Tom Tom UK Speed Limit

[The Red Baron]

For ages now we've been wondering why we manage to makeup so much time when using shortest route on our Tom Tom.
Sticking to the speed limits we still manage to reduce our travelling time by 20 to 30%.

We wondered why that didn't occur on Motorways?

Whilst tinkering with the Tom Tom this evening, planning our next route through Europe we ran a demo.
We found on the UK section, it assumed 51 mph on single and dual carriageways BUT 75mph on motorways (the same as in Europe)

So think carefully when your planning your next trip using the Tom Tom ,the quickest route is not always the quickest, as it assumes your going to break the speed limit if using the motorway.

[Minnie Mouse]

I nearly always set mine to avoid motorways.....seems that is very often the fastest route seeing as I normally have to use the dreaded M25

[R99]

Strange...

I have a TomTom 910 and when I stray over 73mph it flashes red at me to tell me I'm speeding. Which is handy, but can be annoying sometimes because it makes you feel bad when making progress, .

Which model do you have? Just wandering why mine doesn't seem to do this...

James.

[The Red Baron]

Quote: Originally Posted by Minnie Mouse (original)

I nearly always set mine to avoid motorways.....seems that is very often the fastest route seeing as I normally have to use the dreaded M25

I know how you feel
We'll normally do anything to avoid motorways these days especially the M25 and the M1.

But by setting shortest route we've found some great fast roads that all traffic seems to avoid, presumabably because every one elses sat-nav has put them on a blocked motorway.

[The Red Baron]

Quote: Originally Posted by R99 (original)

Strange...

I have a TomTom 910 and when I stray over 73mph it flashes red at me to tell me I'm speeding. Which is handy, but can be annoying sometimes because it makes you feel bad when making progress, .

Which model do you have? Just wandering why mine doesn't seem to do this...

James.

We've got the old 700 model, but have added plenty of the new upgrades.

[CFCZeek]

It bases average speeds on YOUR average speed on that type of road...:-)

[Minnie Mouse]

Quote: Originally Posted by CFCZeek (original)

It bases average speeds on YOUR average speed on that type of road...:-)

How can it do that if it tells you the ETA before you have even set off?

[CFCZeek]

Quote: Originally Posted by Minnie Mouse (original)

How can it do that if it tells you the ETA before you have even set off?

eh? If it is brand new out of the box, it will use the averages, but if you start driving on motorways at 100mph average speed on your journeys, it will use this to calculate future journey times, rather than give you a crap estimate...The software just uses a running average to calculate against over time.

[The Red Baron]

Quote: Originally Posted by CFCZeek (original)

It bases average speeds on YOUR average speed on that type of road...:-)

Jax is a bit of a mathematical genius in this department !

She advises that they collect the data from the sat navs these days to enable them to evaluate the average speed for the type of road. This is applied to all their data, not the individuals driving style.

This data is then used to calculate a time for each section of road, based on the speed and the distance between any two given points.

Example If traveling along a straight road with two turnings off it, the sat nav will allocate a time to travel between each of the junctions (not the road as a whole). This is how it recalculates when you make a wrong turn.

So if you have a road wih a turning at half a mile and your turning at one mile (if you apply 60mph) it would asign a 30 second time for the first section and then a further 30 seconds for the next section.

[Minnie Mouse]

Flippin' Norah......CFCZeek and Jax are far too clever for me!

I'm confused already!

[The Red Baron]

It's gets even more complicated....

The sat nav also assigns a stopping time when aproaching any junction (give way etc). It looks at the speed for the assigned piece of road works out an appropriate stopping distance and the time required to stop completely.

Watch next time your approaching a roundabout. If its from a reasonably fast road (ie dual carriageway) and the routes clear so you can go, you make time up!

[CFCZeek]

Quote: Originally Posted by chrisandjax (original)

She advises that they collect the data from the sat navs these days to enable them to evaluate the average speed for the type of road. This is applied to all their data, not the individuals driving style.

To begin with yes, but if you set a journey which is solely 75 miles of motorway, and set off now, it will set an ETA an hour from now. If you sit in the left lane of that motorway and do 20mph (please don't!) the ETA will change sharpish!

[Harpo]

Quote: Originally Posted by Minnie Mouse (original)

...I'm confused already!

I'm impressed. I generally get to my destination ahead of the ETA.

At the moment anyway.

[Minnie Mouse]

Quote: Originally Posted by chrisandjax (original)

It's gets even more complicated....

Enough already!

Quote: Originally Posted by Harpo (original)

I'm impressed. I generally get to my destination ahead of the ETA.

At the moment anyway.

Paul how can you be impressed with me being confused?

[The Red Baron]

Quote: Originally Posted by CFCZeek (original)

To begin with yes, but if you set a journey which is solely 75 miles of motorway, and set off now, it will set an ETA an hour from now. If you sit in the left lane of that motorway and do 20mph (please don't!) the ETA will change sharpish!

Of course it will but not in the way your thinking..

Example:

If your traveling along a 10mile section of road at 60mph (set of at 8am) your ETA wll be 8.10am
However if after 1min you break down it assess that you've still got 9 miles to go or 9mins in this case, and for every minute your sat there you'll add a minute to your ETA.
Alternatively if i half my speed for the 1st mile to 30mph (the first mile will take 2minutes) and the sat nav calculates that the next 9 miles will only take 9 minutes giving me an ETA of 8.11am (ie i loose 1minute for every minute i half my speed).