reason for A303 absence from Google sat nav?

[bluedonkey]

I often look at the recommended driving route from London to South Devon using Google maps. For years there would normally be two options flagged up, M4/M5 or M3/A303. Now the A303 route never seems to be shown as an option, though occasionally one much further south appears (M3/M27/New Forest). I've tried at different times, different days, so it can't be due to "current" traffic conditions. Does anyone know if the algorithm has changed so that A303 is excluded?

[AJC5001]

I often look at the recommended driving route from London to South Devon using Google maps. For years there would normally be two options flagged up, M4/M5 or M3/A303. Now the A303 route never seems to be shown as an option, though occasionally one much further south appears (M3/M27/New Forest). I've tried at different times, different days, so it can't be due to "current" traffic conditions. Does anyone know if the algorithm has changed so that A303 is excluded?

London to Barnstaple shows it https://www.google.co.uk/maps/dir/London/Barnstaple/@51.2284038,-3.4119562,8z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x47d8a00baf21de75:0x52963a5addd52a99!2m2!1d-0.1275862!2d51.5072178!1m5!1m1!1s0x486c24b330ce603b:0x9bf8c25a0eb44b38!2m2!1d-4.058338!2d51.0781599!3e0

London to Exeter does https://www.google.co.uk/maps/dir/London/Exeter/@51.131665,-3.1475744,7.99z/data=!4m15!4m14!1m5!1m1!1s0x47d8a00baf21de75:0x52963a5addd52a99!2m2!1d-0.1275862!2d51.5072178!1m5!1m1!1s0x486c52c4d4498da7:0xa976e3256bdfad1e!2m2!1d-3.5274889!2d50.7260367!3e0!5i2

London to Plymouth doesn't https://www.google.co.uk/maps/dir/London/Plymouth/@50.956383,-3.4544204,8z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x47d8a00baf21de75:0x52963a5addd52a99!2m2!1d-0.1275862!2d51.5072178!1m5!1m1!1s0x486c8d530e95ea3d:0x3b282cb5cef58593!2m2!1d-4.1426565!2d50.3754565!3e0

No idea why.

Adrian

[DrFfybes]

I don't know about the A303 specifically, but I have noticed that there has been some "skewing" of preferred roads.

For instance, whereas you used to get an option of going through the centre of many small places (eg Whitchurch) that option is gone and you are only directed around the ringroad. Yesterday we were sent quite a way around a village rather than along a 200 yard link over a small bridge to the A road - a road we took on the way back as I missed the first turning(!), and even then it didn't want me to go that way.

There is also some bias towards A5 M54 M5 M6 when heading from Shrewsbury down the M5, whereas we prefer the much shorter (although often a few min slower) A449/A442 through Kidderminster. Often even selecting somewhere along that route diverts you back on to their preferred route.

Another thing I think I've spotted is 'predicted traffic' (my phrase), where arrival time on longer journeys is based on historic data for sections of the route at the time you will arrive there. Perhaps this explains the insistance we stay on the M5 heading towards a huge queue or accident on the M6 some 30 min up the road.

Paul

[didds]

does it have an option of providing a "via" place eg instead of A to C, its A to to B to C ?

If so put a "via" in that would be logical for the A303 route and see what travel time it comes up with ... maybe its only showing the "quickest"/"shortest" three (or whatever) routes and the a303 route is 1 minute/1 mile longer than the shown ones?

This is purely conjecture of course!

[didds]

London to Plymouth doesn't https://www.google.co.uk/maps/dir/London/Plymouth/@50.956383,-3.4544204,8z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x47d8a00baf21de75:0x52963a5addd52a99!2m2!1d-0.1275862!2d51.5072178!1m5!1m1!1s0x486c8d530e95ea3d:0x3b282cb5cef58593!2m2!1d-4.1426565!2d50.3754565!3e0

No idea why.

Adrian

Using that link, at 23:50 hours the A303 route is shown, as a 221 miles, 4hr 15min journey. My guess is that at whatever time AJC5001 checked it just wasn't as quick as the other routes provided (?)

didds

[JohnB]

I had a sat nav that hated the A303. Exeter to Ascot sent you up the M5. For the first 80 miles it wanted to turn left, for another 80 it wanted to turn right. 10 miles out its proposed route was 70 miles long!

[tjh290633]

The other day I was going East along the Hogs Back, A31. Google Maps ignored the B-Road to Elstead and the B-Road to Compton, instead taking me in about a 5 mile double back to get me to the other side of the A31. I find it helps to make it change its mind by taking what you know to be a better route.

It seems that one minute makes it rule out a shorter route.

TJH

[didds]

It seems that one minute makes it rule out a shorter route.

yes, indeed.

depending on the sat nav you may be able to set it to shortest route, rather than fastest. maybe what one really needs is a "fastest per mile" setting so a shorter route with a longer journey time may be selected above a quicker but far longer route!

[9873210]

depending on the sat nav you may be able to set it to shortest route, rather than fastest. maybe what one really needs is a "fastest per mile" setting so a shorter route with a longer journey time may be selected above a quicker but far longer route!

I want a sat nav that pays at least some attention to the standard deviation and skew. "14 to 57 minutes" is not a particularly useful estimate when I have to be somewhere on time. OTOH for some trips I don't care when I arrive, and the average or typical time is more important than the best or worst case. FWIW most sat navs I've used seem to sort by worst case.

[AF62]

I don't know about the A303 specifically, but I have noticed that there has been some "skewing" of preferred roads.

For instance, whereas you used to get an option of going through the centre of many small places (eg Whitchurch) that option is gone and you are only directed around the ringroad.

Various pressure groups have been complaining about sat navs directing traffic through ‘rat run’ routes, so it is possible that Google has tweaked its algorithm accordingly to keep traffic on more main roads unless things are very congested.

Personally I find Waze (also owned by Google) to provide more ‘aggressive’ routing than Google maps, and it does continue to take short cuts if it saves time.

[DrFfybes]

We were using Google maps yesterday to get from Donington Park the Shrewsbury, and back.

The options were M6 Toll, or some circuitous routes either around the bottom of Brum through some roadworks (25 min longer) or North via Stafford (20 min longer).

Selecting "Avoid tolls" then gave us the A5 route, which runs parallel to the M6 toll, and was 10 minutes slower (and £8 cheaper). However with toll roads permitted it refused to give us this route, even when selecting a viaactually on the A5 it still preferred us to use the toll for part of the journey.

Paul