Time to destination - based on assumptions or speed?
#1
Time to destination - based on assumptions or speed?
Anyone know if the 09 TL's nav unit calculates the time to your destination based on your speed and speed limits? My Maxima had a setting where you said "highway speeds are x mph", "residential streets are y mph" and it would use those static numbers in calculating when you'd arrive. It was really not that accurate since traffic could be an issue.
I think some of the TomTom's actually use your speed and the speed limits of the roads (if known) to constantly recalculate when you'll arrive making it much more accurate.
Any ideas how the TL works?
Jared
I think some of the TomTom's actually use your speed and the speed limits of the roads (if known) to constantly recalculate when you'll arrive making it much more accurate.
Any ideas how the TL works?
Jared
#2
Anyone know if the 09 TL's nav unit calculates the time to your destination based on your speed and speed limits? My Maxima had a setting where you said "highway speeds are x mph", "residential streets are y mph" and it would use those static numbers in calculating when you'd arrive. It was really not that accurate since traffic could be an issue.
I think some of the TomTom's actually use your speed and the speed limits of the roads (if known) to constantly recalculate when you'll arrive making it much more accurate.
Any ideas how the TL works?
Jared
I think some of the TomTom's actually use your speed and the speed limits of the roads (if known) to constantly recalculate when you'll arrive making it much more accurate.
Any ideas how the TL works?
Jared
#3
The destination is based on miles driven. Say if you are stuck in traffic, and your speed is 10mph, it will calculate as if you will drive 10mph all the way but as soon as you start moving again and say do 50mph, the Navi will now show you the time to destination at that speed all the way. Mine is usually accurate -5 minutes or I usually get there 5 minutes earlier than indicated on dash.
#4
The destination is based on miles driven. Say if you are stuck in traffic, and your speed is 10mph, it will calculate as if you will drive 10mph all the way but as soon as you start moving again and say do 50mph, the Navi will now show you the time to destination at that speed all the way. Mine is usually accurate -5 minutes or I usually get there 5 minutes earlier than indicated on dash.
For example, if you are traveling 20 miles, 10 of those miles are at 20mph and 10 of those miles are at 40mph it will use this formula
10 miles @ 20 miles per hour = 1/2 hour or 30 minutes
10 miles @ 40 miles per hour = 1/4 hour or 15 minutes.
Total trip = 45 minutes.
Alternatively there may be a route to the same destination that is 30 miles but you're on highway most of the way
30 miles @ 60 miles per hour = 3/6 hour or 30 minutes
Total trip = 30 minutes.
So the Nav system picks the second option because it's faster.
If you leave at 12pm you should arrive at 12:30pm.
However if you instantly get stuck in traffic for 8 minutes you will notice that the time to arrival is still 30 minutes, but it's now 12:08pm so your arrival time is now 12:38pm. If it took into account your current speed (say 3 mph) it would recalculate your time as
30 miles @ 3 miles per hour = 30/3 hour or 10 hours. I've never seen the system increase my destination time (though with up to date traffic it's certainly possible)
So the problem is that traffic**, stop lights, actually speed are generally not taken into account (at least on the Eclipse system). The great thing about the Eclipse (and I guess the Maxima) system is you can adjust the mph for different roads. I remember adjusting residential streets and main roads down 10mph from default and increasing hwy to 65mph which gave me a much more accurate reading.
**unless you have accurate traffic warnings and reroute traffic selected.
#6
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Somewhat related:
This oddity is in the 3G Navi; not sure about the 4G:
When searching/selecitng a destination using the "Sort by Distance" option, the POI's are sorted based on Straight-Line distance (i.e. as the Crow flies).
BUT the route is based on road distance.
In some rare/odd cases, you can choose a store/POI that is, say, 5 miles in the selection list, but the route is, say, 15 miles.
This oddity is in the 3G Navi; not sure about the 4G:
When searching/selecitng a destination using the "Sort by Distance" option, the POI's are sorted based on Straight-Line distance (i.e. as the Crow flies).
BUT the route is based on road distance.
In some rare/odd cases, you can choose a store/POI that is, say, 5 miles in the selection list, but the route is, say, 15 miles.
#7
Somewhat related:
This oddity is in the 3G Navi; not sure about the 4G:
When searching/selecitng a destination using the "Sort by Distance" option, the POI's are sorted based on Straight-Line distance (i.e. as the Crow flies).
BUT the route is based on road distance.
In some rare/odd cases, you can choose a store/POI that is, say, 5 miles in the selection list, but the route is, say, 15 miles.
This oddity is in the 3G Navi; not sure about the 4G:
When searching/selecitng a destination using the "Sort by Distance" option, the POI's are sorted based on Straight-Line distance (i.e. as the Crow flies).
BUT the route is based on road distance.
In some rare/odd cases, you can choose a store/POI that is, say, 5 miles in the selection list, but the route is, say, 15 miles.
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#9
So I decided to open the navigation PDF.
"When you select a destination, the
distance to the destination is the actual
road distance of the calculated route,
and not “as the crow fl ies.” When
viewing a list of destinations (points
of interest), such as restaurants, the
distance is “as the crow flies”
So I guess we have a little of both. It's too bad the POI aren't actual road distance because if your driving on a highway, there can be a HUGE difference between crow flies and road distance.
#10
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I don't think that's how it's calculated. It is based on road miles but it will use a constant formula based on the average speed of the roads involved (best case scenario) or the road's speed limit (less then ideal). This is how the nav system chooses which route is fastest. There are plenty of times where the system 'thinks' a road is faster or slower then it actual is which causes errors.
For example, if you are traveling 20 miles, 10 of those miles are at 20mph and 10 of those miles are at 40mph it will use this formula
10 miles @ 20 miles per hour = 1/2 hour or 30 minutes
10 miles @ 40 miles per hour = 1/4 hour or 15 minutes.
Total trip = 45 minutes.
Alternatively there may be a route to the same destination that is 30 miles but you're on highway most of the way
30 miles @ 60 miles per hour = 3/6 hour or 30 minutes
Total trip = 30 minutes.
So the Nav system picks the second option because it's faster.
If you leave at 12pm you should arrive at 12:30pm.
However if you instantly get stuck in traffic for 8 minutes you will notice that the time to arrival is still 30 minutes, but it's now 12:08pm so your arrival time is now 12:38pm. If it took into account your current speed (say 3 mph) it would recalculate your time as
30 miles @ 3 miles per hour = 30/3 hour or 10 hours. I've never seen the system increase my destination time (though with up to date traffic it's certainly possible)
So the problem is that traffic**, stop lights, actually speed are generally not taken into account (at least on the Eclipse system). The great thing about the Eclipse (and I guess the Maxima) system is you can adjust the mph for different roads. I remember adjusting residential streets and main roads down 10mph from default and increasing hwy to 65mph which gave me a much more accurate reading.
**unless you have accurate traffic warnings and reroute traffic selected.
For example, if you are traveling 20 miles, 10 of those miles are at 20mph and 10 of those miles are at 40mph it will use this formula
10 miles @ 20 miles per hour = 1/2 hour or 30 minutes
10 miles @ 40 miles per hour = 1/4 hour or 15 minutes.
Total trip = 45 minutes.
Alternatively there may be a route to the same destination that is 30 miles but you're on highway most of the way
30 miles @ 60 miles per hour = 3/6 hour or 30 minutes
Total trip = 30 minutes.
So the Nav system picks the second option because it's faster.
If you leave at 12pm you should arrive at 12:30pm.
However if you instantly get stuck in traffic for 8 minutes you will notice that the time to arrival is still 30 minutes, but it's now 12:08pm so your arrival time is now 12:38pm. If it took into account your current speed (say 3 mph) it would recalculate your time as
30 miles @ 3 miles per hour = 30/3 hour or 10 hours. I've never seen the system increase my destination time (though with up to date traffic it's certainly possible)
So the problem is that traffic**, stop lights, actually speed are generally not taken into account (at least on the Eclipse system). The great thing about the Eclipse (and I guess the Maxima) system is you can adjust the mph for different roads. I remember adjusting residential streets and main roads down 10mph from default and increasing hwy to 65mph which gave me a much more accurate reading.
**unless you have accurate traffic warnings and reroute traffic selected.
#11
Had a case yesterday that seems to indicate that the traffic/congestion is used in the calculation. Made a trip I have made multiple times, and I know the estimated time usually shown by the nav. Yesterday it showed a longer time, with some significant traffic delays near the destination - shown by the orange and red route highlights.
Also, it seems that when I first enter an address, it shows the miles as the crow flies until it completes the route calculation, then it shows road miles.
Also, it seems that when I first enter an address, it shows the miles as the crow flies until it completes the route calculation, then it shows road miles.
#12
Had a case yesterday that seems to indicate that the traffic/congestion is used in the calculation. Made a trip I have made multiple times, and I know the estimated time usually shown by the nav. Yesterday it showed a longer time, with some significant traffic delays near the destination - shown by the orange and red route highlights.
Also, it seems that when I first enter an address, it shows the miles as the crow flies until it completes the route calculation, then it shows road miles.
Also, it seems that when I first enter an address, it shows the miles as the crow flies until it completes the route calculation, then it shows road miles.
Overall I'd have to say that the traffic function SUCKS! Anytime we hit traffic, I'd take a quick look at Google maps on the iPhone which showed the traffic congestion, but it didn't appear on the TL most of the time. I'm not sure why Google would update traffic info faster. I would think they're both using the same source.
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