Best proximity settings?

BlankSheep · Occasional Visitor Joined: Mar 14, 2006 Posts: 11

Okay, so when I started out, I tried the single speed cams file in my TTOne to get familiar with the setup. Then I moved on to the "by type" files and set up the proximity warnings/sounds. Then I started finding that while 200-300 yards proximity was fine for round town, at 70mph 300 yards wasn't enough. So now I'm using the whole bunch of "by speed" files and setting up larger proximity distances for higher speeds.

As a rule of thumb I'm setting a proximity of speed(in mph) X 10 = proximity distance (yards) so 30mph uses 300 yards, 70 mph uses 700 yards etc. However, it occurs to me that for some of the mobile sites the detection range of laser equipment can be a mile or more in good conditions (well before you see them!). Then with SPECS you just have to be careful between them.

What distances do you use for different types/speeds? any tips appreciated.

Thanks, BS

Border_Collie · Posted: Thu Aug 17, 2006 1:06 am Post subject:

Choose from the following whether you want a 30 second warning or less.

Mph - 30s - 20s - 15s - 10secs warning.

70 - 1173- 782 - 587 - 391 yards
60 - 1026- 684 - 513 - 342
50 - 879 - 586 - 440 - 293
40 - 732 - 488 - 366 - 244
30 - 588 - 392 - 294 - 196
20 - 441 - 294 - 221 - 147
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RDS · Regular Visitor Joined: Jul 09, 2006 Posts: 242

Are these distances correct ?

As it's the easiest use 60mph.

At 60mph a vehicle will take one minute to travel one mile or 1760 yards.
Therefore in 30 secs 880 yards will be travelled and in 15 secs 440 yards.

From there it is simple to calculate 30mph (distances halved) and so on.

Oldboy · Posted: Thu Aug 17, 2006 10:00 pm Post subject:

Border_Collie · Posted: Thu Aug 17, 2006 10:23 pm Post subject:

RDS · Regular Visitor Joined: Jul 09, 2006 Posts: 242

Fair enough.

I thought there'd be an obvious reason, although to be pedantic it might be worth always mentioning that you have included a margin of error in your recommendations.

Onto another related question.
It's acknowledged that most cars speedometers aren't accurate (I believe the legal requirement is to be within 10%) and Chief Police Officer guidelines allow for a 10% plus 2mph tolerance but how accurate are the speeds recorded by SatNav systems ?
I know both Garmin Nuvi's and TT x10 series include a speed indicator.

peterc10 · Posted: Fri Aug 18, 2006 10:00 am Post subject:

Very accurate (to within 0.1mph) as long as you are travelling at a constant speed and on a reasonably straight and level road. If you have cruise and a length of straight level motorway you can get a very good indication of how accurate your speedo is.

BTW speedos are allowed to read up to 10% too fast but cannot read too slow
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Border_Collie · Posted: Fri Aug 18, 2006 1:49 pm Post subject:

BlankSheep · Occasional Visitor Joined: Mar 14, 2006 Posts: 11

Just a quick thanks for the replies.
Any thoughts on the mobiles/laser range issue?

My old Renault used to indicate about 76mph for a "true" 70mph on the gps (both TTOne and Garmin GPSIII).
One reason for the speedometer tolerances could be to allow for the effects of tyre wear and inflation. If you are keen you can work out work out the indicated speed difference for a change in tread depth of, say 6mm. Actually, there is a nifty calculator at http://www.carbibles.com/tyre_bible.html

Cheers, BS

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