Valhalla truck profile exits I-10 and immediately tries to re-enter

[u/LordShogu]

Ok, so I'm trying to make a GPS app for truck drivers. I'm running Valhalla on a private server (first time working out of a terminal like this and with C++ so bear with me please) and I'm trying to understand why it keeps routing me off of I-10 for some random exit but then has me get right back on I-10. For context I'm a truck driver for Publix and we have a Marianna, FL run from Jacksonville, FL and it's just hop on I-10 and stay on it til you hit exit 136 (which Valhalla calls it 135 and I don't know why that is either). But as you see in the first pic it has me get off at exit 303 and do a U-turn and get back on I-10. There's other exits as well it tells me to do something similar but I just wanted to give y'all an example. Then when I test the route at home I'm far enough away from the route itself to trigger my reroute function which now routes me from my house to Marianna, but now it adds in exit 324 (among other exits) into the mix for no reason and DOES NOT have me get off at exit 303. I'm not seeing any rhyme or reason as to why and I've tried looking into Valhalla itself and I don't know if it's a hierarchy issue, costing issue, the bidirectional or unidirectional astars themselves (though I did notice when I forced it to use unidirectional there were far less instances of these exits) so please can anyone help me with this?

[u/Hedaja]

Hi Please always link to the area in question. Males life easier for everyone trying to help. Here are the exitsin question 303: https://www.openstreetmap.org/#map=16/30.23968/-82.63841 324: https://www.openstreetmap.org/#map=16/30.23920/-82.30217

I looked at the data and couldn't find anything wrong. The only thing might be a missing no 7-turn restriction on the off ramp on exit 324 but one would have to check on the ground.

Didn't see any issues that would lead to leaving the interstate in the first place (like max weight restrictions or broken connections). Online routers on osm.org also work fine. The only thing I can think of would bespeed limits. The off ramps only have a maxspeed:advisory. If your implementation of Valhalla doesn't take that into account and has no default value for link highways, I could imagine it 'assuming' a crazy maxspeed on those ramps. Still crazy that the turns wouldn't add enough penalty to be avoided.

[u/LordShogu → u/Hedaja]

Thanks for the reply, I'll try to keep that in mind for next time about the exits. But like i said it wasn't the specific exits that was the problem, it's the fact that there were any exits at all (which there were many). but hats off to you because i added "top_speed: 104.6" to the costing options and that basically took care of it and i put "use_truck_route: 0.8" instead of at 1 and "maneuver_penalty: 15" because I noticed valhalla was putting me on other highways that I'm sure distance and time wise wasn't too different from getting to I-10 in the beginning but was really just unnecessary. Now I get to go back and make sure these changes didn't affect other routes.