Trip Generation for Street and Highways
Lecture 14
CE 4720
Norman Garrick
Trip Generation Calculations for
Street and Highway Construction
Storrs Center
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Storrs Center Google Earth The Site
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Wetlands
Storrs Center Google Earth The Site
Constraints
Forest Reserve
Norman W. Garrick
Storrs Center Google Earth The Site
Built Area
Norman W. Garrick
Storrs Center
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Storrs Center Model
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Storrs Center Model Village Road
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Storrs Center Google Earth
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Storrs Center 195 Problem
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Storrs Center
Importance of the Network
Norman W. Garrick
Using TG Manual without
Correction
ITE Trip Generation Manual
Proposed Trip Generation
Daily Trips
Land Use
Size
Trip Generation Classification
Trip Gen Rates
Trip Gen
Dwelling Units
Houses
131 DU
Single-Family Detached Housing (210)
9.60
1,258
Town Houses
42 DU
Condominium/Townhouse (230)
5.60
235
Live Work DU
42 DU
Condominium/Townhouse (230)
3.60
151
Apartments
140 DU
6.70
938
Apartment (220)
Commercial
Live Work
21,000 SF
Single Tenant Office (715)
11.60
244
Mixed Use 1
181,800 SF
Specialty Retail Center (814)
44.32
8,057
Mixed Use 2
181,800 SF
Shopping Center (820)
42.90
7,799
8.90
3,115
34.00
1,428
44.00
1,320
16.00
82
Totals
24,628
Lodging
Hotel
Hotel (310)
350 Rooms
Civic
Town Hall
42,000 SF
Library
30,000 SF
Pool
5,150 SF
Government Office (730)
Library (590)
Recreation Center (495)
Proposed size of project
Estimated number of trip ends = 24,600
Norman W. Garrick
Using TG Manual with Correction for Mixed Use
Proposed Trip Generation
Daily Trips
Land Use
Dwelling Units
Houses
Town Houses
Live Work DU
Apartments
Commercial
Live Work
Mixed Use 1
Mixed Use 2
Lodging
Hotel
Civic
Town Hall
Library
Pool
Mixed Use Internal Capture
Pass-by Trips
Size
Trip Generation Classification
131 DU
42 DU
42 DU
140 DU
Single-Family Detached Housing (210)
Condominium/Townhouse (230)
Condominium/Townhouse (230)
Apartment (220)
21,000 SF
181,800 SF
181,800 SF
350 Rooms
42,000 SF
30,000 SF
5,150 SF
Single Tenant Office (715)
Specialty Retail Center (814)
Shopping Center (820)
Hotel (310)
Government Office (730)
Library (590)
Recreation Center (495)
Trip Gen
Rates
Trip Gen
9.60
5.60
3.60
6.70
1,258
235
151
938
11.60
44.32
42.90
244
8,057
7,799
8.90
3,115
34.00
44.00
16.00
1,428
1,320
82
20 % of Residential, Commercial, Lodging and Civic Trips
25 % of External Commercial and Civic Trips
-4,926
-3,786
Totals
15,916
Estimated number of trip ends = 15,900
It is very important to remember that this total includes walking, biking and transit trips
Not just car trips
Norman W. Garrick
360 State, New Haven
Trip Generation
360 State, New Haven
trip Generation over predict trips
The 360 State Street was estimated to produce 674 PM peak hour vehicle trips
Requiring the construction of 500 parking spaces
Live monitoring shows only 116 trips (17% of what was predicted)
- Mixed Use Trip Generation Model (New Haven and SCRCOG)
LOS, Volume Capacity
Sample Calculation
A two lane urban street has an ADT of 20,000 vehicles per day.
Estimate what fraction of the year this street will operate at i)
LOS E, ii) LOS D. Do this calculation for directional splits of
50% and 60%. The hourly volume distribution and the design
hour service volumes are given on the following sheets.
Traffic Distribution
0.11
Hour volume
as % of ADT
0.1
0.09
0.08
0.07
0.06
0.05
0
200
400
600
800
1000
1200
1400
1600
1800
Number of Hours
with traffic great than
shown
Design Hour Service Volume
Urban Streets with Frequent Signal Controlled Intersections
Level of Service
Design Hour Service
Volume
A
B
C
275
D
700
E
850
F
>850
Source: http://www.dot.state.fl.us/planning/systems/sm/los/pdfs/lostables.pdf
Assumptions: > 4.5 Signalized intersection, 1.5 % heavy traffic, 12 % left turn, 12 % right turn
Ocean Springs – Biloxi Bridge
Biloxi – Gulfport Region
Ocean Springs – Biloxi Bridge Location
Ocean Springs – Biloxi Bridge
ADT Pre-Construction
35000
30000
25000
20000
15000
10000
5000
0
2001
2002
2003
2004
2005
Design Hour Service Volume
Level of Service
Controlled Access
Highway
Uncontrolled Access
Highway
Design Hour Service Volume per Lane
Design Hour Service Volume per Lane
A
700
700
B
1100
1100
C
1550
1400
D
1850
1780
E
2000
2000
F
>2000
>2000
Source: AASHTO 1990
LOS, Volume Capacity
Ocean Springs – Biloxi Bridge
Estimate the level of service for the Ocean Springs – Biloxi
Bridge.