1. Use Survey to Improve the DFX Transit Model
Hua Yang, NCTCOG
Hong Zheng, NCTCOG
Kathy Yu, NCTCOG

2. Outline 2014 transit on-board survey
Comparison between model and survey
Investigate specific line – TRE
Access/egress time
Some improvements
Conclusion and future

3. Transit on-board survey
2014
Conducted by NCTCOG, DART, DCTA, and The T (FWTA)
Encompassed all fixed-route transit services in the twelve county modeling area
On-to-Off Survey recorded location where an individual rider boarded and alighted
Onboard survey conducted as a personal interview collected one- way trip mode and locations; fare/payment information; and socio- economic and demographic information

4. Public Transportation Authority Service Area

5. On-Board Survey
The purpose of this project is to gather updated travel behavior data from transit users in the Dallas / Fort Worth metropolitan area
Number of routes: 196
Light rail, commuter rail, express bus, local bus, feeder bus, UNT Shuttles
Number of records: 35,531weekday; 1,404 weekend
Sample rate: 10%
Response Rate: ~85%
Total ridership: 262,145

6. On-Board Survey The final database includes the following:
One-Way Trip
Origin, Destination, Boarding Location and Alighting Locations
Bus Routes/Rail Lines used in one-way trip
Mode, Trip Purpose
Fare – type of pass, duration of pass, reimbursement amount
Person Demographics: Age, Sex, Race/Ethnicity, Employment Status, Student Status, Resident or Visitor, Drivers License
Household Demographics: HH Income, HH Size, # Workers, # HH Vehicles

7. Statistics Ridership (all lines) 247,501 257,515 R^2 0.96 %RMSE 51%
Survey
Model
Statistics
Ridership (all lines)
247,501
257,515
R^2
0.96
%RMSE
51%

8. Overall data comparison

9. Overall data comparison
THET 1
DART 486
DART 183
DART 428
DART 409
DART 400
DART 501
DART 350
Spur
DART164
DART467
DART466

10. Geographical location
Red: overestimate
Blue: underestimate
Possible reasons.

11. North Dallas
Red: overestimate
Blue: underestimate

12. South Dallas
Red: overestimate
Blue: underestimate

13. By agency Agency Survey total Model total R^2 %RMSE DART 110,328
121,106
0.59
64%
THET
26,322
26,178
0.72
71%
DCTA
2,583
3,021
0.33
66%
RAIL
108,268
107,210
0.93
14%

14. DART

15. THET
THET 1
Spur
THET 6

16. By trip purpose
(15%)
(-13%)
(28%)

17. By access mode of the trips
Survey total
Model total
R^2
%RMSE
Walk Access
188,362
178,044
0.88
77%
Drive Access
59,139
79,471
0.95
187%

18. Walk access of the trips
DART-Orange

19. Drive access of the trips

20. Rail, access mode of the trips
Walk access underestimate
Drive access overestimate
Line
Survey
Model
Walk access
Drive access
DART-Blue
14,527
8,557
8,719
10,513
DART-Green
14,961
9,109
13,093
15,913
DART-Orange
12,446
8,193
14,348
11,589
DART-Red
17,823
11,497
11,487
12,657
TRE
2,817
5,829
3,395
5,977

21. DART-Blue

22. Walk on at rail stations DART-Blue
Downton

23. Dart-Green

24. Dart-Orange

25. Dart_Red

26. TRE

27. Investigate specific lines - TRE
Trinity railway express
Commuter rail
Identify network issues
In survey demand of a specific route is known
Assign demand in TransCAD, and check whether the demand is assigned on the specific route
Not all demand are assigned on the specific route
Identify two types of errors
1). some riders are not assigned at all in the model
2). Some riders are assigned but on a different route

28. HBW walk access, BR network, Peak, TRE
Assign TRE survey demand in the model
Total demand: , not assigned 52.3, assigned
Reasons not assigned
Reason for TRE-WA-PK not assigned
Flow
Total %
Picked up by someone
17.35
33%
Bike access
10.22
19.5%
Connector issue
22.8
43.6%
Access/egress time is more than 20 minutes
5.97
11.4%
More than 3 transfers
2.06 4%
52.29
100%

29. Investigate why TRE users not choose TRE
Assigned but not use TRE
Table 1 TRE users assigned in the transit network without using TRE routes
From node
To node
Number of path
Flow
Demand
Survey
7064
41149 1
1.88
Generalized cost on survey path is 21.4, shortest path is
7607
7226 2
9.20
Egress time is minutes. Generalized cost on shortest path is on TRE path is 14.92* * *0.151=14.287
8579
6431
0.98
The survey route has 4 transfers.
40426
7349
17.77
Total
29.83

30. OD 2, 7607 to 7226
It takes DART 63 rather than TRE. One reason is that the egress time from TRE station to the destination node is more than 20 minutes.
TRE station
TRE station

31. OD 3, 8579 to 6431
If takes TRE, it will create more than 3 transfers

32. OD 4, 40426 to 7349 It takes DART_63 rather than TRE
From “Medical/Market Center Station” to “Victory Station” always choose DART_49 rather than TRE
There is a coding error that “Victory Station” is not coded in the transit stop

34. Summary Travel pattern issue: Coding issue Solution
complex access and egress model, pick up by sb, bike, etc.
Access, egress time maybe more than 20 minutes.
Max transfer maybe more than 3
Sometimes take a route which is not with the least generalized cost
Coding issue
Connector issue
Stop station is not reasonable
Solution
Resolve the connector issue
Reassign stops in a reasonable way

35. Access/Egress time comparison
Compare the access/egress time from the model to the on-board transit survey
Identify possible issues that associated with the access/egress time therefore affect the ridership in the model
Improve the model such that the access/egress time are more accurate

36. Methodology 12 68 146 162 Get walk time distribution from survey
Question: how many blocks in the walk access for each person
Assumption: Walk 5 mins for each block
1 block or less cover 90% trips
2 blocks or less cover 90% trips
3 blocks or less cover 90% trips
4 blocks or less cover 90% trips
Transit lines 12 68
146
162

37. Methodology Get walk time distribution from model
From survey get the production TSZs and its demand for each line
Get location of transit stops
Assign those transit demand from TSZ to bus stops
Use GISDK run multiple shortest path module, minimize walk time
Suppose all travelers from TSZ walk to the nearest bus stops
This gets walk time distribution observed in the model
Compare the walk time distribution with the survey

38. Result Walk time in the model is more than in the survey
1 block or less covers 90% trips
2 blocks or less covers 90% trips
3 blocks or less covers 90% trips
4 blocks or less covers 90% trips
5 blocks or less covers 90% trips
6 blocks or less covers 90% trips
Survey 12 68
146
162
168
172
5 mins or less covers 90% trips
10 mins or less covers 90% trips
15 mins or less covers 90% trips
20 mins or less covers 90% trips
25 mins or less covers 90% trips
30 mins or less covers 90% trips
Model 6 39 86
120

39. Improvement Check alignment, headway, stops, and travel time.
Add approach link for TRE at Richarland, Centerport and Medical Center.
Maximum access time change from 20 minutes to 30 minutes for mode 80 and 81.

41. Alignment change
DART 404 add line 54042

42. Add stop TRE, Green and Orange lines add Victory station
Green line adds Fair Park station
DART 164, add several major stops

43. Walk access of the line for mode 80 and 81
Before
After
Survey walk access
Model ridership walk access
Diff(model-survey)
DART - BLUE
7667
4231
-3436
5474
-2193
DART - GREEN
7439
4319
-3119
6094
-1345
DART - ORANGE
6369
4062
-2308
5733
-636
DART - RED
9403
4789
-4614
6075
-3328
TRE
1198
593
-605
1028
-170

44. TRE Richland becomes much better than before
Centerport better but still underestimate
Medical center, victory and union station underestimate

45. TRE walk access at stations

46. Results
DART 164, add stops, walk access increase from 1172 to 2137, almost double;
T6, add one stop, directed walk access increase from 1485 to 1598;
T2, change alignment, drop from 1360 to 1180;
Add approach and add stops can increase ridership significantly.

47. Conclusion Summary of 2014 transit on-board survey
Overall comparison between the survey and model
Comparison of route selection for few lines
Access/egress time comparison
Improvement of few lines

48. Future research

49. Walk on at rail stations DART-Blue
Downton

50. Walk on at rail stations DART-Green
Downton

51. Walk on at rail stations DART-Orange
Downton

52. Walk on at rail stations DART-Red

53. Walk on at rail stations TRE