The spawning distance is set to 50 meters. It takes the player's position, chooses a point 50 meters away in a random direction, and spawns the vehicle at the closest road. It's just unfortunate that in your position you had that massive gap to the bridge. The true distance to where your vehicle spawned ends up being 3x further than intended:
I summoned my vehicle a few times, and the majority of the time it was within the intended range:
That being said, I will reduce the spawn distance from 50 to 30. We'll see how it goes. Changes are live now.