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Interstate Highways as Via Points

Feb
19
2008

A couple of interesting points about using Interstate Highways as via points has come up more and more often recently. Adding an Interstate Highway as a via point isn’t as straightforward as you might think and can lead to some very confusing results! I hope GPS manufacturers take a look at this issue. It is becoming more common as people become more savvy creating routes. So what is the issue?

Picture this, you have created a route on your GPS and it takes you down an interstate, but asks you to get off an exit or two earlier than you would have liked. A fairly common thing to happen. Thinking you are smarter in the GPS, you decide to add a via point a little further down the highway. We’ll say that you are in Florida driving South on I-95 and want to go all the way to Highway 50 near Titusville but the GPS wants you to get off earlier. There are a couple of different ways you can do this.

Intersection

The first thing that might come to mind is to use an intersection as your via point since you know you want to go as far as where I-95 and Highway 50 intersect… You enter I-95 as the first road of the intersection and then try to bring up highway 50… and you can’t find it. :( Basically your GPS tells you that I-95 and Highway 50 don’t intersect!

Now if you think about it– the GPS is perhaps correct based on a technicality. Interstate 95 and Highway 50 don’t intersect. There are a few on and off ramps that connect them, but the GPS can’t pinpoint the exact location you want. There could be a dozen or more places that might represent where those roads intersect based on the numerous on/off ramps. And where the two roads “cross”, I-95 is actually going “over” Highway 50 and they don’t actually intersect in the middle.


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Point on Map

So you get clever and think to yourself that if your GPS can’t find the intersection of those two roads then you can at least pan the map and click on the location of where you want the route to go. Generally speaking this will work, but be very careful to get N/S and E/W lanes properly selected! Look what happens if I accidentally click on the North bound lane of I-95 as the via point when I’m traveling South. The GPS will have you go down I-95, get off at an exit, turn around and go back up I-95 to get on the Northbound via point, then get off and turn around again, completing the circle before finally getting off at the correct location. I’ve done this myself and have heard of other people doing it to.


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Changing the Program

It would be great if GPS devices could better recognize these two flaws. Allow me to select I-95 and Highway 50 as a via point and apply some “fuzzy mapping” to recognize that while those roads don’t technically intersect that I want to get off I-95 at the exit that will take me to I-50. And secondly recognize that if the majority of my route travels from North to South and I insert a via point that makes me go in a circle… at least ask if that really was my intention and if I don’t confirm move the via point to the appropriate lane.

If these two things can trip up me, I’m sure they’ve tripped up plenty of other folks as well. :)

8 Responses


  1. Excellent cover, Tim. I also did the same thing exiting the turnpike into Ocoee. Until reading your comments, I hadn’t realized what I had done.

    Gatorguy - February 19th, 2008
  2. Believe it or not, when you try to find an intersection for interstates I’ve had better results (at least for my Garmin nuvi) just entering (e.g.) 75 instead of I-75. It holds true for all numbered highways where you would normally think of it as S.R.-state route or U.S.- route. Try it on your own to see if it works better.

    kevin stonerock - May 21st, 2008
  3. Thanks Tim. That’s exactly what was happening with me. I was trying to intersect I88 and SR-357, which do not intersect, only by on/off ramps. Thanks so much for your help. Anything else you think I should know about the 750?

    Steve - July 5th, 2008
  4. Well, you can browse through our ongoing GPS 101 series and you might find some good nuggets of info.

    Tim - July 5th, 2008
  5. When I enter a US hwy as a destination, I can not designate either north or south. It automatically takes me to the north end of the US Hwy. This can be a pain when you want to go south and it takes you north. Especially in a large city. Is there a trick to inputting the north/south parameters?

    Gary - December 10th, 2008
  6. Gary, we’d have to know the specific location you are looking at as well as what device you are using. If I have that device then I can take a look.

    Tim - December 10th, 2008
  7. I am a trucker and am assigned routes to travel. I want a gps that will allow me to enter the assigned routes so that I may use the GPS as a tool to keep me on track. What is the best brand and model to purchase? I think this is pertinent to the thread because I have the ultimate via point need.

    mike hill - May 20th, 2009
  8. Is there a way to make my 1300 Garmin avoid freeway driving

    debbie - August 2nd, 2010



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