes to check behind. That small habit and the space left by a cyclist work together.