Commuters leave brains at city limits

[Birdin 10]

I've recently started a brand-new region, and currently have six cities basically strung out in a line.  The total population of the region right now is about 150K.  On one end is Maple Pont, then Sandville, then Carson Pass.  Sandville is supposed to be a big job city (mostly industrial: I+C total is nearly twice the R total) and Maple Pont is mostly residential and commercial, with emphasis on education. So there are about 7,500 commuters travelling across the border from Maple Pont to Sandville, mostly by car, but some by bus.  Besides the clogged neighbor connections, all is well in Maple Pont.

In Sandville, however, it's utter lunacy.  Despite plentiful bus stops in the industrial areas, the bus commuters just roll right through to Carson Pass.  As for the car commuters, only about 10% actually stop at jobs in Sandville.  Jobs in Sandville are more than plentiful.  Most of the industrial buildings query with 60 to 100 jobs occupied, but the route query reveals only one or two cars actually being routed there.  (Is this an "occupant leak" issue of some kind?) With 5,000 or so cars just dumped into the next city (which really doesn't have a lot of jobs at all -- not that they'd stop there anyway) you can see where this can become a major traffic problem for a region.

This problem has been present for quite some time for me.  Nearly all commuter traffic which enters a city just drives directly to the very nearest connection to another neighbor city.  If there are jobs closer than that, there's a chance that a few will actually stop there, but this doesn't account for much, as can be seen in Sandville.  Most of the time, this leads to unrealistic traffic flows across the corners of cities, often curling back towards their origin after crossing two or three city borders.

I'm currently using the NAM Beta version 09.04B.04 with "Better Pathfinding" and "10x Commute" along with the various turning lanes and roundabouts, diagonal streets, the custom highway menu option, and radical automata.  I'm using a few other mods which don't relate to transportation, except the roadtop MT, and marginally, the bridge height mod.  My EXE version is 1.1.638.0. 

Could someone with knowledge of how pathfinding works explain how the game decides where a commuter entering a city attempts to go?  Is there any data about the commuters regarding their wealth level, or what type of job they are seeking?  Most importantly, how can I get commuters entering Sandville to actually stop and work *in* Sandville besides cutting off access to all other neighbors?

[Birdin 10]

In case anyone else with the same problem finds this thread, I'll note here that I also posted it at https://www.simtropolis.com/forum/messageview.cfm?catid=124&threadid=91397&startpage=1 and received an answer. It's not a satisfying solution, but it's an answer nonetheless.