HIGH-OCCUPANCY VEHICLE FACILITIES A SYSTEM PLAN FOR DALLAS, TEXAS. Final Report

Transcription

1 HIGH-OCCUPANCY VEHICLE FACILITIES A SYSTEM PLAN FOR DALLAS, TEXAS Final Report Prepared For State Department of Highways and Public Transportation District 18, Dallas Texas Transportation Institute The Texas A&M University System College Station, Texas August 1985

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3 SUMMARY This study, undertaken to develop a plan for implementing high-occupancy vehicle (HOV) improvements on freeways in the Dallas area, was prepared over a 3-year period for District 18, State Department of Highways and Public Transportation, Dallas. High-occupancy vehicle improvements are techniques for altering the design and/or operation of a freeway in order to give a travel time advantage to HOVs, generally defined as buses, vanpools, and carpools. In conducting this study, the original 1983 DART service plan was taken as a given; the planning presented in this report in no way is an attempt to replace or question the DART plan. The intent of this work, in addition to assisting the State in meeting their responsibility to determine preferred approaches for operating the freeway system, is to present possible approaches for using the HOV technology to complement the DART plan. Essentially, this study has investigated whether high-occupancy vehicle technology can be used to complement and enhance the DART plan by accomplishing any of the following: 1) to bring about needed high-capacity transit improvements in critical corridors at an earlier date; 2) to provide needed transit service to areas not currently included in the DART service area; 3) to use HOV lanes in outlying areas to feed the DART rail lines as those lines develop, thereby increasing rail ridership; and 4) to assist the rail plan in providing transit service to the numerous major activity centers in the Dallas area. Implementation of any HOV improvement needs to be a multi-agency process involving, as a minimum, the State, DART, and the cities. This study, conducted for only one agency, simply identifies possible HOV projects that appear to warrant further discussion among the various agencies in the Dallas area. Thus, this document might be consider>ed as a beginning, r>ather> th:m an end, of an HOV planning pr>ocess for> the Dallas ar>ea. The specific freeway facilities evaluated were identified by the State Department of Highways and Public Transportation (Figure S-1). In considering the freeways, this conceptual planning study was designed to: 1) identify the type of HOV improvement, if any, that should be considered for implementation; 2) identify the time frame in which the HOV improvement should become operational; 3) identify techniques for connecting the various HOV improvements on individual freeways to form an effective system; and 4) assess approaches for using HOV technology to complement or enhance the DART plan. An Approach for Complementary HOY and lrt Improvements The recommendations developed in this report should be viewed as ideas that appear to warrant further discussion among the various agencies. i i i

4 Scale ~ Miles LEGEND { :-:-:-::1 Study Corridors lt) (\') I - Figure S-1. Dallas Area HOV Study Corridors A Rail Intercept Concept DART rail forms the vast majority of the transit system that will be developed to serve the Dallas area. In general, to complement the DART plan, HOV is primarily considered for development either on circumferential freeways or in outlying areas which can feed the DART rail lines. This approach provides high-quality transit service (HOV lanes) to outlying areas at an earlier date and provides a means for rapidly moving transit patrons from remote park-and-ride facilities to the terminal points of the DART rail lines. DART rail then serves the concentrated trip volumes to the final destination. Some of the HOV improvements might even be viewed as interim; once the rail transit is completed to its ultimate terminus, DART bus service on the HOV lane could be discontinued. The HOV lane would then either be used as a carpool/vanpool facility or be converted to additional freeway lanes or emergency shoulders. As part of this rail intercept concept, several bus-to-rail transfer facilities will need to be developed. In an area such as Dallas-- an area with several major activity centers and where it appears that both HOV and 1V

5 LRT technology will be applied -- the transit service plan will become complex. Efficient and acceptable means of handling transfers will be an integral component of such a plan. Potential High-Occupancy Vehicle Improvements A series of potentia 1 HOV improvements that appear to warrant further discussions between the involved agencies are identified. Initial HOV projects, such as the East R.L. Thornton (I-30) contraflow lane, will serve as demonstration projects to help assess the acceptance of HOV technology in the Dallas area. It is suggested that, to the extent possible, construction of any HOV improvements be undertaken in conjunction with planned major highway construction. This approach results in: 1) only one construction period and, therefore, less inconvenience to traffic; 2) certain economies can be realized through joint construction; and 3) both highway and HOV traffic realize benefits once the construction is over, thereby increasing acceptance of HOV improvements by motorists not using the HOV lane. It appears that approximately 75 miles of HOV facilities might be considered to complement the DART plan. The approximate cost for this freeway HOV system would be in the range of $400 to $500 million. Additional funds will be needed to develop required support facilities such as park-and-ride lots, to purchase buses, and to provide maintenance facilities for those buses. Table S-1 presents a series of possible HOV improvements that might be used to complement the DART light rail plan. The possible HOV improvements as well as the DART plan are shown in Figures S-2, S-3, and S-4. It should be reemphasized that, as recommended in this report, HOV improvements should be pursued only after multi-agency agreement has been reached. Other Study Documentation In addition to the material presented in this report, an appendix has been prepared as a separate document. The appendix contains more detailed information on topics such as geometries, FREQ computer simulation of freeway operations, traffic data, and cost effectiveness analyses. Also, in order to make study findings available in a timely manner, the following technical memoranda were prepared during the course of the project Dallas Area High-Occupancy Vehicle Study, East R.L. Thornton (1-30) Freeway Evaluation", November Dallas Area High-Occupancy Vehicle Study, LBJ (I-635) Freeway Evaluation", September Dallas Area High-Occupancy Vehicle Study, Stemmons (I-35E) Freeway Evaluation.., February v

6 Table S-1. Possible HOV Improvements Warranting Further Multi-Agency Consideration < Near-Term, HOV 1 Improvement and Time Frame Approx. Length Benefit/Cost capital Cost 2 Date of Initial (miles) Ratio (millions of 1985 HOV Operation dollars) o East R.L. Thornton contraflow $ o Bottleneck Bypass Ramps, LBJ at both Stemmons and North Central 2-5 each --- $3 - $15 each Mid-Term, o East R.L. Thornton, 1-lane reversible $ o North Central, north of LBJ,!-lane reversible o Stemmons, north of LBJ,!-lane reversible /) o Stemmons, south of LBJ,!-lane reversible 4 6 ' o LBJ, Luna to Skillman, 2-lane, 2-way i I Longer-Term, After 1995., i o LBJ, Skillman to SH 352, 1-lane reversible after 2000 i i i o Old DIFW Turnpike,!-lane reversible after 1995 ' TOTAL $419 - $ unless otherwise noted, HOV lanes are to serve buses, vanpools, and carpools. 2 Planning level cost estimate. Actual costs will be highly dependent upon whether the HOV facilities are constructed as part of major highway construction and the resolution of FHWA policy relative to inside freeway shoulders. 3 Buses and vanpools are only user groups considered. 4vanpools and carpools are only user groups considered.

7 Collin Co. Dallas Co. -- SH j.i Ci c:...j :::. Ci c:: I-30 Belt Line lfl M I - - Contraflow Lane Congestion Bypass Ramp Note; A DART first priority rail line is planned to be in operation by The specific corridor for that line has not been selected. HOV improvements shown in Figure are suggestions. Actua 1 operation would depend on negotiation between agencies. Figure S-2. Possible Near-Term ( ) Development of High-Occupancy Vehicle and Light Rail Improvements vii

8 Denton Co.'-...., -- T -- ~ VJ~". ~ ~ I Belt Line.. Collin Co. Dallas Co. -- Belt Line at) C!') ' - - -Phase I HOV Phase I Rail A Bus Transfer Facility (!)Once DART rail 1 ine extends north of LBJ Freeway these HOV lanes may become carpool/ vanpool lanes or transfer to mixed-flow vehicle use. (g) Transfer facility might not be used by all DART buses depending on final destination. Note: HOV improvements shown in Figure are suggestions. Actual operation would depend on negotiation between agencies. Figure S-3. Possible Mid-Term ( ) Development of High-Occupancy vehicle and Light Rail Improvements viii

9 .r::: c; c::.i c. ~18... ~, ~ -~ I Belt Line lt) M Phase 1 HOV Phase II HOV Phase I Rail,...,...- Phase II & lll Rail A Bus Transfer Facility (!)Once DART rail line extends north of LBJ Freeway these HOV lanes may become carpool/ vanpool lanes or transfer to mixed-flow vehicle use. cg)transfer facility might not be used by all DART buses depending on final destination. Note: HOV improvements shown in Figure are suggestions. Actual operation would depend on negotiation between agencies. Figure S-4. Possible Longer-Term (beyond 1995) Development of High-Occupancy Vehicle and Light Rail Improvements ix

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11 TABLE OF CONTENTS Summary iii Page An Approach for Complementary HOV and LRT Improvements iii Other Study Documentation v I. Introductory Material. 1 General Observation, Areawide Transit Plan 1 A Conceptual Plan 1 Introduction The Study Area. 3 Objectives of the HOV System Plan 5 Role of the HOV Plan in Overall Mobility 5 Other Project Reports II. Background Material 9 Major Employment Centers. 9 Relevant Traffic Data 10 III. High-Occupancy Vehicle Facility Considerations 13 General Advantages and Disadvantages of the Concept. 13 Description of Alternative High-Occupancy Vehicle Improvements 15 Cost Effectiveness of HOV Improvements. 20 Modal Share Factors Influencing the Number of HOV Lanes 27 The FREQ Analysis Tool IV. A High-Occupancy Vehicle System Plan 29 A Rail Interface Concept. 29 Initial Screening of Dallas Area Freeways for HOV Needs 29 Analysis of Individual Freeways 33 East R.L. Thornton (I-30) 34 North Central Expressway (US 75) 41 Dallas North Tollway 44 Stemmons ( I-35E) LBJ {I-635) Carpenter (SH 114)and Airport (SH 183) 58 Old D/FW Turnpike (I-30E) 59 South R.L. Thornton (I-35E) 60 Walton Walker (West Loop 12) 60 V. An Approach for HOV/LRT Compatibility 65 Coordination With DART Potential High-Occupancy Vehicle Improvements 66 HOV Improvements Not Recommended Due to DART Rail Plan 72 xi

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13 I. INTRODUCTORY MATERIAL General Observation, Areawide Transit Plan The Dallas Area Rapid Transit Authority (DART) has a transit service plan, adopted in 1983, for the Dallas area (Figure 1). The principal element of the plan consists of 160 miles of light rail transit (LRT). High-occupancy vehicle improvements are shown in the DART plan in two corridors, East R.L. Thornton (I-30) and LBJ (I-635). The study presented in this report was prepared for the State Department of Highways and Public Transportation, District 18, Dallas. In conducting the study, the DART plan was taken as a given; the planning presented in this report in no way is an attempt to replace or question the DART plan. This study addresses one possible component of an areawide transit plan -- high-occupancy vehicle lanes (HOV) primarily within freeway rights-of-way. The intent of the recommendations is to present possible approaches for using the HOV technology to complement the existing DART plan. The HOV work presented in this report suggests approaches that might provide: 1) transit service via HOV lanes to geographical areas not included in the DART service area; 2) transit service at an earlier date in critical corridors within the DART service area through implementation of HOV lanes; 3) HOV lanes, at least as an interim measure, as a means of feeding DART rail lines, thereby increasing rail ridership; and 4) opportunities to use alternative state and federal highway funds to finance a portion of the HOV transit element. The HOV assessment also assists the State in meeting its responsibility to identify cost effective approaches for operating the state roadway system; HOV lanes are a consideration in those decisions. That responsibility applies to state highways both within and outside of the DART service area. The development, implementation, and funding of an areawide transit improvement plan should be a multi-agency undertaking. The material presented in this document was prepared for one agency -- the State Department of Highways and Public Transportation. Implementation of any HOV improvement should result from agreement between all affected agencies. This report could represent a starting point for discussions with those other agencies, including DART and the various cities. Thus, this document might be consider>ed as a beginning, r>ather> thxn an end, of an HOV planning pr>ocess. A Conceptual Plan The work presented in this report should be considered as conceptual level HOV planning. It is primadly intended to answer three questions: 1) is the HOV project feasible to construct; 2) is the project cost effective; and 3) is the HOV project potentially compatible with the DART plan. 1

14 SCALE Miles 4 Figure 1. The 1983 DART Service Plan 2

15 As a result, if a decision is made to pursue HOV projects suggested in this study, detailed planning, preliminary engineering, and multi-agency negotiations will need to be conducted to more completely define the project. This report presents a way an HOV project could be built in order to demonstrate basic feasibility; more study will be needed to define whether the HOV project should be pursued at all and, if so, the best way to build and prioritize the project. -- Introduction The increases in traffic congestion in the major urban areas in Texas are both well recognized and documented. While continued expansion of the street and highway system is essential, it is not possible nor economically feasible to accommodate all peak-period travel demand through the use of one private auto for every 1.2 commuters. As a result, a recognition is beginning to develop that an efficient and acceptable means must be provided for moving large volumes of urban commuters during peak periods. This role is referred to in this report as mass transportation. Both light rail transit and high-occupancy vehicle (HOV) improvements are approaches for providing mass transportation. This report concentrates on the HOV technology. These are improvements that alter the design and/or operation of a roadway in order to improve the relative travel speed of highoccupancy vehicles--buses, vanpools, and carpools. Such actions can be an effective means of increasing the utilization of high-occupancy vehicles, which will also reduce the demand for auto travel, reduce energy consumption and pollutants emitted, and reduce parking needs within major activity centers. The Texas Department of Highways and Public Transportation has pursued the need for HOV improvements in a highly positive manner. A freeway HOV system in Houston may ultimately include over 100 miles of HOV transitways. Over 60 miles of this system are already in operation, under construction, or in design. Provisions have been incorporated into freeway designs in San Antonio to provide for relatively easy HOV lane implementation in the future. This report describes a possible HOV system plan for the Dallas area that appears to offer the potential to complement the DART plan. Preliminary findings from this study have already partially served as the basis for actions taken in the Dallas area to bring about implementation of HOV lanes on both East R.L. Thornton (I-30) and LBJ (I-635). The Study Area Based on current and projected traffic volumes on the freeway system, the freeways to be evaluated as part of this study were identified by the State Department of Highways and Public Transportation, Regional Planning Office. The resulting HOV study corridors are depicted in Figure 2. Most of this report focuses on the free\1/ays shown in Figure 2; however, to better 3

16 Scale Miles LEGEND f:-:-::::1 Study Corridors I - Figure 2. Dallas Area HOV Study Corridors identify a system plan, some basic analyses are also presented for other freeways. The study was primarily confined to freeway rights-of-way, which leads to some 1 i mi tati ons as to the types of improvements to be considered (e.g., use of ra i 1 road rights-of-way in conjunction with freeway rights-of-way is not considered). This is a further reason why this report represents a starting point for further planning efforts. Study Freeways as Related to the DART Plan. Several of the freeway corridors shown in Figure 2 essentially parallel rail lines proposed by DART. For an HOV lane to be highly cost effective, it is generally necessary that the transit operator provide bus service on the lane; buses will generally transport half or more of the person movement on an HOV lane. As a result, HOV lane cost effectiveness, in general, will be approximately halved if bus transit does not use the priority lane. HOV It would not appear reasonable to expect DART to operate bus service on lanes that directly compete with rail lines. Also, whether the resources 4

17 can be justified to construct two competing parallel transit facilities is open to question. As a result, in the final suggested actions presented in this study, HOV improvements are not suggested for those corridors shown in Figure 2 that parallel rail lines proposed for priority development by DART. However, approaches may exist to develop HOV lanes in critical corridors at a date earlier than that which would occur for the DART second and third priority corridors. With the DART plan, certain corridors that warrant transit service today will not receive such service until after Consequently, HOV lanes may offer a means of providing service at an earlier date; possible approaches for accomplishing this are set forth in this study. Objectives of the HOY System Plan The system plan is primarily designed to address the following four issues. 1. What specific types of HOV improvements, if any, are applicable to the study freeways. 2. In what time frame should the improvements become operational. 3. How do the improvements on individual freeways tie together to form an effective transit system. 4. How does the HOV element supplement and complement the DART service plan. limitations of a Freeway Retrofitn Plan The objectives, described above, relate to an already existing freeway system. While the existing freeway system will, in some cases, be upgraded, the HOV facilities need to be developed within the numerous existing physical constraints. In some instances, these physical constraints will preclude or greatly increase the cost of developing certain sections of HOV-related improvements. These existing constraints must be recognized in HOV plan development. Frequently, HOV traffic can be routed with mixed-flow traffic in some constrained areas to minimize the impacts of physical impediments and to take advantage of uncongested sections of mixed-flow roadways. Role of the HOY Plan in Overall Mobility The Dallas area has reached a- size where development of a mass transportation system is essential. Just as, in highway planning, it is recognized that a freeway system needs to be provided once a city reaches a certain size, a mass transit system is needed to supplement the street and highway system once a larger level of development occurs (Figure 3). This is the 5

18 basic transportation-land use relationship. Since Dallas does not have an ideal street and highway system, the mass transit need is even more critical in the Dallas area than indicated by Figure by Mass ,000 URBAN POPULATION (Thousands) Figure 3. A Generalized Relationship Between Transportation and Land Use Mass transit -- which is what is provided by high-occupancy vehicle lanes as well as light rail transit -- is intended to move large volumes of urban commuters to major employment centers during peak commuter periods. While continued street and highway development is essential, those facilities alone cannot serve peak-period demand. For example, unconstrained traffic projections on North Central Expressway approach 250,000 vehicles per day in the year 2010, well in excess of the roadway capacity. Highway congestion in the vicinity of downtown Dallas is already intense. Yet employment in the downtown is projected to grow by about 100~~ over the next 20 to 30 years. Most of that growth will need to be served by transit. In the peak hour, in 1983, approximately 16,000 persons entered downtown Dallas by transit; that number will need to exceed 40,000 in the next 20 or so years. The relative role of transit in Dallas today, as compared to other large North American cities, is highlighted in Table 1. It 6

19 is reasonable to assume that, for Dallas to realize its growth projections, the percent of trips served by transit will need to essentially double. And, since the base is also increasing, the absolute number of trips served by transit will need to increase by a factor of between 2 and 4. Table 1. Relative Importance of Mass Transportation in Dallas Measure of Relative Importance Corresponding Value Percent of Downtown work Trips by Transit Dallas 3m Avg., 17 Cities Outside Texas 52% Annual Transit Trips Per Capita Dallas 39.6 Avg., 14 Cities Outside Texas 78.6 Percent of Total workers Using Transit (1980) Dallas-Fort worth 3.4% Avg., 13 Cities Outside Texas 13.2% Source: Texas Transportation Institute, Research Report High-occupancy vehicle lanes are one means of providing mass transportation for the Dallas area. The intent of the plan identified in this document is to show an approach for effectively providing mass transportation in the Dallas area. This approach utilizes both light rail transit and HOV facilities. Other Project Reports The HOV system plan work was performed over a 3-year ( ) time period. In order to be responsive to the needs of the study and report findings in a timely manner, the following 3 interim technical memoranda have been prepared as part of the project. 1. "Da 11 as Area High-Occupancy Vehicle Study, East R.L. Thornton (I-30) Freeway Evaluation", November "Dallas Area High-Occupancy Vehicle Study, LBJ {I-635) Freeway Evaluation", September "Dallas Area High-Occupancy Vehicle Study, Stemmons (I-35E) Freeway Evaluation.., February More detail on individual freeway analyses is included in the reports listed above than is presented in this final report. Also, an appendix to this final report has been prepared as a separate document; that appendix includes additional technical material not presented in this final report. 7

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21 II. BACKGROUND MATERIAL As a general guideline, for high-occupancy vehicle (HOV) lanes to have the potential to be effective, two conditions must exist: 1) extreme congestion must be present on the freeway so that the HOV lane offers a potential travel time advantage, and; 2) travel patterns on the freeway must be conducive to being served by transit. These two considerations are explored in more detail in subsequent sections of this report. However, it becomes evident that employment data and traffic data are critical concerns in evaluating HOV lane feasibility. A summary of pertinent data is presented in this section of the report. More definitive data are included in the appendix which is published as a separate document. Major Employment Centers In general, buses will serve approximately half of the total HOV lane demand, with the remainder served by vanpools and carpools. Transit is most effective at serving trip patterns destined to a concentrated employment center, such as the downtown area. Da 11 as has severa 1 major employment centers. Selected characteristics of these centers are summarized in Table 2 and depicted in Figure 4. The greater the volume of traffic on a given freeway destined to one of the major activity centers, the greater the potential success of an HOV lane or other transit improvement (e.g., light rail transit). Table 2. Estimated Employment at Major Centers in the Dallas Area Estimated Employment Land Area Employment Per Square Mile (1000's) (Sq. Mi.) (1000's) Employment Areal Dallas CBD Stemmons Corridor Far North Dallas Las Colinas Oak Lawn D/FW Airport N. Central/LBJ For locations, refer to Figure 4. Source: NCTCOG for all activity centers other than N. Central/LBJ. TTl estimate for that center. 9

22 ~ lw SCALE 2 Miles ;r 4 Figure 4. Location of Major Employment Centers in the Dallas Area The fact that Dallas has several major employment centers complicates the regional transit plan. Effective service must be provided to employment centers other than just the downtown. Transfers become an integral part of such a plan. Relevant Traffic Data In assessing the potential effectiveness of high-occupancy vehicle facilities, the level of congestion on the freeway mixed-flow lanes is a si gni fi cant consideration. The issue of HOV cost effectiveness is explored in more detail in the subsequent section of this report. 10

23 One measure of congestion is average daily traffic per lane. An estimate of ADT per lane for 1983 and the year 2000 is shown in Figure 5. More detailed traffic data are included in the appendix, published as a separate document. These data were provided by the State Department of Highways and Public Transportation. The downtown is the major activity center served by transit. As a result, travel patterns to downtown are a consideration in HOV facility planning. Table 3 presents an estimate of these travel patterns. The trips shown in Table 3 are used subsequently to assist in assessing the cost effectiveness of various HOV configurations. Table 3. Estimated 1982 Work Trips to Downtown Dallas, By Freeway Corridor Freeway Corridor Estimated Daily Work Tripsl North Central (US 75) 12,500 Stemmons (I-3SE) 15,5oo2 Old D/FW Turnpike (I-30) 8,200 East R.L. Thornton (I-30) 12,200 South R.L. Thornton (I-3SE) 12,200 Hawn (US 175) 4,100 I-45 5,000 Airport (SH 183) 5,200 Carpenter (SH 114) 1,200 1 Assumes a CBD employment of 110,000, 80% of downtown trips served by freeways, 95% of employment present on a typical day. Daily work trips are assumed to be generally proportional to the freeway ADT near downtown. Zrhe Stemmons value, taken near downtown, includes trips originating on Airport Freeway, Carpenter Freeway, and the Dallas North Tollway. 11

24 penton c?... -,-- --oallisco:" -- I Collin Co. :!_o.ooo (6) I I 12,650 (6) \ I Belt tine LEGEND 2000 ADT!l.ane (Atlanes) TlJHl"ADTILane ( Lanes) ~ SH ' N 22,500 ( ) 115,150 ~ l-30 ::i... al r:c 19,900 (6).'111,850 (6) 0 d ~,.~ c t:-;;; ~ Source: State Department of Highways and Public Transportation, Regional Planning Office and TTI Analysis.

25 III. HIGH-OCCUPANCY VEHICLE FACILITY CONSIDERATIONS The intent of the high-occupancy vehicle (HOV) technique is to alter the manner in which the roadway facility is designed and/or operated in order to provide high-occupancy vehicles with a travel time advantage. The travel time advantage, combined with other incentives such as trip time reliability and cost, provides the incentive for the user to travel in a high-occupancy vehicle. When i'"mplemented in the proper context, these improvements have proven to be highly cost effective and successful. Extensive technical information pertaining to high-occupancy vehicle technology is included in Texas Transportation Institute Research Report entitled 11 Alternative Mass Transportation Technologies, Technical Data.., July General Advantages and Disadvantages of the Concept Like all transit technologies, the HOV approach has some advantages and disadvantages. Certain potential advantages and disadvantages are listed below. More discussion and data relating to these advantages and disadvantages are included in Texas Transportation Institute Research Report Potential Advantages of the HOY Concept 1. Implementation Cost. At-grade freeway transitways can be constructed for $2 - $6 million per mile. Multi-lane elevated transitways can be built for $10 - $15 million per mile. Limited right-of-way acquisition is required. In general, $10 million per mile represents a reasonable planning cost estimate for development of HOV lanes and their associated support requirements. This is often less expensive than alternative transit technologies. 2. Multi-Agency Funding. These facilities are eligible for local, state and federal funding from both highway and transit funding agencies. For the Houston transitway projects, over 25% of the transitway costs are being paid by highway agencies, and those agencies are also making highly valued right-of-way available. 3. Cost Effectiveness. Evaluation of projects in the Dallas, Houston, and San Antonio areas has shown that, on congested freeways, the benefitcost ratio associated with HOV improvements is frequently in excess of Implementation Time. These facilities can be planned, designed, and constructed in a 3- to 8-year time frame. The construction involves well-known highway construction technology, a technology possessed by numerous firms in Texas. 13

26 5. Staged Opening. Transitways can effectively be opened in sections; the entire system does not have to be completed before benefits can be realized from the facility. 6. limited Risk. Massive sums of money are not required to construct the facilities. If the transitway is not extensively used, it can be converted relatively quickly and inexpensively to other useful purposes, such as additional mixed-flow lanes or emergency shoulders. 7. Multiple User Groups. In addition to transit vehicles, vanpools and carpools can utilize a transitway, thereby increasing total potential person movement. In general, carpools and van pools move 50% of total person movement on an HOV lane. 8. Transit Strikes. During labor disputes, vanpools and carpools can continue to use the system, transporting approximately 75% of the person movement that occurred on the facility prior to the strike. 9. Transit Operating Cost Effectiveness. Operating cost per passenger-mile for bus operations on transitways is competitive with other transit technologies. Also, vanpools and carpools operate at relatively low per passenger-mile costs on HOV lanes and do not require a direct public subsidy. 10. Transit Capacity and Speed. The line-haul transitway capacity is essentially as large as the capacity for any transit technology and in excess of any demand estimated to occur in a Texas city. Average schedule speeds on the Houston contraflow lane are as high as any transit operation in the United States. 11. Park-and-Ride lot locations. Lots can be located remote from the transitway on relatively inexpensive land without requiring a transfer at the line-haul transitway. 12. Flexibility. The transit vehicles can use the existing street system for the collection/distribution function. Extensive transitway development may require constructing a transit mall or off-street bus terminals in the downtown area. Potential Disadvantages of the Concept 1. Activity Center Distribution. The HOV lanes will function well in the individual corridors. The concentration of high bus volumes within the activity centers, particularly in the downtown, may create problems. This appears to be a particular concern in Dallas, and a major reason for not pursuing an "all bus" system in the Dallas area. Rail subway is a "cleaner" approach for downtown di stri buti on. 2. Trips Served. The HOV lanes do an excellent job of serving long distance commute trips occurring during peak periods. The lanes are not as effective at serving short trip lengths and off-peak trips. 14

27 3. Future Operating Cost. While existing operating cost per passenger-mile appears to be comparable to rail, the potential for rail technology to eliminate the use of train operators in the future offers a means of reducing future rail operating costs on fully grade-separated systems. 4. Environmental Concerns. In some highly sensitive corridors, the noise levels and pollutants emitted associated with heavy bus transit volumes may not be acceptable. Description of Alternative High-Occupancy Vehicle Improvements The applicability of the following alternative high-occupancy vehicle improvements is addressed in this study. Separate HOY Facility. Roadways or lanes that are physically separated from other freeway lanes and are designated for the exclusive use of high-occupancy vehicles. This is generally the most effective approach for use as part of a long-range transit plan. Concurrent Flow lane. A freeway lane in the peak-direction of flow (commonly the inside lane), not physically separated from the other general traffic lanes, and designated for exclusive use by highoccupancy vehicles (usually buses, vanpools, and carpools). Contraflow lane. A freeway lane (commonly the inside lane in the offpeak direction of travel) designated for exclusive use by high-occupancy vehicles (usually buses only or buses and vanpools) travelling in the peak direction. The lane is typically separated from the other off-peak direction travel lanes by insertable plastic posts or pylons. Examples of locations where these treatments have been implemented are shown in Table 4. Representative cross sections for these alternative priority treatments are shown in Figure 6. Table 4 and Figure 6 provide a genera 1 fa m il i a r i z at i on w i t h t he d i f fer en t p r i or it y ~e a s u res A more de - tailed description is provided in several other sources. Specific attributes (design and operation) r7quired to make these various treatments feasible are documented elsewhere. 1 JHK and Associates. "High Occupancy Vehicle Facility Development." Report FHWA-IP-82-1, April Texas Transportation Institute. "Alternative Mass Transportation Technologies, Technical Data", Research Report 339-4, July Texas Transportation Institute. "Preliminary Evaluation of Applicable Priority Treatment Techniques on Existing Urban Freeways in Texas." Research Report 205-8,

28 I I I A I I \ I I I Y I ~.. \ I \ I I I I \ I I I I r: ;i I \ \ ' II I I I i!! 1 i \ \ \ r r I I I /i A l\ \ \ \ I I I!i v l\ \ \ \ II 1\ I 1/J /! /! J l I 1 \\\\\\ I I I ~~ 0 \ \ \ 0 1,,,,1, It 1t I r I 1 I I f I I I to I 1 I I I I I I /0 \ \ \ \ o\ \ \ \ 4 lanes at 12' lto l 36' } t2'j. 22' J 12 J 36' j, 12 J ~hlj. 3 lanes HOV Shoulders HOV 3 Lanes Aux. Lane Lane Lane BARRIER-SEPARATED TRANSITWA Y CONCURRENT FLOW BUS LANE 1 shld. 3 Lanes Bus Median Lane,.! 4 Lanes Shld. 48' j CONTRAFLOW BUS LANES Figure 6. Schematic Representation of Alternative High-Occupancy Vehicle Priority Treatment Techniques 16

29 Table 4. Examples of Alternative High-Occupancy Vehicle Improvements Type of Priority Measure Separate HOV Facility Concurrent Flow Lane Contraflow Lane Significant Examples Shirley Busway (I-395), Washington, D.C. I-66, Washington, o.c. PatWay, Pittsburgh Katy (I-10) Transitway, Houston North (I-45) Transitway, Houston I-95, Miami US 101, San Francisco I-495 (Lincoln Tunnel), New Jersey North (I-45), Houston (replaced in 1984) East R.L. Thornton, Dallas (proposal) Special Concerns Involving Concurrent Flow Lanes One of the HOV techniques discussed above is concurrent flow lanes. These are lanes reserved for use by high-occupancy vehicles that are in the same direction of flow as the mixed-flow lanes and not physically separated from those lanes. A more detailed discussion of this concept is included in a technical memorandum entitled 11 Dallas Area High-Occupancy Vehicle Study, LBJ (I-635) Freeway Evaluation 11, prepared as a part of this project. The concurrent flow 1 ane approach to pro vi ding priority treatment has attracted interest for the following reasons: These lanes can be implemented relatively quickly and inexpensively. 1 Many Texas freeways have inside shoulders. Upon initial inspection, it would appear relatively easy to designate that inside space as a concurrent flow lane. 1 Of those priority treatment projects impl em en ted on freeways si nee 1970, the concurrent flow alternative was the most commonly implemented priority treatment. 1 A 3.3 mi 1 e 1 ong concurrent flow 1 ane was i mpl em en ted on the North Freeway (I-45) in Houston in That lane operates during the morning peak and feeds the downstream authorized vehicle lane. It has been highly successful. These points, combined with the recognition that HOV treatments will be an important component of future freeway operations, have focused attention on the concurrent flow lane alternative as a means of providing priority treatment. This section overviews some of the technical considerations and concerns associated with implementing concurrent flow lanes. 17

30 Add-a-Lane Ver>sus Take-a-Lane The concept of concurrent flow can be implemented by either adding a lane to the existing facility or taking an existing lane away from mixed-flow traffic and reserving it for use by high-occupancy vehicles. The take-a-lane concept has been highly controversial; those projects have, in almost every instance, been terminated due to the opposition they have developed. As a result, if concurrent flow is to be implemented in Texas, it should be an add-a-lane project. This would require either designating the inside shoulder as a concurrent flow lane or expanding the freeway cross section. I f the s h o u 1 de r i s u sed, the r e s u 1 t w o u 1 d be t h a t no em e r g en c y r e f u g e a rea would exist on the inside for either high-occupancy or mixed-flow vehicles; no space would exist for enforcement activities either. If the cross section is expanded, the low implementation cost and rapid implementation time advantages may be 1 ost. Eligible User>s One of the advantages of concurrent flow is that, unlike contraflow, carpoolers can be eligible users of the lane. In all projects surveyed except two, carpools were allowed to use the lane. Site specific considerations precluded carpool use on two of the concurrent flow projects (Houston and Brooklyn). However, concurrent flow projects have not generated the increases in total person throughput that have been associated with exclusive HOV facilities. The concurrent flow concept has typically increased person throughput by 0% to 20%, whereas the exclusive lanes have increased person throughput by 50% or more. This occurrence has been attributed to the lack of permanence and reliability associated with the concurrent flow concept. Also, to make the concurrent flow projects appear to be utilized and to reduce the violation rates, roughly 40% of the projects have revised their definition of an eligible carpool in order to make more vehicles eligible users. Often, it has not been possible to operate a lane successfully with a 3+ definition due to utilization and enforcement problems. It has been found in several instances that, once the carpool definition is lowered to 2+, traffic in the priority lane becomes as congested as traffic in the nonpriority lanes, thereby defeating the purpose of an HOV lane. In fact, the Federal Highway Administration no longer supports the 2+ concept. Pr>ojeet Length For most Texas freeways warranting HOV lanes, the lanes will be 10 to 20 miles in length. Most of the concurrent flow projects implemented to date have been relatively short (less than 4 miles long) bottleneck bypass lanes. The 1 onger concurrent flow lanes have been much more controversi a 1 and subject to termination. The project on the Santa Monica Freeway in Los Angeles (12.6 miles) was terminated due to public pressure. The Southeast Expressway project in Boston (8 miles) was terminated as a result of public 18

31 pressure, as was the Garden State project (10+ miles) in New Jersey. The I- 95 project in Miami (6.7 miles) has experienced a 30% to 40% violation rate after the carpool definition was reduced to 2+. In essence, there is 1 ittle successful experience nationwide in concurrent flow lane implementation of the length that would exist if such a treatment were implemented for the length required on a Texas freeway. Oper>ational Concer>ns A concurrent flow lane may result in a significant speed differential between two adjacent 1 anes. Research suggests that, once that speed di f ferential exceeds 15 mph, a safety problem may result. Concurrent flow lanes have continuous access and egress, with high- and low-speed traffic continuously merging with each other. A user of a concurrent flow lane, implemented on a 6 to 8 lane Texas freeway, would have to weave across 3 to 4 mixed-flow lanes to enter the priority lane and then weave back across those lanes to exit the freeway. In addition to the obvious safety problems this poses, the vehicle would spend approximately 2 miles of its trip length simply getting into and out of the lane. Thus, the lane would only be attractive in serving relatively long trips. Since no shoulder would remain if the lane were implemented by taking away the shoulder, enforcement of the lane would be difficult to impossible. Violations have been an ongoing problem on all concurrent flow projects, and police have found enforcement to be difficult. A safety study conducted by the Federal Highway Administration found that, of the 5 projects evaluated, all but 1 experienced an increase in accident rates following concurrent flow lane implementation. The study further concluded that concurrent flow is "one of the most hazardous priority treatments" and "it may be preferable to use other priority treatments." Pr>oject Life Concurrent flow projects have demonstrated an ability to generate tremendous public and political pressure. An improper application in Texas could jeopardize the success experienced to date in implementing HOV projects. In spite of the apparent advantages associated with concurrent flow projects, the project implemented on the North Freeway in Houston is the only project implemented since 1976; that project will be replaced by an exclusive lane in The longer projects and the take-a-lane projects are the least likely to survive public scrutiny. For a concept with numerous apparent advantages, it has not experienced widespread application. 19

32 Concl-usions Concurrent flow lanes can be an effective means of providing priority treatment through short (less than 4 miles) bottleneck areas. It is essential that an effective termination treatment be provided. The concurrent flow lane currently operating on I-45 in Houston is evidence that, under very spec i a 1 circumstances (i.e., it is connected to the authorized vehi c 1 e 1 ane downstream), these 1 anes can be "successful." In general, as a major 1 ine-haul priority measure, this treatment is significantly inferior to other forms of HOV treatment. Enforcement, safety, and operational problems can be expected and, as a minimum, at least sections of inside shoulder should exist after implementation of the lane for both safety and enforcement reasons. Of perhaps a greater concern, however, is the tremendous political and public opposition these lanes can generate. One bad experience with this type of project could "undo" much of what has been done to date to develop public support for HOV priority treatment in Texas. It appears that, in some sections and under certain conditions, some concurrent flow lane implementation may be appropriate in the Dallas area; these would be short, bottleneck bypass type applications or transitions to other types of priority treatment. Operational experience with this type of treatment suggests that large-scale, long-distance applications of concurrent flow treatment will not constitute a major part of the Dallas HOV system plan. Short-range use of concurrent flow as bottleneck bypass treatments warrants consideration; that treatment must be compatible with long-range actions. Cost Effectiveness of HOY Improvements Planning for high-occupancy vehicle facilities has determined that two major considerations impact HOV 1 ane cost effectiveness: 1) traffic congestion on the freeway; and 2) tra ve 1 patterns on the freeway. Intense traffic congestion must exist on the freeway in order for the HOV lane to offer a significant travel time advantage. Transit is best suited for serving concentrated trip patterns to a major activity center, such as the downtown. Thus, as the number of trips on a freeway destined to a major activity center(s) increases, potential utilization of an HOV lane also increases. Recent research has begun to quantify some of the values associated with HOV 1 ane cost effectiveness. This section documents some of the cri ti ca 1 relationships that are used subsequently in assessing potential HOV project feasibility. Freeway Traffic Congestion Based on observation at numerous HOV projects, it was evident that, a~ freeway congestion increased, so did HOV lane utilization. Research 1 D. Baugh and Associates. "Freeway High-Occupancy Vehicle Lanes and Ramp Metering Evaluation Study." Prepared for U.S. Department of Transportation,

33 sponsored by the United States Department of Transportation began to quantify this relationship. This study concluded that "as a general rule of thumb, the point at which time savings perceived by motorists cause a significant shift to HOV's appears to be when time savings exceed 1 minute per mi 1 e." Of the six projects evaluated in that study that had time savings in excess of 1 minute per mi 1 e, the average increase in auto occupancy was 9.8%. For the five projects evaluated that provided time savings of less than 1 minute per mile, the average increase in auto occupancy was 4.4%. The results of this analysis are summarized in Figure 7. The Figure 7 data bring out one other conclusion. Assuming the average speed in the priority HOV lane is 50 mph, the speed in the non priority 1 anes must be 1 ess than 30 mph (Figure 8) for the improvement to be highly cost effective. In other words, the freeway has to be operating at level-of-service E or F for that to occur. 70 Shirley (Both Lanes) LIJ 60- z <..I )o : 0 0: c.. z 40. 1'1) z 0 ~ 30- LIJ c.. u. 0 "'C :;.! Efi~tit~~i~I~ ] l-95 co :: Projects which are generally effective South Dixie Kalanianaole Shirley (Each Lane) San Bernardino (Peak Hour) San Bernardino (Peak-Period) ;.;.;.;.~.,.,.,::: :;.,. ~;.;. ~ R ~::::::l=:=:[ llli "'-~An tlclpated Level of HOV Usage 0: t( : : : :. LIJ Santa ;j C.. Monica ::. 10 Moanalua A11tlclpated Le_vl!j of HOV Usage ~~-~~~~~~::::~:,_ , ~~:~:~=~j~p~r~o~je~c~t=s~w~h~l:c:h~ar~e... marginally or not iiiil effective u TIME SAVING (MINUTES/MILE) Figure 7. HOV Priority Measure Time Savings As Related to Percent of Persons Using thi HOV Lane 21

34 ~ E:; I ill 0!llllll ;;::: :t I~l!::: ;;:::: -- - ~ , ::: :;:;:::., Priority Lane Effective (Savin 2::. 1.0 ::~:~ : : : \\~1~~\! z -0 0 ~~I ljj ljj 0.. CJ) 1 0 ::::: 7 mii;/ml~~e~r :t : ::: :?' : ::: ::::::::3 :=J ::::;:;: ;;; Priority Lane Not Effective t 7 (Saving~ 1.0 min/mile) ::::: p ;y SPEED IN NON PRIORITY LANES (MILES/HOUR) I Figure 8. Required HOV Priority Lane Speed to Attain a One Minute Per Mile HOV Time Savings Texas Transportation Institute has extensively evaluated the cost effectiveness of HOV lanes on Texas freeways. Analyses have been conducted using FREQ simulation models for freeways in Houston, Dallas, and San Antonio. Recently, those analyses have been reviewed in an effort to develop relatively simple indicators of HOV lane cost effectiveness on radial freeways. One 22

35 readily available measure of congestion would be average daily traffic per lane (ADT per lane). A preliminary evaluation of Texas freeways suggests that, for an HOV lane to be cost effective, in the first year (base year) of operation of the HOV lane, the ADT per lane on the freeway should be approximate 1 y 15,000 (Figure 9); this is a necessary but not sufficient indicator of HOV lane needs. Consideration also must be given to freeway travel patterns. Al 1 of the above present general guidelines for use in obtaining an initial assessment of cost effectiveness. Travel patterns, as discussed below, are also a consideration. Freeway Travel Patterns High-occupancy vehicle lanes are a technique to increase utilization of transit and ridesharing. As a result, the lanes offer the potential to attract more ridership if the travel patterns served on the freeway are conducive to being served by transit. As the number of trips on the freeway to a major activity center(s) increases, so does the attractiveness of transit service and ridesharing. As part of the TTI analysis of HOV lane cost effectiveness, travel patterns on freeways were reviewed. Using modal shares typically associated with HOV projects (and discussed subsequently in this report), estimates were made of peak-hour HOV utilization in the design year (20 years after implementation of the HOV 1 ane). A preliminary assessment of this relationship is depicted in Figure 10. While the correlation is not extremely good, it is evident that, once ridership exceeds about 5,000 to 6,000 passengers per hour, the lanes are cost effective. This is roughly the same as moving the equivalent person volume of 3 mixed-flow lanes in the HOV lane. However, Figure 10 also suggests that HOV lanes may be marginally cost effective with design year peak-hour ridership as low as 2,500 to 3,000, or the equivalent of just over one mixed-flow traffic lane. Again, this is a necessary but not sufficient criteria and must be considered in conjunction with congestion levels on the freeway facility. 23