Transit Capacity and Quality of Service Manual, Third Edition (2013) / Chapter Skim
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Pages 93-140
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From page 93... ...
1. User's Guide 2.
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From page 95... ...
Organization of Chapter 3. Transit Capacity and Quality of Service Manual, 3rd Edition 1.
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From page 96... ...
Transit Capacity and Quality of Service Manual, 3'd Edition While an effort has been made to select representative conditions when developing the illustrative exhibits, all relationships presented in the exhibits apply only to the set of assumptions used to create the exhibit (and listed with each exhibit)
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From page 97... ...
Factors influencing capacity also influence speed and reliability. Recovery time is time included in the schedule between vehicle runs to allow late-arriving vehicles to start their next runs on time.
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From page 98... ...
Transit Capacity and Quality of Service Manual, 3rd Edition small number of buses will often have all of the buses meet at a central location. Because delays in bus arrivals will often result in delays to the other bus departures (to avoid missing transfer connections)
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From page 99... ...
Person capacity defined. Transit Capacity and Quality of Service Manual, 3rd Edition The person capacity of a given transit route or facility is defined as follows: The maximum number of people that can be carried past a given location during a given time period under specified operating conditions; without unreasonable delay, hazard, or restriction; and with reasonable certainty.
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From page 100... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Vehicle Capacity The vehicle capacity of a given transit route or facility is defined as follows: The maximum number of transit vehicles (buses, trains, vessels, etc.) that can pass a given location during a given time period at a specified level of reliability.
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From page 101... ...
Exhibit 3-1 Factors Influencing Person Capacity Factors influencing vehicle passenger capacity. Factors influencing dwell time.
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Transit Capacity and Quality of Service Manual, 3'd Edition Other Capacity Considerations The following considerations are also important (2)
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From page 103... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Passenger Traffic Density As an illustration of the relative abilities of different modes to carry large numbers of passengers, the concept of passenger traffic density (passenger miles per directional route mile) is employed.
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From page 104... ...
Exhibit 3-2 Average Weekday Passenger Traffic Densities (2010) Transit Capacity and Quality of Service Manual, 3'd Edition , -- Heavy rail Light rail legacy streetcar Automated guideway Commuter rail Commuter bus large bus system Ferry Vintage trolley Medium bus system Small bus system Very small bus system Demand response 0 .0001 0 .001 0.01 0 .1 1.
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From page 105... ...
Exhibit 3-3 Factors Influencing Transit Speed Running time, passenger service time, and delay are the main components of transit speed. The number of stops along a route influences transit speed in several ways.
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From page 106... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Illustrative Transit Speeds Exhibit 3-4 shows ranges of average system speeds (revenue miles per revenue hour) by mode in 2010, along with median speeds, based on all transit agencies reporting to the NTD (7)
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From page 107... ...
Transit Capacity and Quality of Service Manual, 3rd Edition A number of observations can be made about Exhibit 3-4: • Higher speeds, regardless of mode, typically reflect long stop or station spacings and relatively high operating speeds. • The modes with the highest median speeds also tend to operate in environments that provide some degree of separation from other traffic.
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From page 108... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Finance & Purchasing Vehicle quality Vehicle age .. Maintenance Vehicle availability Environment Vehicle breakdowns Snow/ice Track/guideway maintenance Extreme heat -- -- -1 Human Resources Leaffall Driver availability Ca!
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From page 109... ...
Exhibit 3-6 Illustrative Time-ofDay Variations in Transit Demand Transit Capacity and Quality of Service Manual, 3'd Edition 3. PASSENGER DEMAND CHARACTERISTICS It is clear from the previous section that the demand to use transit, and variations in that demand, are important factors that influence transit capacity, speed, and reliability.
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From page 110... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Despite the wide range of population sizes and land use patterns represented by these locations, all share an a.m. peak that is highest in the 7:00-8:00 hour and (except for Wausau)
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From page 111... ...
Exhibit 3-7 Illustrative Variation in Peak-Hour Demand Transit Capacity and Quality of Service Manual, 3'd Edition low-density residential areas and major activity centers may only be feasible during peak periods or at a very low frequency (hourly or worse) during off-peak periods (13)
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From page 112... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Even though the average load throughout the peak hour, relative to the peak 15 min, is fairly even, it can be seen from the exhibit that there are considerable variations from one train to the next. Furthermore, the average load during the peak 15 min is 35 passengers per train higher than the average for the peak hour.
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From page 113... ...
Exhibit 3-8 presents residential densities based on net acres. The "transit-supportive area" definition used in Chapter 5 is based on gross acres.
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Transit Capacity and Quality of Service Manual, 3'd Edition Transit Service Local bus, 1 bus/h Local bus, 2 bus/h Local bus, 6 bus/h Light rail, 5-min peak headway Rapid transit, 5-min peak headway Commuter rail, 20 trains/day Minimum Residential Density 4.5 dwelling units/net acre 7 dwelling units/net acre 15 dwelling units/net acre 9 dwelling units/net acre in 25-100 mi2 corridor 12 dwelling units/net acre in 100-150 mi2 corridor 1-2 dwelling units/net acre CBD Commercial/Office Density 5-8 million ft 8-20 million fe 20-50 million fe 35-50 million fe (20 million fe if 100% at-grade) >50 million ft2 >100 million ft2 Sources : Pushkarev and Zupan (20)
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From page 115... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Transit-Oriented Development Transit -oriented developments (TO Ds) can be good generators of transit trips because many of the density and demographic characteristics that are indicative of higher propensities of transit use are found there.
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From page 116... ...
Transit Capacity and Quality of Service Manual, 3'd Edition • When transit availability at a site was high (in terms of frequency and number of routes, although the criteria are not specifically stated in TCRP Report 95) , VTRs were 14 percentage points higher than when transit availability was medium or low-in other words, the presence of good transit service was correlated with better overall TDM program results.
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From page 117... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 4. DWELL TIME DEFINITION For the purposes of the TCQSM, dwell time is defined as the time spent at a stop or station serving passenger movements, including the time required to open and close the doors.
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From page 118... ...
Transit Capacity and Quality of Service Manual, 3'd Edition DWELL TIME VARIABILITY Dwell time variability-the variation in dwell times between successive vehicles using a stop or station-is an important factor influencing both transit reliability and capacity. Dwell time variability can arise from, among other reasons: • Variations in passenger demand for a particular route over the course of 15 min, 30 min, or an hour; • Variations in passenger demand between different routes sharing the same stop; • Irregularities in maintaining the planned schedule or headway, which can result in more passengers accumulating when a transit vehicle runs late, causing it to fall farther behind schedule; • Crowded conditions on board a vehicle, which causes passengers to board and alight more slowly than normal; • Wheelchair and lift deployment, and bicycle rack usage; and • Driver interactions with passengers (e.g., answering questions, fare disputes)
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From page 119... ...
Exhibit 3-10 Illustrative Impact of Dwell Time on Bus Facility Capacity Exhibit 3-11 Illustrative Impact of Bus Dwell Time Variability on Capacity Source: Note: Source: Note: Transit Capacity and Quality of Service Manual, 3'd Edition 100% c: 0 E 90% "'C c: 8 80% ..
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Transit Capacity and Quality of Service Manual, 3'd Edition headway. Exhibit 3-13 shows the impact of operating margin (an allowance for longerthan-average dwells and other irregularities)
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From page 121... ...
Exhibit 3-14 Illustrative Impact of Dwell Time on Average Bus Speed Exhibit 3-15 Illustrative Impact of Dwell Time on Average Train Speed Transit Capacity and Quality of Service Manual, 3'd Edition ILLUSTRATIVE IMPACTS OF DWELL TIME ON SPEED Exhibit 3-14 and Exhibit 3-15 illustrate the effects of increasing dwell time on bus and rail speeds, respectively, for the stated conditions. Dwell time has a smaller impact on busway speed than for urban street speeds due to the longer stop spacing typically found on busways.
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From page 122... ...
Transit Capacity and Quality of Service Manual, 3'd Edition 5. OPERATING ENVIRONMENT Chapter 2, Mode and Service Concepts, introduced four main types of operating environments for transit vehicles.
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Exhibit 3-16 Impacts of Other Modes on Transit Speed and Capacity Transit Capacity and Quality of Service Manual, 3rd Edition capacity can be constrained when a sharp curve, downgrade, or policy speed restriction occurs just before a station, causing trains to enter the station more slowly or to begin to decelerate sooner than they would have otherwise. Exhibit 3-16 summarizes the magnitudes of the traffic interactions associated with each guideway type.
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From page 124... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Interaction Other modes on transit Transit on other modes Motorized Vehicles • Traffic congestion delays transit vehicles operating in mixed traffic • Traffic may delay buses reentering roadway from bus stops • Day-to-day variation in traffic volumes and delays affects transit travel time and reliability • Buses are equivalent to 2 cars in terms of their effect on roadway capacity • Transit vehicles stopped in travel lane at bus stops reduce available roadway capacity and create delay • Transit signal priority reallocates green time, with potential capacity and delay impacts {both Bicyclists • May delay buses sharing a lane with bicycles • Bicyclists delay buses reentering roadway from bus stops • Bicycle environment quality influences ability of transit passengers to bike to transit service • Heavy vehicle volume and speed in curb lane {including transit vehicles) negatively impacts bicycle quality of service • Stopped transit vehicles may delay bicyclists or force them to shift lanes • Bicyclists and buses have similar average speeds, creating leapfrog passing patterns when sharing positive and negative)
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From page 125... ...
Exhibit 3-18 Illustrative Impact of Traffic Signalization on Bus Facility Capacity Transit Capacity and Quality of Service Manual, 3'd Edition The gjC ratio is 1.00 for bus stops not located in the vicinity of a traffic signal.
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Transit Capacity and Quality of Service Manual, 3'd Edition 100% r -- c: 90% 0 :e "'0 80% c: 0 u 70% |
From page 127... ...
Exhibit 3-21 Illustrative Impact of Station Approach Grade and Speed on Line Capacity Transit Capacity and Quality of Service Manual, 3rd Edition they result in low capacities, low speeds, and poor reliability. Capacities are highest when only transit vehicles are allowed to use the curb lane (general traffic vjc = 0)
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From page 128... ...
Transit Capacity and Quality of Service Manual, 3'd Edition The exhibit shows that both modes are generally sensitive to the increased traffic control and traffic delay effects of less-exclusive operating environments, but there are a few differences. Bus operations at or near capacity in a street median, typically involving high volumes of buses, generally do not allow transit signal priority or preemption to be employed, as it would be too disruptive to cross-street traffic and pedestrian operations.
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From page 129... ...
Exhibit 3-23 Illustrative Impacts of Traffic Signals on Bus Speeds Transit Capacity and Quality of Service Manual, 3rd Edition ILLUSTRATIVE IMPACTS OF OPERATING ENVIRONMENT ON SPEED Traffic Control Exhibit 3-23 depicts the impact of traffic signals on bus speeds in semi-exclusive and mixed traffic environments. (Although calculated specifically for buses, streetcar operation would be similar.)
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From page 130... ...
Transit Capacity and Quality of Service Manual, 3'd Edition 100% c :~ 90% "'C c 8 80% ~ 70% co ()
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Exhibit 3-25 Illustrative Impact of Operating Environment on Average Transit Speed Reliability is discussed in more detail in Chapter 4, Quality of Service Concepts.
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From page 132... ...
Transit Capacity and Quality of Service Manual, 3'd Edition 6. STOP AND STATION CHARACTERISTICS VEHICLE-PLATFORM INTERFACE Factors involving the vehicle-platform interface that affect transit speed and capacity include: • Height differential between the vehicle floor and the platform, • Platform position relative to the guideway, and • Number of transit vehicles that can stop simultaneously.
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From page 133... ...
With proof-of-payment fare collection, passengers purchase their fare prior to boarding and can be asked to show proof-ofpayment during their trip, with a potential fine if they are traveling without a valid fare. Transit Capacity and Quality of Service Manual, 3rd Edition vs.
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Transit Capacity and Quality of Service Manual, 3'd Edition 1: 100% 0 ·.;::; 90% :c 1: 80% 0 u Q)
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From page 135... ...
Exhibit 3-28 Illustrative Impact of Number and Type of Loading Areas on Bus Facility Capacity Transit Capacity and Quality of Service Manual, 3rd Edition Type and Number of Loading Areas Exhibit 3-28 illustrates how bus facility capacity increases as the number of loading areas provided at the critical stop increase. With 1-3 loading areas, for the conditions used to develop the exhibit, on-line stops provide the greatest capacity, as buses are not delayed by other traffic when they are ready to continue after serving passengers.
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From page 136... ...
Transit Capacity and Quality of Service Manual, 3'd Edition result in average speeds 20% or more higher than with exact-change fare collection. However, the type of operating environment has a greater impact on speed than the choice of fare collection method.
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Exhibit 3-30 Illustrative Impact of Stop Spacing on Average Transit Speed 100% s: 0 90% :~ -g 80% 0 u Cll 70% "' nl In 60% ....
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Transit Capacity and Quality of Service Manual, 3'd Edition 7.
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From page 139... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 14. Hamburger, W.S.
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From page 140... ...
Transit Capacity and Quality of Service Manual, 3'd Edition 27. Kuzmyak, J.R., J.E.
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