TRB Lianyu Chu *, K S Nesamani +, Hamed Benouar* Priority Based High Occupancy Vehicle Lanes Operation * California Center for Innovative Transportation (CCIT), University of California, Berkeley + Institute of Transportation Studies (ITS), University of California, Irvine TRB 2007

2 Current HOV lane Operation in Southern California HOV operations –HOV lane operates 24 hours a day HOV lane restrictions –HOV 2+, Buses & Car pools HOV lane type –Barrier-separated Criticism –Congested during peak period & underutilize the roadway capacity during off-peak –Limited ability to shift SOV to transits & Car pools

TRB Alternative Strategies Allowing Single occupant Hybrid vehicles in HOV lanes –e.g. California, Virginia Part-time HOV operation –e.g. Northern California High Occupancy Toll Lanes –Solo drivers can use by paying toll –e.g. SR-91, I-15, I-10

TRB Priority Based HOV Lane Concept Proposed HOV lane operation: –Vehicles are prioritized based on occupancy, emissions & toll; –Allows vehicles with a certain priority level based on dynamic traffic conditions Purpose: –To optimally utilize the current HOV lane facility Priority LevelVehicle Type 6Bus 5HOV 4+ 4HOV 3+ 3HOV 2+ 2Hybrids, LEV 1SOV with toll 0SOV Suggested priority levels

TRB Implementation Strategy Operational objective: –Maintain the traveling speed > 45mph (defined by SAFETEA-LU) System requirements –Reliable vehicle detection system –Variable message signs –User identification –Automatic payment system –Enforcement Determine priority levels based on –Dynamic traffic condition, which is measured by Level of service (LOS) Speed Throughput

TRB Priority Based HOV Operation Algorithm Algorithm –Define: HOV section: the segment of HOV lane from a HOV entry point to HOV exit point. –HOV section speed measured by detectors in the section. –HOV speed prediction –SOV toll is assumed to be a fixed dollar amount in the study –Priority decision model Algorithm implementation –A plugin developed using Paramics API –Priority Decision Model Priority decision model

TRB Evaluation Methodology Perform Paramics simulation runs Calibrate the micro- simulation network Performance measures Compare different scenarios Control strategy Build micro- simulation model Evaluation scenarios

TRB Study Site

TRB Microscopic Simulation Model Study network: –Located in Orange county, California (freeways) –Including 18-mile I-5, 12-mile I-405, and 10-mile SR-55 freeways Simulation model: –Paramics, developed by Quadstone –Model inputs: network geometry, driver behavior, vehicle characteristics, demand and zones Simulation model calibration: –Based on a previous study Simulation Period: –Morning peak period (6:00 – 8:00)

TRB Simulation Network

TRB Scenario Design Two scenarios: –Baseline: HOV 2+ HOV lane operation –Priority based HOV lane operation HOV lane changing –occurs only at existing egress and ingress area Performance Measures –Overall network performance Vehicle hours traveled (VHT) Vehicle miles traveled (VMT) Total passenger travel time Average travel speed –HOV lane performance Average lane speed LOS Average lane flow Vehicle groupsShare of vehicles (%) Bus0.5 HOV 4+ (including vanpool) 1.0 HOV 33.5 HOV Hybrid (0.3%) and LEV (0.5%) 0.8 SOV willing to pay toll 3.6 SOV79.4 Share of different types of vehicles

TRB Overall Network Performance - Priority based scenario performs better in-terms of speed & travel time

TRB HOV Lane Speeds on Different Corridors - HOV lane speed in priority based scenario has reduced marginally due to increase in flow

TRB Mainline Speeds on Different Corridors - Mainline speed has increased in priority-based scenarios due to shift of SOV demand to HOV lanes

TRB HOV Flows on Different Corridors - HOV flow throughput has increased in priority-based scenarios

TRB Level of Service on HOV Lanes - Priority based operation has reduced LOS since it has moved more vehicles to HOV lanes

TRB Time Spent in Different Priority Levels Freeways Priority level 1 (%) Priority level 2 (%) Priority level 3 (%) Priority level 4 (%) Priority level 5 (%) Priority level 6 (%) I-405N I-405S I-5N I-5S SR-55N SR-55S Total

TRB Findings The proposed priority based HOV lane operation performs better: –Total passenger travel time is improved by 10.3% –Travel speed is improved by 6.78% –HOV lane speed reduces marginally due to increase in flow –Mainline speed increases due to shift of SOV demand to HOV lanes –HOV flow throughput increases –LOS is improved since more vehicles are moved to HOV lanes

TRB Possible System Solution Possible system components –FasTrack Electronic toll collection system used in California Each vehicle has a transponder for user identification and payment –CMS Placed at proper locations Showing current priority levels –Algorithm for determining priority levels Tradeoff between HOV lane performance & throughput –Easy to be implemented in a barrier-separate HOV system e.g. in Southern California –Enforcement Camera to identify priority evaders Keys to success –Technology –System reliability –Enforcement –Education Increase the awareness of the concept to users