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3. Trip Assignment Trip assignment is the process of allocating the current or forecast trips to the roadway network. Assignment of daily trips to the network is completed in a two-step process once the network is defined. a) Determine the most direct and logical path from each traffic zone to all other traffic zones on the basis of speed and distance of each roadway segment. b) Assign distributed trips to the shortest path between an origin- destination zone pair to determine the number of vehicles desiring to use each roadway segment on the network. Before future volumes were assigned to the roadway network, existing trips were assigned and compared to current daily traffic volumes. Adjustments were made to link speeds until a close approximation (within 10 percent) of the existing volumes was achieved by the modeling process. F. FORECAST TRAFFIC ON EXISTING PLUS COMMITTED NETWORK Future trips based on forecasted development are allocated to the existing plus committed network. The forecasted traffic volumes are then analyzed to determine the adequacy of the system to accommodate the additional traffic without any further improvements. Assignment of the 2010 & 2020 traffic to the roadway system is shown in Figures Trans-S & Trans-9. Table Trans-1 illustrates the increase in traffic forecast to occur between 1990 and 2010 on some of the key roadways in the City. G. YEAR 2010 CAPACITY DEFICIENCIES Roadway capacity problems arise when the roadway cannot efficiently carry the traffic using it. Efficient traffic movement is described in terms of the "level of service" (LOS) provided, and is categorized using the letters" A" through "F" to describe conditions on the roadway. Tables Trans-2 and Trans-3 illustrate LOS characteristics. Roseville Comprehensive Plan - 2003 Update Transportation - Page 18 of 28