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a crew from the available crews that have the lowest driving hours and, after adding the new duty, the total driving hours should not exceed maximum daily driving hours.
The next subsections discuss examples of the crew rescheduling rules applied to every type of event in detail.
4.2.3 LFSO and
DFSO
The rules regarding LFSO and DFSO are the same because they are the same except for the difference in timing as explained in the previous section. In the event of LFSO or
DFSO, the available crews are those that have sign-on at least 5 minutes before the work start time of the late-crew’s duty and those whose work start is later than the work
start time of the late-crew’s duty. The chosen crew is the one that has the same or later starting time of duty as the ready time of the late-crew. If there are more than one crews
available, then the latest starting time will be chosen. To aid understanding of these rules, this section will explain some of the examples of the rescheduling process.
Table 4.1 shows a summary of a crew schedule, which was taken from a bus company in London. This schedule will be used to show some examples. It has 45 duties. Crew
ID shows the identification of a crew. Duty no. indicates the number of a duty, sign-on indicates the time for a crew to report for duty,
start work 1 refers to the starting time of the first
work piece. Normally, a duty has two work pieces. End work 1 shows the end time for the first
work piece. Start relief and end relief show the start and finish timed for reliefbreak.
Start work 2 refers to the starting time of the second work piece. End work 2 indicates the end time of second work piece. Sign-off indicates the time of a
crew signing off from work.
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Table 4.1: Example of a Crew Schedule
Crew ID Duty No
Sign-On Start
Work 1 End
Work 1 Start
Relief End
Relief Start
Work 2 End
Work 2 Sign-Off
A 1
03:34:00 03:49:00
08:10:00 08:15:00 09:00:00 09:05:00 11:02:00 11:07:00
B 2
03:43:00 03:58:00
08:16:00 08:21:00 09:30:00 09:35:00 11:34:00 11:53:00
C 3
03:53:00 04:08:00
08:52:00 08:57:00 09:51:00 09:56:00 11:58:00 12:17:00
D 4
04:03:00 04:18:00
08:52:00 08:57:00 10:03:00 10:08:00 12:10:00 12:41:00
E 5
04:13:00 04:28:00
09:09:00 09:14:00 10:15:00 10:20:00 12:22:00 12:41:00
F 6
04:23:00 04:38:00
09:22:00 09:27:00 10:27:00 10:32:00 12:34:00 12:53:00
G 7
04:33:00 04:48:00
09:58:00 10:03:00 11:03:00 11:08:00 13:10:00 13:35:00
H 8
04:41:00 04:56:00
10:10:00 10:15:00 11:09:00 11:14:00 13:16:00 13:35:00
I 9
04:48:00 05:03:00
08:26:00 08:31:00 09:24:00 09:29:00 13:02:00 13:21:00
J 10
04:56:00 05:11:00
10:40:00 10:45:00 11:35:00 11:40:00 13:14:00 13:35:00
K 11
05:03:00 05:18:00
10:46:00 10:51:00 11:53:00 11:58:00 13:32:00 13:53:00
L 12
05:11:00 05:26:00
08:53:00 08:58:00 09:53:00 09:58:00 13:34:00 13:53:00
M 13
05:18:00 05:33:00
09:05:00 09:10:00 10:05:00 10:10:00 13:46:00 14:05:00
N 14
05:30:00 05:45:00
09:29:00 09:34:00 10:35:00 10:40:00 14:16:00 14:35:00
O 15
05:47:00 06:02:00
09:56:00 10:01:00 10:57:00 11:02:00 14:38:00 15:05:00
P 16
05:55:00 06:10:00
11:10:00 11:15:00 12:05:00 12:10:00 13:44:00 14:05:00
Q 17
05:56:00 06:11:00
10:08:00 10:13:00 11:05:00 11:10:00 14:46:00 15:05:00
R 18
05:59:00 06:14:00
10:20:00 10:25:00 11:17:00 11:22:00 14:58:00 15:17:00
S 19
06:00:00 06:15:00
11:22:00 11:27:00 12:17:00 12:22:00 13:56:00 14:23:00
T 20
06:05:00 06:20:00
10:32:00 10:37:00 11:27:00 11:32:00 14:56:00 15:17:00
U 21
06:09:00 06:24:00
10:38:00 10:43:00 11:33:00 11:38:00 13:40:00 14:05:00
V 22
06:10:00 06:25:00
09:35:00 09:40:00 10:33:00 10:38:00 14:14:00 14:35:00
W 23
06:13:00 06:28:00
10:50:00 10:55:00 11:47:00 11:52:00 13:26:00 13:53:00
X 24
06:15:00 06:30:00
11:02:00 11:07:00 11:57:00 12:02:00 14:04:00 14:23:00
Y 25
06:17:00 06:32:00
11:08:00 11:13:00 12:03:00 12:08:00 14:10:00 14:35:00
Z 26
06:20:00 06:35:00
11:14:00 11:19:00 12:11:00 12:16:00 13:50:00 14:23:00
AA 27
06:25:00 06:40:00
11:52:00 11:57:00 12:47:00 12:52:00 14:26:00 14:45:00
AB 28
06:26:00 06:41:00
11:26:00 11:31:00 12:33:00 12:38:00 14:40:00 15:05:00
AC 29
06:35:00 06:50:00
11:38:00 11:43:00 12:41:00 12:46:00 14:20:00 14:45:00
AD 30
06:42:00 06:57:00
11:50:00 11:55:00 13:03:00 13:08:00 15:10:00 15:45:00
AE 31
06:46:00 07:01:00
11:56:00 12:01:00 13:15:00 13:20:00 15:21:00 15:45:00
AF 32
06:57:00 07:12:00
12:08:00 12:13:00 13:47:00 13:52:00 15:26:00 15:45:00
AG 33
07:14:00 07:29:00
12:26:00 12:31:00 13:27:00 13:32:00 15:32:00 16:09:00
AH 34
07:20:00 07:35:00
12:38:00 12:43:00 13:45:00 13:50:00 15:50:00 16:09:00
AI 35
08:36:00 08:51:00
12:16:00 12:21:00 15:16:00 15:21:00 19:56:00 20:01:00
AJ 36
10:26:00 10:50:00
12:52:00 12:57:00 14:05:00 14:10:00 19:01:00 19:06:00
AK 37
10:56:00 11:20:00
13:22:00 13:27:00 14:35:00 14:40:00 19:28:00 19:33:00
AL 38
10:56:00 11:26:00
15:02:00 15:07:00 16:09:00 16:14:00 19:39:00 19:44:00
AM 39
11:26:00 11:56:00
13:58:00 14:03:00 15:05:00 15:10:00 19:53:00 19:58:00
AN 40
11:26:00 11:50:00
13:52:00 13:57:00 14:57:00 15:02:00 20:28:00 20:33:00
AO 41
11:56:00 12:26:00
14:28:00 14:33:00 15:27:00 15:32:00 20:05:00 20:10:00
AP 42
11:56:00 12:20:00
14:22:00 14:27:00 15:21:00 15:26:00 20:43:00 20:48:00
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For example, crew P is assigned duty No.16. The crew is supposed to sign-on at 5:55 but for some reason the crew is 15 minutes late. The crew then informs the supervisor at
the garage that heshe will arrive at 6:10. The ready time for crew P is 6:15 arrival time plus 5 minutes. According to the rules, the available crews are those who have sign-on
before or at 6:05 5 minutes before the start work 1 of duty No.16. Based on the crew schedule presented in Table 4.1, we do the rescheduling process according to the rules
stated above. The results show that crews Q, R, S and T are available to take duty No.16 as shown in Table 4.2.
Table 4.2: The Rescheduling of 15 Minutes LFSO of Duty 16
Crew ID Duty No Sign-On Start
Work 1 New Start
Time Need More
Rescheduling Waiting Time
for Late-Crew
Q 17
05:56:00 06:11:00
06:10:00 Y NA
R 18
05:59:00 06:14:00
06:10:00 Y NA
S 19
06:00:00 06:15:00
06:10:00 N
00:00:00 T
20 06:05:00
06:20:00 06:10:00
N 00:05:00
Table 4.2 shows crew ID, duty no., sign-on, start work 1, new start time, need more
rescheduling and waiting time for late-crew. New start time is a start working time for duty No.16.
Need more rescheduling shows that if a crew takes the duty, hisher original duty will need to be rescheduled to other or it will be taken by the late-crew,
and waiting time for late-crew shows the time for the late-crew to wait before heshe
can start their new duty if that duty is assigned to the late-crew. In this example, crew S is the best option to take duty 16. The new start time for crew S is 6:10, no further
rescheduling is needed and the late-crew does not need to wait when he arrives. The late-crew will take crew S’s duty, which is duty no.19.
If more rescheduling is needed to find matches then in the first round the late-crew’s duty will be assigned to the available crew that has the latest start time of hisher
original duty. This is because the later the starting time of the original duty is; the closer it is to the arrival time of the late-crew. This will result less in rounds of
rescheduling and fewer crews will be affected by the changes. After that, rescheduling will continue until the system finds a new duty for the late-crew. For example, crew P is
30 minutes late. HeShe arrives at 6:25 and heshe is ready to work at 6:30. The rescheduling process in Table 4.3a shows that show that all the available crews need
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more rescheduling because crew P is only available at 6:30, which does not match any of the available duty. In this case, we need to find the crew that has the latest start work
1, which in this example is crew T 6:20. Therefore, crew T is chosen to take over duty 16. The second round reassignment is needed to reassign duty no. 20, which was
originally assigned to crew T. Duty no. 20’s start work time is 06:20. Whoever has a sign-on before or at 06:15 is eligible to take over duty 20. Table 4.3b shows the results
of second round rescheduling. The results show that crew X is the most suitable to take duty no. 20 because no more rescheduling is needed and there is zero waiting time for
late-crew. The overall results from this example show that crew P takes duty no. 24, crew T takes duty no. 16 and crew X takes duty no. 20.
Table 4.3a: First Round Rescheduling: 30 Minutes LFSO
Crew ID Duty No Sign-On Start
Work 1 New Start
Time Need More
Rescheduling Waiting Time for
Late-Crew
Q 17
05:56:00 06:11:00
06:10:00 Y NA
R 18
05:59:00 06:14:00
06:10:00 Y NA
S 19
06:00:00 06:15:00
06:10:00 Y NA
T 20
06:05:00 06:20:00
06:10:00 Y
NA
Table 4.3b: Second Round Rescheduling: Reassign Duty No. 20
Crew ID Duty No Sign-On Start
Work 1 New Start
Time Need More
Rescheduling Waiting Time for
Late-Crew
U 21
06:09:00 06:24:00
06:20:00 Y NA
V 22
06:10:00 06:25:00
06:20:00 Y NA
W 23
06:13:00 06:28:00
06:20:00 Y NA
X 24
06:15:00 06:30:00
06:20:00 N
00:00:00
4.2.4 LFR, LFSW and DFSW
