A 'lay-by' is a widening of the road for a short distance to provide an area where a vehicle can stop and the regular traffic can continue.
For example, see here
Don't forget we drive on the LEFT of the road.
And I have a thought that the little b* who sneaked is going to be in trouble; for being a sneak.
[sneak - a tell-tale, one of tittle tattle, spreader of rumour and tales. ]