Halifax Transit is now tracking and releasing data on the reliability of it's bus routes. The number is the percentage of buses arriving between 1 minute early and 3 minutes late. There is no exact target identified but 80%+ is considered reliable.
Halifax Transit - 2017/18 Q1 Report
WEEKDAY OFF-PEAK (STANDARD ROUTES ONLY)
1. 56 - DARTMOUTH CROSSING (96%)
1. 83 - SPRINGFIELD (96%)
1. 88 - BEDFORD COMMONS (96%)
4. 58 - WOODLAWN (95%)
5. 57 - RUSSELL LAKE (94%)
6. 89 - BEDFORD (93%)
7. 63 - WOODSIDE (90%)
...
39. 2 - WEDGEWOOD (69%)
40. 87 - GLENDALE (69%)
41. 1 - SPRING GARDEN (67%)
42. 14 - LEIBLIN PARK (65%)
43. 17 - SAINT MARY'S (64%)
44. 20 - HERRING COVE (59%)
WEEKDAY ON-PEAK (STANDARD ROUTES ONLY)
1. 56 - DARTMOUTH CROSSING (97%)
1. 57 - RUSSELL LAKE (97%)
3. 88 - BEDFORD COMMONS (96%)
4. 83 - SPRINGFIELD (95%)
5. 58 - WOODLAWN (94%)
6. 89 - BEDFORD (93%)
7. 63 - WOODSIDE (90%)
...
37. 66 - PENHORN (59%)
38. 6 - QUINPOOL (58%)
39. 17 - SAINT MARY'S (57%)
40. 18 - UNIVERSITIES (54%)
41. 2 - WEDGEWOOD (52%)
41. 14 - LEIBLIN PARK (52%)
43. 1 - SPRING GARDEN (51%)
44. 20 - HERRING COVE (49%)
WEEKDAY ON-PEAK (NON-STANDARD ROUTES)
1. 78 - MOUNT EDWARD EXPRESS (100%)
2. 330 - SHELDRAKE LAKE / TANTALLON (92%)
...
19. 23 - TIMBERLEA / MUMFORD (69%)
19. 64 - AKERLEY (64%)
21. 86 - BASINVIEW EXPRESS (64%)
It's not surprising that the most reliable routes are suburban feeders that usually serve one terminal and cover short distances. The least reliable routes are also not surprising for the most part. These routes are located in the heart of the urban area and have to battle traffic on congested arterial streets. Many also have very long routes raising the likelihood of something going wrong.