Firstly, check to see whether the area of road is actually part of your lot or still crown reserve. This may change the outcome. Given you've stated that the right of access was granted by your lot, I'm going to assume the land has been amalgamated into your lot.
When I said it depends on the terms of the right of access, to grant an easement a document must be registered which links the two lots: yours as the 'burdened' lot (called the 'servient tenement') and theirs as the benefited lot (called the dominant tenement). The grant does not give total rights to the use of the defined area to the dominant tenement. It only gives the rights stated in the grant document, and those are given subject to any conditions. For example:
- Granting the right of access between the lot and the roadway does not automatically allow the parking of vehicles on the easement;
- A right of access doesn't allow storage of items or building of structures - but it often does allow the construction of roadway;
- A right of access could be just for pedestrian traffic, which would mean motorised vehicles can't be used; or
- It could have limited hours or days for use (unlikely in this case, especially if it is the only means of access).
In terms of liability for accident and damage, that's a whole other issue. From your point of view, I'd be seeing whether the easement requires you to provide/maintain a roadway. If so, it best be to the standard required by the easement or you may wear some liability. Onwards from there, it's not my area of expertise so you'd be best off getting some comments from someone else.