Irvine PA12 Project: Task 4

The goal of this phase is to quantify the impact of the initial phase of the proposed development on the local circulation system. In the prior task, you computed some simple performance measures (VC ratios, speeds, etc.) for the base (1995) system. In this Task, the analysis will be extended to ICU analysis for both base conditions (1995) and for the initial development phase (1999).

Task 4.1: Estimate Project Phase I O/D Demands

The local circulation system has exhibited an overall growth of approximately 2 percent per year. The estimated origins and destinations for the project are summarized in Table 4.1 below.

Table 4.1 Summary of Proposed Land Use and Trip Generation

Zone	Land Use	Units	AM/In	AM/Out	AM/Tot	PM/In	PM/Out	PM/Tot	ADT
5	109 Commercial	50 TSF	79	73	152	138	144	282	3622
	103 Cluster B	205 DU	27	109	136	113	57	170	1808
8	109 Commercial	150 TSF	182	168	350	318	331	649	8318
	103 Cluster B	61 DU	8	32	40	34	18	52	538
12	102 Cluster A	242 DU	44	152	196	177	80	257	2623
	103 Cluster B	242 DU	31	128	159	133	68	201	2134

All demands are person trips and must be converted to vehicle trips prior to factoring the matrix and loading the network. Use an average vehicle occupancy from Project II. These demands, and the general 2 percent growth rate, must be reflected in updating the base 1995 O/D matrix to 1999. Use TransCAD's Doubly-constrained Growth Factor Model (i.e., Fratar balancing), under Planning / Trip Distribution / Growth Factor Method to update the base AM and PM matrices.

This technique factors a base matrix to reflect new marginals (origins, or row totals, and destinations, or column totals). Your input must include a dataview (or equivalent) which contains the updated origins and destinations by zone. All external zones increase by 2 percent per year. Assume all internal zones remain the same except for those in the proposed development. Note that a weakness of this method is that cells with no base activity cannot be factored to reflect future activity, thus, be sure to revise the base matrix to reflect at least a single trip in each cell which potentially will have future trips.

See the Tutorial on factoring a base matrix to reflect new marginals.

Task 4.2: Assign Project Phase I O/D Demands to the Base Network

Task 4.3: Intersection and Link Performance

1. ADT Arterial Link Volumes
   1. Link V/C not to exceed 0.90 (LOS D or better) or 1.00 for Irvine Center Drive. Use ADT capacities of 10,000 vph/land for arterials and 20,000 for freeways.
   2. For V/C greater than acceptable LOS, mitigation of project contribution is required to bring link back to acceptable LOS or to no project conditions if project contribution is 0.02 or more.
2. Peak Hour Intersection Capacity Utilization
   1. ICU not to exceed 0.90 (LOS D or better) or 1.00 on Irvine Center Drive. Assume the following parameters for ICU analysis: capacity = 1700 vph/lane, Clearance interval = 0.05, RTOR allowed (Adjustment Factor = 0.75).
   2. For ICU greater than acceptable LOS, mitigation of project contribution is required to bring intersection back to acceptable LOS or to no project conditions if project contribution is 0.02 or more.

Perform ICU Analysis for existing and planned intersections adjacent to the proposed projects for both base and planned conditions.

Task 4.4: Final Report