US35 in OH crashes Route Calculation

[DiamondDan]

trying to route from US35 north of Milledgeville, OH to Dayton, and the correct route is along US35. However SA2009 wants to route along "old US35" and selecting a via of US35 causes a route error that can't be fixed. Any ideas on what's causing something like this? SA seems to know the road is there, but it doesn't want to route along it.

[John Moran_2]

trying to route from US35 north of Milledgeville, OH to Dayton, and the correct route is along US35. However SA2009 wants to route along "old US35" and selecting a via of US35 causes a route error that can't be fixed. Any ideas on what's causing something like this? SA seems to know the road is there, but it doesn't want to route along it.

Confirmed with Topo8. The curving US35 road would be difficult to force to route as desired in any case, because the 'old road is straighter and shorter. In addition it seems that onramps are not shown in logical places as well, and there may even be a break in the road vectors.

I would not even try to route over those roads with SA2009 or Topo8 except as a fun exercise if you like debugging. You might find a workaround, but you cannot patch the US35 road category with the Routable Road Draw feature. Bummer, or so it seems on first glance.
JM_2

[xapie128]

Any ideas on what's causing something like this?

Yes, it's a break in the road database at 39.66970, -83.73063 where US-35 crosses over So. Charleston Rd.

You can use a work-around, but it isn't very pretty . . .

• First, you must be using Advanced File Management (not Simplified), see page 12 of the SA2009 User Guide for more
  
  
• Download the attached file (named US-35 patch.an1) to your \DeLorme Docs\Draw\ folder
  
  
• From the Map Files tab, click the Add button on the right, select Draw File then the file you just downloaded
  
  
• The patch still has limitations (I won't go into all the whys here) but in order to use it, whenever you are routing on US-35 west in that area, you will also need to place a Via on the off-ramp or on-ramp at the intersection just to the west of where the break is, like this . . .
  
  

  

As I said, it isn't very pretty. Note that because we can't set road speeds of user added Routable Roads (that's what the patch is) it means that the 6 mile section of Routable Road is a 25 MPH road, which will throw your estimated trip time off; but at least you can route via US-35 this way.

BTW, this problem exists in SA2010 also, so it wouldn't help you to purchase an upgrade.

[John Moran_2]

The curving US35 road would be difficult to force to route as desired in any case, because the 'old road is straighter and shorter.

With road preferences set to default, the routing should pick the Limited Access road over the Secondary "old road". In this case it did not, but only because of the road break.

Not necessarily so if the I-35 limited access route is neither quicker nor shorter. Usually the limited access interstates are quicker by Delorme's default road category settings, but not always. A few years back it was necessary to use vias to get around the partially completed horseshoe shaped bypass of Memphis.

Delorme may be throwing in a few unseen "penalty" factors for problem routings. This has been posted in regard to at least one location near Xapie128 in the DelMarva region.
JM_2

[DiamondDan]

Thanks for the patch. It works for me. Can you explain how you found the road database?

[xapie128]

Can you explain how you found the road database?

I started with your route (US-35 near Milledgeville to US-35 in Dayton) and verified that it didn't take the most logical route.

I then added a Via somewhere in the middle on US-35 and got the "Failed to calculate" error.

At that point, I moved the finish to somewhere in the middle. If the route calculates, then I know that the break is after that point, if it doesn't calculate then I know the break is somewhere between the Start and the new Finish location. From there it's just trial-and-error as you continue to move the Start or Finish so the route is smaller and smaller, but it continues to fail to calculate, and zero in to a very small segment.

Note that once you find the bad section of road, it doesn't necessarily point to a road break. Sometimes it means that a small segment of road is set to one-way when it should be two-way or the opposite direction. There are other strange things that can be the problem that users can't fix, but they are rare.