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Commonsense Approaches for Improving Transit Bus Speeds (2014)

Chapter: Chapter Two - Literature Review

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Suggested Citation:"Chapter Two - Literature Review ." National Academies of Sciences, Engineering, and Medicine. 2014. Commonsense Approaches for Improving Transit Bus Speeds. Washington, DC: The National Academies Press. doi: 10.17226/22421.
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Suggested Citation:"Chapter Two - Literature Review ." National Academies of Sciences, Engineering, and Medicine. 2014. Commonsense Approaches for Improving Transit Bus Speeds. Washington, DC: The National Academies Press. doi: 10.17226/22421.
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Suggested Citation:"Chapter Two - Literature Review ." National Academies of Sciences, Engineering, and Medicine. 2014. Commonsense Approaches for Improving Transit Bus Speeds. Washington, DC: The National Academies Press. doi: 10.17226/22421.
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Suggested Citation:"Chapter Two - Literature Review ." National Academies of Sciences, Engineering, and Medicine. 2014. Commonsense Approaches for Improving Transit Bus Speeds. Washington, DC: The National Academies Press. doi: 10.17226/22421.
×
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Suggested Citation:"Chapter Two - Literature Review ." National Academies of Sciences, Engineering, and Medicine. 2014. Commonsense Approaches for Improving Transit Bus Speeds. Washington, DC: The National Academies Press. doi: 10.17226/22421.
×
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Suggested Citation:"Chapter Two - Literature Review ." National Academies of Sciences, Engineering, and Medicine. 2014. Commonsense Approaches for Improving Transit Bus Speeds. Washington, DC: The National Academies Press. doi: 10.17226/22421.
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9 • Enforce restrictions on use of bus lanes by other vehicles, • Balance the number of stops with passenger convenience and demand, • Consider supplementing local service with limited-stop service, and • Implement skip-stop operation. With a running speed of 50 mph (80 kph), actual speed on a busway or exclusive freeway high-occupancy vehicle (HOV) lane can vary based on stop distance and dwell time at stops, with a range from 46 (dwell time = 0, stop spacing = 2.5 mi/ 4 km) to 16 (dwell time = 60 s, stop spacing = 0.5 mi/0.8 km) mph (74 to 26 kph). TCQSM provides formulas for estimat- ing speeds on arterial streets in bus lanes and in mixed traffic flow. With regard to bus rapid transit (BRT) service, TCQSM presents typical effects on speed of station spacing and dwell times. The only level of service ranking related to bus speed is the travel time difference between fixed-route transit and automobile, in which “A” is faster by transit and “F” is more than 60 min slower by transit. A study conducted by the Finland Ministry of Transport and Communications (5) gathered examples, best practices, and experiences on speeding up public transport to evaluate the effects on competitiveness and transportation econom- ics. The study reported that changes in travel time have a bigger effect on travel mode selection than do changes in ticket prices. Field tests were conducted to evaluate accel- eration and door functions on different bus models. Accel- eration on buses varies by 5% and door functions by 12% on an average bus line in Helsinki. Among the speed-related findings: • Bus lanes increase speed and improve punctuality by 15% to 20%. In some cases, the bus-only streets show operation cost savings. • Traffic signal priority reduces delays caused by traffic lights by 40% to 50%. • If timetable and service frequency are included or inte- grated, punctuality and regularity improve even more. Rutherford and Watkins (6) explored causes of travel time variability. Three questions were addressed: (1) What are the characteristics of route segments where travel times (as measured by runtime) are the least variable? (2) What are the characteristics of route segments where drivers are least likely to fall behind? (3) What are the characteristics of route INTRODUCTION This chapter summarizes findings from a literature review related to bus speeds. A Transportation Research Information Database (TRID) search was conducted to aid the literature review, using keywords such as “bus speed,” “transit speed,” “bus delay,” and “transit travel time.” COMPARATIVE AND GENERAL STUDIES Some of the most interesting work in the literature assessed the relative impacts of different actions to improve bus speeds. Levinson (1) conducted a detailed analysis of transit speeds, delays, and dwell times based on surveys conducted in a cross section of U.S. cities. Major conclusions from this analysis included: • Reducing bus stops from eight to six per mile (five to 3.75 per kilometer) and dwell times from 20 to 15 s would reduce travel times from 6.0 to 4.3 min/mi (3.75 to 2.69 min/km), a time saving greater than that which could be achieved by eliminating traffic congestion. Transit performance can be improved by keeping the number of stopping places to a minimum. • Fare collection policies and door configurations and widths are important in reducing dwell time, especially along high-density routes. Such time savings likely will exceed those achieved from providing bus priority measures or improving traffic flow. St. Jacques and Levinson (2) analyzed the operation of buses along arterial street bus lanes and derived procedures for mea- suring the impacts of various factors on bus flow and speeds. In a follow-up study, St. Jacques and Levinson (3) conducted field tests in four cities to assess how well the procedures outlined in TCRP Report 26 to estimate bus speeds in downtown matched observed speeds. Adjustments for default values for incremen- tal traffic delay were suggested to reflect more accurately the range of conditions commonly encountered. The Transit Capacity and Quality of Service Manual (TCQSM) lists factors influencing bus speeds and ways to improve speeds (4). Bus speeds can be improved in the fol- lowing ways: • Reduce dwell time, • Implement transit preferential treatment, chapter two LITERATURE REVIEW

10 as average signal delay per intersection. Results in the morn- ing peak period showed a 12.1% reduction in bus travel times (from 33 to 29 min), a decrease in average signal delay from 24% to 20% of the total travel time, and an improvement in on-time performance from 66.7% to 75%. The results con- firmed that nearly every intersection experienced less delay with the TSP activated. Results in the afternoon peak period were insignificant. Albright and Figliozzi (10) analyzed the effectiveness of conditional transit priority, or the manipulation of traf- fic signal timing plans to reduce delay of late transit buses. The study involved a 5-mi corridor along SE Powell Boule- vard with 14 signalized intersections, all TSP-equipped. TSP tends to be most effective at lower volume intersections, where queuing on the street of travel is less problematic. In addition, TSP effects are localized. The stop and intersection level analysis shows a TSP effectiveness that can be hidden or evened out when analyzing effectiveness at a route level. TSP is more effective for late buses, but other factors such as delays caused by lift usage can preclude schedule recovery. Surprenant-Legault and El-Geneidy (11) evaluated the impact of adding a reserved bus lane on the running times and on-time performance of two parallel bus routes, one of them a limited-stop bus service and the other a regular bus service. The reserved bus lane yielded savings of 1.3% to 2.2% in total running time, and benefits were more note- worthy when congestion levels were high. The introduction of a reserved lane increased the odds of being on time by 65% for both routes. A decline in the variability of running time was noticed after implementation of the reserved lane, indi- cating that the reliability of the service being offered along the corridor had improved. Reserved lanes had a substantial effect on both service reliability and on-time performance, two key variables in customer satisfaction. Schwartz et al. (12) evaluated the impacts of an exclusive dual-width bus lane, defined by pavement markings and over- head signs accompanied by intense enforcement, on Madison Avenue in midtown Manhattan. Results indicated that (a) peak hour bus speed was increased by 83%, (b) peak hour bus reli- ability was increased by 57%, (c) traffic speed on Madison Avenue was increased by 10% for all vehicles, and (d) aver- age speed on eastbound cross streets was unchanged and on westbound cross streets was reduced by 6%. Pangilinan and Carnarius (13) investigated traffic signal timing as a means of improving transit service specifically; they used the San Francisco Municipal Transportation Agen- cy’s signal timing project for the Inner Geary bus corridor as a case study in the development and evaluation of signal timing for transit progression. For most cases, traffic signal timing for a one-way street is a fairly simple exercise: automobile speeds and distances between intersections are measured to create a progression of vehicle platoons along a corridor. For transit, however, stop spacing and dwell time variability increase the segments where drivers are most likely to be able to catch up if they have fallen behind schedule? Results included: • The characteristic with the highest impact on on-time status and additional runtime beyond scheduled is the presence of some kind of issue with service (e.g., detours, accidents) that would cause a service alert to be issued within the agency. • The presence of high-floor buses increased delays by several seconds per trip segment. • Through-routing, a practice in which a bus alternates trips between two routes throughout the day, had an even greater impact, adding almost a minute to the actual run- time beyond that scheduled. • Standees on a bus had a similar negative impact on on- time status and overall runtime, indicating that agencies need to pay attention to their passenger loads to avoid delays. • Interestingly, express buses and the percentage of exclu- sive lanes in the form of HOV lanes or business-access transit lanes had an inconsistent impact on reliability. In speed and delay studies in the Jacksonville, Florida, region, Ryus and Bartee (7) found a linear relationship between bus and auto travel times (and speeds) across the range of sam- pled travel times, unlike the regional model structure, which uses three different linear functions for various ranges of auto speeds. Bus travel times were a consistent proportion of auto travel times during peak and off-peak periods, although abso- lute travel times were longer during peak periods. Finally, the current model structure was found to underestimate the maxi- mum observed bus speeds in the field. These results are con- sistent with those of an earlier study conducted in the Tampa Bay, Florida, area. Maloney and Boyle (8) analyzed components of running time on the Glendale (California) Beeline system. Results were reported by route for three local and two routes. The primary component of in-service time is actual travel time or time when the bus is moving, accounting for 59%. Recovery time (13%) and deadhead time (9%, inflated by extensive deadheading on one express route) ranked second and third, followed by time maneuvering in and out of traffic at bus stops (7%), dwell time (7%, higher on the local routes), sig- nal delay (5%), and traffic delay (less than 1%). TRAFFIC ENGINEERING ACTIONS Studies cited in this section examined actual results from implementation of actions to improve bus speeds. Actions include signal priority, reserved bus lanes, and signal timing. Pessaro and Van Nostrand (9) measured the effects of imple- menting transit signal priority (TSP) for the I-95 Express Bus Service in South Florida. The measures included before and after results for travel times, on-time performance, components of delay (e.g., dwell time, signal delay, turnout delay), as well

11 practicality of this approach. Results show how stop consoli- dation plans can be adjusted to maximize the societal benefit. King (19) summarized early experiences with yield-to- bus programs at a time when only four states and two prov- inces in North America had enacted yield-to-bus laws. This study reported greater agency satisfaction when a flashing light-emitting diode was used instead of a decal on the bus. Approximately one-third of survey respondents reported an increase in schedule adherence, but none was able to provide supporting data. Fabregas et al. (20) examined the operational impacts of yield-to-bus electronic warning signs. The authors concluded that electronic warning signs lowered the reentry time from pullout bays, thus increasing overall bus speed. Estrada-Romeu et al. (21) and Alonso et al. (22) both exam- ined the impact of multiple loading areas at bus stops in Span- ish cities. Estrada-Romeu et al. (21) found that in Barcelona, a capacity gain of 30% to 70% can be achieved, with a greater gain if buses spend more time at the stop and the variability in dwell time is low, and suggested a revision of the TCQSM by which the “effective number of berths” concept should be considered a variable (instead of a constant) that depends on the dwell time characteristics. Alonso et al. (22) reported that arrivals at stops can be better staggered if bus stops are divided into more than one berth. In the city of Santander, Spain, the quantified benefits of an optimal route-stop assignment show increases of 10% in average bus speed. BUS RAPID TRANSIT IMPACTS Bus rapid transit implementation has spawned several studies looking at impacts on bus speeds. Levinson et al. (23) noted operating speeds for BRT on arterial streets ranged between 8 and 19 mph (13 to 31 kph), with 14 mph (23 kph) reported as typical. The study reported that bus speeds in Los Angeles had declined by 12% in recent years and that two-thirds of the increases in bus speeds brought about by BRT in Los Angeles were the result of fewer stops, whereas one-third were the result of signal priority. This study also reported a wide range of BRT travel time savings in minutes per mile, with higher estimates for busways and lower estimates for arterial BRT service. Volume 2 of study by Levinson et al. cited several factors affecting BRT bus speeds, including stop distance, dwell time, and the volume/capacity ratio at bus stops. The report docu- ments afternoon peak period bus speeds in selected cities with bus lanes, ranging from 2.6 to 12.8 mph (4.2 to 20.6 kph). The authors address the impact of the fare collection method on dwell time and discuss how bus speed affects operating cost and fare box recovery. Kittelson & Associates et al. (24) report travel time sav- ings per mile associated with busways and arterial bus lanes. complexity of this task. The main conclusion of the study by Pangilinan and Carnarius is that signal timing for transit is shown to improve transit travel time and reduce travel time variability. However, the strategy has limitations on where it can be applied. BUS STOP ACTIONS The Texas Transportation Institute (14) presented a compos- ite of prevailing practices regarding bus stop spacing. Typical spacing was 600 ft (183 m) in the central business district (CBD), 750 ft (229 m) in urban areas, 1,000 ft (305 m) in suburban areas, and 1,250 ft (381 m) in rural areas. The study noted the essential trade-off in stop spacing between shorter walk distances and higher speeds but did not explore the effects of changes in stop spacing. Cooper (15) evaluated a series of traffic and transit-related improvements in Victoria, British Columbia. Direct transit- related modifications, mainly involving bus stop reductions or adjustments, had the most marked and beneficial effect on bus operation. This net operational benefit, while not of a mag- nitude that would in itself lead directly to real cost savings, nevertheless derived from minor, low-cost traffic and transit improvements and resulted in demonstratively smoother bus operation. Service to the public, as represented by the num- ber of available stops within the study area, was effectively unchanged. Fitzpatrick et al. (16) studied the impacts of bus bulbs. A major advantage of bus bulbs is the creation of additional space at a bus stop for shelters, benches, and other bus patron improvements when the inclusion of these amenities would otherwise be limited without the additional space. Bus bulbs also eliminate the bus-weaving maneuver into and out of stops. An evaluation of pedestrian operations found that vehi- cle and bus speeds increased on the block and in the corri- dor. The nearside stops, which experienced higher delays to buses, saw a reduction in the average delay with the installa- tion of the bus bulb. Furth and SanClemente (17) analyzed delay associated with the bus stop location. The marginal impact of slope on stopping delay ranged from -4 to 11 s, depending on grade. Far-side stop placement causes a very small reduction in delay or has no effect. Near-side placement can reduce delay in a few cases, such as reserved bus lanes, but more often increases delay, sometimes considerably depending on factors such as traffic signal timing, the volume/capacity ratio, cycle length, and stop setback. Measures that reduce interference with the queue tend to reduce the net delay from a near-side location; these measures include increasing stop setback, shortening cycle length, and giving the bus a (near) exclusive lane. Furth et al. (18) presented an analytical approach to bus stop location based on a parcel-level geographic database and a street network. Case studies in two cities demonstrated the

12 SIGNAL PRIORITY AND MODEL-BASED STUDIES Many of the reports and articles in this literature review address traffic model results. These are clearly important as the indus- try continues to refine and expand its modeling capabilities but perhaps have less relevance to this study owing to their theoretical nature. Nonetheless, interesting and sometimes counterintuitive findings have been reported in the literature. Foletta et al. (30) described a new methodology for solv- ing the bus network design problem, covering both network design and frequency setting. The models were applied to the street network of Barcelona, Spain, and it was found that the new models produce bus networks with faster average travel speeds, smaller fleet size, fewer route kilometers, and fewer buses per link than did previous methodologies. Consideration of the variability of bus speeds and required route frequencies during route generation and frequency setting can appreciably improve the performance of a bus network. Bekhor (31) proposed a methodology to estimate capac- ity and speed for bus lanes. The main difference between the TCQSM method and the proposed method is related to the estimation of bus speeds. Analysis of microsimulation results enabled the estimation and calibration of volume-delay func- tions for bus lanes. The initial validation results show a satis- factory match between modeled results and field observations. Tranhuu et al. (32) addressed the implementation of bus lanes and median busways for Asian cities in which traffic is dominated by motorcycles, concentrating particularly on Hanoi, Vietnam. Model results show that the level of motor- cycle violations has an important impact on the success of bus lane schemes: there is no major speed improvement on bus lanes if enforcement is weak. Busways can achieve much higher bus speeds than can bus lanes, but the potential extra delay caused by a poorly designed busway is greater than that resulting from a poorly designed bus lane. Muzyka (33) conducted a simulation of traffic flow within a specified traffic system to predict the effect on bus service and general traffic performance of implementing candidate bus priority strategies. The model was calibrated to current peak hour traffic conditions within an urban street grid representa- tive of the CBD of Minneapolis. Various bus priority strategies designed to increase bus speeds by providing bus-only lanes were evaluated. The important elements in bus travel time were shown to be frequency of station stops and red light signals. Saberi et al. (34) assessed existing reliability measures proposed by the TCQSM and developed new reliability mea- sures at the stop level. Three new reliability measures at the stop level are proposed: (1) an Earliness Index to measure the relative frequency of early buses; (2) a Width Index to mea- sure the variability of headway deviations; and (3) a Second Order Stochastic Dominance Index to measure the distribu- tion of delay and headway deviations. Evidence from arterial lanes indicates that speed increases of 1.5 to 2.0 mph (2.4 to 3.2 kph) can be expected, representing percentage changes between 22% and 47%. Examples show the impact of increased bus speeds on the number of vehi- cles required (keeping headway constant) and on headway (keeping number of vehicles constant). Peak hour travel time rates for various stop spacings, dwell times, and operating environments are presented; these suggest that the number of stops has a greater impact on speed than does dwell time at stops. The study provides a variety of ways to estimate BRT travel time savings and concludes with a detailed analysis of six BRT scenarios. Callaghan and Vincent (25) assessed the Metro Orange Line of Los Angeles County, California, one of the first full- feature BRT systems in the United States, and compared the Orange Line with two recent transit investments in Los Angeles: the Gold Line light rail and Metro Rapid, a rapid bus service with limited BRT features. The study found that the Orange Line is performing better than the Gold Line, which costs considerably more yet carries fewer riders. Metro Rapid appears to have some cost-effectiveness advantages but lacks travel time consistency and a premium transit ser- vice image. Safety changes to the Orange Line operation, such as reduced bus speeds through intersections, reduced travel time savings. Levinson (26) described the design, operations, and effec- tiveness of different types of BRT: mixed traffic, normal or contraflow curb bus lanes, and/or arterial median busways. The Levinson study identified the key issues and tradeoffs and showed that with proper design, BRT can improve bus speeds, reliability, and identity, while minimizing adverse impacts to street traffic, pedestrians, and property access. Diaz (27) examined the impacts of TransMetro in Gua- temala City, Guatemala, the first full BRT system in Central America. TransMetro’s buses are able to achieve average speeds seven times greater than the previous average speeds (which were very low). These speeds are mostly because the system has five underpasses that allow buses to avoid inter- sections and only two traffic lights in the segregated infra- structure sections. Two studies reported findings from the first two select bus service (SBS, New York’s term for BRT) routes in New York City. Barr et al. (28) examined the Fordham Road SBS in the Bronx. Results showed a 20% reduction in travel time along the corridor and an 11.5% increase in ridership in the corridor. A total of 98% of bus customers surveyed described themselves as satisfied or very satisfied with the service. Beaton et al. (29) analyzed the First and Second Avenue SBS in Manhattan and reported a 15% to 18% improvement in travel time and a 10% increase in corridor ridership. In chapter five, the case exam- ples include greater detail on changes in bus speed resulting from SBS implementation.

13 TSP strategies were considered: green extension, red trunca- tion, phase skip, and phase insertion. Queue jump lanes without TSP were ineffective in reducing bus delay. Queue jump lanes with TSP strategies that included a phase insertion were found to be more effective in reducing bus delay while also improv- ing general vehicle operations than were strategies that did not include this treatment. Near-side bus stops were preferred for queue jump TSP over far-side bus stops. Through vehicles on the bus approach were found to have only a slight impact on bus delay when the volume/capacity (v/c) ratio was below 0.9, but bus delay increased quickly when v/c exceeded 0.9. Right- turn volumes were found to have a very small impact on aver- age bus delay, and an optimal detector location that minimizes bus delay under local conditions was shown to exist. Pye and Bode (40) reported on bus priority measures imple- mented in London, United Kingdom, to improve bus speed and reliability. Using a range of microsimulation models on a section of Route 149, Kingsland Road, Hackney, the authors found that traffic signal timings had the most impact on journey times and that bus lanes provided the most benefits under con- gested conditions. These priority measures were introduced onto Bus Route 149 progressively from 2000, and the effects of the different measures were monitored. It was shown that a successful approach would seek to include improvements at traffic signal junctions, provision of bus lanes, and control of curbside activity. Rouphail (41) evaluated the impact of the use of two bus priority techniques on the operation of bus and nonbus traf- fic in a simulated environment. The strategies studied were (1) contraflow bus lane on a downtown street and (2) signal settings based on minimizing passenger, rather than vehicle, delays. The operational setting reflected actual observations on a Chicago downtown street. It was found that predicted bus operation improved considerably as a result of dedicating an exclusive lane to bus traffic. However, the degree of bus opera- tion improvement was dependent on whether the buses oper- ated in mixed traffic or on exclusive lanes. A limited field study was conducted to test bus performance indices predicted by the model. The observed and simulated overall bus travel speeds were found to compare favorably at the 5% significance level. Horn and Widstrand (42) evaluated several improvements, including adding dedicated bus lanes along the length of the corridor and completing individual intersection projects to the NE 85th Street and Redmond Way arterial corridor in Kirkland and Redmond, Washington. The improvements were evalu- ated by conventional intersection measures of performance, such as average delay and queue length. Benefit-to-cost ratios were used to determine the return on investment by the tran- sit agency of each enhancement alternative. The bus travel time benefits realized from corridorwide and combinations of relatively small intersection improvements were comparable and noteworthy. In addition, the benefit-to-cost ratio for the intersection improvements was comparable and outweighed Fernandez and Valencia (35) presented a macroscopic simulation model that represents the operation of a public transport corridor with enough detail to take into account all sources of delays, mainly running time, signal, and stop delays. The model has been validated against real data in a busway in Santiago, Chile. The authors found that bus speed can be improved between 9% and 20% if stops are optimally spaced. An additional 2% to 7% can be achieved if passing lanes are provided at stops. If traffic signals are set so that they take into account the bus progression, an additional 3% to 5% increase in commercial speed can be attained. Furth et al. (36) explored signal control logic for reducing bus delay around a major bus terminal in Boston, Massachu- setts, where the busiest intersections see almost four buses per signal cycle. A traffic microsimulation model evaluated a suc- cession of signal priority tactics and found a reduction in bus delay of 22 s per intersection, with minor impact on general traffic. The general strategy was to provide buses with green waves, so that they are stopped at most once, coupled with strategies to minimize initial delay. The greatest delay reduc- tion came from passive priority treatments: changing phase sequence, splits, and offsets to favor bus movements. Green extension and green insertion were found to be effective for reducing initial delay and providing dynamic coordination. Cycle-constrained free actuation, in which an intersection has a fixed cycle length within which two phases can alter- nate freely, provided flexibility for effective application of early green and green extension at one intersection with excess capacity. Emphasis was given to the approach of providing aggressive priority with compensation for interrupted phases. Li et al. (37) described the development and implementa- tion of adaptive TSP on an actuated dual-ring traffic signal control system. Adaptive TSP is responsive to transit priority requests in real time in the context of current traffic conditions. At a congested intersection, it is found that the average bus delay was reduced by 43%, and the average traffic delay along the bus movement direction was reduced by 16%. The average delay of cross-street traffic was increased by about 12%. Winters and Abbas (38) sought to determine the benefits of TSP in Blacksburg, Virginia, a college town of 50,000. The road modeled for this analysis runs on the north side of campus, and three intersections were included in the analy- sis. A total of 56 buses per hour move through the network. Maximum transit extension times varied from zero to 45 s in 5-s intervals. Based on statistical analysis, it was recom- mended that the signals be reprogrammed to allow 20 s of transit green extension. This would decrease bus delay by 15%, decrease bus stops by 6%, and increase car delay by 5% while having no impact on car stops and heavy vehicles. Zhou and Gan (39) evaluated the performance of queue jump lanes under different TSP strategies, traffic volumes, bus volumes, dwell times, and bus stop and detector locations. Four

14 SUMMARY The literature review reveals several local analyses of the impacts of actions to improve bus speeds but few compari- sons of which actions are most effective. Stop spacing and traffic engineering actions, such as TSP and reserved lanes, have been shown to work, although some actions such as TSP produce localized results that may not be apparent at the route level. Fare policies also have an impact. BRT has received considerable attention, and analysis of BRT implementations highlights the difficulty of separating and specifying the outcomes of individual actions. The literature includes a wealth of modeling efforts that have the practi- cal effect of identifying actions with a high payoff in terms of speed. These reports provide a good starting point for this study. The literature review has informed the survey instrument used to gather input from transit agencies. Survey results and case example findings have been checked against findings in the literature for consistency. Chapter six reflects the litera- ture review as well as the survey and case examples. Addi- tional research needs have been developed based on unclear or conflicting information. Chapters three and four present the results of a survey of transit agencies regarding approaches to improving bus speeds. Survey results provide a snapshot of the state of the practice as it exists today with regard to approaches to improving bus speeds. those of the corridorwide improvements. The study showed that in this suburban setting, getting buses moving means getting all of the traffic moving. Koonce (43) authored a white paper summarizing barri- ers associated with the implementation and maintenance of TSP systems. The white paper also described partnerships between transit and traffic engineering professionals that have helped to identify and overcome technical and policy- related limitations to implementation. Conclusions focused on next steps for advancing the integration of transit into transportation engineering projects. HISTORICAL SPEED DATA Blake and Jackson (44) summarized streetcar speeds in vari- ous cities in the early 1920s. Average speed ranged from 9.4 to 10.9 mph (15.1 to 17.5 kph) in 12 large cities and from 7.7 to 10.8 mph (12.4 to 17.4 kph) in 20 medium cities. Levinson (45) analyzed peak hour bus travel times in a number of cities. Peak hour travel times (measured in min- utes per mile) were greatest in CBDs, averaging 11.5 min/mi (7.1 min/km) compared with 6.0 min/mi (4.4 min/km) in cities exclusive of CBDs and 4.2 min/mi (2.6 min/km) in the suburbs. The percentage of time the bus was in motion (as opposed to stopped in traffic or at bus stops) was less than 50% in the CBD, 65% in other areas of the city, and 71% in the suburbs. The ratio of automobile-to-bus speeds in the afternoon peak hour ranged from 1.4 to 1.6.

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TRB’s Transit Cooperative Research Program (TCRP) Synthesis 110: Commonsense Approaches for Improving Transit Bus Speeds explores approaches transit agencies have taken to realize gains in average bus speeds.

The report also identifies metrics pertaining to measures such as changes in travel speed and its components, operating cost, and ridership. It shows the results of each or a combination of approaches implemented.

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