12th International HOV Systems Conference: Improving Mobility and Accessibility with Managed Lanes, Pricing, and BRT
BREAKOUT SESSION — DON'T FORGET TDM AND SUPPORT ELEMENTS
Heidi Stamm, HS Public Affairs, Presiding
Integrating Ridesharing Promotion and Incentives into HOV Lane Projects: Current Experience and Future Needs
Eric Schreffler, Eric Schreffler Transportation Consultant
Eric Schreffler discussed potential approaches for increasing the use of HOT lanes by HOVs. He provided an overview of the I-15 FasTrak™ project in San Diego, including the promotion of alternative modes. He also described a potential approach using revenues for user choice subsidies to help encourage the use of HOV modes.
- The I-15 FasTrak™ project uses the eight-mile reversible HOV facility in San Diego. Carpools and vanpools with two persons or more can use the lane for free. SOVs pay a toll of between $0.50 — $4.00 per trip. The toll varies with volumes in the HOV lanes. FasTrak™ accounts are debited monthly. The revenue from the project is used to pay for operations of the facility and transit services. FasTrack is transitioning to a managed lanes project.
- Results from ongoing monitoring and evaluation activities highlighted some key findings from the project. First, the FasTrak™ program has improved the efficiency of the HOV lanes. Second, pricing is an option, not an imposition. Third, people who use FasTrak™ love it; while non-users do not really care. Fourth, carpoolers did not revolt when the program was implemented. Finally, FasTrak™ cross-subsidizes transit in the corridor.
- Transit ridership in the corridor has not grown as fast as the rest of the region, however. Many riders on the new Inland Breeze Bus Service previously rode the bus. HOV volumes have decreased during FasTrak™ in both the HOV lanes and the main lanes. The FasTrak™ project did not really integrate new HOV promotions.
- Some enhancements have been made to try to address many of these concerns. Additional commuter runs were added to the Island Breeze Bus Service. The Island Breeze is now averaging approximately 140,000 annual boardings or 550 boardings per day. Approximately 770 riders or 1,522 boardings a day are on all commuter express routes using the HOV lanes.
- In addition, some 420 vanpools operate in the region, serving 3,800 commuters daily. Approximately 175 vans use the I-15 corridor, which equates to 1,500 vanpoolers per day. Also, telework is increasing in the area.
- There is a need to rethink the role of HOVs in HOT and managed lane projects. Actively promoting HOVs should be a priority. Employers and commuters in a corridor can be targeted and a full range of alternatives should be marketed and promoted. There is also a need to provide incentives for using HOV lanes beyond travel time savings.
- One approach would be to promote user choice subsidies. This strategy would let commuters make choices among paying a toll and receiving a carpool subsidy, a vanpool subsidy, a bus rider subsidy, a bicycle subsidy, and a telework subsidy. A voucher system could be used and incentives could be provided to encourage people to try different modes.
- If the goal is still to move people in fewer vehicles, maximizing the use of HOV lanes by HOVs should be a priority. Efforts should focus on increasing rideshare mode shares and increasing toll, not occupancy restrictions. Consideration should be given to using some toll revenue for user choice subsidies.
An Analysis of Casual Carpool Passenger Behavior in Houston
Justin Winn, Wilbur Smith Associates
Justin Winn discussed the use of casual carpooling on the Houston HOV lanes. He provided an overview of casual carpooling with HOV lanes in the U.S. and described the results of surveys of Houston casual carpoolers conducted as part of the QuickRide value pricing project.
- Casual carpooling has existed for over 30 years. Casual carpooling involves people meeting in public areas to be picked up by drivers so they can use the HOV lanes. The drivers are known as "bodysnatchers," while the people waiting to be picked up are known as "slugs." Three known locations where casual carpooling currently occurs are northern Virginia, San Francisco, and Houston.
- The study of casual carpooling in Houston had four objectives. The first objective was to review current practices associated with casual carpooling in the U.S. The second objective was to determine the time savings realized by casual carpool passengers in Houston. The third objective was to determine the characteristics of casual carpool passengers in Houston. The fourth objective was to identify factors that significantly influence travelers' decision to choose casual carpooling over other modes.
- Casual carpooling occurs on the Bay Bridge crossing in the San Francisco/Oakland area. Commuters use casual carpooling in the morning, and take transit in the evening for their return trip. It appears that some individuals use casual carpooling on a regular basis on the Bay Bridge.
- Casual carpooling also occurs on the I-95/I-395 HOV lanes in northern Virginia. There area at least 20 locations where people gather for rides. Casual carpooling is used in both the morning and evening, and previous studies have indicated that casual carpooling accounts for approximately 10 percent of the person movement in the morning peak hour.
- Surveys were conducted of casual carpoolers in November 2003, as part of the Houston Value Pricing project. Surveys were also conducted of travelers in the freeway general-purpose lanes, carpoolers in the HOV lanes, and bus riders. The surveys included questions on trip purpose, trip time, and socioeconomic information. A total of 538 casual carpoolers were given surveys at three park-and-ride lots. Two of the lots were on the I-10 West HOV lane and one lot was on the US 290 HOV lane. A total of 216 surveys were returned for a 40 percent response rate.
- In addition to the survey results, travel speed data for the HOV lane and the freeway general-purpose lanes on I-10 West and US 290 were obtained from Houston TranStar. Visual observations were made of the casual carpooling formation process. Observers recorded the walk time to the casual carpooling queue and the time spent waiting in the queue before a ride was obtained.
- The travel time savings associated with using the HOV lanes was computed from the travel speed data obtained from TranStar. The travel time differential was computed as the difference between the travel time on the general-purpose lanes and the travel time on the HOV lane. The total travel time savings was computed as the differential in drive time plus the access walk time and the time spent in the queue. Based on this analysis, it appears that during the 7:00 a.m. and 8:30 a.m. time period, casual carpooling saves between one minute and a little over six minutes.
- Four traveler groups were examined in the surveys. These four travel groups were drivers in the general-purpose freeway lanes, carpool drivers in the HOV lanes, bus riders, and casual carpool passengers. The survey results were tested for significant difference in travel and socio-economic characteristics.
- Approximately 96 percent of the casual carpoolers were making a commute trip, compared to 89 percent of the bus riders, 85 percent of the freeway drivers, and 80 percent of the carpool drivers. Some 28 percent of the casual carpoolers were in the 25 to 34 age group and 68 percent reported professional/managerial occupations.
- Additional questions were asked of casual carpoolers. The results from these questions indicated that 75 percent of casual carpool passengers use this mode at least three times per week and that over half have been casual carpooling for more than a year. Saving time and saving money were the two major reasons identified for casual carpooling. Almost 70 percent of the respondents reporting using transit for their return trip, while 13 percent said they used casual carpooling on their return trip.
- A discrete choice logit model was used to analyze some of the results. Two scenarios were examined. The first scenario examined casual carpooling and transit. The second scenario examined casual carpooling, freeway drivers, carpool drivers, and bus riders.
- The analysis results indicate that individuals making commute trips, those making higher total trips per week, and those in the 25 to 34 age group were more likely to use casual carpooling. In addition, individuals in the professional/managerial and the administrative/clerical job categories were more likely to use casual carpooling. Individuals with incomes between $25,000 and $35,000 and those in the 55 to 64 age group were less like to use casual carpooling.
- The survey results indicate that casual carpool passengers are more likely to be on a commute trip, to be young, and to have professional or administrative occupations. Additional research is needed to examine the characteristics of the evening return trips, casual carpool drivers, and stated preference data.
Reservation-Based ITS Systems: Real-Time Variable Congestion Pricing on the Proposed I-75 HOV/BRT Facility
Weimin Huang, Georgia Tech University
Weimin Huang discussed the potential of using real-time variable congestion pricing on the proposed I-75 HOV/BRT facility in Atlanta. He recognized Randy Guensler, Michael Hunter, Seung Kook Wu, and Joonhoo Ko at the Georgia Institute of Technology for their assistance on the project.
- The proposed I-75 HOV/BRT project would include construction of new barrier-separated HOV lanes and BRT stations on I-75 from I-285 to I-575. It would also include HOV access points at new HOV interchanges. Continuous HOV and BRT operations on I-75 between downtown and I-575 would be in operation by 2011.
- The area examined in the study for possible real-time congestion pricing is south of the existing HOV segment on I-75 from I-285. It is approximately seven miles in length. Recurring congestion occurs on weekday mornings. The proposed project would include four-to-five general-purpose lanes, and one dedicated HOT lane. It would also include five interchanges and two access points.
- The reservation system concept was identified as one way to address first-come first-serve queues in the general-purpose lanes, which are not as efficient as priority-based queues. Priority-based queues would include HOV/HOT lanes and ramp metering. HOT benefits include travel reliability, time savings, and revenue generation. A reservation system further improves the efficiency of priority-based queues.
- The goals of the research project were to present a proof-of-concept for a reservation-based HOT operation and to use a toll elasticity mechanism to maximize the HOT lane utility while maintaining the LOS on the HOT lane.
- The reservation-based ITS system includes two concepts. Regular HOT operations, where drivers pay tolls at HOT access points and a reservation component. The reservation component would allow drivers to pay a certain percentage, 25 percent was used in the analysis, of the access-point toll price in advance, thereby securing their rights to use the HOT lanes. When these drivers pass HOT access points, they are charged the remaining toll price. If a driver does not use the lane, the deposit is forfeited. The anticipated no-show rate can be computed based on elasticity.
- The operation of a reservation-based system would monitor HOV use of the HOT lanes. The available capacity in the lanes would be identified. Pricing for access points/reservations on the HOT lanes would be established, the numbers of reservations on HOT lanes and the number of no-shows would be monitored, along with the numbers of drivers using HOT lanes without reservations. The system would continually monitor and update available capacity, pricing, and space available for reservations.
- The Atlanta Regional Commission (ARC) travel demand model was used as the base travel demand model for assessing the reservation-based ITS program. The future model includes adding one lane and imposing turn restrictions to HOVs. The four-step model was rerun with these changes. The origin/destination table for the I-75 sub-network was extracted from the model.
- The traffic simulation development used the VISSIM model. VISSIM uses various vehicle classes depending on vehicle types and their routes. Traffic volumes in the general lanes were increased until congestion started. The maximum numbers of vehicles that can be moved from general lanes to HOT lanes while maintaining freeflow conditions on the HOT lane was determined.
- The demand simulation results indicated that with HOV only using the HOT lane, speeds on general-purpose lanes were 29 mph. Speed on the HOT lane with HOV only was 64 mph and the travel time difference was 7.4 minutes. The simulation moved vehicles from general-purpose lanes to the HOT lane when the speed in the general-purpose lanes was 33 mph. Speed on the HOT lane was 55 mph and the travel time difference was 4.7 minutes.
- The assumptions used for pricing included a reservation price of 25 percent of the access-point price, a constant elasticity of 0.569, and a willingness-to-pay of $30 per hour saved. The access-point price varied from $2.35 to $3.70. An initial toll of $3.70 at access points and $0.93 for reservations was set. At this price, the model shifted 780 vehicles into the HOT lane based on elasticity. The model was rerun with 780 vehicles shifted. The time difference was 5.45 minutes, the new toll was $2.70, which leads to 940 vehicles shifted. If the 940 shifted vehicles causes congestion on the HOT lane, the $2.70 toll would be rejected and the $3.70 toll price would be kept.
- Based on the demand simulation the suggested allowed vehicles and tolls were 400 vehicles at $3.70 at the access point, 380 vehicles at $0.93 for reservations, and a no-show rate of 15 percent at $0.93. The reservation concept ensures travel time reliability for reservation customers and maximizes HOT lane utility. Future research is needed to determine the exact reservation demand.