Section 3.9 Intermediate Stop Frequency Model

The individual tour stop frequency model predicts the number of stops for each person by primary tour purpose (work, school, university, shopping, escorting, maintenance, discretionary, visiting, and eating). The number of stops is predicted by tour direction - outbound (stops made between home and the primary destination) versus inbound (stops made on the way back home). Thus the models have 16 alternatives: the number of inbound stops (0 through 3) combined with the number of outbound stops (0 through 3). The base alternative for calibrating the individual tour stop frequency model is the 0 outbound and 0 inbound stops alternative. Several runs through the model were done to achieve satisfactory levels of calibration. Table 3-13a shows the target intermediate stop frequency shares for each tour purpose, while Table 3-13b shows the model estimated tour stop frequency probabilities by tour purpose. The model matches the observed stop frequency shares reasonably close.


Table 3-13a. Survey Tour Stop Frequency by Tour Purpose

Stop Frequency Work University School Escort Shop Maintenance Social/Eating Out Discretionary Work-Based
0 outbound, 0 inbound 54.1% 64.5% 73.1% 70.7% 43.4% 51.8% 69.2% 65.1% 77.8%
0 outbound, 1 inbound 14.8% 11.5% 11.3% 11.3% 10.4% 16.7% 7.5% 12.6% 8.1%
0 outbound, 2 inbound 5.3% 4.6% 3.8% 2.6% 3.0% 4.9% 2.1% 3.3% 1.8%
0 outbound, 3 inbound 3.1% 3.9% 1.5% 1.4% 1.8% 3.7% 1.2% 1.7% 0.8%
1 outbound, 0 inbound 6.8% 5.6% 4.8% 6.6% 16.3% 6.9% 9.0% 7.8% 5.8%
1 outbound, 1 inbound 5.3% 2.5% 3.2% 2.3% 6.4% 5.1% 4.1% 3.5% 2.7%
1 outbound, 2 inbound 2.0% 0.9% 0.5% 0.6% 3.0% 1.5% 0.8% 1.0% 0.2%
1 outbound, 3 inbound 1.2% 1.0% 0.3% 0.4% 1.3% 1.8% 0.1% 0.3% 0.2%
2 outbound, 0 inbound 1.9% 2.0% 0.5% 2.3% 5.4% 3.1% 2.8% 1.5% 1.5%
2 outbound, 1 inbound 1.5% 0.7% 0.5% 0.3% 2.1% 1.3% 1.1% 0.8% 0.3%
2 outbound, 2 inbound 0.7% 0.8% 0.3% 0.2% 1.1% 0.6% 0.4% 0.2% 0.1%
2 outbound, 3 inbound 0.4% 0.3% 0.0% 0.1% 0.8% 0.1% 0.1% 0.2% 0.1%
3 outbound, 0 inbound 1.1% 1.2% 0.1% 1.0% 2.6% 1.4% 1.0% 1.2% 0.3%
3 outbound, 1 inbound 0.9% 0.1% 0.0% 0.2% 1.5% 0.4% 0.3% 0.6% 0.1%
3 outbound, 2 inbound 0.5% 0.3% 0.0% 0.0% 0.4% 0.3% 0.2% 0.2% 0.1%
3 outbound, 3 inbound 0.5% 0.0% 0.1% 0.0% 0.5% 0.4% 0.0% 0.1% 0.1%

Table 3-13b. Model Tour Stop Frequency by Tour Purpose

Stop Frequency Work University School Escort Shop Maintenance Social/Eating Out Discretionary Work-Based
0 outbound, 0 inbound 53.3% 69.6% 73.2% 71.8% 43.6% 51.2% 69.6% 65.8% 77.7%
0 outbound, 1 inbound 15.5% 15.5% 11.1% 11.0% 10.8% 16.4% 7.7% 12.5% 8.8%
0 outbound, 2 inbound 4.9% 0.0% 4.4% 2.6% 3.7% 5.2% 1.8% 2.9% 1.5%
0 outbound, 3 inbound 3.0% 0.0% 2.0% 1.4% 1.7% 4.3% 0.8% 1.3% 0.8%
1 outbound, 0 inbound 7.3% 8.5% 4.0% 5.7% 16.3% 6.8% 9.5% 8.1% 5.3%
1 outbound, 1 inbound 5.2% 6.4% 2.5% 2.2% 5.8% 4.1% 4.4% 3.9% 2.8%
1 outbound, 2 inbound 2.2% 0.0% 0.6% 0.7% 3.1% 1.6% 0.6% 1.1% 0.3%
1 outbound, 3 inbound 1.2% 0.0% 0.3% 0.4% 1.2% 1.9% 0.1% 0.4% 0.5%
2 outbound, 0 inbound 1.9% 0.0% 0.5% 2.2% 4.9% 3.2% 2.4% 1.5% 1.3%
2 outbound, 1 inbound 1.5% 0.0% 0.4% 0.2% 2.1% 1.6% 0.9% 0.8% 0.2%
2 outbound, 2 inbound 0.8% 0.0% 0.3% 0.1% 0.9% 0.4% 0.5% 0.1% 0.0%
2 outbound, 3 inbound 0.4% 0.0% 0.5% 0.1% 0.6% 0.3% 0.3% 0.3% 0.2%
3 outbound, 0 inbound 1.1% 0.0% 0.1% 1.5% 2.7% 1.5% 1.1% 0.9% 0.3%
3 outbound, 1 inbound 0.7% 0.0% 0.0% 0.2% 1.4% 0.5% 0.3% 0.3% 0.2%
3 outbound, 2 inbound 0.5% 0.0% 0.0% 0.0% 0.5% 0.4% 0.2% 0.0% 0.0%
3 outbound, 3 inbound 0.4% 0.0% 0.1% 0.0% 0.5% 0.6% 0.0% 0.1% 0.0%

Section 3.10 Intermediate Stop Location Choice Model

This model predicts the location of each intermediate stop (each location other than the primary destination) on the tour. The total number of stops is determined by the stop frequency model described above. The ARC stop location model was calibrated to match the target distributions. The stop location choice is determined based on deviation from the shortest path to the primary destination from the current origin. This technique, also known as “rubber-banding” relies on out-of-direction distance to determine the stop location. The calibration of the stop location choice model involves generating the out-of-direction distance distributions for the stops from the survey and comparing them with the observed data. The calibration process is similar to the process described for the tour destination choice model - the distance terms are adjusted using regression based adjustments until the shape of the observed curves and estimated curves converge. Bin specific adjustments were also incorporated to get the shape correct.


Section 3.11 Tour Mode Choice Model

The tour mode choice model uses a nested logit model to predict the tour mode for each tour. Tour mode share summaries were prepared by tour purpose and auto sufficiency. The data for the calibration of trip and tour mode choice uses the 2011 Household Travel Survey (HTS) as the primary source for the tour mode share information. The travel survey is a rich source of tour level information. However, the survey did not have sufficient coverage for transit trips - hence the 2010 Transit On-Board Survey data, expanded to 2015 conditions, was used to augment the transit mode choice information. The transit survey is a trip intercept survey that gives detailed information about transit trips. The following steps were used to process the transit trip data into tour data:

  • Summaries of tour mode choice from the household survey were prepared by tour purpose and auto sufficiency. Transit trips by tour purpose and auto sufficiency were summarized from the on-board survey.

  • The summaries were inspected for logical consistency. The following updates were made to the summaries:

    • The park and ride mode share for the school purpose was asserted as zero. Any observed data for this segment was added to the work tour as it was likely that the survey was responded by individuals who worked at school (such as teachers) and hence got miscoded as school tours.
    • The drive alone tour for joint tours was asserted as zero - the data was very sparse for this segment and hence there was no significant loss of data points because of this change.
    • The drive alone tours under the zero auto household market were reallocated to the auto deficient market.
    • School bus tours for non-school purposes were reallocated to the school tour purpose.
  • Next, the average number of trips per tour was derived for each access mode (walk access, park and ride, and kiss and ride) and tour purpose using the household survey. The implied number of transit tours from the on-board survey could be derived in a straightforward manner by dividing the total transit trips by the 2011 HTS average trips per tour, by purpose and mode. This approach ensures that the estimate of trips per tour is completely consistent with the home interview survey and that the transit tour targets are consistent with the transit trip targets observed in the on-board survey.

  • Further, the totals derived in step 3 were split into the different auto sufficiency segments based on the observed percentage of transit trips by tour purpose, auto sufficiency and access mode as implied by the on-board survey.

  • Finally, the number of transit tours by transit access mode and auto sufficiency was held constant, and total tours for other modes were scaled to match the total number of tours generated in the model by tour purpose and auto sufficiency. This ensures that the total transit trips, which are based upon observed on-board survey data expanded to transit boardings, will be matched well when the model is applied.


Base Category for Calibration

The tour mode choice model has all of the detailed modes represented in the trip mode choice model described below. The base modes include Drive Alone, Shared Ride 2 persons, Shared Ride 3+ persons, Bike, Walk, Walk-Transit, Park-and-Ride Transit, and Kiss-and-Ride Transit. Each auto mode includes both free and pay sub-modes, and each transit mode includes both an all-transit option and a premium-only sub-mode option. However, the sub-modes are not considered in later models; in effect, even though utilities are being calculated for each sub-mode, only the base modes described above influence later choices such as stop location and trip mode. The calibration process therefore focuses on matching the base modes by tour purpose and auto sufficiency. The sub-mode constants (such as the MARTA rail constant that measures the non-included attributes of MARTA rail compared to local bus) are introduced in tour mode choice, but held consistent from their calibrated trip mode choice value. That is, since tour mode choice is applied to round-trip travel characteristics, the sub-mode constants are doubled in terms of equivalent in-vehicle time minutes. This ensures consistent elasticities in tour mode choice and trip mode choice, and provides sensitivity in sub-mode options in tour mode choice, as well as time-of-day choice and destination choice through tour mode choice logsums. For the zero auto households market, Shared Ride 2 persons mode is used as the base category. In all other cases except for joint tours, the drive alone mode was held as the base category. For joint tours the Shared Ride 2 persons mode is fixed as the base category for all auto sufficiency markets as drive alone is not available by default. Tour mode choice was also calibrated to ensure that the transit use in individuals in households with different income levels match the observed transit use.

The results of the calibration are shown in Tables 3-14a through 3-14n.


Table 3-14a. Tour Mode Choice - Target Mode Shares of Work Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 108,286 1,226,167 1,334,453 0% 44% 74% 68%
Shared 2 14,466 84,622 263,330 362,418 30% 34% 16% 19%
Shared 3+ 3,782 21,707 121,993 147,482 8% 9% 7% 8%
Walk 4,352 4,636 6,864 15,852 9% 2% 0% 1%
Bike 0 2,368 10,126 12,494 0% 1% 1% 1%
Walk All Transit 20,999 17,259 8,090 46,347 43% 7% 0% 2%
Walk Premium Only 3,271 3,908 3,647 10,826 7% 2% 0% 1%
PNR All Transit 0 436 1259 1,695 0% 0% 0% 0%
PNR Premium Only 0 2,590 11,082 13,672 0% 1% 1% 1%
KNR All Transit 830 1,219 757 2,806 2% 0% 0% 0%
KNR Premium Only 876 1,742 1,208 3,826 2% 1% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 48,576 248,772 1,654,523 1,951,871 100% 100% 100% 100%
Walk-Transit 24,270 21,166 11,737 57,173 93% 78% 45% 72%
PNR-Transit 0 3,026 12,341 15,367 0% 11% 47% 19%
KNR-Transit 1,706 2,961 1,965 6,632 7% 11% 8% 8%
Premium Transit 4,147 8,240 15,937 28,323 16% 30% 61% 36%

Table 3-14b. Tour Mode Choice- Estimated Mode Shares of Work Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 108,139 1,226,510 1,334,649 0% 43% 74% 68%
Shared 2 14,632 84,284 262,990 361,906 30% 34% 16% 19%
Shared 3+ 3,670 21,776 121,764 147,210 8% 9% 7% 8%
Walk 4,113 4,182 6,673 14,968 8% 2% 0% 1%
Bike 0 2,382 9,842 12,224 0% 1% 1% 1%
Walk All Transit 21,249 17,611 8,009 46,869 44% 7% 0% 2%
Walk Premium Only 3,145 4,139 4,068 11,352 6% 2% 0% 1%
PNR All Transit 0 506 1450 1,956 0% 0% 0% 0%
PNR Premium Only 0 2,726 10,936 13,662 0% 1% 1% 1%
KNR All Transit 913 1,252 1,071 3,236 2% 1% 0% 0%
KNR Premium Only 854 1,775 1,210 3,839 2% 1% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 48,576 248,772 1,654,523 1,951,871 100% 100% 100% 100%
Walk-Transit 24,394 21,750 12,077 58,221 93% 78% 45% 72%
PNR-Transit 0 3,232 12,386 15,618 0% 12% 46% 19%
KNR-Transit 1,767 3,027 2,281 7,075 7% 11% 9% 9%
Premium Transit 3,999 8,640 16,214 28,853 15% 31% 61% 36%

Table 3-14c. Tour Mode Choice - Target Mode Shares of University Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 3,870 75,476 79,347 0% 38% 68% 58%
Shared 2 1,499 903 19,498 21,900 10% 9% 18% 16%
Shared 3+ 0 0 7,390 7,390 0% 0% 7% 5%
Walk 0 258 808 1,066 0% 3% 1% 1%
Bike 10404 0 1,067 11,472 67% 0% 1% 8%
Walk All Transit 2,569 2,992 2,397 7,957 16% 29% 2% 6%
Walk Premium Only 951 806 1,241 2,998 6% 8% 1% 2%
PNR All Transit 0 180 199 379 0% 2% 0% 0%
PNR Premium Only 0 498 1,320 1,819 0% 5% 1% 1%
KNR All Transit 74 503 405 982 0% 5% 0% 1%
KNR Premium Only 77 252 456 784 0% 2% 0% 1%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 15,574 10,262 110,257 136,093 100% 100% 100% 100%
Walk-Transit 3,520 3,797 3,638 10,954 96% 73% 60% 73%
PNR-Transit 0 679 1,519 2,197 0% 13% 25% 15%
KNR-Transit 151 755 861 1,767 4% 14% 14% 12%
Premium Transit 1,027 1,556 3,017 5,601 28% 30% 50% 38%

Table 3-14d. Tour Mode Choice - Estimated Mode Shares of University Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 3,866 75,604 79,470 0% 38% 69% 58%
Shared 2 1,496 905 19,646 22,047 10% 9% 18% 16%
Shared 3+ 0 0 7,191 7,191 0% 0% 7% 5%
Walk 0 112 685 797 0% 1% 1% 1%
Bike 10245 0 834 11,079 66% 0% 1% 8%
Walk All Transit 2,567 2,997 2,442 8,006 16% 29% 2% 6%
Walk Premium Only 1,064 857 1,407 3,328 7% 8% 1% 2%
PNR All Transit 0 208 190 398 0% 2% 0% 0%
PNR Premium Only 0 517 1,175 1,692 0% 5% 1% 1%
KNR All Transit 121 507 552 1,180 1% 5% 1% 1%
KNR Premium Only 81 293 531 905 1% 3% 0% 1%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 15,574 10,262 110,257 136,093 100% 100% 100% 100%
Walk-Transit 3,631 3,854 3,849 11,334 95% 72% 61% 73%
PNR-Transit 0 725 1,365 2,090 0% 13% 22% 13%
KNR-Transit 202 800 1,083 2,085 5% 15% 17% 13%
Premium Transit 1,145 1,667 3,113 5,925 30% 31% 49% 38%

Table 3-14e. Tour Mode Choice - Target Mode Shares of School Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 1,280 35,859 37,138 0% 1% 4% 3%
Shared 2 3,838 7,782 146,198 157,818 11% 8% 15% 14%
Shared 3+ 705 16,429 253,554 270,688 2% 17% 26% 25%
Walk 3,504 3,379 20,504 27,387 10% 3% 2% 2%
Bike 0 180 3,616 3,796 0% 0% 0% 0%
Walk All Transit 529 611 949 2,089 2% 1% 0% 0%
Walk Premium Only 13 11 48 72 0% 0% 0% 0%
PNR All Transit 0 0 10 10 0% 0% 0% 0%
PNR Premium Only 0 0 12 12 0% 0% 0% 0%
KNR All Transit 10 66 97 173 0% 0% 0% 0%
KNR Premium Only 2 8 115 125 0% 0% 0% 0%
School Bus 26,415 66,978 507,152 600,544 75% 69% 52% 55%
Total 35,017 96,723 968,112 1,099,852 100% 100% 100% 100%
Walk-Transit 542 622 997 2,161 98% 89% 81% 87%
PNR-Transit 0 0 22 22 0% 0% 2% 1%
KNR-Transit 12 74 212 298 2% 11% 17% 12%
Premium Transit 15 19 175 209 3% 3% 14% 8%

Table 3-14f. Tour Mode Choice - Estimated Mode Shares of School Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 854 35,592 36,446 0% 1% 4% 3%
Shared 2 3,825 7,877 146,503 158,205 11% 8% 15% 14%
Shared 3+ 714 16,673 253,898 271,285 2% 17% 26% 25%
Walk 3,877 3,258 20,426 27,561 11% 3% 2% 3%
Bike 0 149 3,642 3,791 0% 0% 0% 0%
Walk All Transit 233 752 471 1,456 1% 1% 0% 0%
Walk Premium Only 1 7 10 18 0% 0% 0% 0%
PNR All Transit 0 0 0 0 0% 0% 0% 0%
PNR Premium Only 0 0 0 0 0% 0% 0% 0%
KNR All Transit 8 56 36 100 0% 0% 0% 0%
KNR Premium Only 0 0 62 62 0% 0% 0% 0%
School Bus 26,359 67,097 507,472 600,928 75% 69% 52% 55%
Total 35,017 96,723 968,112 1,099,852 100% 100% 100% 100%
Walk-Transit 234 759 481 1,474 97% 93% 83% 90%
PNR-Transit 0 0 0 0 0% 0% 0% 0%
KNR-Transit 8 56 98 162 3% 7% 17% 10%
Premium Transit 1 7 72 80 0% 1% 12% 5%

Table 3-14g. Tour Mode Choice - Target Mode Shares of Individual Non-Mandatory Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 62,435 1,089,595 1,152,031 0% 32% 46% 44%
Shared 2 28,562 73,000 624,535 726,097 35% 37% 27% 28%
Shared 3+ 9,212 41,046 533,076 583,334 11% 21% 23% 22%
Walk 27,724 10,710 79,107 117,540 34% 5% 3% 4%
Bike 2492 1,083 11,641 15,216 3% 1% 0% 1%
Walk All Transit 11,735 4,757 3,214 19,706 14% 2% 0% 1%
Walk Premium Only 1,854 875 937 3,665 2% 0% 0% 0%
PNR All Transit 0 38 80 118 0% 0% 0% 0%
PNR Premium Only 0 332 766 1,098 0% 0% 0% 0%
KNR All Transit 335 242 231 809 0% 0% 0% 0%
KNR Premium Only 274 235 284 792 0% 0% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 82,187 194,753 2,343,466 2,620,406 100% 100% 100% 100%
Walk-Transit 13,589 5,632 4,151 23,372 96% 87% 75% 89%
PNR-Transit 0 370 846 1,216 0% 6% 15% 5%
KNR-Transit 609 478 514 1,601 4% 7% 9% 6%
Premium Transit 2,127 1,442 1,986 5,555 15% 22% 36% 21%

Table 3-14h. Tour Mode Choice - Estimated Mode Shares of Individual Non-Mandatory Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 61,812 1,089,154 1,150,966 0% 32% 46% 44%
Shared 2 28,321 73,060 624,759 726,140 34% 38% 27% 28%
Shared 3+ 8,998 41,469 532,717 583,184 11% 21% 23% 22%
Walk 27,582 10,586 79,140 117,308 34% 5% 3% 4%
Bike 2497 1,006 11,626 15,129 3% 1% 0% 1%
Walk All Transit 12,033 4,995 3,538 20,566 15% 3% 0% 1%
Walk Premium Only 2,272 983 881 4,136 3% 1% 0% 0%
PNR All Transit 0 0 242 242 0% 0% 0% 0%
PNR Premium Only 0 329 608 937 0% 0% 0% 0%
KNR All Transit 277 262 353 892 0% 0% 0% 0%
KNR Premium Only 207 251 448 906 0% 0% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 82,187 194,753 2,343,466 2,620,406 100% 100% 100% 100%
Walk-Transit 13,589 5,632 4,151 23,372 96% 87% 75% 89%
PNR-Transit 0 329 850 1,179 0% 5% 14% 4%
KNR-Transit 484 513 801 1,798 3% 8% 13% 6%
Premium Transit 2,479 1,563 1,937 5,979 17% 23% 32% 22%

Table 3-14i. Tour Mode Choice - Target Mode Shares of Joint Non-Mandatory Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 0 0 0 0% 0% 0% 0%
Shared 2 1,665 43,993 575,933 621,591 9% 43% 49% 48%
Shared 3+ 7,422 43,141 560,092 610,655 41% 42% 48% 47%
Walk 6,316 13,351 27,642 47,309 35% 13% 2% 4%
Bike 0 0 1,855 1,855 0% 0% 0% 0%
Walk All Transit 2,206 894 604 3,704 12% 1% 0% 0%
Walk Premium Only 475 224 240 939 3% 0% 0% 0%
PNR All Transit 0 12 25 36 0% 0% 0% 0%
PNR Premium Only 0 57 132 189 0% 0% 0% 0%
KNR All Transit 60 43 41 144 0% 0% 0% 0%
KNR Premium Only 0 0 0 0 0% 0% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 18,143 101,716 1,166,564 1,286,423 100% 100% 100% 100%
Walk-Transit 2,681 1,118 844 4,643 98% 91% 81% 93%
PNR-Transit 0 69 157 225 0% 6% 15% 4%
KNR-Transit 60 43 41 144 2% 4% 4% 3%
Premium Transit 475 281 372 1,128 17% 23% 36% 23%

Table 3-14j. Tour Mode Choice - Estimated Mode Shares of Joint Non-Mandatory Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 0 0 0 0% 0% 0% 0%
Shared 2 1,602 43,418 576,542 621,562 9% 43% 49% 48%
Shared 3+ 7,430 43,071 560,018 610,519 41% 42% 48% 47%
Walk 6,498 13,886 27,663 48,047 36% 14% 2% 4%
Bike 0 0 1,643 1,643 0% 0% 0% 0%
Walk All Transit 2,098 1,119 459 3,676 12% 1% 0% 0%
Walk Premium Only 453 222 94 769 2% 0% 0% 0%
PNR All Transit 0 0 0 0 0% 0% 0% 0%
PNR Premium Only 0 0 125 125 0% 0% 0% 0%
KNR All Transit 62 0 20 82 0% 0% 0% 0%
KNR Premium Only 0 0 0 0 0% 0% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 18,143 101,716 1,166,564 1,286,423 100% 100% 100% 100%
Walk-Transit 2,551 1,341 553 4,445 98% 100% 79% 96%
PNR-Transit 0 0 125 125 0% 0% 18% 3%
KNR-Transit 62 0 20 82 2% 0% 3% 2%
Premium Transit 453 222 219 894 17% 17% 31% 19%

Table 3-14k. Tour Mode Choice - Target Mode Shares of At-Work Sub-Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 10,127 180,553 190,680 0% 31% 68% 63%
Shared 2 317 11,841 40,431 52,590 10% 36% 15% 17%
Shared 3+ 0 1,206 22,509 23,716 0% 4% 8% 8%
Walk 515 7,919 21,755 30,189 16% 24% 8% 10%
Bike 0 546 148 694 0% 2% 0% 0%
Walk All Transit 1,049 567 366 1,981 33% 2% 0% 1%
Walk Premium Only 1,260 921 1,575 3,756 40% 3% 1% 1%
PNR All Transit 0 0 0 0 0% 0% 0% 0%
PNR Premium Only 0 0 0 0 0% 0% 0% 0%
KNR All Transit 0 0 0 0 0% 0% 0% 0%
KNR Premium Only 0 0 0 0 0% 0% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 3,142 33,127 267,337 303,606 100% 100% 100% 100%
Walk-Transit 2,310 1,488 1,940 5,738 100% 100% 100% 100%
PNR-Transit 0 0 0 0 0% 0% 0% 0%
KNR-Transit 0 0 0 0 0% 0% 0% 0%
Premium Transit 1,260 921 1,575 3,756 55% 62% 81% 65%

Table 3-14l. Tour Mode Choice - Estimated Mode Shares of At-Work Sub-Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 10,393 180,129 190,522 0% 31% 67% 63%
Shared 2 373 11,994 40,884 53,251 12% 36% 15% 18%
Shared 3+ 0 1,338 22,475 23,813 0% 4% 8% 8%
Walk 596 7,806 22,026 30,428 19% 24% 8% 10%
Bike 0 530 122 652 0% 2% 0% 0%
Walk All Transit 995 404 337 1,736 32% 1% 0% 1%
Walk Premium Only 1,178 662 1,364 3,204 37% 2% 1% 1%
PNR All Transit 0 0 0 0 0% 0% 0% 0%
PNR Premium Only 0 0 0 0 0% 0% 0% 0%
KNR All Transit 0 0 0 0 0% 0% 0% 0%
KNR Premium Only 0 0 0 0 0% 0% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 3,142 33,127 267,337 303,606 100% 100% 100% 100%
Walk-Transit 2,173 1,066 1,701 4,940 100% 100% 100% 100%
PNR-Transit 0 0 0 0 0% 0% 0% 0%
KNR-Transit 0 0 0 0 0% 0% 0% 0%
Premium Transit 1,178 662 1,364 3,204 54% 62% 80% 65%

Table 3-14m. Tour Mode Choice - Target Mode Shares of All Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 185,064 2,606,989 2,792,053 0% 27% 40% 38%
Shared 2 50,249 221,538 1,671,324 1,943,111 25% 32% 26% 26%
Shared 3+ 20,812 124,327 1,498,063 1,643,202 10% 18% 23% 22%
Walk 42,666 39,830 156,613 239,109 21% 6% 2% 3%
Bike 12742 4,067 27,709 44,518 6% 1% 0% 1%
Walk All Transit 39,175 27,878 15,256 82,309 19% 4% 0% 1%
Walk Premium Only 8,113 6,870 7,824 22,807 4% 1% 0% 0%
PNR All Transit 0 714 1882 2,596 0% 0% 0% 0%
PNR Premium Only 0 3,572 12,844 16,416 0% 1% 0% 0%
KNR All Transit 1,381 2,077 2,032 5,490 1% 0% 0% 0%
KNR Premium Only 1142 2,319 2,251 5,712 1% 0% 0% 0%
School Bus 26359 67097 507472 600928 13% 10% 8% 8%
Total 202,639 685,353 6,510,259 7,398,251 100% 100% 100% 100%
Walk-Transit 47,288 34,748 23,080 105,116 23% 5% 0% 1%
PNR-Transit 0 4,286 14,726 19,012 0% 1% 0% 0%
KNR-Transit 2,523 4,396 4,283 11,202 1% 1% 0% 0%
Premium Transit 9,255 12,761 22,919 44,935 5% 2% 0% 1%

Table 3-14n. Tour Mode Choice - Estimated Mode Shares of All Tours

Mode Zero Car Autos < Workers Autos >= Workers Total Zero Car Autos < Workers Autos >= Workers Total
Drive Alone 0 10,393 180,129 190,522 0% 31% 67% 63%
Shared 2 373 11,994 40,884 53,251 12% 36% 15% 18%
Shared 3+ 0 1,338 22,475 23,813 0% 4% 8% 8%
Walk 596 7,806 22,026 30,428 19% 24% 8% 10%
Bike 0 530 122 652 0% 2% 0% 0%
Walk All Transit 995 404 337 1,736 32% 1% 0% 1%
Walk Premium Only 1,178 662 1,364 3,204 37% 2% 1% 1%
PNR All Transit 0 0 0 0 0% 0% 0% 0%
PNR Premium Only 0 0 0 0 0% 0% 0% 0%
KNR All Transit 0 0 0 0 0% 0% 0% 0%
KNR Premium Only 0 0 0 0 0% 0% 0% 0%
School Bus 0 0 0 0 0% 0% 0% 0%
Total 3,142 33,127 267,337 303,606 100% 100% 100% 100%
Walk-Transit 2,173 1,066 1,701 4,940 100% 100% 100% 100%
PNR-Transit 0 0 0 0 0% 0% 0% 0%
KNR-Transit 0 0 0 0 0% 0% 0% 0%
Premium Transit 1,178 662 1,364 3,204 54% 62% 80% 65%

Section 3.12 Trip Mode Choice Model

The trip mode choice model determines the mode used by the individual at the trip level. It uses a mode-switching framework. In essence, it computes the probability of a trip mode being chosen conditional on the tour mode. This model was calibrated to ensure the trip mode shares match by tour purpose and tour mode. Similar to the tour mode choice model, the calibration targets for the trip mode choice model use both the 2011 HTS and the 2009-2010 Transit On-Board Survey. The approach to create the trip mode choice calibration targets is similar to those already described above under tour mode choice. Note that if there were no household survey transit trips observed for a specific mode, symmetry (no mode switching) was assumed.

The base alternative for calibrating the trip mode choice model was as follows:

  • For drive-alone tours, the base alternative was the drive alone trip mode
  • For shared-ride 2 persons tours, the base alternative was shared-ride two-person trip mode
  • For shared-ride 3+ person tours, the base alternative was the shared-ride three-plus trip mode
  • For walk tours - no mode switching was allowed
  • For walk-transit tours, the base alternative was the walk-transit trip mode
  • PNR and KNR assume symmetry - hence no constants were applied.




Atlanta Regional Commission, 2026