Froggie's mostly right on field signage - it's the last you see of 202 until the signage Doug mentioned at US2, and
this doozie.
Field verified October or November 2007 (possibly more recently?), and no reason to believe signage has been removed.
if US 202 does not extend beyond US 1A, then there is no route at all that continues straight to US 2.
There is a route 1C - which is
MDOT-speak for US1A Business. However, this is not signed in the field.
Or, is it possible that MDOT never actually truncated US 202?
They truncated it all right - enough to conspire with AASHTO to have it end at 1A. Also consider
what recent route logs had to say. ("Ramp"?)
Also, I got it together enough to find out where 168.52 mi from NH gets us. Mapquest Schmapquest! The PRIM_EMP field was right there in the shapefile the whole time, giving the ending milepost on PRIM_RTE for any given segment. For 202 at 395, that figure is 168.51. That about clinches it. (Though intriguingly imprecise... rounding errors, perhaps?)
Also consider, like the NJDOT Straight Line Diagrams, the Maine shapefiles are far from perfect, and the lack of 202 designations on the ramps may just have been oversight on their part.
Hey now! Depends on how we define "far"!

I find the shapefile to be pretty error-free in terms of route numbers and where they go. Sometimes, it agrees with field signage and disagrees with the route log (Route 214), or disagrees with field signage and agrees with the route log (25, 26, 196), but I've never seen the shapefile the odd one out with those other two elements agreeing.
With the mileage as provided in the route log matching 202's mileage arriving at I-395 in the shapefile, it appears this was intentional and not an oversight.
Could it be simply that their published information was inaccurate or incomplete? I've always wondered why they would've truncated the US 202 designation, and yet leave all the signs up...
The latter, well, that's the $65536 question; I've had to wonder that myself. Maybe signs were gone for a while and then reappeared? Who knows...
As far as inaccurate info, well... the DOT documentation was pretty consistent in and of itself. As noted above, there are a few instances of field signage disagreeing with route logs, what's in the shapefile, or both. It should be noted that the wandering termini of routes 25, 26, 121, and 196 are all in Urban Compact municipalities, where state and state-aid highways are maintained by the municipality. So this could be indicative of the left hand not knowing what the right is doing between different levels of government - similar to the AASHTO vs MDOT situation. (Though that wouldn't explain the 202 signage on I-395's BGSs.)
As for the ME214 scenario, it could be that the route log definition has changed since the (2006?) revision as published on
RAME, to be in line with what's in the field & shapefile. (Or short of that, maybe miscommunication between MDOT Region 4 and the central offices in Augusta? Who knows...)
If Cameron gets an updated route log to post to RAME, we may just see the mileage of US-202 get longer...