Bus Use of Shoulders (2006)

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5This chapter provides an overview of survey findings, presents the experience of areas where projects have been implemented or planned, identifies salient concerns, describes operational experience, and discusses intelligent transportation systems (ITS) applications. Detailed discussion of selected case stud- ies are presented in chapter three and Appendix C contains supporting materials. SURVEY RESPONSES Seventy-one responses to the screening survey were received. Respondent agencies included 17 transit operators, 27 state or provincial departments of transportation (DOTs), 25 metro- politan planning organizations (MPOs), and two other agen- cies (motor vehicle commission and turnpike authority). Appendix B identifies the 71 responding agencies. Locations with BBSs were divided into two groups: • Current applications and • Potential new bus use of shoulder projects. Following a description of these shoulder use projects, general features of the current and planned shoulder use applications are described. CURRENT BUS USE OF SHOULDER LOCATIONS A primary purpose of the synthesis project was to identify current and planned bus shoulder use projects in North America. At the outset of the study, applications were un- derstood to exist in four states and two provinces: Maryland, Minnesota, Virginia, Washington, British Columbia, and Ontario The screening survey confirmed bus shoulder use appli- cations in these six regions and identified several more loca- tions. Some of the bus shoulder applications are continuous lanes, whereas others are essentially queue jumpers. Table 1 summarizes current and planned BBS operations. These BBS projects are described in the following order: • Minnesota, Twin Cities Area (Case Study 1) • Virginia, Falls Church Area (Case Study 2) • Maryland, Metro Washington, D.C. Area • Delaware, Wilmington Area • New Jersey, Central Area • Georgia, Atlanta Metro Area • Washington, Seattle Area • Miami, Florida (Case Study 3) • San Diego, California (Case Study 4) • Ottawa, Ontario • Toronto, Ontario (Case Study 5) • Vancouver, British Columbia • Dublin, Ireland (Case Study 6) • Auckland, New Zealand. Overview descriptions are provided in this section for the six case study BBS applications, with more detailed infor- mation provided in the next section of the report. Minnesota, Twin Cities Area The Minneapolis–St. Paul Twin Cities area is at the forefront of implementation and operations of the bus use of shoulder concept in the United States (see Case Study 1). It is cur- rently operating approximately 230 mi of bus shoulder use highway segments. As such, a comprehensive network of bus shoulder use facilities is provided. The network has planned for expansion to nearly 300 mi by 2007. Approximately 400 buses operating on 14 routes use the bus shoulder facilities to bypass congestion. Bus drivers have the option of using the designated bus shoulder facilities whenever speeds in the general traffic lanes drop below 35 mph. The BBS system involves a minimal level of BBS signing and no special pave- ment markings. Signs are periodically placed along a shoulder designating it for “Authorized Buses Only.” Warn- ing signs (“Watch for Buses on Shoulders”) are also provided along on-ramps before the merge with shoulder and freeway traffic. Small yellow advisory signs are posted along the shoulder at places where the shoulder narrows. The initial application of BBS in the Twin Cities area was on an arter- ial highway. After a major flood, the BBS concept was expanded to include freeway segments and it has continued to expand. Virginia, Falls Church Area The Virginia DOT allows public transit buses to use a 1.3-mi segment of the shoulder on the inbound direction of the Dulles Access Highway (Route 267) to facilitate bus access to the West Falls Church Metrorail station. The shoulder lane allows CHAPTER TWO OVERVIEW OF FINDINGS

6Location Type Description Use Status Metropolitan Minneapolis–St. Paul Twin Cities Area (Minnesota) Comprehensive network 230 mi No BBS time restrictions, primarily transit buses, speeds limited to use when congestion slows to 35 mph—buses allowed to move 15 mph faster than general traffic Continually expanding since 1991 Virginia near Falls Church Eastbound queue jumper on Route 267 1.3-mi segment with no interchange weaves Buses limited to maximum speed of 25 mph between 4 and 8 p.m. Appears to have been operational for some years Appears to have been operational for some years Appears to have been operational for several years Maryland near Burtonsville US-29 southbound and northbound corridor 4-mi arterial hwy. segment with several signalized junctions SB 6 to 9 a.m. NB 3 to 8 p.m. No information on maximum bus speed Maryland near Bethesda I-495 northbound queue jump of I- 270 interchange About 3 mi in length NB 6 to 9 a.m. NB 3 to 7 p.m. No information on maximum bus speed Washington Seattle Region SR-520 westbound corridor BBS 2.7 mi with several interchanges Buses and 3+ carpools use shoulder lane, no restrictions on speed or time of day Early 1970s Washington Seattle Region SR-522 arterial BBS corridor 2.2 mi with several signalized intersections Buses only; no restriction on speed or time of day WB opened in 1970 and EB in 1986 New Jersey near Mountainside Route 22 eastbound BBS corridor About 1 mi in length Buses only; no information on speed or time-of-day limits Appears to have been in operation some years New Jersey near Old Bridge Route 9 NB and SB arterial BBS About 4 mi in length Morning NB and evening SB, buses only, no information on speed restrictions Nearing implementation Georgia near Alpharetta GA 400 freeway BBS corridor 6 mi initially expanding to 12 mi When general traffic drops to 35 mph BBS buses allowed to run 15 mph faster Opened on Sep. 12, 2005 Delaware near Wilmington Route 202 southbound BBS queue jumper About 1,500 ft with one intermediate signal No time restriction for BBS use Appears to have been operational for some years Vancouver, BC Route 1 queue jumper NA NA NA Toronto, Ontario Highway 403 congestion bypass both directions About 3 mi When traffic slows to 38 mph BBS allowed 12 mph faster Started in 2003 Ottawa, Ontario Highways 417 and 174 About 14 mi BBS buses allowed to operate at posted speed of 62 mph In operation for many years Dublin, Ireland Many segments in the network 50 to 70 mi Rules vary by BBS location Expanding since 1998 initial application Auckland, New Zealand Several corridors NA No speed restrictions Expanding since 1991 Miami, Florida Area SR-821/SR-836 I-75/SR-826 SR-826/I-95 SR-874/SR-878 I-805/SR-52 Corridor applications When traffic slows below 35 mph About to begin operations California, San Diego Area 1-year pilot BBS project of about 4 mi When general traffic slows below 30 mph, bus allowed to move up to 10 mph faster Opened on Dec. 2005 Notes: SB = southbound; NB = northbound; WB = westbound; EB = eastbound; NA = not available. TABLE 1 SUMMARY OF BUS BYPASS SHOULDER PROJECTS

7buses destined for the Metrorail station to bypass the conges- tion queue, which develops during the evening commute for the Route 267 exit movement onto I-66 (the next interchange downstream from the Metrorail station). Although the seg- ment is relatively short, the passenger and motorist perception of travel time savings is substantial, as buses move at 25 mph past traffic stopped in the general traffic lanes. Case Study 2 describes the Dulles Access Road BBS project in more detail. Maryland, Metro Washington DC Area Shoulder use bus lanes are provided on US-29 southward from Burtonsville approximately halfway toward the Washington Beltway (I-495). Figure 1 shows this BBS location. US-29 is a six-lane, 50 mph arterial roadway with some signalized intersections and a few grade-separate interchanges on the northern segment (55 mph). This shoulder use project is ap- proximately 4 mi long. The southbound lane restriction is in effect on weekdays from 6:00 to 9:00 a.m. The northbound bus shoulder use lane is operational from 3:00 to 8:00 p.m. The operation has faded diamond lane pavement markings on the shoulders and conventional HOV type signage, using the HOV diamond (Figure 2). Another Maryland shoulder use application is in operation on the I-495 Washington Beltway near I-270 (see Figure 3). This BBS application is essentially a queue jumper for east- bound buses to bypass congestion at the I-270 interchange. The project operates from 6 a.m. to 9 a.m. and from 3 p.m. to FIGURE 1 Maryland US-29 BBS location.

7 p.m. Monday through Friday. I-495 has five eastbound lanes along the BBS segment and a posted speed limit of 55 mph. Delaware, Wilmington Area Delaware has a BBS operation on US-202 north of Wilm- ington The BBS application is a short queue jumper for southbound traffic that is bound toward I-95 (see Figure 4). The BBS is located between Powder Mill Road and Foulk Road for a distance of 1,500 ft. One signalized “T” intersec- tion is located on this segment. Pavement markings and sig- nage use the diamond symbol. Signs clearly mark the length of the BBS operation and a special bus signal indication is provided for BBS buses. The signal indication for buses is similar to a walk–don’t walk display, but provides a green bus for go and a green bus with a red X for stop. The BBS operation is available to buses any hour of the day. New Jersey, Central Area A bus use of shoulder project is in operation on New Jersey Route 22 in Mountainside (see Figure 5). It is a short east- bound segment of an arterial road leading toward Perth Amboy. This project has minimal BBS signage (“Buses May Use Shoulder”) and no special pavement markings. 8 The New Jersey DOT is about to implement an additional BBS project on US-9 in Middlesex County near the town of Old Bridge (Figure 6). The Old Bridge BBS project is ap- proximately 4 mi long and is scheduled to open in mid-2007. The BBS operation will be between Spring Valley Road and Cindy Street and between Fairway Lane and Perrine Road. The project is estimated to cost approximately $8.5 million, and includes new sidewalks and pedestrian refuge islands as well as shoulder improvements. Existing 12-ft-wide shoul- ders will be replaced with full-depth pavement for buses. The drainage cross slopes of the shoulders will also be reduced from their current 4% to 2.5%. To maintain effective drainage, 78 new drainage inlets are planned for the BBS segment. The project is an element of New Jersey DOT’s En- hanced Bus Improvement Program and is designed to reduce delays and increase on-time bus service performance. US-9 is a six-lane arterial highway with an 18-ft-wide grass me- dian. BBS operation would serve northbound buses toward New York City during the morning commute peak period and southbound buses during the afternoon/evening com- mute peak period. Approximately 440 buses and 6,800 pas- sengers use the Route 9 corridor daily. Pavement markings for the US-9 project will consist of “Bus Only” markings and signage will indicate “Bus Only” with the hours of BBS op- erations. The posting of “Yield to Bus” signs has been sug- gested for the beginning of the BBS operations. New Jersey’s vehicle code includes the “yield to bus” right-of-way rule, where motorists are required to yield the right-of-way for buses merging back into traffic. Georgia, Atlanta Metro Area The Georgia Regional Transportation Authority and Geor- gia DOT opened a BBS operation on September 12, 2005, for the GA-400 freeway between the North Springs Metro- politan Atlanta Rapid Transit Authority (MARTA) rail sta- tion and Mansell Road (Figure 7). The BBS project will eventually extend northward to the Windward Parkway, connecting Alpharetta with the MARTA North Springs Station, a distance of approximately 12 mi (broken line in Figure 7). The shoulders of GA-400 were widened by 2 ft and reinforced to accommodate the shoulder use at a cost of approximately $2.8 million. The initial segment is approxi- mately 6 mi long, and when complete the BBS will be 12 mi long. The operating plan allows MARTA buses to use shoul- ders when general traffic speeds drop below 35 mph. Buses are only allowed to operate at a maximum speed of 35 mph; however, they can travel no more than 15 mph faster than general traffic. To minimize conflicts at interchanges, buses are required to reenter general traffic lanes before the inter- change and not to reenter the shoulder until after the interchange. Commuter buses are estimated to save between 5 and 7 min of travel time using the shoulders and might save up to 25 min at times when major disruptions occur. A change in the vehicle code was required to permit buses to use the shoulder lanes. FIGURE 2 Maryland US-29 BBS signage.

9Washington, Seattle Area Two bus shoulder use projects are currently in operation in the Seattle area. The first, a 2.7-mi westbound BBS segment of SR-520 from I-405 to the Evergreen Bridge, allows buses and 3+ HOVs to use the freeway shoulder lane to bypass con- gestion. SR-520 is basically a 60-mph posted-speed limit, four-lane freeway connecting Bellevue to Seattle. Buses and HOVs are allowed to operate at the posted speed while using the shoulder. This BBS was originally opened in 1970 as a toll booth bypass and it was later converted to its current HOV 3+ usage. The shoulder is 13 to 14 ft wide along this section of SR-520. Shoulders are marked with a solid white line separating them from general traffic lanes and HOV di- amond markings are provided (see Figure 8). Wayside HOV diamond lane traffic signs also identify the special use lane. Only limited physical improvements were made to the shoul- ders to implement the BBS. HOV drivers and buses must weave with exiting traffic at interchanges and again with en- tering traffic at on-ramps. Figure 9 describes signage and lane marking guidelines for interchange areas. Motorists with automobile troubles are encouraged to exit the freeway rather than use the shoulders, and tow trucks are strategically stationed to remove disabled vehicles from shoulders and FIGURE 3 Maryland I-495 BBS location.

traffic lanes of SR-520. Overall, motorist compliance has been good as has the safety record. The second BBS project is on SR-522, a five-lane ma- jor arterial highway serving the northern suburbs of Seat- tle. For both directions of travel on a 2.2-mi segment of SR-522 (NE Bothel Way) between NE 165th Street and 73rd Avenue NE (Kenmore, Washington) the shoulder lanes are restricted for bus use only. The westbound BBS opened in 1970 and the eastbound BBS in 1986. The shoul- der pavement is marked with “Only Transit” (see Figure 10) and “Transit Only” signs are intermittently placed 10 along the route. On SR-522, the BBS allows buses to queue jump congestion at traffic signals. Some conflicts have been reported with bicycles on the SR-522 shoulders. Both of these BBS operations in the Seattle area are full- time operations. Special speed restrictions are not posted for the shoulder lane operations, allowing buses to operate at the full posted speeds. Travel time and reliability perfor- mance has been good on both BBS projects. An advantage of the BBS operations as seen by bus operators is that they eliminate the weaving movements across general traffic lanes to enter and exit center median HOV lanes. In addition, FIGURE 4 Southbound US-202 BBS, north of Wilmington, Delaware.

11 the shoulders offer opportunities to serve passengers with on- line freeway bus stops along the corridor. The Washington State DOT also has about a dozen on- ramps where buses and HOVs are allowed to use shoulder lanes through interchange areas to bypass congestion. These interchange applications are limited to commute periods when ramp metering is operational. Miami, Florida The Miami–Dade MPO completed a Special Use Lane Study for the region in 2005 that addressed BBS projects patterned after the Minneapolis program. The Special Use Lane Study recommended further analysis of an Express Core System that would consist of buses using shoulders on the Homestead Extension of Florida’s Turnpike, SR-826 (Palmetto Expressway), and SR-836 (Dolphin Express- way). Subsequent discussions reportedly have expanded this feasibility analysis to consider bus shoulder use on I-95 from SR-112 to downtown Miami. The work scope for the further studies is provided in Appendix C, which also lists key concerns raised by agencies participating in the study. Agreements between Miami–Dade Transit, the Miami– Dade Expressway Authority, and the Florida DOT have been executed. Actual operation is anticipated for May or June 2006. The first BBS express service will be on the Dolphin Expressway from NW 107th Avenue to downtown Miami. Operations on the Don Shula Expressway and the Snapper Creek Expressway should follow shortly. Interstate Freeway BBS Eastbound Local Arterials Local Roads FIGURE 5 New Jersey Route 22 Mountainside eastbound BBS.

Future BBS projects under study include a section of the Homestead Turnpike extension project (Homewood Exten- sion of Florida’s Turnpike) extends from the Turnpike inter- change with I-75 to Homestead; however, the shoulder use concept is being considered from SR-836 (Dolphin Expressway) to Kendall Drive (SW 88th Street). The Palmetto Expressway is a major north–south wide urban expressway serving the western and northern edges of Miami. The Dolphin Expressway links Miami’s downtown to the Miami International Airport and also to the Miami Dolphin football stadium. At I-95, the Dolphin Expressway becomes I-395. The bus use of shoulders concept that is currently under study is envisioned to limit bus speeds to a maximum of 35 mph when using the shoulder. Only public buses traveling in 12 the peak direction of travel would be allowed to use the shoulders, and special training would be given to bus drivers. The training program is currently under development by Miami–Dade Transit. Legislation is now pending to allow the bus use of shoul- der facilities and the projects are anticipated to be imple- mented late in 2005. A marketing program is envisioned to educate motorists about of the program and an enforcement program is under development. Details of ITS features of the bus shoulder use program are still under development, but are expected to include transponders on buses to allow them to use the SunPass lanes at toll plazas. FIGURE 6 New Jersey Route 9 BBS in Middlesex County, New Jersey.

13 San Diego, California Initially the pilot BBS concept was considered for I-15. Cur- rent plans are to operate a 1-year pilot project on I-805 and State Highway 52 between Kearney Mesa and University City. The California DOT (Caltrans) has assumed the lead for this project, which opened in December 2005. Caltrans led the preparation of the signage and striping plans and pro- cessing National Environmental Policy Act 1989 environ- mental clearance for the project, and the MPO and transit operator developed the bus operating plan and a training pro- gram for bus drivers. It is understood that in some places the travel lanes were restriped to provide 10-ft minimum shoul- der widths. Messages (“Freeway Shoulders for Buses Only”) are posted on the back of buses. Case Study 4 provides more details on this BBS project. FIGURE 7 Georgia Route 400 BBS location. FIGURE 8 Washington State DOT SR-520 BBS on-ramp diamond weave markings.

Ottawa, Ontario Ottawa operates 14 mi of bus use of shoulders on limited access facilities. Only public transit buses are allowed to use the shoulder lanes. No special speed restrictions are defined and buses are allowed to operate up to the posted speed at 14 their discretion. The buses normally get on and off at most interchanges to make station stops and the BBS operation helps to minimize conflicts with traffic at the ramps. Figure 11 portrays Ottawa’s station stopping concept. Additional shoulder facilities have been developed on some segments to accommodate disabled vehicles. Buses using shoulder lanes are allowed to operate at speeds of up to 100 kph (62 mph). Therefore, buses can operate at substantially higher speeds during periods of con- gestion than vehicles in the adjacent general purpose traffic lanes. Figure 12 describes two cross-section plans for bus use on shoulders in Ottawa. Regional Road 174 was opened for shoulder bus use in 1992 and has a 5 m (16.4 ft) width to edge of pavement. A 2% cross slope is allowed. Regional Road 417’s bus use of shoulders operation is more recent. Its shoulder cross section spans 7 m (23.0 ft) and includes a 3.5 m bus shoulder, plus a 1 m shoulder and 1 m refuge edge area. The adjacent general purpose lane is 3.75 m (12.3 ft). The Ottawa experience suggests that where an emergency shoulder can be provided adjacent to the bus shoulder it is desirable, but not essential. Again, these shoulder cross sec- tions allow for buses to operate at speeds of up to 62 mph. FIGURE 9 Washington State DOT BBS interchange signage and striping. FIGURE 10 Washington State DOT SR-522 BBS pavement markings.

15 Bus volumes are relatively high (100 buses per hour) and this constant use of the shoulder might help to minimize sur- prises to motorists in the adjacent general purpose lane. Toronto, Ontario GO Transit has implemented a bus use of shoulders project for Highway-403 between Erin Mills Parkway and Mavis Road. Buses are permitted to use the shoulder when speeds drop below 38 mph, and are instructed to go no more than 12 mph faster than traffic using the general traffic lanes. The shoulder is 12.3 ft wide in both the eastbound and westbound directions. The presentation used to train bus drivers on the use of the shoulder lane is provided in Appendix C (C6). Ad- ditional information on the Highway-403 BBS is provided in Case Study 5. Vancouver, British Columbia The British Columbia Northbound Route 1 approach to the Ironworkers Memorial Bridge (Highway 1) into Vancouver has a BBS queue jumper. This application functions similar to a long queue jumper. Dublin, Ireland The Ministry of Transport and Eireann Bus operate BBS proj- ects on dual carriageways connecting Dublin to satellite towns. BBS projects include the N2, N3, N4, N6, N8, and N11. Some of the BBS projects have adjacent bicycle lanes. Case Study 6 provides details. Auckland, New Zealand The Auckland, New Zealand, Bus Priority Initiatives 2003 program identifies a number of shoulder use applications for its Northern Motorway, Northwest Motorway, and Southern Motorway. These were implemented from 1997 through 2002. BBS has been implemented in several of Auckland’s major travel corridors, none of which are lo- cated in the center city core. The longest BBS projects are located on the north and west sides of Waitemate Harbor. The Northern Motorway projects extend from just across Waitemate Harbor from Auckland to Takapuna and the Northwest Motorway BBS serves the area toward Massey West. A short section of BBS was implemented on the Southern Motorway. The Auckland Regional Transport Authority considers its BBS projects to be one of their suc- cess stories and is interested in setting up other BBS sites. Northern Motorway BBS • Tristan Avenue to Exmouth Road a.m. peak shoulder lane (pre-1996 implementation)—travel time savings reported as “high.” • Constellation Drive to Tristan Avenue a.m. peak BBS (1997)—travel time savings reported to be “high.” • Northcote Road Interchange a.m. peak BBS (2000)— travel time savings reported to be “moderate.” • Esconde Road Interchange a.m. peak BBS (2000)— travel time savings reported as “minor.” • Esconde Road to Onewa Road a.m. peak BBS (2000)— travel time savings reported as “minor.” • Greville Road to Constellation Drive BBS extended to p.m. peak. FIGURE 11 Ottawa Bus station stopping concept.

• St. Marys Bay BBS extended eastward to start at Fanshawe off-ramp (2001)—travel time savings re- ported to be “moderate.” Northwest Motorway BBS • Lincoln Road to Patiki Road a.m. peak BBS segments (1996)—travel time savings reported to be “high.” 16 • Patiki Road to Rosebank Road a.m. peak BBS (2001)— travel time savings reported as “high.” Southern Motorway BBS • Mt. Wellington to Ellerslis/Penrose a.m. peak BBS (1999)—travel time savings reported to be “high.” FIGURE 12 Typical shoulder bus lane sections in Ottawa. (Source: John Bonsall, McCormick Rankin International.)

17 BBS operations were implemented in June 2005 along a 0.9 mi extension of the Northwest Motorway between Great North Road and Rosebank Road. The shoulder improve- ments cost approximately $1 million. The BBS projects in Auckland generally require buses to merge into general traffic at interchanges. The BBS lanes generally start at the off “nose” and end before the off-ramp gore point. Buses use the BBS through the on-ramp merge area. This practice has reportedly worked well, because the buses are all large (visible) and on-ramp traffic is aware that the buses will not be competing for space in the general traf- fic lanes once past the interchange. The minimum shoulder width for BBS operations is 3.0 m (10 ft). Buses are allowed to operate at safe speeds of up to 70 kph (44 mph). BUS USE OF SHOULDER CONCERNS Survey respondents were asked what types of concerns they have regarding the design, operation, and implementation of the bus use of shoulders concept. The following types of con- cerns were expressed. Loss of Intended Shoulder Functions Shoulders provide a range of important functions. Use of the shoulder by buses at times when the highway is congested and moving slowly compromises these functions, even if shoulders are limited to bus use only. Four shoulder use func- tions were identified as concerns by survey respondents. • Removal and storage of disabled vehicles and accidents, • Emergency vehicle use, • Staging area for maintenance work, and • Snow storage. It was pointed out that highways tended to be most con- gested when accidents have occurred, when disabled vehi- cles are being attended to along the roadside, when highway maintenance work was ongoing, and when weather condi- tions are poor (e.g., when it snows). Accident situations also are the times when emergency vehicles most need to use shoulder facilities. Some of these functional concerns seem to be based on the perception that high volumes of vehicles would use the shoul- der and the shoulder itself would become congested. If shoul- der use is restricted to bus traffic only and bus drivers were in close radio communications with central dispatch, most of the shoulder use concerns could be effectively addressed. Because no physical barriers would be constructed between the shoulder lane and the right-most general traffic lane, buses could merge into general traffic lanes to bypass obstructions along the shoulder. Advisories to bus drivers could also address the maintenance staging and snow storage concerns. Loss of intended shoulder functions has not proven to be a problem at established BBS sites. Traffic Safety The most common concerns that were raised by survey re- spondents dealt with traffic safety. Eleven types of traffic safety concerns were identified. • Conflicts at on- and off-ramps; • Sight distance adequacy, particularly at on-ramps; • Conflicts for motorists pulling onto the shoulder; • Loss of safe evasive movement shelter area; • Need for bus driver training; • Speed differential; • Impact on adjacent lane motorists; • Return merge distance adequacy; • Shoulder area debris hazards; • Reduced clearance for buses at bridge abutments; and • Drainage and hydroplaning. The first five of these safety concerns relate to potential traffic conflicts along the shoulder lane. Motorists exiting from the general traffic lane will not be expecting a bus approaching from behind using the shoulder. Motorists need- ing to pull onto the shoulder similarly will not be expecting traffic using the shoulder. Most motorists pulling onto the shoulder use their turn signals, which would warn buses using the shoulder as well as motorists that are following in general traffic lanes. Traffic entering the highway will not expect traf- fic using the shoulder lane and typically will have shorter merging sight distances. On occasion, motorists use shoulders to evade collisions and abrupt changes in traffic speeds. If buses are using the shoulder lane, this evasion option could be compromised. Establishment of good operating protocols, training of bus drivers, and good signage can help minimize these safety issues, but the more intense use of the highway right-of-way will inherently increase traffic safety risks. By limiting use of the shoulders to conditions when general traf- fic is operating slowly and limiting the speeds of buses using the shoulder facilities, the risks are more manageable. The next three of the safety concerns relate to potential impacts on traffic using the general traffic lanes. Unexpected traffic traveling at high speed in the shoulder lane could sur- prise some motorists and lead to accidents. If the develop- ment of shoulder use lanes involves narrowing general traffic lanes to provide a wide shoulder, the narrowed general traf- fic lanes will likely lead to increased accident risks (particu- larly at periods of high speed when the shoulder is not being used). The importance of safe design to accommodate the transition from shoulder to general traffic lanes was also identified as a concern. With the exception of the narrowing of general traffic lanes, these safety concerns all appear man- ageable using good design and operations practices.

The last three of the traffic safety concerns identified by survey respondents relate to obstructions and physical features. • Regular use of the shoulders probably would require in- creased efforts to remove debris from the shoulder area. • Operations of wide vehicles on the shoulder also re- duces the horizontal clearance between moving traffic and bridge abutments, railings, sign posts, and other lat- eral obstructions. • Drainage failures most often affect shoulder facilities rather than high-speed general traffic lanes. One respon- dent felt that this would increase hydroplaning risks. Good bus driver training, good operating protocols, and care- ful design would appear to address most of these issues. Physical Design Design practices and operating environments vary by juris- diction. Seven concerns were identified for physical design. • Shoulder width adequacy, • Shoulder pavement strength, • Signage needs, • Lateral obstruction adjacent to shoulder, • Need to narrow general traffic lanes, • Modifications to drainage inlets compromise function, and • Conflicts with pavement edge rumble strips. Shoulders generally have not been constructed to accom- modate regular use by large vehicles. Most modern shoulders are 10 to 12 ft wide; however, many older highways have nar- rower shoulders and less clearance to lateral obstructions. Buses are 8.5 ft wide excluding mirrors and approximately 10 ft wide with mirrors. Shoulder pavement typically is not designed to the same thickness and strength as general traffic lane pavement. Conventional traffic signage is not designed to support shoulder use operations. Drainage inlets along shoulders are not designed for comfortable traverse by buses and reconstruction can compromise their ability to effectively remove water from the roadway. Electrical junction boxes also often need to be relocated. Lastly, some highways are de- signed with rumble strip warning edges between the general travel way and the shoulder. These rumble strips would not support comfortable use of the shoulder and would need to be removed. An issue that was not identified from the project sur- vey, but is also important concerns drainage cross slopes. Shoulders typically have cross slopes greater than general traf- fic lanes and the higher cross slopes increase the level of dis- comfort for bus passengers. These are all important design considerations; however, they can generally be addressed by physical upgrades to the highway facility. The costs for these upgrades vary widely, but are modest compared with most highway widening and interchange reconstruction costs. 18 Legal Codes in most states do not allow vehicles to use shoulder lanes for congestion bypass purposes and without enforce- ment abuses are inevitable. Concerns related to this are reg- ulatory authority and enforcement of abuses. The implementation of bus use shoulders needs to include a framework and facilities to enforce regulations. As most abuses would typically include cheating by exiting and entering motorists, rather than continuous travel by general traffic on the shoulder, clear boundaries need to be defined for the exit and merge interchange movements. Costs In addition to the cost needed to upgrade shoulders to allow for bus use, concerns were also raised about the added cost of maintenance necessary to keep shoulders free from debris and to maintain the shoulder pavement. Special issues that were raised for toll road facilities in- cluded the acceptance of toll paying motorists for the prefer- ential use of the shoulders and also how to handle the shoulder use at toll plazas. OPERATIONAL EXPERIENCE Safety A 1998 study of the Minneapolis bus shoulder use found: 1. Travel time savings are quite variable and depend greatly on weather and traffic conditions. The worse the weather and traffic, the greater the time savings. During snowy conditions, the 4-mi I-35 segment between Lake Street and Highway 62 (the Cross-town) realized a 9-min travel time savings using the shoulder. 2. Bus-only shoulder operations are inherently safe; from February 1996 to June 1996 there were only three crashes, none of them serious. 3. A 10-ft-wide shoulder is marginally adequate. Drivers are uncomfortable with the narrow lanes, especially during adverse weather conditions (and adverse weather conditions are where travel time savings are the greatest). Snow and other debris that obstruct visi- bility add to the discomfort level. NCHRP Report 369: Use of Shoulder and Narrow Lanes to Increase Freeway Capacity (3) provides the most extensive analysis of narrowing lanes to use shoulder facilities for general traffic. This study did not address the more controlled concept of allowing only buses to use the shoulder lanes. NCHRP Report 369 cautions against using the right shoulder, particularly for segments with high truck volumes. It found that accident rates increase for

19 shoulder use application when the shoulders are less than 12 ft wide. The accident rate increase was greatest for the first 2 years (up to a 60% increase) and tended to level off at 10% to 15% higher than unaltered conditions after the first 2 years. INTELLIGENT TRANSPORTATION SYSTEMS The potential benefits of driver assistive technology are cur- rently being researched by the University of Minnesota. Their research is aimed specifically at making it easier and safer for Metro bus drivers to operate on narrow shoulder lanes. The research is addressing virtual mirror and virtual bumper sys- tems, as well as the lane keeping assist concept. It is a global positioning system-based approach. Magnets embedded in the roadway pavement are another technology approach that is under development for the lane keeping assist concept. Other ITS technologies of potential application for BBS lane use include incident monitoring systems and variable mes- sage signs. Virginia’s DOT currently uses overhead message signs to advise motorists on I-66 as to when shoulder lanes are open for general purpose traffic use (see Figure 13). Incident monitoring systems could alert bus drivers to shoulder lane blockages and also to mainline freeway travel speeds. The latter could provide a consistent definition for buses shifting to shoulder use running. ITS signage could alert motorists to shoulder bus operations. FIGURE 13 I-66 shoulder lane use control sign and signal (Fairfax County, Virginia).