ryca

I just returned from a trip using the Nav system in my fairly new 2011 RX 350. While the route information was good, the estimated time of arrival was terrible. The ETA decreased over 90 minutes as the 6 hour trip went on. I did not stop at all and followed the exact route it gave. My old Garmin was always spot on with ETA. Is this a common problem with nav system.

kitlz

Do you have the speeds set accurately in the nav (i.e. highway 55 MPH)? It could be too low.

MC5Wes

You can adjust your ETA times. Go to settings. And there will be screen where you can adjust your MPH. Say it's set for 55 on the highway. You can change it to 70.

ryca

I checked and the highway setting is set for 55. I will try to adjust before the next trip and see if that improves the accuracy

ryca

Is the nav system unable to know your speed? Again, on the cheap Garmin, it actually reports my speed on the display. I would have a hard time knowing if a rural road that has a speed limit of 55 is considered a highway or not. Seems very unnecessary and silly to have to adjust these speeds for each trip

kitlz

The ETA will fluctuate slightly based on the value entered as you drive. Unfortunately it can't tell the actual speeds of the roads traveled. Mine is pretty accurate. I think I set the highway speed to 65 which is the speed limit around here. I may go a little faster or slower depending on traffic. Usually the difference is only minutes during trips of one hour or less.

DunWkg

I glanced at the Garmin web site, but I didn't see where it said it uses your actual speed. Would someone please point me in the right direction. (Yes, a pun) I got the impression it uses a preprogrammed average by road type.

Cruiter

Going up to Lexington NC Monday, mine was off by 10 min for the whole trip. Not bad at all. Coming back tho the Nav traffic showed red up ahead and sure enough, hit a 7 mile back up of rubber neckers due to a wreck in the North bound lane. But because I had the highway speed pre-set in the Nav route guidance as 70mph on highways it kept re-calculating and was pretty close coming back too.

Evitzee

All Arrival Times are estimated, even with Garmin and TomTom.......the unit cannot predict with accuracy what your speed on the remaining distance to go will be, you may run into traffic, stop for fuel/food, or drive faster/slower than the speed limit. I left Houston the other day on a drive to Austin (161 mi) and wanted to arrive at 5pm at the restaurant we were going to. When we left Houston at 2 pm it showed arrival time as 5:03pm and we actually got there at 4:48pm. Close enough for me.

JellyBean

Ryca, check the thread about this very topic I started last month. And no, the nav doesn't know the posted speed limits as our cheap Garmins do. It relies on the speed settings. Also, setting the driving speeds influences the routing--a benefit I didn't expect. Check my last post on that thread.

JB

InRBigness

Well here in Winnipeg the highway speeds are 60mph and regular roads are 70-80 k with residential roads at 50K. Problem I have found here is that the Nav system thinks that I am on a regular road even though I was on the TransCanada highway. Yes I can make it work but still silly. They should look at their road classifications better. Unless you are on a US interstate it figures you are on a secondary highway.

Oh and by the way, my Tom Tom is also rediculously brutal with the arrival time so I turned it off.

sightdev

x2

both TomTom and Garmin are very close with ETA and they both [most models] have the traffic/speed camera warning integrated so I use both TomTom mostly as a warning device and OEM navi to navigate to my destinations during hockey season all over NE. for me its good to have both TomTom and OEM navigation so I can compare the routing method as they vary depending on distance/city. For example, from Fairfax VA to Niagara NY, TomTom routing was about 110 miles shorter but to Lake Placid NY only about 30 miles shorter. Lexus Navi uses as much hwy road as possible so some of the remote cities will include long detour on hwy.

MC5Wes

You can make adjustments to the Lexus nav systems. And it will make the distance different for the same location. Punch in no toll roads, ferrys or the shortest didstance.

For example. When I first bought my RX it had me taking a short cut. Get off the highway. Take a side street then get back on another highway. Instead of using the exchange.

Because it was a 1/10 of a mile shorter distance.

MoonShell

My $140 Nuvi GPS knows the speed limit of the roads I am driving on and the speed I am driving. It estimates my arrival time using both figures. We’ve just returned from a trip to Zion NP and the Lexus Navigation ETA was 3 hours more than the 5.5 actual and Google Maps ETA. Yes, I could readjust the non-freeway speed each time we take a long distance trip [many 2 lane roads in AZ and UT are 55 or 65 MPH] and then change it back to 35 MPH when we return to town, but why should I have to do the work? Isn’t time for a software upgrade to bring the $2K Lexus system up to par with a $140 one?

ryca

I have given up on the ETA. It is very frustrating that I can not get an accurate time even with the adjustments. If I want an accurate time I input it into my Garmin as well. Certainly seems ridiculous after spending $2000 for the nav system that I need to do this.