The problem is with the basic data.
The main database for the UK is a single database which relies hevily on the OS system.
The OS System has a number of road types... before you ad the byways, BOATs etc
However when the data is used for SatNav use then these are greatly simpified.
Minor roads, tracks, drives and some BOATS are given the same value and this is used as part of the algorithm to calculate the route.
For this reason you may think that you are on a 4 m wide road, when it is in fact a narrow track
The trick is to realise that like any computer it is not foolproof and use it with caution
The main database for the UK is a single database which relies hevily on the OS system.
The OS System has a number of road types... before you ad the byways, BOATs etc
However when the data is used for SatNav use then these are greatly simpified.
Minor roads, tracks, drives and some BOATS are given the same value and this is used as part of the algorithm to calculate the route.
For this reason you may think that you are on a 4 m wide road, when it is in fact a narrow track
The trick is to realise that like any computer it is not foolproof and use it with caution