Hey, my relatively expensive Garmin GPS does the same thing.
it is a problem with the inherrent inaccuracies of the GPS calculations and is not really a fault of the S5's GPS, nor the app you are using.
Take a look at this app, GPS STATUS.
* GPS Status & Toolbox - Android Apps on Google Play
This is my "Go To App" for GPS issues, it puts it all in one place for you.
Today, it is common for us to get location fix accurate down to around 11 meters, or 33 feet.
10 years ago, when we only had 5 satellites up there, location fixes that were within a half mile were considered pretty good.
GPS Status has at times, shown me with a fix down to 9 meters.
It depends on How many SATs are in view at the time of the fix. At times, I can get 11 satellites which gives me altitude accurate to with a few feet and even shows me setting at my office desk when I am home.
Now, as for the lag when you exit the freeway? That 33 foot location fix is the problem. Once you deviate about 100 feet off the route, the GPS program will realize that you are no longer "up there" on the freeway.
We have a couple of exit ramps here where the off ramp runs down underneath the highway.... now that really gives a GPS program a fit..... I'm still within about 50 feet of where I was and then I go under the highway to exit at 90 degrees left eventually....
I don't think you are going to get a real fix on that situation... unless you opt to purchase a Military Grade GPS device.... that will get you down to about 5 CM of accuracy.
That's 5 centi-meters. Remember the bombs being dropped into Chimneys?
