FINAL DRAFT REPORT
UPDATING AND VALIDATING THE TRAVEL DEMAND FORECASTING PROCESS
Transportation
Modeling Using Quick Response System II
or Huntington- Ironton Area Transportation Study
KYOVA Interstate Planning Commission
400 Third Avenue
Huntington, WV 25701
October 04
The purpose of this report is to present the details of the methodology followed in implementing the travel demand forecasting process using the Quick Response System II (QRSII) Version 7.0 with advanced General Network Editor (GNE)Version 7.0 Transportation Planning Computer Software package. Known travel data for the year 2000 was used to verify the outputs of existing transportation models. Most of FHWA urban model calibration targets have been met by this model. The trip generated model produced expected trip end volumes. The trip distribution model resulted in average trip length comparable to other travel studies and the traffic assignments produced volumes reasonably within FHWA standards. Therefore, the model can be used in forecasting 2030 traffic to examine the future capacity deficiencies and to perform future year plan development and analysis.
In the past, KYOVA Interstate Planning Commission and the West Virginia Division of Highways have used both household origin-destination surveys and mathematical techniques in formulation of traffic models. The approach which has proven the most practical for small and medium urban areas as well as larger areas, such as the Huntington-Ironton Areas Transportation Study (HIATS) urbanized area, has been the mathematical simulation of internal and external travel. This technique involves the development of trip generation equations based on the relationships found valid in past studies and parameters calibrated for the particular area under study. This approach was adopted for the Huntington-Ironton area to simulate traffic for both present (2000) and the future (2030).
INTRODUCTION
This report describes development of an updated Quick Response System II (QRS11) Transportation Demand Model for the Huntington, West Virginia Metropolitan Area. The previous model developed in the mid-1990’s was utilized in developing the 2025 Long-Range Transportation Study for the Huntington Ashland-Ironton (HAITS) region by the KYOVA Interstate Planning Commission [1]. The previous travel demand model utilized QRSII software and represented the areas KYOVA was responsible for in 1990 (Cabell and Wayne Counties in West Virginia and Lawrence County in Ohio) and excluded the Kentucky Counties. The current model includes Cabell and Wayne Counties in West Virginia, Lawrence County in Ohio and Boyd and Greenup Counties in Kentucky.
The decision was made to utilize the framework of the HAITS model and supplement it with the recently completed Ashland Travel Model conduct by the Corradino Group [2]. The Ashland model was developed in TransCAD which is not directly compatible with the QRSII software. The parameters of the HAITS model were developed by earlier studies used to produce the 1990 and 2000 Long-Range Plan [3][4].
The major activities involved:
1. Expand the traffic analysis zone (TAZ) structure to include all of Cabell, Wayne and Lawrence Counties. The TAZ’s structure developed for the two Kentucky Counties, Boyd and Greenup Counties, as part of the Ashland Travel Model were adopted for inclusion in this study. The TAZ’s by county are as follows:
|
Wilbur Smith - HAIATS Model [4} |
HAITS Model [1] |
2004 Updated Model |
Base Year Data |
1970 |
1990 |
2000 |
Lawrence Co., Ohio |
88 |
88 |
98 |
Cabell Co., WV |
138 |
138 |
158 |
Wayne Co., WV |
41 |
41 |
47 |
Greenup Co. KY |
130 |
-- |
60 |
Boyd Co., KY |
|
-- |
120 |
Internal Zones – Total |
397 |
267 |
483 |
External Stations - Total |
28 |
28 |
27 |
In Ohio and West Virginia the expanded TAZ structure added an additional 57,379 persons over a base population of 143, 772 from the 1990 study (Table 1). The revised TAZ structure for the Ohio and West Virginia Counties was presented as the “1999 TAZ District Map” in the KYOVA Year 2025 Long Range Transportation Plan [1]. The 1990 socio-economic profile for each TAZ was updated from the 2000 census. The updated variables for each TAZ included:
a. Dwelling Units
b. Population
c. Labor Force
d. Non-Retail Employment
e. Retail Employment
f. Automobile Ownership
g. School Attendance
h. Resident Students
The network was extensively edited to remove extraneous nodes and links in order to better reflect the regional highway system. Additional roadways constructed since the original networks were added as links.
Table 1
Population By Counties Included in 2004 Travel Model
|
TAZ Number |
1990 Population |
2000 Population |
Lawrence Co., OH |
1-88 |
52,732 |
48,585 |
600-609 |
--- |
12,892 |
|
Sub Total |
52,732 |
61,477 |
|
Wayne Co. WV |
186-226 |
19,042 |
19,446 |
550-555 |
--- |
23,438 |
|
Sub Total |
19,042 |
42,884 |
|
Cabell Co. WV |
89-185 227-267 |
85,123 |
75,741 |
550-519 |
-- |
21,049 |
|
Sub Total |
85,123 |
96,790 |
|
WV and OH Study Area |
|
156,897 |
201,151 |
Greenup Co. KY |
|
--- |
36,891 |
Boyd Co., KY |
|
--- |
49,752 |
Total Study Area |
|
156,897 |
287,794 |
Source: [1], Chpt. 6
NETWORK REPRESENTATION AND ROADWAYS
All regionally significant roadways classified as collector or better have been included in the travel demand models. The major roadway attributes used in the model are noted in Table 2. Additional link and node data items are presented in Table 3.
Nodes-Point Data:
The nodes represent: 1) intersections that facilitate traffic flow between links or between traffic analysis zone centroids and the network, 2) external stations and 3) “dummy” nodes to more accurately reflect curvature along the road. In the model there are:
· external stations - 27
· zone centriods- 483
· nodes – 7300
· signalized intersections – 223 (20 in Wayne County, 35 in Lawrence County, 147 in Cabell County and 38 in Boyd/Greenup Counties).
Zone centroids represent the trip ends associated with the origin and destination of trips entering the roadway networks. External stations represent the origin and/or destination of trips having at least one end located externally to the study area. The data included for each node representation are as follows:
Table 2 Roadway Characteristics in Network
Roadway Type |
Functional Class FC |
Saturation Flow in PCEs/Hour/Lane |
Posted Speed** (mph) |
Rural |
|
|
|
· Freeway |
1 |
1700-2400 |
65-70 |
· Principal, Minor Arterials and Major Collections |
2-7 |
1200-1700 |
45-55 |
· Minor Collections and Locals |
8-9 |
1000-1700 |
35-45 |
Urban |
|
|
|
· Freeway |
11-12 |
1600-2400 |
55-65 |
· Principal Interials |
14 |
1000-1490 |
40-45 |
· Minor Arterials |
16 |
910-1385 |
35-40 |
· Collection |
17 |
910-1385 |
30-40 |
· Local |
19 |
910-1385 |
25-35 |
*Varies by Specific Location
**Depends on State Regulations
Table 3 Node – Link Input Variables
Node Input Variables |
Link Input Variables |
Intersection w/o Delay 1. Area Weight 2. Production Extra Time 3. Attraction Extra Time Intersection w/Delay 1. Through Adjustment 2. Left Adjustment 3. Immediate Right Adjustment 4. Other Movements Adjustment 5. Cycle Length 6. Minimum Unsignalized Capacity 7. U-Turns Allowed 8. Areas Weight 9. Production Extra Time 10. Attraction Extra Time 11. Unit Extension
Centroid 1. School Enrollment 2. Number of Automobiles 3. Number of Retail Employees 4. Number of Non-Retail Employees 5. Number of Dwelling Units 6. Intrazonal Travel Time 7. Total Labor Force 8. Total School Attendance 9. Intrazonal Trips 10. Type and Parameter Set
External Station 1. HBW Productions 2. HBNW Productions 3. HB? Productions 4. NHB Productions 5. HBW Attractions 6. HBNW Attractions 7. HB? Attractions 8. NHB Attractions 9. Travel Time from Seed |
Two-way Street (one ways same w/o B-A) 1. Approach Codes – Through Traffic Codes, Lane geometry, Progression Code, Functional Class, Cross-Section 2. Free Speed 3. Travel Time A-B 4. Travel Time B-A 5. Base Volume A-B 6. Base Volume B-A 7. Hourly Sat. Flow A-B 8. Hourly Sat. Flow B-A 9. Free Travel Time 10. Distance 11. Federal Functional Class 12. AADT Count 200 13. Posted Speed Limit 14. Lanes Each Direction 15. Volume A-B 16. Volume B-A Centroid Connector 1. Speed 2. Travel Time A-B 3. Travel Time B-A 4. Distance 5. Volume A-B 6. Volume B-A |
1. Zone centroids: Year 2000 socio-economic characteristics used to estimate trip ends for the following trips:
· Home based work trips
· Home based other trips
· Non-home based trips
· School trips
· Commercial – truck trips
· Internal-External trips
2. External Stations: The locations where major roadways cross the study cordon line were defined as external stations. A list of external stations is recorded in Table 4. Each station was associated with an estimate of:
· Total Average Annual Daily Traffic (AADT) for Year 2000
· Internal-External AADT for Year 2000
· External-External Traffic AADT for Year 2000
· Trip Purpose Allocation for Home Based Work, Home Based School, Home Based Other, Non-Home Based Trips
Link Data:
Links represent sections of roadway traveled by vehicles. Most links were part of the regional highway network and were characterized by: functional classification, speed, capacity, etc. Ultimately the number of vehicles assigned to a link represents the vehicle utilization of the regional highway networks. Other links represent zonal centroid connectors or the local road system, which connected the zone centroids to the regional highway systems. There are 1,056 zone centroid connector links and over 7,000 roadway links.
Table 4 External Stations
|
Station Number |
State |
AADT Volume 2000 |
9001 |
US52 W |
OH |
9731 |
9002 |
OH522 |
OH |
677 |
9003 |
OH93 |
OH |
1798 |
9004 |
OH141 |
OH |
843 |
9005 |
OH7 E |
OH |
2542 |
9006 |
WV2 E |
WV |
3733 |
9007 |
Mason Rd |
WV |
1467 |
9008 |
I-64 E |
WV |
32667 |
9009 |
US60 W |
WV |
14333 |
9010 |
Bulls Gap |
WV |
467 |
9011 |
WV10 |
WV |
3667 |
9012 |
CR21 |
WV |
300 |
9013 |
WV37 E |
WV |
717 |
9014 |
12-Pole Creek Rd |
WV |
317 |
9015 |
US52 S |
WV |
6300 |
9016 |
WV73 W |
WV |
9900 |
9017 |
US23 S |
KY |
9560 |
9018 |
KY3 |
KY |
816 |
9019 |
US60 W |
KY |
3873 |
9020 |
I-64 W |
KY |
18791 |
9021 |
KY207 W |
KY |
305 |
9022 |
KY1 S |
KY |
2340 |
9023 |
KY2 W |
KY |
1098 |
9024 |
KYAA W |
KY |
1405 |
9025 |
KY8 W |
KY |
6590 |
9026 |
US23 N |
KY |
12200 |
9027 |
KYAAE |
KY |
8300 |
TRIP GENERATION
Regression Equations:
A decision was made to utilize the trip generation relationships applied in the current KYOVA travel demand model to simulate person traffic for 2000 (validation) and 2005-2030 (forecasting) [1]. The KYOVA model relationships were based on the original HAIATS model developed in the late 1960s by Wilbur Smith and Associates [3]. These equations were utilized in the “1973 Major Review and 2000 Plan Update” and “Year 2025 Long-Range Transportation Plan”[4][5].
The HAIATS and KYOVA trip generation module included six trip purposes. They are:
· Home Based Work (HBW)
· Home Based Other (HBO)
· Non-Home Based (NHB)
· Commercial Motor Vehicle* (CMV)
· Internal-External/External-Internal
· Home Based School (HBS)
Traditionally trip production models were used to estimate the number of trips generated at the TAZ. It is generally accepted that the characteristics of the household best determine trip end productions. Similarly the attraction equations determine the number of trip ends attracted typically to non-residential land uses. The equations utilized to estimate trip ends for each TAZ were as follows:
· Productions
HBW = -8.25 + 1.74 TAZ Labor Force
HBO = 3.42 + 3.61 TAZ Auto Ownership
HBS = 3.36 + 1.82 TAZ School Enrollment
· Attractions
HBO = 7.58 + 1.77 TAZ Total Employment
HBO = 65.10 + 10.58 TAZ Retail
Employment + 1.48 TAZ
Dwelling Unit + .44
TAZ Other Employment
HBS = 7.08 + 1.50 TAZ Total School Attendance
· Production/Attractions
NHB = -14.68 + 4.70 TAZ Retail
Employment + .81 TAZ Other
Employment + .81 TAZ Dwelling
Units + .20 TAZ Total School Attendance
Truck = 12.32 + .52 TAZ Retail
Employment + .23 TAZ
Other Employment + .28
TAZ Dwelling Units
Internal-External = 31.93 + 1.19 TAZ Retail Employment
+ .26 TAZ Other Employment + .10 TAZ
Dwelling Units + .05 TAZ Total School Attractions
The independent variables used in the equations are defined as follows:
Dwelling Units – Dwelling Units
Automobile Ownership - Automobiles Garaged in the Zone of Resident
Labor Force – Total Resident Labor Force
School Enrollment – Total Resident Students including Primary, Secondary Attendant, and College Students
Retail Employment – Retail Employment within the Analysis Zone
Other Employment – Non-retail Employment within the Analysis Zone
These trips were defined as daily person trips using all modes of travel. The model update did not include any significant changes to the original HAITS travel demand model. The Kentucky zones whose data were developed from the Ashland Travel Study were analyzed with the HAITS trip generation travel relationships.
Base Year Socio-Economic Factors:
In order to estimate trip productions and attractions by TAZ, socio-economic data were obtained from the 2000 census. For the Kentucky zones the Ashland study relied on different independent variables to estimate trip productions and attractions, since the Census information was not available by zone and had to be estimated. This process was completed by the KYOVA staff and Sam Granato of the Ohio Department of Transportation. The characteristics of the study area are noted in Table 5 and compares the 1990 KYOVA study to the current 2000 study for those portions of the study area that are directly comparable. In this area the population decreased 8.3 percent between 1990 and 2000. Likewise the labor force declined 20.3 percent and auto ownership declined 8.6 percent, while employment for the comparable Huntington/Ironton area increased 13.6 percent. The new areas of Lawrence, Wayne and Cabell counties and the two Kentucky counties almost doubled the population of the study area. In the expanded area auto ownership was at a slightly lower rate than in the original study area (population/auto of 1.60 vs 1.67), labor force was at a slightly higher rate (labor force/population .37 vs. .40), but employment was at a lower rate than exists in the original study area (employment/population .59 vs. .38). These demographic shifts will have implications on the number of trip ends estimated by trip purpose. The major shifts are reported in Table 6.
Table 5 Socio-Econ Trends – 1990 and 2000 Study Comparisons
Comparable Area |
1990 |
2000 |
Percent Change |
|
Population |
156,897 |
143,772 |
-8.3% |
|
Labor Force |
67,702 |
53,969 |
-20.3% |
|
Employment |
75,275 |
85,513 |
+13.6 |
|
Auto Ownership |
94,066 |
85,982 |
-8.6 |
|
Population/Auto |
1.67 |
1.67 |
--- |
|
If/Population |
.43 |
.37 |
-14.0 |
|
Employment/Population |
.48 |
.59 |
+22.9 |
|
New Area 2000 |
|
|
||
Population |
144,018 |
|
||
Labor Force |
57,384 |
|
||
Employment |
54,554 |
|
||
Auto |
89,843 |
|
||
Population/Auto |
1.60 |
|
||
If/Population |
.40 |
|
||
Employment/Population |
.38 |
|
||
Current Study Area 2000 |
|
|
||
Population |
287,790 |
|
||
Labor Force |
111,353 |
|
||
Employment |
140,060 |
|
||
Auto |
175,837 |
|
||
Population/Auto |
1.64 |
|
||
If/Population |
.39 |
|
||
Employment/Population |
.49 |
|
||
1990 Data reported in HAITS – Long Range
Plan 2025 [1].
Table 6 Demographic Shifts 1990 vs 2000 Study
|
1990 |
2000 |
||||||
Pop. du. |
Pop. auto. |
Ifpop. |
Emp. Pop. |
Pop. du. |
Pop. auto. |
IfPop. |
Emp. Pop. |
|
Comparable Area |
2.41 |
1.67 |
.43 |
.48 |
2.35 |
1.67 |
.37 |
.59 |
New Area |
|
|
|
|
2.54 |
1.60 |
.40 |
.38 |
Total Study Area |
2.41 |
1.67 |
.43 |
.48 |
2.44 |
1.64 |
.39 |
.49 |
1990 Data reported in HAITS Long Range Plan 2025 [1].
Estimates of Trip Productions by TAZ
After applying the regression equations, estimates were made of trip productions and trip attractions by TAZ. A summary by County and State is presented in Table 7.
Greater reliance was placed on the estimate of trip productions, which provides good regional control totals. The person trips per household or per capita can be compared to external sources to determine if trip making in the Huntington Metropolitan Area reflects typical conditions. The comparisons are provided in Table 8 and indicate that the Huntington trip rates at 10.7 household person trips per day and 4.4 per capita person trips per day was compatible with national sources although on the high side. National sources suggest the appropriate household trip rates for a community of 300,000 was on the order of 11.8-7.6 trips per day from NCHRP Report 187 [6], 9.0 trips per day from NCHRP Report 365 [7] or 10.7 trips per day for the 1995 National Personal Transportation Study [8] (Table 8). However, it is generally accepted that trip making in smaller communities has higher household trip rates than larger urban areas. The Huntington distribution of trips by trip purpose indicated about 15 percent HBW, 50 percent HBO, 26 percent NHB and 9 percent HBS. These percentages were compatible with household trip rate data recently collected in Tennessee (see Table 9) [9]. National guidelines have been published for trip generation and are presented in Table 10 [10]. The trip generation relationships indicate the rates calculated for the Huntington Metropolitan Area were generally within the guidelines.
Table 7 2000 Study Area
Population |
287,794* |
Auto Ownership |
175,837 |
Household |
117,690* |
Population/Household = |
2.45 |
Population/Auto = |
1.64 |
Person Trips/Household |
10.7** |
Person Trips/Capita |
4.4 |
Percent Trips |
|
HBW |
15.1 |
HBO |
50.3 |
NHB |
25.7 |
HBS |
8.9 |
Total |
100.0 |
*2000 Census Data
**Ashland used 10.4 trips per household with 20% HBW, 55% HBO
and 25% NHB. [2]
Households are defined for TAZ Socio-Economic data and are used as DU’s.
Table 8 Comparative National Trip Rate Data
NCHRP 187 |
NCHRP 365 |
NPTS |
||||
Urbanized Area Population |
Person Trips/ Household |
Urbanized Area Population |
Person Trips/ Household |
Urbanized Area Population |
Person Trips/ Household |
|
50,000 to 100,000 |
14.1 |
50,000 to 200,000 |
9.2 |
Less Than 250,000 |
10.8 |
|
100,000 to 250,000 |
11.8 |
200,000 to 500,000 |
9.0 |
250,000 to 499,999 |
10.7 |
|
250,000 to 750,000 |
7.6 |
500,000 to 1,000,000 |
8.6 |
500,000 to 999,999 |
10.7 |
|
750,000 to 2,000,000 |
7.6 |
>1,000,000 |
8.5 |
1,000,000 to 2,999,999 |
10.4 |
|
|
Overall |
10.5 |
||||
Conditions: early 1970’s |
Conditions: early 1980’s |
Conditions: mid-1990’s |
||||
Source 2 NCHRP 365 [7]
Source 3 NPTS – National Personal Transportation Survey [8]
Table 9 Person Trip Summary by Household (Total and By Purpose)
MPO |
n |
Total Trips/hh |
HBW |
HBS |
||
Trip/hh |
% |
Trip/hh |
% |
|||
Chattanooga |
816 |
7.53 |
1.49 |
19.79 |
0.12 |
1.59 |
Knoxville |
1381 |
8.04 |
1.21 |
15.08 |
0.50 |
8.52 |
Nashville |
1817 |
8.44 |
1.38 |
16.60 |
0.50 |
6.02 |
Memphis |
2229 |
8.27 |
1.57 |
19.01 |
1.04 |
12.58 |
MPO |
HBO |
NHB |
HBW&S |
|||
Trip/hh |
% |
Trip/hh |
% |
Trip/hh |
% |
|
Chattanooga |
3.19 |
42.36 |
2.73 |
36.25 |
1.61 |
21.38 |
Knoxville |
3.44 |
42.72 |
2.71 |
33.68 |
1.90 |
23.60 |
Nashville |
3.65 |
44.02 |
2.76 |
33.35 |
1.87 |
22.63 |
Memphis |
3.46 |
41.87 |
2.19 |
26.54 |
2.61 |
31.59 |
HBW = Home Base Work Trip
HBS = Home Base School Trip
HBO = Home Base Other Trip
NHB = Non-Home Base Trip
HBW & HBS = Combination of Home Base Work and School Trips
Total Trip Rate = Combination of HBW, HBS, HBO, and NHB
Source [9]
Table 10 Trip Generation Calibration Guideline
National Experience |
2000 Huntington Study |
Person Trips per Household: 8.5 to 10.5 |
10.7 |
HBW Person Trips per Household: 1.7 to 2.3* |
2.6 |
HBO Person Trips per Household: 3.5 to 4.8 |
5.4 |
NHB Person Trips per Household: 1.7 to 2.9 |
2.8 |
NBW Trips: 18% to 27% of all Trips* |
24% |
HBO Trips: 47% to 54% of all Trips |
50% |
NHB Trips: 22% to 31% of all Trips |
26% |
*Includes home based school trips
Source [10]
Comparisons are provided in Table 11 with the early KYOVA traffic model calibrated with 1990 data. Since labor force and school enrollment declined between 1990 and 2000, the percent of home based work and school trips also declined. Increases in employment increased the percent of non-home based, and home based other trips. For both models internal trips remained between 91 to 92 percent of all vehicle trips between 1990 and 2000, but the percent of the work and school trips declined. After applying vehicle or occupancy factors there were 7.5 auto trips per household, 3.5 auto trips per person and 8.1 vehicle trips per household. Table 12 presents the county household trip rates and trip purpose distribution by county.
Internal-External Trips (IE/EI)
Internal-external and external-internal trips were movement that cross the study boundary (cordon-line). One portion of the movement had a trip end within the study area and the other trip end was outside the study area. The estimates of EI/IE were provided by Sam Granato of the Ohio Department of Transportation based upon an analysis of average annual daily traffic (AADT) at the external station. Using default values derived from other sources and local knowledge these trips were distributed by trip purposes as noted in Table 13. The analysis was based on recent data collected for the region including bridge origin-destination interviews conducted by the Ohio Department of Transportation. It was assumed only 7 percent of the trips were classified as external-external to the study area. With a year 2000 AADT of 160,000 vehicles at external stations,
Table 11 Trip Comparisons 1990 vs 2000 Studies
Person Trips |
||||
|
1990* |
2000 |
||
HBW |
155,000 |
18% |
190,038 |
15% |
HBS |
146,000 |
17% |
113,364 |
9% |
HBO |
355,000 |
41% |
636,420 |
50% |
NHB |
204,000 |
24% |
325,327 |
26% |
Total |
860,000 |
|
1,265,147 |
|
Vehicle Trips |
||||
|
1990 |
2000 |
||
HBW |
122,000 |
21% |
175,961 |
18.3% |
HBS |
32,000 |
6% |
31,666 |
3.3% |
HBO |
216,000 |
38% |
388,061 |
40.5% |
NHB |
151,000 |
26% |
282,893 |
29.5% |
Sub-total |
521,000 |
91% |
878,581 |
91.6% |
Truck |
50,000 |
9% |
79,592 |
8.4% |
Total |
571,000 |
100% |
958,173 |
100% |
1990 |
2004 |
2000 |
|
|
*Occupancy Used in 1990 |
* Occupancy Used in Study |
Ashland, KY Occupancy |
HBW |
1.27 |
1.08 |
1.11 |
HBS |
4.56 |
3.58 |
|
HBO |
1.64 |
1.20 |
1.58 |
NHB |
1.35 |
1.15 |
1.66 |
1990 Data in HIATS Long Range Plan – Technical Analysis 1997
*Data from Clarksville Tennessee study [11]
Table 12 2000 TAZ Data Summary Table
|
HBW |
HBNWP |
School P |
NHBP |
% Trips P |
|||||
HBW |
HBNW |
School |
NHHB |
Trips/pop |
Trips/DU |
|||||
Wayne |
25,971 |
91,090 |
14,555 |
31,157 |
16% |
56% |
9% |
19% |
3.8 |
9.4 |
Cabell |
64,142 |
203,851 |
40,286 |
142,628 |
14% |
45% |
9% |
32% |
4.7 |
10.9 |
Lawrence |
37,095 |
142,202 |
23,924 |
48,935 |
15% |
56% |
9% |
19% |
4.0 |
10.2 |
Greenup |
26,576 |
87,843 |
14,214 |
29,507 |
17% |
56% |
9% |
19% |
4.3 |
10.9 |
Boyd |
36,252 |
111,432 |
20,382 |
73,097 |
15% |
46% |
8% |
30% |
4.8 |
12.1 |
Total |
190,037 |
636,420 |
113,364 |
325,326 |
15% |
50% |
9% |
26% |
4.4 |
10.7 |
Table 13 External Station
|
Station Number |
AADT Volume 2000 |
Thru Trips |
XHBW-P |
XHOB-P |
XHOB-P |
XNHB-P |
9001 |
US52 W |
9731 |
364 |
1232 |
33 |
1236 |
2183 |
9002 |
OH522 |
677 |
0 |
89 |
2 |
89 |
158 |
9003 |
OH93 |
1798 |
0 |
236 |
6 |
237 |
419 |
9004 |
OH141 |
843 |
0 |
111 |
3 |
111 |
196 |
9005 |
OH7 E |
2542 |
140 |
316 |
8 |
317 |
560 |
9006 |
WV2 E |
3733 |
19 |
488 |
13 |
490 |
865 |
9007 |
Mason Rd |
1467 |
0 |
193 |
5 |
194 |
342 |
9008 |
I-64 E |
32667 |
1188 |
4139 |
110 |
4155 |
7335 |
9009 |
US60 W |
14333 |
0 |
1885 |
50 |
1892 |
3340 |
9010 |
Bulls Gap |
467 |
0 |
61 |
2 |
62 |
109 |
9011 |
WV10 |
3667 |
16 |
480 |
13 |
482 |
851 |
9012 |
CR21 |
300 |
0 |
39 |
1 |
40 |
70 |
9013 |
WV37 E |
717 |
0 |
94 |
3 |
95 |
167 |
9014 |
12-Pole Creek Rd |
317 |
0 |
42 |
1 |
42 |
74 |
9015 |
US52 S |
6300 |
0 |
828 |
22 |
832 |
1468 |
9016 |
WV73 W |
9900 |
0 |
1302 |
35 |
1307 |
2307 |
9017 |
US23 S |
9560 |
723 |
1162 |
31 |
1166 |
2059 |
9018 |
KY3 |
816 |
0 |
107 |
3 |
108 |
190 |
9019 |
US60 W |
3873 |
0 |
509 |
14 |
511 |
902 |
9020 |
I-64 W |
18791 |
1613 |
2259 |
60 |
2267 |
4002 |
9021 |
KY207 W |
305 |
0 |
40 |
1 |
40 |
71 |
9022 |
KY1 S |
2340 |
0 |
308 |
8 |
309 |
545 |
9023 |
KY2 W |
1098 |
0 |
144 |
4 |
145 |
256 |
9024 |
KYAA W |
1405 |
69 |
176 |
5 |
176 |
311 |
9025 |
KY8 W |
6590 |
3560 |
398 |
11 |
400 |
706 |
9026 |
US23 N |
12200 |
3641 |
1126 |
30 |
1130 |
1994 |
9027 |
KYAAE |
8300 |
34 |
1087 |
29 |
1091 |
1926 |
26%
were assigned as home based work, 1% home based school, 26% home based
other and 47% non-home based vehicle trips ends (Table 13). The
internal-external trip generation regression equation discussed earlier
was utilized in calculating the internal location of the trip end.
External-External Trips
An estimated 11,400 trips were determined by Sam Granato of the Ohio Department of Transportation as crossing through the Huntington Metropolitan Area. The resulting external-external matrix is presented in Table 13. The external-external trips were defined in an external trip table and were defined as vehicle trips.
Total Area-wide Trips
In Table 14, a summary of vehicle trips by trip category were defined and compared to the 1990 HAITS calibrated model. The 1990 network reported a higher percent of external-external trips, but since the study excluded the two Kentucky Counties some internal trips between Kentucky and Ohio or West Virginia would have been defined as external travel. Outside of this situation there was a similar allocation of trips between the two studies.
BALANCING PRODUCTIONS AND ATTRACTIONS
Since different mathematical models were utilized in estimating trip productions and attractions it was necessary to reconcile any differences. Over a 24 hour period it was assumed each production has an attraction. Thus, its
Table 14 Vehicle Trip Type
|
1990* |
2000 |
||
% |
Vehicle trips |
|||
Internal |
562,000 |
|
|
|
Truck |
|
|
|
|
Sub Total |
562,000 |
85% |
958,173 |
86% |
Ext./Int. |
75,000 |
11% |
147,991 |
13% |
Ext./Ext. |
25,000 |
4% |
11,367 |
1% |
TOTAL |
662,000 |
|
1,117,531 |
|
**KYOVA Table 4.7 Does Not Include KY [1]
1990 Data from HIATS Long Range 2025 Plan [1]necessary for productions and attractions to balance before applying the gravity model in trip distribution. For this analysis, HBW and HBO trip attractions were balanced to the trip production totals. Since the same regression equation was used to estimate NHB and truck trip productions, balancing was not required.
TRIP DISTRIBUTION
Internal Trips Gravity Model
Once the trip ends, in terms of productions and attractions, were estimate by TAZ, then the trip distribution models determined the trip linkage between zones. For internal travel the gravity model has been traditionally utilized. Its mathematical form is:
Where:
Tij = Trip from zone i to zone j
Pi = Total trips sent from zone i (trip generation)
Aj = Total trips received by zone j (trip attraction)
Fij = Travel time factor between zone i and zone j
A key component in applying the gravity model was the friction factors or trip length distribution for trips of different purposes. Without a recent origin-destination or household travel survey, the friction factors had to be estimated from secondary sources. In this application the friction factors were utilized from the previous QRSII model. The factors depended on the shortest travel time calculated between zones.
The gravity model was calibrated to represent trip distributions within the Huntington Model area. An iterative process was applied where average trip lengths were compared to estimated trip lengths. Without a recent locally derived trip length frequency curve a relationship assumed to reflect local conditions was taken from previous models [5]. Thirty iterations were made with exponential factors. The exponential values used are as follows:
HBW = .15
HBO = .18
HB School = .27
NHB = .18
CMV = .18
Terminal trips were not utilized.
A trip distribution trip table was produced, which included trips between TAZ’s (internal-internal I-I) and between TAZs and external stations (internal-external I-E). A comparison of travel times are noted in Table 15.
External Trips
Added to the matrix were trips traveling through the study area defined as External-External trips (E-E). The linkages between external stations were checked by the equations suggested in the Quick Response Manual NCHRP 365 [7], which relied on an estimate of functional classification, AADT and percent trucks. With limited linkages in the Huntington Metropolitan area, these equations
Table 15 Average Trip Lengths (min.)
|
O-D Survey 60’s |
1972 Model** |
1990 Model** |
Ashland* 2002 |
2002° Survey |
HBW |
13.2 |
13.1 |
20.75 |
20.976 |
16.5 |
HBO |
10.6 |
10.6 |
18.71 |
19.465 |
15.4 |
NHB |
10.1 |
10.1 |
15.66 |
20.364 |
13.3 |
CMV |
9.5 |
9.7 |
--- |
--- |
13.3 |
Ext. |
19.9 |
--- |
--- |
--- |
--- |
School |
8.5 |
7.2 |
15.90 |
--- |
19.5 |
Overall |
11.3 |
10.2 |
17.86° |
20.00° |
15.0 |
Ref. |
[3] |
[4] |
[1] |
[2] |
|
*Includes Int.-ext. and terminal times
**Int.-Int. only. Includes terminal times
°Calculated as weighted average
proved to be unreliable. Therefore, estimates were based on local knowledge and bridge surveys data provided by Sam Granato of the Ohio Department of Transportation. The resulting external-external linkages were noted in Table 16. The external-external trips were designated as a separate table and combined with the internal-internal and internal-external trips to represent an all “travel trip matrix.”
Table 16 External-External Matrix Daily Two-Way Volumes
External Station |
E-E |
ADT |
|
US52W |
9001 - |
9006 9011 9020 9017 |
15 16 112 182 |
WV 2 E |
9007 - |
9005 |
4 |
I64 E |
9008 |
9001 9017 9020 9025 |
39 44 1101 4 |
US23 S |
9017 - |
9005 9025 9026 |
26 21 231 |
I64 W |
9020 - |
9005 9017 9026 9027 |
110 219 58 13 |
KY8 W |
9025 - |
9026 9027 |
3518 21 |
US23 N |
9026 - |
9024 |
65 |
TOTAL |
|
|
5799 |
MODE CHOICE AND VEHICLE OCCUPANCY
The next step in the four step travel demand process was to factor the trip table generated in the trip distribution step into automobile and transit trips. Because the Huntington region has very low transit ridership, as a percent of all trips, all person trips were assumed to be made by automobile or commercial vehicles. The auto occupancy factions utilized were utilized as follows:
HBW = 1.08 persons/vehicle
HBO = 1.20 persons/vehicle
HBW School = 3.58 person/vehicle
NHB = 1.15 person/vehicle
CMV = 1.00 person/vehicle
TIME OF DAY ANALYSIS
The Huntington model was utilized for a 24 hour or daily travel analysis, therefore time of day factors were not applied. If in future applications time of day analysis are desired, a time of day distribution (H-Rates File) was developed by Sam Granato of the Ohio Department of Transportation.
TRAFFIC ASSIGNMENT AND VALIDATION
The final step of the four step travel demand modeling process was traffic assignment. Before application, the model needs to be validated. The results of the validation process was based on traffic assignment. The assignment process involved a method of successive averages to reflect capacity restraint assignment procedures. The BPR global information included:
Travel Time Step Size = 1.0
Base Traffic Multiplier = 1.0
Actual Speed Multipler = 1.0
Free Speed Multipler = 1.15
Opposite Direction Factor = 0.4
In this sections statistics are presented on the validation process and comparisons of the simulated volumes to recommended tolerances. Validation involves comparing average daily traffic (ADT) collected from field counts against ADT values generated by the model for the base year. Counts for 580 links were provided by the Ohio Department of Transportation, West Virginia Department of Transportation, and Kentucky Transportation Cabinet. Additional checks were made for vehicle-miles of travel (VMT) by functional class. Estimates of VMT were provided by Sam Granato of the Ohio Department of Transportation. Over 146 assignment iterations were conducted to validate the base your model.
Table 17 provides the validation statistics for the road links by ADT volume range. The results are presented by the Percent Root Mean Square (PRMS) between the ground counts and simulated counts. The PRMS was calculated as follows.
RMS =
PRMS =
Xgc = total synthetic volume
Xta = total ground counts
N = number of observations (links)
Xgc = average of ground counts
The PRMS gives greater weight to larger errors than small ones and weights positive and negative errors the same. The overall Percent PRMS was found to be 43.1 percent. Additionally as part of validation four screenlines were established as follows:
Screenline 1 = WV-OH Bridge Crossings (US52 Bridge, WV 527 Bridge, WV106 Bridge)
Screenline 2 = KY-OH Bridge Crossings (KY10 Bridge, Ironton Bridge, Ashland Bridge)
Screenline 3 = WV-KY Bridge Crossings (US60 Bridge, I-64 Bridge)
Screenline 4 = Wayne/Cabell Boundary (Adams/US60, I-64, WV152, Madison Ave.)
Table 18 contains comparisons between the screenline counts and simulated traffic. Table 19 provides validation of VMT by functional classification system.
TABLE 17 PRMS By ADT VOLUME GROUPS
Total ADT |
Model |
Tolerance |
0 – 999 |
95.9% |
72.3% |
1,000 – 2,499 |
82.9 |
57.8 |
2,500 – 4,999 |
54.5 |
48.9 |
5,000 – 9,999 |
30.5 |
40.9 |
10,000 – 19,999 |
28.6 |
33.9 |
720,000 |
20.2 |
27.7 |
TABLE 18 SCREENLINE COMPARISONS
Screenline |
Location |
Model |
Ground Count |
% Diff. |
1 |
US52 WV527 WV106 Total |
22,851 14,067 15,563 52,481 |
22,000 15,000 16,500 53,500 |
-1.9 |
2 |
KY10 Ironton Ashland Total |
8,238 12,059 32,003 52,300 |
8,300 13,063 32,928 54,291 |
-3.7 |
3 |
US60 I-64 Total |
12,295 23,759 36,054 |
13,710 24,900 38,610 |
-6.7 |
4 |
Adams/US60 I-64 WV152 Madison Ave. Total |
8,135 33,060 17,748 13,769 72,712 |
14,000 30,100 16,000 9,400 69,500 |
+4.6 |
Bridges |
|
140,835 |
146,401 |
-3.8 |
Total |
|
213,547 |
215,901 |
-1.1 |
Screenline 1 = WV-OH Bridge Crossings (US52 Bridge, WV 527 Bridge, WV106 Bridge)
Screenline 2 = KY-OH Bridge Crossings (KY10 Bridge, Ironton Bridge, Ashland Bridge)
Screenline 3 = WV-KY Bridge Crossings (US60 Bridge, I-64 Bridge)
Screenline 4 = Wayne/Cabell Boundary (Adams/US60, I-64, WV152, Madison Ave.)
TABLE 19 VMT Comparisons
FC-Rural |
Model |
Required* |
Percent Difference |
Req’d Percent Difference |
1 |
636,809 |
607,342 |
+4.9% |
7.0% |
2 6 |
1,121, 797 |
1,019,080 |
+10.0% |
10.0-5.0% |
7 8 9 |
1,930,674 |
1,828,275 |
+5.6% |
25.0% |
Total |
3,689,262 |
3,454,697 |
+6.7% |
|
FC-Urban |
||||
11 12 |
1,133,703 |
1,187,906 |
_4.5% |
7.0% |
14 16 |
1,621,403 |
1,928,727 |
-15.9% |
10.0-15.0% |
17 19 |
900,660 |
774,117 |
16.3% |
25% |
Total |
3,655,766 |
3,890,748 |
-6.0% |
|
TOTAL |
7,345,028 |
7,345,495 |
0.0% |
3% |
*VMT estimates provided by Sam Granato of the Ohio Department of Transportation, January 26, 2004.
UPDATE NETWORK AND FUTURE YEAR 2030 TRAVEL FORECAST
Based on ADT growth at the external stations a growth factor of 1.9 was applied to external-external stations and the external ends of internal-external trips. External trips were distributed by trip purpose as presented in NCHRP 365 [7] and were: 25% HBW, 50% HBO, and 25% were NHB. Future year socio-economic data was extrapolated from a number of sources including:
· Huntington-Ironton Area – The year 2025 Long Range Transportation Plan [1].
· Ashland Travel Model [2].
· Update of Cabell County, Wayne County and Lawrence County TAZ-by KY Staff.
The following networks changes were complete:
From the HIATS Long Range Transportation Plan for 2025 Document (chap. 8) [1]:
· Changed Hal Greer from 12th Ave. (where TAZ 164 intersects) to Washington Blvd approach codes changed to all end in “2” instead of “R” or “U” to account fro a new center turn lane.
· Changed sat. flow rate on 8th Ave. from 24th St. (where TAZ 155 intersects) to 31st St/US60 from 1385 to 2770 and from 2200 to 4400 to account for going from 2 lanes to 4 lanes.
· Changed sat. flow rate on Merrick Creek/CR 19 from WV2 to I-64 from 2200 to 4400 to account for going from 2 lane to 4 lane.
· Changed approach code on Spring Valley/CR7 from WV75 to James River to end with “2” instead of “U” to account for a new center turn lane.
· Changed sat. flow rate on WV10 from Davis Creek to Madison Creek from 1700 to 3400 and 1385 to 2770 to account for going from 2 lane to 4 lane.
· Changed sat. flow rate on WV152 from south of TAZ 228 to WV75 from 1700 to 3400 to account for going from 2 lane to 4 lane.
· Change sat. flow rate on US60 from I-64 Exit 15 to Cabell County Border from 1385 to 4155, 1490 to 4470, 2980 to 4470, 3400 to 5100, and 3800 to 5700 to account for going from 2 or 4 lanes all going to 6 lanes.
· Changed sat. flow rate on I-64 from US60 (Exist 15) to Cabell County Border from 4800 t0 7200 to account for 4 lane to 6 lane.
· Changed sat. flow rate on 1st St. (in Huntington) from 4th Ave. to 7th Ave. from 1385 to 2770 to account for going from 2 lane to 4 lane.
· Changed sat. flow rate on US52 from I-64 (WV Exit 1) to southern Wayne County Border from 1800 to 3600, 2000 to 400, and 2200 to 4400 to account for going from 2 lane to 4 lane.
· Changed sat. flow rate on OH93 from just south of TAZ 41 to northern Lawrence County Border from 1700 to 3400 to account for going from 2 lane to 4 lane.
· Changed approach code on OH141/Campbell from US52 to OH21/217 to end with “2” instead of “R” or “U” to account for a center turn lane.
· Added Chesapeake Bypass (Alt20a.1.dta) to come up with the geometry, interchange locations and layouts, and the input data. Used 4000 sat. flow rate per direction and 55 mph free speed. Interchanges located at OH243 north of Bent creek Rd. (c-118), WV106 Bridge extension, OH77, Big Paddy Rd. north of OH243, and OH7.
· Added new bridge across Ohio River from WV2/CR19 intersection to eastern terminus of the new Chesapeake Bypass.
· Signalized the intersections at the OH141 and US52 interchange. Assumed a 70 sec. cycle length.
· Changed sat. flow rate on US52 WB (only) at the Ashland Bridge (4 links total) from 4800 to 720 to account for an additional lane.
· Signalized interchange of US52 and Marion Pike/OH243. Assumed 70 sec. cycle length.
· Replace cloverleaf at US52 and OH93 interchange with a diamond.
From the Cabell County Land Use Report (p.22ft) [1]
· Changed sat. flow rate on WV10/16th St. from south of I-64 to Davis Creek from 1400 to 2800 and 1700 to 3400 to account for 2 lane to 4 lane.
From the Ashland Report (p. 47th) [2]
· Change approached code on 13th St./US60 from Pollard/Oakview to Sycamore St. (intersection of TAZ 1042) to end with “2” instead of “U” to account for a center turn lane.
· Changed approach code on Pond Run Rd. from US23/Seaton to Raceland Rd. to end with “2” instead of “U” to account for a center turn lane.
·
Changed I-64 WB off ramp onto KY180 from cloveleaf to
diamond.
References
1. Huntington-Ironton Area Transportation Study. The Year 2025 Long-Range Transportation Plan. KYOVA Interstate Planning Commission Huntington, West Virginia. February 2002.
2. Ashland Travel Model. The Corradino Group. Louisville, Kentucky. August 2002.
3. HAIAT’s Phase II Future Travel and Highway Needs. Wilbur Smith and Associates, New Haven, CT. May 1971.
4. Huntington-Ashland-Ironton Area Transportation Study 1973 Major Review and 2000 Plan Update. HAIATS Technical Advisory Committee. January 1975.
5. Validation of Huntington-Ironton Area Transportation Study Travel Forecasting Model for the Base Year of 1990. KYOVA Interstate Planning Commission. Huntington, West Virginia. July 1998.
6. Sosslau, A., et al., “Quick Response Urban Travel Estimation Techniques and Transferable Parameters: Users Guide.” NCHRP 187, Transportation Research Board, Washington DC, 1978.
7. William Martin and N. McGuckin. “Travel Estimation Techniques vs. Urban Planning.” NCHRP 365. Transportation Research Board. Washington, DC, 1998.
8. Web-site National Personal Transportation Study. US Department of Transportation. Washington DC, 1995.
9. Introduction to Urban Travel Demand Forecasting. National Highway Institute Course. Federal Highway Administration. Washington, DC. March 2002.
10. Wegmann, F, et al. Household Survey and Transferable Parameters for Travel Demand Forecasting in Tennessee, Center for Transportation Research, University of Tennessee, Knoxville, Tennessee, March 2004.
11. Clarksville Urbanized Area Travel Demand Model – Model Documentation and Users Guide. Kimley-Horn and Associates, Memphis, Tennessee, July 2001.
* Referred to as the Truck Equations