Operational Effect of Allowing Single Occupant Hybrid Vehicles into High Occupancy Vehicle Lanes

Chris BreilandFehr & Peers Associate

Lianyu Chu, Hamed BenouarCalifornia Center for Innovative Transportation (CCIT)UC Berkeley

Energy Use/Air Quality Issues

Increased Vehicle Miles Traveled

Antipathy Toward HOV Lanes

Hybrid Hype

Origins of “Hybrid-HOV” Laws

• SAFETEA-LU Requirements

– States can allow energy efficient, clean air SOVs in HOV lanes

– No operational degradation

Policy Specifics

• Implemented prior to passage of SAFTEA-LU

• Different definition of HOV lane degradation

– Primarily density/LOS based versus speed based

Policy Specifics - California AB 2628

Hybrid Population Data

PolicyDesign scenario

Estimate hybrid demand

Select study site

Build micro-simulation model

Calibrate micro-simulation model

Run simulation for each scenario

Performance measures

Estimate SOV / HOV demand

Planning model

Compare simulation results

Policy Implications

Methodology

Study Scenarios

• Baseline: Existing Conditions

• Scenario 1: Existing Hybrid Population

• Scenario 2: 50,000 Hybrid Checkpoint

• Scenario 3: 75,000 Hybrid Maximum

• Scenario 4: Eight Percent Hybrid Share

• Scenario 5: Nineteen Percent Hybrid Share

• Irvine, CA

– Highly Detectorized

– Fairly Busy

– Variety of HOV

Lane Geometries

Source: Google Maps

Study Location

Paramics Simulation Model

Paramics Simulation Model

Criteria and Measures Acceptability Targets

Model Performance

Hourly flows: modeled versus observed

Individual Link Flows Within 400 vph for flow > 2700 vph

Total (summed) Link Flows Within 5%

GEH Statistic – Individual Link Flows GEH < 5

GEH Statistic – Total (summed) Link Flows GEH < 4

> 85% of all cases All links

> 85% of all cases

All links

TOTA L: 153 mainline and ramp links

75%* Yes – Average error 3.61%

92%

Yes – Average GEH 3.17

Travel Time: modeled versus observed

Point-to-point Travel Times Within 15% or one minute, whichever is higher

> 85% of all cases

TOTA L: 6 trips

83%**

Visual Audits

Individual Link Speeds Visually acceptable speed-flow relationship

Bottlenecks Visually acceptable queuing

To analyst’s satisfaction

To analyst’s satisfaction

Acceptable Acceptable

* If criteria were expanded to allow flows of 408 or less, then 92% of cases would have been acceptable ** Due to a limited number of Caltrans travel time measurements, only six travel time comparisons can be made with 5 of the 6 trips within one minute of the measured time.

Model Calibration / Validation

• Based on California Law and Virginia HOV Task Force Report

– HCM 2000 Level of Service based on density

– Change in HOV lane travel time

– HOV lane flow rates

Performance Measures

HOV Lane Segment Performanc e Measure

Baseline Scen ario

1 Scen ario

2 Scen ario

3 Scen ario

4 Scen ario

5

Min 4.7 4.7 4.7 4.6 5.0 5.6 Mean 12.0 12.1 12.5 12.4 13.2 14.5 Density (vpm) Max 19.8 19.9 20.0 20.7 21.9 23.7 Min N/A -2.2% -2.3 -1.8% -0.5% -0.4% Mean N/A 0.85% 0.76% 0.94% 1.24% 1.78%

% Cha nge in HOV Lane Travel Time

Max N/A 5.3% 7.3% 4.7% 8.1% 8.0% Mean 1064 1065 1061 1077 1206 1225

Flow (vph) Max 1265 1264 1290 1289 1380 1515

Results

Performanc e Measure Baseline Scenario

1 Scenario

2 Scenario

3 Scenario

4 Scenario

5 Number of Sections with LOS A

25 23 24 25 19 13

Number of Sections with LOS B

15 17 14 13 20 23

Number of Sections with LOS C

1 1 3 3 2 5

Number of Sections with LOS D or Above

0 0 0 0 0 0

Number of Periods where Flow > 1800 vph

0 0 0 0 0 0

Results

• No significant degradation of HOV lane operations in study area

– Flows on SB I-5 in Santa Ana reached 1515 vph

• Results do not preclude degradation on other facilities in the state or country

Conclusions

• Policy may be implemented without widespread HOV lane degradation

• Hybrid sales strong

• “Take away” problem

• Virginia law set to expire on July 1, 2006

• Phase in toll lanes

• Better use of HOV lanes

• HOT lane

• Priority-based HOV operation

Policy Implications

Questions?