Getting on 101 at Cesar Chavez in SF

[jfirebaugh]

OSRM produces the same incorrect routing as Apple Maps:

http://osrm.at/6cZ

The U turn is not technically illegal, just dangerous and contrary to the signed route.

What's the best way of fixing this? Increasing the U-turn penalty in the profile?

[emiltin]

adding a turn penalty method to the car profile might solve most of these, see #860.

[woodbri]

Seems like you need to add a turn restriction in OSM to prevent that turn.

[emiltin]

i reported a very similar issues about two years ago: #65

[jfirebaugh]

@woodbri There is no signage at that intersection prohibiting a U-turn, it's just very ill advised and not something a local is likely to attempt. The intended route to 101N, which is signed, is to turn right on Kansas, right on Marin, and right onto the on-ramp.

[emiltin]

is there a fully painted line on the road that you're not allowed to cross?

in any case, i think sharp turns should simply be penalized more. perhaps it could be increased if you're on a big road, rather than a small one?

[emiltin]

there's an issue for using the road type when calculating turn penalties: #477

[emiltin]

why is a u-turn dangerous at this place? because it's a big road?

[DennisOSRM]

Turn penalties for steep turns are on my plate for tomorrow

[DennisOSRM]

@jfirebaugh could post a link to the wanted route here? Thx

[jfirebaugh]

@DennisOSRM http://osrm.at/6d8

[DennisOSRM]

Thx

[DennisOSRM]

@jfirebaugh How reasonable does this look? It avoids the U-turn and uses ramps instead:

[jfirebaugh]

@DennisOSRM I've never tried going that way. It would probably work fine, but it's contrary to the signed directions to 101N which direct you to take Cesar Chavez, so it would be somewhat confusing.

[DennisOSRM]

k, will put some more effort into further tuning the penalties.

[daniel-j-h]

@jfirebaugh How does the following look to you?

If you can live with it, feel free to close this issue :)

[jfirebaugh]

Looks great, that's the signed route.