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Toolbox for Regional Policy Analysis Report (2000)

Case Study: Sacramento, California

Table 2. Scenario Elements: Description and Modeling Approach

Scenario Element

Description

SACMET96 Modeling Approach

MEPLAN Modeling Approach

Base Case

  • Modest number of road-widening projects and new major roads

  • One freeway HOV lane segment
  • Limited extension of light rail
  • Same 2005 and 2015 networks
  • Modified roadway and transit networks

  • Modified roadway and transit networks

Pricing

  • Parking cash-out, VMT tax, and peak-period toll policies

  • Home-based work trips charged $5 per day for workplace parking in zones eligible under state parking cash-out law

  • Per mile cost of auto travel in mode choice models increased by $0.05
  • Extra $0.10 per mile added to auto operating cost in the home-based work mode for peak period
  • 30% increase in the operating cost of private vehicle

  • CBD parking tax representing an average surcharge of $4 for work trips and $1 for other trips

Light Rail Transit (LRT)

  • 46 new track miles of light rail by 2005; 75 new track miles by 2015

  • Light rail and bus headways are halved
  • Modified roadway and transit networks

  • Modified roadway and transit networks

Advanced Transit

  • ATIS pre-trip transit service information

  • Demand-responsive transit to suburban LRT stations
  • Maximum initial wait times for all transit service in the model reduced to five minutes

  • New transit-only routes with short direct routes to LRT zones
  • Value of wait time is reduced by a factor of three

  • Access time to transit in the TOD zone is reduced by 3 minutes

Transit-Oriented Development (TOD)1

  • 9 TODs located around light rail stations with higher-density, mixed-use, pedestrian-friendly environment

  • 2015 scenarios only

  • Includes light rail and advanced transit elements
  • Development shifted manually from zones at least 1 mile from LRT stations to zones within ¼ mile radius of LRT stations

  • Average TOD density of 15 households per acre, 10 retail employees per acre, and 20 non-retail employees per acre
  • Pedestrian environment factors are increased for TOD zones
  • Land subsidies of 5% of expenditures in the year 2000 on land rent in the TOD zones. Subsidies are offset by 30% land rent surcharges in other zones so that region-wide the effect is revenue neutral

High-Occupancy Vehicle (HOV)

  • HOV lanes are increased from 26 to 82 lane miles in 2005 and 179 lane miles in 2015

  • Express bus service added to transit network
  • Mixed-flow freeway lanes increased by 6% compared to Base Case
  • Modified roadway and transit networks

  • Modified roadway and transit networks

High-Occupancy Toll (HOT)

  • HOV lanes in HOV scenario converted to HOT lanes

  • Tolls of $0.05/mile charged to one- and two-occupant vehicles only

  • Toll of $0.50/mile charged where necessary to maintain free-flow
  • Mode choice model for home-based work trips expanded to include the HOT drive-alone mode and HOT two occupants mode

(Not modeled)

Road-Oriented Development (ROD)

  • Concentration of development similar to TOD scenario, but located at major intersections near ramps along HOV or HOT lane corridors

  • Development shifted manually from other zones to major intersection ROD zones

  • Same densities as TOD
  • No change pedestrian environment factors

(Not modeled)

1 In general, the TOD densities in SACMET96 are greater than in MEPLAN. This is because the MEPLAN simulation could not match the SACMET96 TOD densities with a reasonable subsidy and taxation policy. Assuming MEPLAN accurately models land and real estate markets, the implication is that the TOD densities assumed in SACMET96 are higher than could realistically be expected. However, other variables such as shifting consumer preferences could potentially change this factor in the future.

Base Case

The base case scenario represents a financially conservative expansion of the Sacramento region's transportation system and includes a relatively modest number of road-widening projects, new major roads, one freeway HOV lane segment, and a limited extension of light rail. The 2005 and 2015 base case scenarios use the same roadway and transit networks.

Pricing Policies

It is widely believed that road pricing policies may be some of the most effective policies to reduce VMT and emissions. In this study, parking cash-out, VMT tax, and peak-period toll policies are examined in combination with some of the other scenarios described above.

To simulate the parking cash-out scenario in SACMET96, home-based work trips are charged $5.00 per day for workplace parking in the few zones identified by SACOG staff as eligible under a state parking cash-out law. The income benefits of the parking cash-out program are simulated in the economic benefit estimates by returning the parking charges to the travelers. A $0.05 VMT tax for the Sacramento region is obtained from the low end of the average national estimates of the external costs of auto use (Delucchi, 1997). The per mile cost of auto travel ($0.05) included in the mode choice models of SACMET96 was increased by $0.05 to represent the VMT tax. In addition, a peak-period pricing policy to reduce congestion during commute hours is also examined. To simulate a peak-period charge, an extra $0.10 per mile is added to the per-mile auto operating cost of travel in the home-based work mode in the mode choice model.

Pricing policies are modeled in MEPLAN through a 30 percent increase in the operating cost of private vehicles (to simulate a gas tax) and a CBD parking tax representing an average surcharge of $4.00 for work trips and $1.00 for other trips.

Light Rail

The light rail scenario represents an extensive expansion of the Sacramento region's light rail system. In total, these expansions include approximately 46 new track-miles of light rail by 2005 and 75 new track-miles of light rail by 2015. Light rail and bus headways are halved in this scenario.

Advanced Transit

In this scenario, advanced transit refers to improved and/or new transit that uses information and automation technologies. Two types of advanced transit are examined: Advanced Traveler Information Systems for Transit (ATIS) and Demand Responsive Transit (DRT). Many believe that the faster transit travel times provided by these advanced transit technologies may allow transit to compete more effectively with the auto for riders and thus reduce traffic congestion and emissions.

In both the 2005 and 2015 advanced transit scenarios, ATIS for transit takes the form of pre-trip transit service information. Transit users are assumed to access real-time transit scheduling information through 100 kiosks located at transit stations and workplaces, the telephone, the Internet, and cable television. DRT service is added to the light rail networks described above to provide an additional transit option to travelers in nine suburban zones and to connect travelers to light rail transit. DRT service is assumed to make use of computers to satisfy real-time transit trip requests, providing transit service to travelers when and where they need it.

In SACMET96, the maximum initial wait times for all transit service is reduced to five minutes to represent ATIS and paratransit service is simulated by adding new bus only routes with short direct routes between TOD zones in the transit network. In MEPLAN, the value of wait time is reduced by a factor of three to represent ATIS, and the access time to transit in the TOD zone is reduced by three minutes to represent paratransit service.

Transit-Oriented Development (TOD)

Transit-oriented developments, or TODs, describe rail station centers with a relatively high-intensity mix of shopping, other jobs, and housing located around light rail stations. In TODs, many activities are within walk or bike distances, and high-quality transit service is readily available for activities that are near the TOD. The TODs in this study include zones within a quarter-mile radius of light rail stations. TODs are examined only in the 2015 scenarios. Twenty years was viewed as the timeframe needed to generate enough new households and employment to create effective TODs.

The increased densities in the TOD scenarios were modeled differently in the MEPLAN than in the SACMET96 model. The method of simulation in each model illustrates some of their respective strengths and weaknesses. Both scenarios include the light rail network and advanced transit measures described above.

The MEPLAN model is theoretically comprehensive, representing land markets with endogenous prices and market clearing in each period. As a result, MEPLAN can simulate such policies as, for example, the release of zoning density caps near rail stations, tax benefits for infill development, and land development fees on raw-land projects near the urban edge. In this MEPLAN simulation, increased densities in the TODs are achieved through land subsidies of five percent of expenditures in the year 2000 on land rent in the TOD zones. The subsidies are offset by 30 percent land rent surcharges in other zones so that regionwide the effect is revenue neutral.

SACMET96 does not have a land use model and thus cannot simulate large-scale land use policies such as land subsidies and taxes. However, SACMET96 has small zones, detailed travel networks, and includes zone-based walk and bike accessibility variables. Thus, in the SACMET96 simulation, increased densities in the TODs are achieved by manually adjusting zonal land use. Seventy-nine TODs were located around light rail stations and have an average density of 15 households per acre, 10 retail employees per acre, and 20 non-retail employees per acre. Growth in households, retail employment, and non-retail employment from 1995 to 2015 in the outer zones (farther than one mile from the light rail lines) is moved to the zones in the TODs. The ratios of the household classifications are held constant in all zones, and thus only the total number of households is changed in zones. School enrollments are also adjusted to correspond to the changes in households. To reflect the improved walk and bike environment of the TODs, the pedestrian environment factors are increased.

In general, the TOD densities in SACMET96 are greater than in MEPLAN. This is because the MEPLAN simulation could not match the SACMET96 TOD densities with a reasonable subsidy and taxation policy. Assuming MEPLAN accurately models land and real estate markets, the implication is that the TOD densities assumed in SACMET96 are higher than could realistically be expected. However, other variables such as shifting consumer preferences could potentially change this factor in the future.

High-Occupancy Vehicle (HOV) Lanes

The HOV lane scenario represents an extensive expansion of the Sacramento region's HOV lane system to encourage the use of carpools and reduce traffic congestion and emissions. HOV lanes are increased from 26 lane-miles in the base case scenario to 82 lane-miles in the 2005 HOV lane scenario and to 179 lane-miles in the 2015 HOV lane scenario. Mixed-flow freeway lanes are increased by six percent (98 lane-miles) compared to the base case scenarios. Express bus service that takes advantage of the HOV lanes is also added to the transit network. HOV lanes are separately coded in the highway network used in SACMET96.

High-Occupancy Toll (HOT) Lanes

In this scenario, the HOV lanes in the HOV lane scenarios are converted to HOT lanes. HOT trips are assigned to the separately coded HOT lanes. A $0.05 per mile toll is charged for using the HOT lanes. Tolls are charged to single occupant vehicles (SOVs) and two occupant vehicles, but no tolls are charged to vehicles with three or more people. Where congestion is not eliminated on the HOT lanes with the $0.05 toll, a $0.50 per mile toll is imposed in order to achieve non-congested conditions on those roadway segments. This toll level was selected after numerous other tolls were tried to obtain the lowest toll level that would eliminate congestion on the HOT links. It is assumed that tolls from the HOT lane scenarios are used to offset the capital and O&M costs of the HOT scenarios.

To simulate the use of HOT lanes in SACMET96, the mode choice model for the home-based work trip purpose was expanded to include the HOT drive-alone mode and the HOT shared-ride two occupants toll mode. The variable coefficients specific to the drive alone mode were used for the HOT drive-alone mode, and the variable coefficients specific to the shared-ride mode were used for the HOT shared-ride two occupants toll mode.

Road-Oriented Development (ROD)

RODs are developed to examine a road-oriented land use intensification scenario that might be similar to a transit-oriented development (TOD) scenario with respect to potential travel and emissions benefits. RODs, like TODs, are mixed-use centers with a relatively high intensity mix of shopping, jobs, and housing. RODs are different from TODs in that they would be located at major intersections near ramps along HOV or HOT lane corridors as opposed to light rail stations. The purpose of RODs is to facilitate carpooling and express bus service. Less emphasis is placed on improving the walk and bike environment of the RODs than in the TODs. Average densities, the number of RODs, total changes in zonal household and employment, and changes in school enrollments are the same as in the TOD scenario. Ramps and arterials are expanded as needed to keep congestion levels without the RODs approximately the same as with the RODs to avoid impeding access to HOV and HOT lanes.

Updated: 04/26/2012
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