12th International HOV Systems Conference: Improving Mobility and Accessibility with Managed Lanes, Pricing, and BRT
BREAKOUT SESSION — DESIGNING FOR MULTIPLE USER GROUPS
William Finger, City of Charlotte, Presiding
Managed Lanes in San Diego — Trade-Offs in Designing a Multi-Modal Facility
Heather Werdick, San Diego Association of Governments
Heather Werdick described the I-15 corridor BRT and managed lanes project in San Diego. She summarized the major components of the project and discussed the design of the BRT stations. She noted that Dave Schumacher, San Diego Association of Governments, who was scheduled to give the presentation, was unable to attend the conference.
- The I-15 corridor BRT and managed lanes project is approximately 35 miles in length. It stretches from Escondido in the north to downtown San Diego in the south. BRT stations are spaced every four-to-five miles. The facility is part of the regional network of high-speed LRT and BRT routes. BRT service will be operated every 10-to-15 minutes.
- Construction of Stage 1 began late in the summer of 2003 and is schedule for completion in December 2007. This stage includes BRT stations and direct access ramps in the northern section of the corridor.
- A number of issues had to be addressed in the design of the managed lane facility. First, there was a need to ensure freeflow conditions for BRT. Second the desire to extend the FasTrak™ program had to be accommodated. Third, the ability to respond to traffic emergencies was critical. Finally, the design needed to accommodate long-term needs.
- To accommodate these and other issues, a four-lane managed lane facility using a moveable barrier is being pursued. The FasTrak™ program is being extended. Direct access ramps and BRT stations are being incorporated as an integral part of project.
- The movable barrier will be used to adjust the number of lanes in each direction of travel based on traffic conditions. Multiple access points will be provided from the freeway main lanes to the managed lanes. The managed lanes will act as a freeway within a freeway, providing priority for transit, carpools, and FasTrak™ users.
- The Rancho Bernardo Transit Center will include a BRT station, park-and-ride lots, and direct-access ramps to the managed lanes. It will also include direct access to the arterial street system. The direct-access ramps will be open to buses, carpools, and FasTrack™ users.
- A number of issues had to be addressed in the design of the Rancho Bernardo Transit Center. These issues included concerns about out-of-direction movements for the BRT vehicles, the need for interface with local buses, and concerns about the freeway noise and impacts from traffic on-ramps. To address these issues the decision was made to locate the station off the freeway to create a more pleasant and safe passenger waiting environment.
- A number of issues also had to be addressed in the design of the Sabre Springs Station. These issues included the right-of-way cost for the preferred parcel adjacent to the freeway and out-of-direction movements for the BRT vehicles. To address these concerns, the decision was made to locate the station on an undeveloped parcel of land.
- The BRT strategy in the I-15 corridor includes two types of routes. First, a trunk line providing all-day service will be operated on I-15. Second, point-to-point commute service will operate from remote stations and park-and-ride lots to the transit stations on I-15.
- At City Heights, locating the transit station in the freeway median was the only choice due to the inability to construct access ramps to the bridge deck. The arterial transit plaza required widening the bridge decks. Access to the freeway level BRT platform will be by elevator and stairs.
- A number of issues are being addressed with the design of the City Heights Station. Concerns about noise from the freeway are being addressed by locating the waiting platforms on the median platform not directly under bridge deck, and using plexi-glass barriers and enclosed waiting shelters. Concerns about security and safety perceptions are being addressed by locating platforms away from the bridge deck for increased visibility, using designs that avoid hidden areas, and proving for well-lit platforms at night. The concerns related to access between the plaza decks and the median station platforms are being addressed by providing elevators and stairs on both sides of the bridge deck and providing a walkway link under the bridge deck.
- The I-15 project provides insight into the design tradeoffs associated with BRT stations along a freeway corridor. Locating stations along freeways and managed lanes is less than desirable due to noise and safety concerns, conflicts with other traffic, and out-of-direction travel for BRT vehicles. The design of the freeway stations on the I-15 project has involved a series of tradeoffs. A peer review process will be used to evaluate designs for possible future station changes. Additional managed lanes and BRT corridors are included in the 2030 RTP. There is a regional commitment to managed lanes and BRT in the San Diego area.
Traffic Control Devices for Managed Lanes
Sue Chrysler, Texas Transportation Institute
Sue Chrysler discussed traffic control devices for managed lanes. She described the findings from research projects sponsored by TxDOT and FHWA. She noted the assistance of Jerry Ullman, Steve Schrock, and Beverly Kuhn from TTI with these projects.
- The amount and the complexity of information needs increases with the flexibility provide by managed lanes. Possible vehicle user groups for managed lanes include SOVs, HOVs, bus and BRT vehicles, trucks, ILEVs, motorcycles, taxis, and emergency vehicles. The selection of user groups will depend partially on the corridor characteristics, project goals and objectives, and policy issues. The selection of user groups will impact the design, operations, enforcement, and technology associated with managed lanes.
- A driver-decision model for managed lanes was developed to help focus on key elements. The model identifies decision points, influences on decisions, and information needs. These elements may be a function of driver type, which include unfamiliar drivers, semi-familiar drivers, and familiar drivers.
- The driver-decision model first focuses on if the lane is opened or closed. Desired information at this point includes entrance location, hours of service, if the lane is open or closed, the type of managed lane, and incident management. The second decision a driver has to make is to determine if they are eligible to use the lane. Information needed at this point includes vehicle restrictions, occupancy requirements, and toll rates. If a driver is eligible to us the lane, the next decision is to determine the benefits of using the managed lanes versus using the general-purpose lanes. Desired information includes the desire to avoid a late arrival, perceived value of time, travel times, travel time savings, and perceived safety. Finally, a potential user will want to determine the cost of using the managed lanes versus the general-purpose lanes. Desired information includes toll rates, potential perceived discomfort from barrier-separated facility, and exit information.
- The current MUTCD provides some guidance for signing managed lanes. The terminology "preferential lane use," is used, but guidance is spread across several sections. There are many topics that are not addressed in the MUTCD. There are also inconsistencies across sections and some inaccuracies.
- Current MUTC guidance focuses primarily on regulatory signs. There are some conflicts and confusing language for barrier versus buffer separated facilities. There is good guidance on sign placement, however.
- The MUTCD provides guidance on pavement markings for some types of preferential lanes. It also provides guidance on signing for some types of managed lanes, such as barrier-separated HOV facilities. The MUTCD provides good sign-sequencing guidance, including signing for intermediate access points.
- The MUTCD provides an example of signing for the entrance to and exit from an HOV lane, including guidance for both signs and pavement markings. MUTCD guidance is also provided on general-purpose lane transitions to preferential lanes.
- Another example focuses on signing for a direct-access ramp to an HOV lane from a park-and-ride facility. This section includes guidance for trailblazer signs from residential and arterial streets feeding the park-and-ride facility. An example of signing for a direct-access ramp to an HOV lane from a local street is also provided including guidance on trailblazer signs. The possible need for coordination and approvals from local jurisdictions is noted.
- The current MUTCD provides an example of signing for a direct-access ramp between HOV lanes on separate freeways. Diagrammatic advance guide signs are suggested because of the left exit. Houston METRO uses diagrammatic signs along the HOV lanes to provide advance guidance for park-and-ride lot entrances. The MUTCD also provides guidance on lane-use control signals, including reversible lane operations.
- The two projects have helped identify research needs related to signing managed lanes. Topics for further research include the use of unique background color and the use of banners and plaques across the top of guide signs, and on regulatory and warning signs. Another possible issue is the use of uniform toll tag symbols. Distance and destination signing for exit points, signing for travel time information, and posting of toll rate information all may need further research. The use of horizontal signing and application of additional pavement markings would also benefit from further research. For example conflicts between signing for general-purpose and managed lane exit information needs to be examined. Alternatives to address these types of issues include using unique colors for managed-lane signs, using separate structures, using unique banners, and using auxiliary plaques.
- The MUTCD does not address signing for pricing. Different approaches are currently being used on the value pricing projects underway. Possible research needs related to signs providing pricing information include the use of a different color, the use of horizontal signs, and the use of a uniform ETC symbol.
- Reports from the projects are available at http://managed-lanes.tamu.edu.
Design and Operations Associated with Single Lane Directional Managed Lanes
Casey Toycen, Texas Transportation Institute
Casey Toycen described recent research conducted by TTI for TxDOT examining single lane directional managed lanes. She summarized recent factors in Texas influencing interest in the topic, highlighted case study examples, and discussed potential design and operational issues.
- Recent legislation in Texas provides additional opportunities for managed lanes, toll facilities, and innovative financing. In addition to the congestion and mobility issues facing most metropolitan areas throughout the country, truck traffic is a major issue in Texas. Truck volumes on I-35 and other freeways in the state are expected to increase based on the North American Free Trade Agreement (NAFTA).
- The research project first examined current guidelines relating to the design and operation of HOV and HOT facilities. The American Association of State Highway and Transportation Officials (AASHTO), TxDOT, and Caltrans HOV guidelines were reviewed, along with the FHWA guidance on HOT facilities.
- Case studies of existing HOV and HOT lanes were developed. The case studies included the I-10 West and US 290 HOV lanes in Texas, and I-394 HOV lanes in Minneapolis, the I-680 HOV lanes in the San Francisco Bay Area, and the SR 167 HOV lanes in Seattle. The two Houston HOV lanes include a HOT component. MnPASS will be implemented on the I-394 HOV lanes in May 2005. HOT components are planned for both I-680 and SR 167.
- The HOV lanes on I-10 West and US 290 are both barrier-separated reversible lanes. A 3+ vehicle-occupancy requirement is in effect from 6:45 a.m. to 8:00 a.m. on both facilities and also from 5:00 p.m. to 6:00 p.m. on I-10 West. The I-10 West HOV lane is 13 miles in length and the US 290 HOV lane is 15 miles in length. A HOT program, QuickRide, was implemented on the I-10 West HOV lanes in 1998 and on US 290 in 2000. The QuickRide program allows registered two-person carpools to use the HOV lanes for a $2.00 per trip fee during the 3+ restricted periods.
- The I-394 HOV lanes are 11 miles in length. These are two HOV sections — a three-mile, two-lane, barrier-separated section and eight miles of concurrent flow HOV lanes. MnPASS, a HOT program, will be implemented in May 2005 allowing SOVs to use the lane for a variable charge. The concurrent-flow section will operated 24/7 and the reversible section will operate inbound from 5:00 a.m. to 1:00 p.m. and outbound from 2:00 p.m. to 4:00 a.m.
- The I-680 concurrent flow HOV lanes are 14 miles in length. A HOT Program is scheduled to be implemented southbound in 2009. The operational characteristics have not yet been determined, but 24/7 is being considered.
- The SR 167 concurrent flow HOV lanes are nine miles in length. A HOT pilot program is planned for implementation in the next few years. A 24/7 operating plan is anticipated.
- The cross-section for the five HOV lanes were examined. The two Houston projects included a 12-foot travel lane and 4-foot buffers on each side before the barriers. The I-394 concurrent flow HOV lanes include a 10-foot shoulder, the 12-foot HOV lane, and a 2-foot stripe buffer. The I-680 HOV lanes include a 10-foot shoulder in most sections, a 12-foot HOV lane, and a 4-foot painted buffer. The two HOV lanes in Houston are barrier-separated. Both barrier and buffer separation are being considered on SR 167. None of the projects allow passing.
- The case studies use a variety of access controls. The Houston HOV lanes use slip ramps at the ends and direct access ramps to park-and-ride lots and transit centers. I-394 concurrent flow HOV lanes will change from unlimited access to six access points with the implementation of the MnPASS program. The I-680 lanes use slip ramps at the ends, two mid-point ingress locations, and two mid-point egress locations. The SR 167 HOV lanes are anticipated to change from unlimited access to four northbound and three southbound access points of at least 1,000 feet.
- The QuickRide program in Houston uses a fixed price of $2.00 per trip with a registered account. The MnPASS program on I-394 will use dynamic pricing with rates of $0.25 during the off-peak periods and up to $8.00 during the peak period. The I-680 project will use dynamic pricing of $0.22 to $0.38 per mile based on LOS. The SR 167 project will use dynamic pricing, with tolls ranging from $0.60 to $1.25 per trip.
- A number of other design and operation issues are being examined in the study. These issues include modeling for managed lanes, new construction versus conversion, and accommodating and monitoring vehicles with free access. ITS infrastructure needs, enforcement technologies and strategies, and incident management are also being examined.
Managed Lane Ramp Design Issues
Marcus Brewer, Texas Transportation Institute
Marcus Brewer discussed ramp design issues associated with managed lanes. He noted that the presentation is based on information from research projects sponsored by TxDOT and FHWA. He also recognized the involvement of Kay Fitzpatrick and Steven Venglar in both the projects and developing the conference presentation.
- There is increasing interest in managed lanes to help address traffic congestion in urban corridors in Texas. The emphasis of the research effort was on access-ramp design treatments. All types of managed lanes were considered, not just HOV lanes. However, the research indicated that the experience with HOV lanes is applicable to other types of managed lanes. The research study included a literature review, an assessment of current practices in different states, case studies, and computer simulations.
- A literature review was conducted to assess potential issues and experiences with managed-lane ramp designs. The findings from a literature review identified the importance of considering speed-change lanes, taper designs for exit ramps, and large truck characteristics in the design of managed-lane ramps.
- The review of current practices in other states helped identify the definition of ramp design elements. It also provided information on the benefits and use of exclusive HOV ramps. Information on ramp design speed, ramp/interchange spacing, and weaving section length was also obtained. The results from the literature review also highlighted the preference for right-side ramps in most states.
- One of the case studies examined ramp designs on the New Jersey Turnpike. The dual-dual roadway on the turnpike separates heavy vehicles from light vehicles and provides flexibility during periods of heavy traffic congestion. There are separate ramps for each barrel or roadway. There is no weaving across the outer roadway, which enhances safety. All merging occurs prior to the toll plazas, which enhances efficiency.
- An initial crash analysis conducted shortly after conversion to the dual-dual roadway indicated an 18 percent reduction in crashes. A recent study found that the dual-dual segment had between 26 to 61 percent less crashes than non-separated segments. It is possible that similar benefits may be realized from managed lanes due to direct access and the separation of vehicles.
- The goals of the computer simulation were to quantify the effects of ramp spacing and to help identify when to consider direct-access ramps. The variables in the simulation were speed, ramp spacing, volume, and weaving percentages. The geometric layout was a single-direction freeway with four mainlanes and two managed lanes, which restricted weaving from managed ramps.
- The simulation examined the influence of different measures for ramp spacing, initial freeway volumes, and weaving percentages. Ramp spacing of 1,000, 2,500, 4,000, and 5,500 feet were examined. Initial freeway volumes of 1,250, 1,500, 1,750, and 2,000 vehicles per hour per lane were included in the simulation. The weaving percentages of zero, 10, 20, and 30 percent were examined. A total of 64 scenarios were run with four values for each of the three variables. Each scenario was modeled three times for a total of 192 unique simulations.
- Traffic conditions were defined in the simulation. First, heavy vehicles accounted for 10 percent of the total traffic. Second, vehicle volumes in the managed lanes was less than or equal to 75 percent of the freeway volume. Third, freeway entrance ramp volumes were set at 70 percent of freeway volumes per lane. Fourth, freeway exit ramp volumes were set at 60 percent of freeway volumes per lane. Finally, managed-lane entrance ramp volumes were based solely on weaving percentage.
- Previous studies indicated that a direct-connect ramp should be considered when ramp volumes are 400 vehicles per hour. This recommendation was supported by the findings from this simulation. For a more conservative approach, the research results indicate a direct-connect ramp should be considered at 275 vehicles per hour.
- At least three key findings resulted from the study. First, there is a need for guidance concerning the placement of managed-lane ramps. Second, weaving directly affects freeway speeds. Finally, direct-connector ramps should be considered at 400 vehicles an hour to maintain speeds, or a more conservative 275 vehicles an hour.