TomTom not returning drivetime distance for all datapoints

Question

Hey

I am trying to calculate the distance from every SA3 in Australia to nearest Target sites. There are total 340 SA3 names.
I had set the max mins to be 4000.

I am using TomTom to run the drivetime calculation.

1st run - 35 out of 340 SA3s resulted to NULL (that means none of our target sites fall within 4000 drivetime mins)
2nd attempt- i ran only for those 35 null SA3s with the same 4000 mins drivetime threshold - where 16 out of 35 SA3s resulted to Null (So i was able to get 19 more results when i ran the subset)

Is there a fix for it? Or am i doing anything wrong?

I have attached the Distance Tool configuration in the screenshot.

Thanks!

Distance tool.png

RAZOR2525 · Answer

SA3 is quite a large area to run a drivetime from. Are you running it from an SA3 polygon file or an SA3 centroid point file.

Are the SA3s in question in remote areas?

If your SA3 points are not on a road then the drive time module assumes a really slow speed like 8kmh until it reaches the nearest road.

So you can either increase your minutes threshold or you can manually move the SA3 points on to a road an re-run.

Incidentally, how do you find the Tom-Tom drivetimes? Are they fixed drivetimes or live? Do they have them for NZ do you know?

I'm currently using Experian drive times