Does the driving direction have an impact on distances?

[Bernd Welter]

Hi there,

every once in a while customers wonder about the difference of distances depending on the relations direction.
In other words:

• Why is the distance(A:B) not always equal to distance(B:A)?
• Why is a distance matrix not symmetric?

The core answer to these questions is simple but requires more details:
The geometry of the routes is not the same, e.g. other roads are used.

Route from Stuttgart to Madrid and back.
In the region of Lyon the router takes different superregional tracks

Of course the next question is then "why does the router not use the same streets?"

And then it comes to speed values and optimization. Here's another example:

DIR	Distance	Period	COST	Track
N to S	206070	7194	101666	WEST
N to S +	186209	7733	102025	EAST
S to N	184261	7786	102031	EAST
S to N +	204647	7370	102765	WEST

So sometimes adding waypoints creates better distances and worsens the period. If the route is focused on period the +ROUTE is not better then.

Best regards,
Bernd

[Bernd Welter]

"Frankfurt Abflugbogen" (Frankfurt Airport: Departure) to "Frankfurt Ankunftbogen" (Frankfurt Airpoirt, Arrivals)

Absolute difference is not that big but from a relative perspective it is enormous:
1.200m versus 86m