Support Thread for the TND 500, TND 700 or future Rand McNally products. (part two)

Discussion in 'Trucking Electronics, Gadgets and Software Forum' started by Mark Kling, Jul 7, 2014.

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  1. Mark Kling

    Mark Kling Technology Contributor

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    What is the model number on the back
     
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  3. Mark Kling

    Mark Kling Technology Contributor

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    Home button on top/Truck Tools/Status,trails,mileage, fuel

    Thanks,
    Mark
     
  4. Kamkor

    Kamkor Road Train Member

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    You didn't have to go into all that. I'm not stupid. I know how to calculate an ETA when I know all the numbers, which is why I was asking for help figuring out the only one I didn't know.

    This is from your companies website. I didn't know it was such a closely guarded secret...

    ETA is calculated based on the average speed of vehicles on each road segment of your route, without traffic. The unit adds up the time for each road segment to get a total estimate of how long it will take. The average speed is based on industry standard known values that are part of the data in our devices. ETA is not based on the posted speed limit or the speed your vehicle is traveling. You can vary the ETA in the Tools > Info section on your device.

    How is my ETA calculated? - Rand McNally Support

    Maybe you should tell them to fix the segments in known areas where they are way off. Like entire states that have a much lower max speed statewide. I'm sure a simple IF/THEN statement would fix it up.

    If State = CA then Seg_AVG <=55

    Maybe a SQL statement?

    update [State_max_speed] set [California] =
    replace([California],'[75]','[55]');

    Figure they would actually want their devices accurate. Then again its been that way since the TND 510.
     
  5. Mark Kling

    Mark Kling Technology Contributor

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    1. I don't know what you do or do not know, so I gave the simplest answer to your question.
    2. Speeds are set by the states and vary all the time. Maps cannot keep up with them. RM does put out a quarterly file to correct those sections that are a major area like a freeway. Smaller segments such as a town are passed to HERE for correction in the yearly map update.
    3. Unless you have a Tablet, your maps are over a year old. Tablets just got updated to the newest maps.
    4. ETA does take into affect the movement from Point A to Point B based time/distance. Next time you get an ETA watch it... slow down the ETA will increase. Speed up the ETA will decrease.
    5. California in the map data does NOT have truck speeds listed. This has been reported to HERE for many years, but it is California that has to correct their database to include truck speeds. So, unless the state has the correct information, HERE cannot just put it in their database. The States are the ones that drive the road data. IF HERE inputs it then they are liable for any incorrect data because they don't have a basis to determine the correct speed.

    I use the RM's all the time and the ETA is usually within 10 -15 minutes of what it says when set at ETA OK.

    Update

    I will expound on this a little more.. back in 2008 when Truck GPS units became more Stand alone the map data was not totally accurate in Truck type of items such as restrictions. There was not a driving force to keep this data totally accurate. If you look at the map data then and now, a huge difference has been made in the accuracy. It is not 100% by no means. RM found a restriction last week that was missing. Split speeds back then and now are still some of an issue. If the states do not show this truck speed then it is not in the final map data that is published. Texas had a Day/Night speed, but the map database is not set up for a Day/Night type of situation.

    If your setting is on "Show Car speed if no Truck Speed", then if the posted speed on the TND is white that is the car speed. If it is Orange it is a truck speed. If the speeds are the same then most times a state will not show a truck speed and it will be White.

    So yes, RM does take into account the posted speeds, but if no truck speeds, then it uses car speeds. it has to have something for the input. But, that is only part of how an ETA is derived. I cannot tell you the whole process as this is proprietary in the way the formula is done.

    So ETA OK = about 63-65, ETA More - about 58, and ETA Less - about 68..

    Thanks,
    Mark



    Due to this thread becoming rather lengthy, future support discussions are being moved into a new thread:

    Rand McNally Support Thread. (Part 3)
     
    Last edited: Dec 3, 2017
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