When a driving journey begins or ends away from a road, we 'snap' to the nearest node on the road network.
The snapping.penalty parameter can be configured to control whether the time taken for this snapping to take place should be included in the overall journey time:
When enabled (as is the default), the walking time and distance from the departure location to the nearest road, and from the nearest road to the arrival location, are added to the total travel time and distance of a journey.
When disabled, these walking times and distances are not added to the total reported values (i.e the journey effectively starts and ends at the nearest points on the road network).
Other mapping providers (such as Google Maps) don't typically include a snapping penalty.
The default maximum snapping distance is 1km - locations further away than this from the nearest point in the road network will be marked as Unreachable.
If you want to increase the maximum snapping distance, this can be configured using the snapping.threshold parameter.