§ 41.01 – Under what conditions may I use ready-to-use sampling plans?

(a)    Small Systems – If you operate no more than 30 vehicles operated in maximum service for all modes combined and if you choose to sample for determining your annual service-consumed data for any of the modes you operate. 

(b)   New Mode – If you will be sampling and reporting for the first time this current report year for a particular mode that you do not already operate.  For example, you would meet this condition if you will add light rail (LR) service this year, but you have not operated this service previously, or

(c)    New Type of Service – If you will be sampling and reporting this current report year for a particular type of service for the first time.  For example, you would meet this condition if you previously directly operated all of your bus (MB) service, but will contract out part or all of that service to a private entity for this year, or

(d)   Major Changes of Service – You have made major changes to your service since your last sampling year, or

(e)    No Sample Data – If you have reported your service to the NTD before through random sampling, but no longer have the original sample data, or

(f)    Sample Data Not Reliable – If you have reported your service to the NTD before through random sampling, but the sample data are found to be not reliable, or

(g)   Sample Data Not Enough – if you have reported your service to the NTD before through random sampling, but the sample size is smaller than 50 service units.

§ 41.03 – If I am using a ready-to-use sampling plan this year, may I use it again for my next report year?

(a)    You should not use it again if your next report year is your mandatory sampling year.  After you have collected the sample data from this year, you should develop a template sampling plan with that sample data for your next report year.

(b)   You may use it again for the next report year if that year is not your mandatory sampling year.

(c)    You may use it while you operate no more than 30 vehicles operated in maximum service for all modes combined.

§ 41.05 – For what modes are ready-to-use sampling plans available?

(a)    For non-scheduled services, they are available for demand response services (DR and DT) and commuter vanpool.  You should not use the ready-to-use sampling plans for commuter vanpool if your vanpool service does not serve commuters exclusively.

(b)   For scheduled services, they are available for bus services (bus (MB), commuter bus (CB), bus rapid transit (RB), and trolleybus (TB)), commuter rail (CR), and other rail modes. 

§ 41.07 – What sampling options are available?

(a)    The available sampling options vary in:

(1)   the unit of sampling and measurement,

(2)   sampling structure,

(3)   efficiency options, and

(4)   sampling frequency.

(b)   The particular unit of sampling and measurement used in these ready-to-use sampling plans varies by mode and whether the service is scheduled (Table 41.01).

(1)   For non-scheduled services, the unit is in vehicle days.

(2)   For bus services (MB, CB, RB, and TB), separate sampling plans are available with units in one-way trips and in round trips.

(3)   For commuter rail, the unit is in one-way car trips.

(4)   For other rail modes, separate sampling plans are available in units of one-way car trips and one-way train trips.

Table 41.01.  Options for Unit of Sampling and Measurement

Service

Mode

Units of Sampling and Measurement

Non-Scheduled

Demand Response (DR, DT)

Vehicle days

Commuter Vanpool

Vehicle days

Scheduled

Bus (MB, CB, RB, TB)

One-way trips, round trips

Commuter Rail (CR)

One-way car trips

Other Rail Modes

One-way car trips, one-way train trips

(c)    Two options are provided for sampling structure—period-based and interval-based.  Interval-based sampling plans are available for bus services only.

(d)   Three efficiency options are provided:

(1)   Base Option – you must estimate both UPT and PMT through random sampling.

(2)   APTL Option – you must report a 100% count of UPT, estimate the average passenger trip length (APTL) through random sampling, and obtain annual PMT by multiplying the 100% UPT with the estimated APTL.

(3)   Grouping Option – you must divide your bus routes into two groups by route length.  The grouping option is available for period-based sampling plans only.

(e)    Three frequency options are provided for period-based sampling plans—quarterly, monthly, or weekly.  You may choose whichever of these options is best suited for your agency.  One factor to consider is that the annual realized sample size may be larger at a lower sampling frequency due to rounding.  Another factor is that a lower sampling frequency means a larger annual number of acts for random sampling.

(f)    Up to six frequency options are provided for interval-based sampling plans—every day, every 2nd day, every 3rd day, every 4th day, every 5th day, and every 6th day.  Three sets of these sampling plans are available for 7-day weekly service, 6-day weekly service, and 5-day weekly service, respectively.  The sampling plans for 7-day weekly service and the base option are similar to those in Circular 2710.1A.

§ 43.01 – What period-based sampling plans are available for non-scheduled services?

 (a)    Table 43.01 shows the sampling plans available for demand response services (DR and DT) and commuter vanpool, respectively.

(b)   Sample size is stated in the number of vehicle days.

(c)    Separate sampling plans are available for the base option and the APTL option.

(d)   Sample size is shown for the entire year and for the relevant period for each frequency.

Table 43.01.  Period-Based Ready-to-Use Sampling Plans for Non-Scheduled Services

Sampling Frequency Sample Size

Demand Response

Commuter Vanpool

Reporting 100% UPT

(APTL Option)

Not Reporting 100% UPT

(Base Option)

Reporting 100% UPT

(APTL Option)

Not Reporting 100% UPT

(Base Option)

Quarterly Vehicle Days for a Quarter

13

22

31

45

Total Sample Size for Year

52

88

124

180

Monthly Vehicle Days for a Month

5

8

10

15

Total Sample Size for Year

60

96

120

180

Weekly Vehicle Days for a Week

1

2

2

4

Total Sample Size for Year

52

104

104

208

§ 43.03 – What period-based ready-to-use sampling plans are available for bus services?

(a)    Table 43.03 shows the available ready-to-use sampling plans for bus services, including bus (MB), commuter bus (CB), bus rapid transit (RB), and trolleybus (TB). 

Table 43.03.  Period-Based Ready-to-Use Sampling Plans for Bus Services

Sampling Frequency

Sample Size for Period and Year

One-Way Trips

Round Trips

Reporting 100% UPT

(APTL Option)

Not Reporting 100% UPT

(Base Option)

Reporting 100% UPT

(APTL Option)

Not Reporting 100% UPT

(Base Option)

With Route Grouping

Without Route Grouping

With Route Grouping

Without Route Grouping

(1)

(2)

(3)

(4)

(5)

(6)

Quarterly

Trips for a Quarter

52

78

138

39

59

103

Total Sample Size for Year

208

312

552

156

236

412

Monthly

Trips for a Month

18

27

46

13

20

35

Total Sample Size for Year

216

324

552

156

240

420

Weekly

Trips for a Week

4

6

11

3

5

8

Total Sample Size for Year

208

312

572

156

260

416

(b)    Sampling plans are provided separately for one-way trips and round trips. 

(c)   The number of one-way trips in a sampling plan based on round trips is about 50% greater than the number of one-way trips in a sampling plan based on one-way trips.  A sampling plan based on round trips requires a larger number of one-way trips because the pair of one-way trips making up a round trip are not selected randomly or independently.

(d)    If you choose the base option:

(1)   use column (3) to find the sample size in one-way trips, and

(2)   use column (6) to find the sample size in round trips.

(e)   If you choose the APTL option, you may choose one of two options:

(1)   With Route Grouping – Use column (1) to find the sample size in one-way trips and column (4) to find the sample size in round trips.  In using this option, you must divide your routes into two groups on the basis of route length and do sampling and estimation separately for each group.  For example, if you operate 10 routes, put the 5 routes with the shortest route distances in the group of short routes and the other 5 routes in the group of long routes. 

(2)   Without Route Grouping – If you prefer not to deal with grouping your routes, use column (2) to find the sample size in one-way trips and use column (5) to find the sample size in round trips.

§ 43.07 – What period-based sampling plans are available for commuter rail?

(a)    Table 43.05 shows the available ready-to-use sampling plans for commuter rail (CR). 

(b)   Sample size is in one-way car trips.

(c)    Separate sampling plans are available for the base option and the APTL option.

Table 43.05.  Period-Based Ready-to-Use Sampling Plans for Commuter Rail (CR)

Sampling Frequency

Sample Size for Period and Year

Reporting 100% UPT

(APTL Option)

Not Reporting 100% UPT

(Base Option)

Quarterly

One-Way Car Trips for a Quarter

13

80

Total Sample Size for Year

52

320

Monthly

One-Way Car Trips for a Month

5

27

Total Sample Size for Year

60

324

Weekly

One-Way Car Trips for a Week

1

7

Total Sample Size for Year

52

364

§ 43.09 What period-based sampling plans are available for other rail modes?

(a)    Table 43.07 shows the available ready-to-use sampling plans for other rail modes, including light rail (LR), heavy rail (HR), monorail and automated guideway (MG). 

(b)   Separate sampling plans are available for one-way train trips and one-way car trips.

(c)    Separate sampling plans are available for the base option and for the APTL option.

Table 43.07.  Period-Based Ready-to-Use Sampling Plans for Other Rail Modes

Sampling Frequency

Sample Size for Period and Year

One-Way Train Trips

One-Way Car Trips

Reporting 100% UPT

(APTL Option)

Not Reporting 100% UPT

(Base Option)

Reporting 100% UPT

(APTL Option)

Not Reporting 100% UPT

(Base Option)

Quarterly

Trips for a Quarter

13

45

13

72

Total Sample Size for Year

52

180

52

288

Monthly

Trips for a Month

5

15

5

24

Total Sample Size for Year

60

180

60

288

Weekly

Trips for a Week

1

4

1

6

Total Sample Size for Year

52

208

52

288

§ 43.11 – What interval-based ready-to-use sampling plans are available for bus services?

(a)    Table 43.09 shows the available ready-to-use sampling plans for bus services, including bus (MB), commuter bus (CB), bus rapid transit (RB), and trolleybus (TB). 

(b)   Separate sampling plans are available for the base option and the APTL option.

(c)    In determining whether using interval-based sampling plans, you should consider the tradeoff between at least two factors:

(1)   the advantage of using a sampling plan that you have been using for years, and

(2)   the potentially lost opportunity of a lower sample size.

(d)   You should first determine the number of weekly operating days for your next sampling year, and choose the set of sampling plans accordingly.  For example, if you will be operating 7 days a week, you should not consider any of the sets for the other weekly operating patterns.

(e)    You may choose any of the above plan numbers that correspond to the weekly operating pattern of your service.

Table 43.09.  Interval-Based Ready-to-Use Sampling Plans for Bus Services

Plan Number

Frequency of Sampling

Operating 7 Days a Week

Operating 6 Days a Week

Operating 5 Days a Week

Daily One-Way Bus Trips

Total Sample Size for Year

Daily One-Way Bus Trips

Total Sample Size for Year

Daily One-Way Bus Trips

Total Sample Size for Year

Base Option

1

Every Day

2

730

2

624

2

520

2

Every 2nd Day

3

549

3

468

4

520

3

Every 3rd Day

5

610

6

624

7

609

4

Every 4th Day

7

644

9

702

12

780

5

Every 5th Day

10

730

13

819

N/A

N/A

6

Every 6th Day

15

915

N/A

N/A

N/A

N/A

APTL Option

1

Every Day

1

365

1

312

1

260

2

Every 2nd Day

2

366

2

312

3

390

3

Every 3rd Day

3

366

4

416

5

435

4

Every 4th Day

4

368

6

468

8

520

5

Every 5th Day

6

438

8

504

 

 

6

Every 6th Day

10

610