I have an 07 TL-S.

I've always wondered how navigation systems calculate how much time is left til you get to the destination. I wondered if it was by the speed limit, or by your current speed (either avg amt over/under speed limit or avg % over/under speed limit).

I just took a road trip this weekend and noticed that it was not anything sophisticated. The speed limit was 70, but the time remaining definitely was off, it was using something lower than the speed limit. Anyone have any insight?

Thanks

 

I believe that it uses the mileage left with the average spped that is read out by the trip computer or by the MID. I have found my Tl's to be accurate some times and to be way off other times.

 

how would the car know the speed limit?

for the most part it uses basic math, distance left, and average speed. the navi system is hooked to your speed sensor

 

Even if the Navi isn't connected to your speed sensor...(aftermarket GPS). RBF351 is right, it use basic math with all the information that it has to determine what time you'll arrive and alot more.

 

I'm always doing the 4 hour trip from Bakesfield to Vegas. The navi alway starts off with a longer time and gradually adjusts as I drive. If you look at the time remaining and figure up the exact time you should arrive, you will notice that you usually always arrive earlier than it initially says (on freeway trips) but the time remaining happens to be accurate when you arrive at your destination.

 

Don't really know, but I take it as a personal challenge to get there before the system says that I should! It also helps to keep the kid quiet when she wants to know "are we there yet?". I can give her an answer and then impress her when we show up early.

She thinks Daddy is the best!