Concurrent segment detection

[yakra]

Some background info: Re: PA: US 19 Truck (Pittsburgh)
http://forum.travelmapping.net/index.php?topic=316.msg12112#msg12112

TL;DR:

Search for Wait. Did we mean to do that?, in the 9th response below.

if s.concurrent is None:
 s.concurrent = []
 other.concurrent = s.concurrent
 s.concurrent.append(s)
 s.concurrent.append(other)
 concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
else:
 other.concurrent = s.concurrent # ADD THIS HERE!
 if other not in s.concurrent:
 s.concurrent.append(other)
 # ...

may be what we need. It should link up segments beyond just the 2nd one with the 1st segment's concurrency list, and prevent erasing the 1st segment's list followed by needlessly re-detecting its concurrencies.

[yakra]

for h in highway_systems:
# h = usai
 for r in h.route_list:
 # r = pa.i376
 for s in r.segment_list:
 # s = [69A to 69B via pa.i376]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 for w1 in s.waypoint1.colocated:
 # w1 = pa.us019@I-376(69A)
 if w1.route is not r:
 # w1.route = pa.us019; True
 .-> for w2 in s.waypoint2.colocated:
 | # w2 = pa.us019@I-376(69B)
 | if w1.route is w2.route:
 | # True
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other = [I-376(69A) to I-376(69B) via pa.us019]
 | if s.concurrent is None:
 | # First pass; True
 | s.concurrent = []
 | # empty list
 | other.concurrent = s.concurrent
 | # 2 empty lists, quantum entangled
 | s.concurrent.append(s)
 | # I-376 & US19 get I-376
 | s.concurrent.append(other)
 | # I-376 & US19 get US19
 |__________________ concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 else:
 if other not in s.concurrent:
 #
 s.concurrent.append(other)
 #
 #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 concurrencyfile.write("Extended concurrency ")
 for x in s.concurrent:
 concurrencyfile.write("[" + str(x) + "]")
 concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	None	None	None	None
US19	US19

[yakra]

for h in highway_systems:
# h = usai
 for r in h.route_list:
 # r = pa.i376
 for s in r.segment_list:
 # s = [69A to 69B via pa.i376]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 .-> for w1 in s.waypoint1.colocated:
 | # w1 = pa.us019@I-376(69A)
 | if w1.route is not r:
 | # w1.route = pa.us019; True
 | for w2 in s.waypoint2.colocated:
 | # w2 = pa.us022@I-376(69B), pa.us030@I-376(69B), pa.us019trkpit@I-376(69B)_S, pa.us019trkpit@I-376(69B)_N
 | if w1.route is w2.route:
 |______________ # False for all remaining
 other = w1.route.find_segment_by_waypoints(w1,w2)
 if other is not None:
 #
 if s.concurrent is None:
 #
 s.concurrent = []
 #
 other.concurrent = s.concurrent
 #
 s.concurrent.append(s)
 #
 s.concurrent.append(other)
 #
 concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 else:
 if other not in s.concurrent:
 #
 s.concurrent.append(other)
 #
 #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 concurrencyfile.write("Extended concurrency ")
 for x in s.concurrent:
 concurrencyfile.write("[" + str(x) + "]")
 concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	None	None	None	None
US19	US19

[yakra]

for h in highway_systems:
# h = usai
 for r in h.route_list:
 # r = pa.i376
 for s in r.segment_list:
 # s = [69A to 69B via pa.i376]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 .-> for w1 in s.waypoint1.colocated:
 | # w1 = pa.us022@I-376(69A)
 | if w1.route is not r:
 | # w1.route = pa.us022; True
 | .-> for w2 in s.waypoint2.colocated:
 | | # w2 = pa.us022@I-376(69B)
 | | if w1.route is w2.route:
 |_______* # True for US22; false for all remaining
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other = [I-376(69A) to I-376(69B) via pa.us022]
 | if s.concurrent is None:
 | # False; received items in earlier pass
 | s.concurrent = []
 | #
 | other.concurrent = s.concurrent
 | #
 | s.concurrent.append(s)
 | #
 | s.concurrent.append(other)
 | #
 | concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 | else:
 | if other not in s.concurrent:
 | # True
 | s.concurrent.append(other)
 | # I-376 & US19 get US22
 | #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 | concurrencyfile.write("Extended concurrency ")
 | for x in s.concurrent:
 | concurrencyfile.write("[" + str(x) + "]")
 |______________________ concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	None	None	None	None
US19	US19
US22	US22

[yakra]

for h in highway_systems:
# h = usai
 for r in h.route_list:
 # r = pa.i376
 for s in r.segment_list:
 # s = [69A to 69B via pa.i376]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 .-> for w1 in s.waypoint1.colocated:
 | # w1 = pa.us030@I-376(69A)
 | if w1.route is not r:
 | # w1.route = pa.us030; True
 | .-> for w2 in s.waypoint2.colocated:
 | | # w2 = pa.us030@I-376(69B)
 | | if w1.route is w2.route:
 |_______* # True for US30; false for all remaining
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other = [I-376(69A) to I-376(69B) via pa.us030]
 | if s.concurrent is None:
 | # False; received items in earlier pass
 | s.concurrent = []
 | #
 | other.concurrent = s.concurrent
 | #
 | s.concurrent.append(s)
 | #
 | s.concurrent.append(other)
 | #
 | concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 | else:
 | if other not in s.concurrent:
 | # True
 | s.concurrent.append(other)
 | # I-376 & US19 get US30
 | #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 | concurrencyfile.write("Extended concurrency ")
 | for x in s.concurrent:
 | concurrencyfile.write("[" + str(x) + "]")
 |______________________ concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	None	None	None	None
US19	US19
US22	US22
US30	US30

[yakra]

for h in highway_systems:
# h = usai
 for r in h.route_list:
 # r = pa.i376
 for s in r.segment_list:
 # s = [69A to 69B via pa.i376]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 for w1 in s.waypoint1.colocated:
 # w1 = pa.us019trk@I-376(69A), and that's the last colocated point
 if w1.route is not r:
 # w1.route = pa.us019trk; True
 .-> for w2 in s.waypoint2.colocated:
 | # w2 = yadda, yadda, pa.us019trk@I-376(69B)_S ...
 | if w1.route is w2.route:
 | # True
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other = [I-376(69B)_S to I-376(69A) via pa.us019trkpit]
 | if s.concurrent is None:
 | # False; received items in earlier pass
 | s.concurrent = []
 | #
 | other.concurrent = s.concurrent
 | #
 | s.concurrent.append(s)
 | #
 | s.concurrent.append(other)
 | #
 | concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 | else:
 | if other not in s.concurrent:
 | # True
 | s.concurrent.append(other)
 | # I-376 & US19 get [I-376(69B)_S to I-376(69A) via pa.us019trkpit]
 | #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 | concurrencyfile.write("Extended concurrency ")
 | for x in s.concurrent:
 | concurrencyfile.write("[" + str(x) + "]")
 |______________________ concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	None	None	None	None
US19	US19
US22	US22
US30	US30
TrkS	TrkS

[yakra]

for h in highway_systems:
# h = usai
^ for r in h.route_list:
| # r = pa.i376, last Interstate we care about at this segment
| .-> for s in r.segment_list:
|___* # s = [69A to 69B via pa.i376], and then other I-376 segments we're not concerned with
 | if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 | # True
 | for w1 in s.waypoint1.colocated:
 | # w1 = pa.us019trk@I-376(69A), and that's the last colocated point
 | if w1.route is not r:
 | # w1.route = pa.us019trk; True
 | for w2 in s.waypoint2.colocated:
 | # w2 = pa.us019trk@I-376(69B)_N, and that's the last colocated point
 | if w1.route is w2.route:
 | # True
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other = [I-376(69A) to I-376(69B)_N via pa.us019trkpit]
 | if s.concurrent is None:
 | # False; received items in earlier pass
 | s.concurrent = []
 | #
 | other.concurrent = s.concurrent
 | #
 | s.concurrent.append(s)
 | #
 | s.concurrent.append(other)
 | #
 | concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 | else:
 | if other not in s.concurrent:
 | # True
 | s.concurrent.append(other)
 | # I-376 & US19 get [I-376(69A) to I-376(69B)_N via pa.us019trkpit]
 | #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 | concurrencyfile.write("Extended concurrency ")
 | for x in s.concurrent:
 | concurrencyfile.write("[" + str(x) + "]")
 |______________________________________ concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	None	None	None	None
US19	US19
US22	US22
US30	US30
TrkS	TrkS
TrkN	TrkN

[yakra]

for h in highway_systems:
# h = usaus
.-> for r in h.route_list:
| # r = pa.us019
| .-> for s in r.segment_list:
|___* # s = [I-376(69A) to I-376(69B) via pa.us019] etc.
 | if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 | # True
 | for w1 in s.waypoint1.colocated:
 | # w1 = pa.i376@69A, <pa.us019@I-376(69A)>, pa.us022@I-376(69A), pa.us030@I-376(69A), pa.us019trkpit@I-376(69A)
 | if w1.route is not r:
 | # True for all but pa.us019@I-376(69A)
 | for w2 in s.waypoint2.colocated:
 | # w2 = pa.i376@69B, pa.us019@I-376(69B), pa.us022@I-376(69B), pa.us030@I-376(69B), pa.us019trkpit@I-376(69B)_S, pa.us019trkpit@I-376(69B)_N
 | if w1.route is w2.route:
 | # True for I-376, US19, 22, 30, and True twice for US19Trk because it has two "w2"s
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other is not None:
 | if s.concurrent is None:
 | # False; received items in earlier pass
 | s.concurrent = []
 | #
 | other.concurrent = s.concurrent
 | #
 | s.concurrent.append(s)
 | #
 | s.concurrent.append(other)
 | #
 | concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 | else:
 | if other not in s.concurrent:
 |__________________________________ # False: s.concurrent was fully populated in previous pass; nothing else happens
 s.concurrent.append(other)
 #
 #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 concurrencyfile.write("Extended concurrency ")
 for x in s.concurrent:
 concurrencyfile.write("[" + str(x) + "]")
 concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	None	None	None	None
US19	US19
US22	US22
US30	US30
TrkS	TrkS
TrkN	TrkN

[yakra]

for h in highway_systems:
# h = usaus
 for r in h.route_list:
 # r = pa.us022
 for s in r.segment_list:
 # s = [I-376(69A) to I-376(69B) via pa.us022]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 for w1 in s.waypoint1.colocated:
 # w1 = pa.us022@I-376(69A)
 if w1.route is not r:
 # w1.route = pa.us022; True
 for w2 in s.waypoint2.colocated:
 # w2 = pa.i376@69B
 if w1.route is w2.route:
 # True
 other = w1.route.find_segment_by_waypoints(w1,w2)
 if other is not None:
 # other = [69A to 69B via pa.i376]
 if s.concurrent is None:
 # First pass for US22; True
 s.concurrent = []
_______________________________________ # empty list _______________________________________
 other.concurrent = s.concurrent
 #
 s.concurrent.append(s)
 #
 s.concurrent.append(other)
 #
 concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 else:
 if other not in s.concurrent:
 #
 s.concurrent.append(other)
 #
 #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 concurrencyfile.write("Extended concurrency ")
 for x in s.concurrent:
 concurrencyfile.write("[" + str(x) + "]")
 concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
I-376	I-376	[]	None	None	None
US19	US19
US22	US22
US30	US30
TrkS	TrkS
TrkN	TrkN

[yakra]

for h in highway_systems:
# h = usaus
 for r in h.route_list:
 # r = pa.us022
 for s in r.segment_list:
 # s = [I-376(69A) to I-376(69B) via pa.us022]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 for w1 in s.waypoint1.colocated:
 # w1 = pa.us022@I-376(69A)
 if w1.route is not r:
 # w1.route = pa.us022; True
 for w2 in s.waypoint2.colocated:
 # w2 = pa.i376@69B
 if w1.route is w2.route:
 # True
 other = w1.route.find_segment_by_waypoints(w1,w2)
 if other is not None:
 # other = [69A to 69B via pa.i376]
 if s.concurrent is None:
 # First pass for US22; True
 s.concurrent = []
 # empty list
 other.concurrent = s.concurrent
_______________________________________ # The I-376 segment's list becomes empty too. Wait. Did we mean to do that? _______________________________________
 s.concurrent.append(s)
 #
 s.concurrent.append(other)
 #
 concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 else:
 if other not in s.concurrent:
 #
 s.concurrent.append(other)
 #
 #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 concurrencyfile.write("Extended concurrency ")
 for x in s.concurrent:
 concurrencyfile.write("[" + str(x) + "]")
 concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
[]	I-376	[]	None	None	None
	US19
	US22
	US30
	TrkS
	TrkN

[yakra]

for h in highway_systems:
# h = usaus
^ for r in h.route_list:
| # r = pa.us022
|___. for s in r.segment_list:
 | # s = [I-376(69A) to I-376(69B) via pa.us022]
 | if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 | # True
 |_______. for w1 in s.waypoint1.colocated:
 | # w1 = pa.us022@I-376(69A)
 | if w1.route is not r:
 | # w1.route = pa.us022; True
 |_______. for w2 in s.waypoint2.colocated:
 | # w2 = pa.i376@69B
 | if w1.route is w2.route:
 | # True
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other = [69A to 69B via pa.i376]
 | if s.concurrent is None:
 | # First pass for US22; True
 | s.concurrent = []
 | # empty list
 | other.concurrent = s.concurrent
 | # I-376 segments' list empty too.
 | s.concurrent.append(s)
 | # I-376 & US22 get US22
 | s.concurrent.append(other)
 | # I-376 & US22 get I-376
 |__________________ concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 else:
 if other not in s.concurrent:
 #
 s.concurrent.append(other)
 #
 #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 concurrencyfile.write("Extended concurrency ")
 for x in s.concurrent:
 concurrencyfile.write("[" + str(x) + "]")
 concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
US22	I-376	US22	None	None	None
I-376	US19	I-376
	US22
	US30
	TrkS
	TrkN

...and so on until the rest of the two lists are populated.
...and so on with each new route overwriting I-376's progress with an empty list, until...

[yakra]

for h in highway_systems:
# h = usausb
 for r in h.route_list:
 # r = pa.us019trkpit
 for s in r.segment_list:
 # s = [I-376(69B)_S to I-376(69A) via pa.us019trkpit]
 if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 # True
 .-> for w1 in s.waypoint1.colocated:
 | # w1 = pa.i376@69B, pa.us019@I-376(69B), pa.us022@I-376(69B), pa.us030@I-376(69B) ...
 | if w1.route is not r:
 | # True for I-376, US19, US22, US30
 | for w2 in s.waypoint2.colocated:
 | # w2 = pa.i376@69A, pa.us019@I-376(69A), pa.us022@I-376(69A), pa.us030@I-376(69A) ...
 | if w1.route is w2.route:
 | # True once for each
 | other = w1.route.find_segment_by_waypoints(w1,w2)
 | if other is not None:
 | # other is not None:
 | if s.concurrent is None:
 | # First pass for [I-376(69B)_S to I-376(69A) via pa.us019trkpit] True; subsequent passes false
 | s.concurrent = []
 | # empty list
 | other.concurrent = s.concurrent
 | # 1st pass: I-376 segments' list empty too.
 | s.concurrent.append(s)
 | # 1st pass: I-376 & TrkS get TrkS
 | s.concurrent.append(other)
 | # 1st pass: I-376 & TrkS get I-376
 | concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 | else:
 | if other not in s.concurrent:
 | #
 | s.concurrent.append(other)
 | # 2nd+ passes: I-376 & TrkS get US19, 22, 30
 | #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 | concurrencyfile.write("Extended concurrency ")
 | for x in s.concurrent:
 | concurrencyfile.write("[" + str(x) + "]")
 |______________________________ concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
TrkS	I-376	US22	US30	TrkS	None
I-376	US19	I-376	I-376	I-376
US19	US22	US19	US19	US19
US22	US30	US30	US22	US22
US30	TrkS	TrkS	TrkS	US30
	TrkN	TrkN	TrkN

[yakra]

for h in highway_systems:
# h = usausb
 for r in h.route_list:
 # r = pa.us019trkpit
 .-> for s in r.segment_list:
 | # s = [I-376(69B)_S to I-376(69A) via pa.us019trkpit]
 | if s.waypoint1.colocated is not None and s.waypoint2.colocated is not None:
 | # True
 | for w1 in s.waypoint1.colocated:
 | # w1 = ... pa.us019trkpit@I-376(69B)_S, pa.us019trkpit@I-376(69B)_N
 | if w1.route is not r:
 |______________ # w1.route is r for both remaining points; nothing else happens; concurrency remains at 5 routes
 for w2 in s.waypoint2.colocated:
 #
 if w1.route is w2.route:
 #
 other = w1.route.find_segment_by_waypoints(w1,w2)
 if other is not None:
 #
 if s.concurrent is None:
 #
 s.concurrent = []
 #
 other.concurrent = s.concurrent
 #
 s.concurrent.append(s)
 #
 s.concurrent.append(other)
 #
 concurrencyfile.write("New concurrency [" + str(s) + "][" + str(other) + "] (" + str(len(s.concurrent)) + ")\n")
 else:
 if other not in s.concurrent:
 #
 s.concurrent.append(other)
 #
 #concurrencyfile.write("Added concurrency [" + str(s) + "]-[" + str(other) + "] ("+ str(len(s.concurrent)) + ")\n")
 concurrencyfile.write("Extended concurrency ")
 for x in s.concurrent:
 concurrencyfile.write("[" + str(x) + "]")
 concurrencyfile.write(" (" + str(len(s.concurrent)) + ")\n")

I-376	US19	US22	US30	TrkS	TrkN
TrkS	I-376	US22	US30	TrkS	None
I-376	US19	I-376	I-376	I-376
US19	US22	US19	US19	US19
US22	US30	US30	US22	US22
US30	TrkS	TrkS	TrkS	US30
	TrkN	TrkN	TrkN

...Finally we test the one last segment, [I-376(69A) to I-376(69B)_N via pa.us019trkpit].
As with [I-376(69B)_S to I-376(69A) via pa.us019trkpit], two of the w1 points are for its own route.
[I-376(69A) to I-376(69B)_N via pa.us019trkpit] thus plugs itself into its own concurrency list, and I-376, and doesn't detect [I-376(69B)_S to I-376(69A) via pa.us019trkpit].
This leaves our final concurrency lists looking like:

I-376	US19	US22	US30	TrkS	TrkN
TrkN	I-376	US22	US30	TrkS	TrkN
I-376	US19	I-376	I-376	I-376	I-376
US19	US22	US19	US19	US19	US19
US22	US30	US30	US22	US22	US22
US30	TrkS	TrkS	TrkS	US30	US30
	TrkN	TrkN	TrkN

...which we can see in concurrencies.log.

[yakra]

Why the differences in concurrencies.log?

One more line sometimes, in concurrency detection:

• Lines occur in clusters, when a new currency is found, and when it's extended.
• A cluster for the 2nd route in a concurrency is not shown: new concurrencies are not found because they were flagged during the 1st pass, from the 1st route's HighwaySegment.
• Sometimes 6 concurrencies are found, and sometimes 5: 5 when searching for a concurrent segment for US19TrkPit itself, and 6 when searching for a concurrent segment for one of the other routes.
• Normally, as is the case when running siteupdate with 1 thread, US19 (or another non-US19TrkPit route) is second, and we don't see a cluster of 5 lines for a 6-segment concurrency. Sometimes when multithreaded, US19TrkPit is second, and we don't see a cluster of 4 lines for a 5-segment concurrency. US19 (or whatever else) is no longer second, so we do see its cluster of 5 lines now. BOOM! Extra line.

We see this on line 114911 of
http://yakra.teresco.org/tests/concurrencies/y20181119/m/concurrencies-3.log :
Extended concurrency [69A to 69B via pa.i376][I-376(69B)_S to I-376(69A) via pa.us019trkpit][I-376(69A) to I-376(69B)_N via pa.us019trkpit][I-376(69A) to I-376(69B) via pa.us019][I-376(69A) to I-376(69B) via pa.us022][I-376(69A) to I-376(69B) via pa.us030] (6)
This also explains...

Why we have 18 more augments for the travelers .listing only the I-376 segment:

• When running siteupdate with 1 thread, the northern US19Trk segment is tested last, overwriting the concurrency list for I-376 in the process. The southern US19Trk segment isn't detected, so it gets no entry in I-376's list, and thus these 18 travelers get no concurrency augment.
• When running with multiple threads, a different route (US30 in the above example) is usually last. All concurrencies are found & written to I-376's list, and these travelers get their augments.

As noted in the OP, adding a single other.concurrent = s.concurrent to the ELSE block ought to fix things.

What if US19TrkPit is tested first?

Shouldn't be a problem. 5 concurrencies will be detected in the first pass. On the second pass, when checking a different route, all 6 concurrencies will be found. The 6th one, newly detected, will be added to all the lists.

Yeah man. I'm gonna try this out!

[jteresco]

Wow, thanks for the epic debugging session. If this works (or even if not) I hereby award you TM's first ever Excellence in Finding Insidious Bugs award, and all the rights, privileges, and responsibilities appertaining thereto.