I often find myself "stuck" to parallel roads because Waze routed me that way and I "must" be following the route--even though my GPS places me over 20m (65ft) away!
When I go to Taco Bell on my way to work, it's so I can go through the drive thru, NOT so I can roll past the front door as Waze would have me do. But the 15m (50ft) out of the parking lot is "close enough" to assume that I'm following the route.
This also happens when I'm trying to train Waze to take a longer route out of my parking lot to a shorter wait at a light. Waze misses that I didn't turn out of the parking lot and am on a parallel road 65m (80ft) away, and just assumes I'm on the road it wants me to take.

Update the "route stickiness" algorithm to stay locked to the nearest segment within, say, 1.25 * the current accuracy. The GPS in my phone is usually accurate to within 3m (10ft). At time's, I've had as bad as 10. Even this should be good enough to determine when I've left a parking lot.

Part of this may have to do with things like large intersections where the junction node in the middle could be 10-15m away from a vehicle taking a right turn, but surely that can be tweaked for the street type, i.e. tighter tolerance for streets and parking lot roads, wider tolerance for primary streets and highways.
Incidentally, I think freeway interactions are restrictive enough that you can probably keep them tight too. I know it often takes a while for Waze to realize I've taken an unexpected exit. I mean, I can be on one of two different segments and I just slowed down drastically, where the heck do you think I am!?

Perhaps transitions to/from parking lot roads or ramps could incorporate some kind of delta-v tracking.