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From page 30... ... CHAPTER FOCUS Chapter 3 contains detailed information for 26 signal performance measures. After practitioners have applied the selection process introduced in Chapter 2, they should use the information in this chapter to learn more about the signal performance measures that have been chosen (i.e., required inputs, resulting outputs, example applications, and additional references) Read the entire page →
From page 31... ... EXHIBIT 3-1 provides descriptions of the 26 signal performance measures and list example uses. EXHIBIT 3-2 summarizes inputs and outputs for all 26 signal performance measures in a single reference table. Read the entire page →
From page 36... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.1 COMMUNICATION STATUS 1 2 43 5 CATEGORY STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify communication equipment that is malfunctioning. • Compare different types of communication. Read the entire page →
From page 37... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES Communications technology can be used to connect equipment at a signalized intersection (i.e., controller, cameras, ITS equipment) both to other signalized intersections for coordination purposes and/or to a central system for monitoring. Read the entire page →
From page 38... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.2 FLASH STATUS 1 2 43 5 CATEGORY STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections operating in flash. • Determine frequency and duration of flash events to identify cause(s) Read the entire page →
From page 39... ... DESCRIPTION Flash is a mode of operation that effectively turns a traffic signal into a two-way or four-way stop-controlled intersection by flashing the traffic signal displays (either yellow or red) at a constant rate. Read the entire page →
From page 40... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.3 POWER FAILURES STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify power equipment that is malfunctioning. • Identify locations that can benefit from back-up power supply (BPS) Read the entire page →
From page 41... ... DESCRIPTION Power failures can cause traffic signal outages, so agencies sometimes install back-up power supply (BPS) systems to allow traffic signal controllers to continue operating for a period of time. Read the entire page →
From page 42... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.4 DETECTION SYSTEM STATUS STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify detection equipment that is malfunctioning. • Compare different types of detection. Read the entire page →
From page 43... ... DESCRIPTION Detection is used at a signalized intersection to determine the presence of transportation system users, so that the traffic signal controller can allocate right-of-way safely and efficiently. Broken detection typically defaults "on" to prevent users from being skipped, but this can result in inefficiencies when a phase receives more time than needed. Read the entire page →
From page 44... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.5 VEHICLE VOLUMES STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify time-of-day plan adjustments. • Identify intersections with high vehicle volumes (which can be compared to capacity) Read the entire page →
From page 45... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES Volume data can be useful when programming signal timing values or troubleshooting detection issues, and is also often collected for planning purposes. This metric reports the number of vehicles (or bicycles, depending on available detection) Read the entire page →
From page 46... ... EXAMPLE USE 1 When are the peak traffic periods and what is their duration? EXHIBIT 3-7 shows northbound and southbound flow rates (calculated using 15-minute volumes) Read the entire page →
From page 47... ... EXAMPLE USE 2 How were traffic volumes impacted during a special event? During the total solar eclipse on August 21, 2017, the Oregon Department of Transportation (ODOT) Read the entire page →
From page 48... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.6 PHASE TERMINATION STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify phases that potentially require an adjustment to green time (proxy for split failures) Read the entire page →
From page 49... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES Actuated phases terminate either because there is a gap in traffic or because the phase has reached its maximum programmed time. This metric reports the reason that individual phases terminated (i.e., a gap-out, maxout, force-off, or skip) Read the entire page →
From page 50... ... EXAMPLE USE Do any phases need an adjustment to green time? EXHIBIT 3-9 shows the distribution of phase termination types aggregated into 30-minute bins, rather than for individual cycles, for each phase at an intersection. Read the entire page →
From page 51... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.7 SPLIT MONITOR STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify phases that potentially require an adjustment to green time (proxy for split failures) Read the entire page →
From page 52... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES This metric is used to report detailed information about the performance of an individual phase. Using high-resolution data, it combines a plot of phase duration with several other pieces of information– termination type, pedestrian phase service, and programmed splits. Read the entire page →
From page 53... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.8 SPLIT FAILURES STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify phases and/or intersections experiencing split failures (i.e., requiring adjustments to green time or detection settings) Read the entire page →
From page 54... ... DESCRIPTION A "split failure" is an occurrence when there are unserved vehicles at the end of green. A phase that has multiple consecutive split failures is very likely to have an operational problem that can potentially be fixed by increasing the split (or the max time under fully actuated control) Read the entire page →
From page 55... ... DETECTION NEEDS REFERENCES CALIBRATION • For calculating GOR and ROR, stop bar presence detection is required. Lane-by-lane detection provides more accurate results than detectors tied together across lanes; multilane detectors may over-estimate occupancy ratios. Read the entire page →
From page 56... ... EXAMPLE USE 1 Are there corridors that can benefit from split adjustments? During which time periods? Read the entire page →
From page 57... ... EXAMPLE USE 2 Did implementation of an adaptive cycle length improve the number of split failures? EXHIBIT 3-14 depicts the number of split failures along a five-intersection corridor before and after implementation of an adaptive cycle length. Read the entire page →
From page 58... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.9 ESTIMATED VEHICLE DELAY STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify phases/intersections with high vehicle delay. • Identify phases/intersections with high bicycle delay (depending on available detection) Read the entire page →
From page 59... ... DESCRIPTION Vehicle delay is a metric that is commonly modeled by agencies to identify whether intersection operations are acceptable. Using high-resolution data, this metric can be computed directly. Read the entire page →
From page 60... ... DETECTION NEEDS CALIBRATION REFERENCES • Arrival and departure models require advance detection to measure arrival times. • HCM model requires detection that is capable of counting volumes (refer to Section 3.5: Vehicle Volumes) Read the entire page →
From page 61... ... EXAMPLE USE Did split adjustments improve vehicle delay? EXHIBIT 3-16 shows cumulative distributions of maximum vehicle delay for eight phases before and after split adjustments. Read the entire page →
From page 62... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.10 ESTIMATED QUEUE LENGTH STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify locations and durations of long queues. Read the entire page →
From page 63... ... DESCRIPTION Long queues can interfere with progression, increase vehicle delay, and cause safety issues. Queue management is particularly important at tightly spaced intersections, interchanges, and congested locations. Read the entire page →
From page 64... ... EXAMPLE USE During what times of day is an approach experiencing long queues? EXHIBIT 3-17 is a plot of the maximum queue lengths observed during individual cycles over a 24-hour period for a signalized approach in Indiana. Read the entire page →
From page 65... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.11 OVERSATURATION SEVERITY INDEX STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify oversaturated intersections and possible mitigations. Read the entire page →
From page 66... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES The temporal oversaturation severity index (TOSI) and spatial oversaturation severity index (SOSI) Read the entire page →
From page 67... ... EXAMPLE USE Did signal timing adjustments improve oversaturated conditions (i.e., downstream blockages and split failures) Read the entire page →
From page 68... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.12 PEDESTRIAN VOLUMES STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify time-of-day plan adjustments. • Identify intersections with high pedestrian volumes. Read the entire page →
From page 69... ... DESCRIPTION At locations with high pedestrian demand, it may be a priority to keep the cycle length low (to prevent delay) and maintain splits that are longer than the pedestrian clearance intervals (to prevent dropped coordination) Read the entire page →
From page 70... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.13 PEDESTRIAN PHASE ACTUATION AND SERVICE STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections with high frequencies of pedestrian phase service. • Identify detection equipment that is malfunctioning. Read the entire page →
From page 71... ... DESCRIPTION Pedestrian actuations can serve as a proxy for pedestrian volumes at intersections without pedestrian-specific detection. At locations with low pedestrian actuations, a practitioner may decide to program vehicle splits that are less than the time required to serve the pedestrian clearance intervals (if allowed by the controller) Read the entire page →
From page 72... ... EXAMPLE USE 2 Will an exclusive pedestrian phase impact how often pedestrians request service (using the pedestrian push button) Read the entire page →
From page 73... ... EXAMPLE USE 3 Which locations (i.e., signalized intersections and corridors) have high rates of pedestrian activity? Read the entire page →
From page 74... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.14 ESTIMATED PEDESTRIAN DELAY STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify phases/intersections with high pedestrian delay. Read the entire page →
From page 75... ... DESCRIPTION If there are certain times of day or certain intersections with high levels of pedestrian delay, an agency can consider implementing measures that prioritize pedestrians. These can include pedestrian-specific treatments such as Rest in Walk, leading pedestrian intervals (LPIs) Read the entire page →
From page 76... ... EXAMPLE USE 2 What level of service do pedestrians experience at a signalized intersection? EXHIBIT 3-24 is a chart of pedestrian delay at a fully actuated, non-coordinated traffic signal. Read the entire page →
From page 77... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.15 ESTIMATED PEDESTRIAN CONFLICTS STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections with a high number of potential conflicts between vehicles and pedestrians. Read the entire page →
From page 78... ... Detectors past the stop bar are required for accurate identification of turning vehicles that conflict with the pedestrian crossings. These detection zones should be small (and lane-by-lane if possible) Read the entire page →
From page 79... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.16 YELLOW/RED ACTUATIONS STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections with high numbers of red-light-running vehicles and/or severe violations. Read the entire page →
From page 80... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES Red light running is a safety concern. If vehicles are frequently running the red light, an agency should consider countermeasures that will reduce the likelihood of vehicles entering the intersection on red. Read the entire page →
From page 81... ... EXAMPLE USE Are there times of day with high numbers of vehicles running the red light? EXHIBIT 3-26 shows 24 hours of yellow and red actuations for a phase. Read the entire page →
From page 82... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.17 RED-LIGHTRUNNING (RLR) OCCURRENCES STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections with high numbers of red-light-running vehicles and/or severe violations. Read the entire page →
From page 83... ... RLR occurrences are determined based on maximum values of tarr and ton (to avoid counting RTOR and left-turn clipping) Read the entire page →
From page 84... ... EXAMPLE USE Did a split increase result in a reduced number of red-light-running vehicles? EXHIBIT 3-28 shows RLR as a daily count for a single phase over a 5-month period. Read the entire page →
From page 85... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.18 EFFECTIVE CYCLE LENGTH DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Confirm coordinated plans are operating as intended. • Confirm how adaptive systems are adjusting effective cycle lengths. Read the entire page →
From page 86... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES Effective cycle length is the amount of time used to serve all the phases at an intersection. Each phase will usually have an opportunity for service within a cycle, unless it is skipped (or omitted) Read the entire page →
From page 87... ... EXAMPLE USE What are the seasonal impacts on effective cycle length for a corridor utilizing an adaptive system? EXHIBIT 3-29 shows cycle lengths over several months for a corridor in Utah that uses an adaptive cycle length algorithm. Read the entire page →
From page 88... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.19 PROGRESSION QUALITY STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections/corridors with poor progression (i.e., low POG, platoon ratios, or arrival types) Read the entire page →
From page 89... ... Advance detection upstream of a signalized approach is used to estimate vehicle arrivals at the stop bar. Detectors located at the beginning of the decision zone (approximately 5 seconds of travel time from the stop bar) Read the entire page →
From page 90... ... CALIBRATION REFERENCES An adjustment is made to the vehicle detection times to estimate the time each vehicle arrives at the stop bar. This can be done by adding the travel time to the detection time. Read the entire page →
From page 91... ... Did offset adjustments increase or decrease progression quality along a corridor? EXHIBIT 3-32 summarizes POG before and after offset adjustments on a corridor in Utah. Read the entire page →
From page 92... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.20 PURDUE COORDINATION DIAGRAM STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify when vehicles are arriving during the cycle (i.e., on green or red) for a particular phase or overlap at an intersection. Read the entire page →
From page 93... ... DESCRIPTION While similar to Progression Quality metrics (see Section 3.19: Progression Quality) , the Purdue Coordination Diagram (PCD) Read the entire page →
From page 94... ... DETECTION NEEDS CALIBRATION REFERENCES Advance detection upstream of a signalized approach is used to estimate vehicle arrivals at the stop bar. Detectors located at the beginning of the decision zone (approximately 5 seconds of travel time from the stop bar) Read the entire page →
From page 95... ... EXAMPLE USE Did offset adjustments improve progression for a particular approach at an intersection? The Virginia Department of Transportation adjusted offsets along a corridor near Charlottesville, Virginia. Read the entire page →
From page 96... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.21 CYCLIC FLOW PROFILE STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections/corridors with poor progression. Read the entire page →
From page 97... ... DESCRIPTION This metric reports the distribution of green time and vehicle arrivals during an "average" cycle over some time period. The information is similar to that in the Purdue Coordination Diagram (PCD, Section 3.20: Purdue Coordination Diagram) Read the entire page →
From page 98... ... DETECTION NEEDS CALIBRATION REFERENCES Advance detection upstream of a signalized approach is used to estimate vehicle arrivals at the stop bar. Detectors located at the beginning of the decision zone (approximately 5 seconds of travel time from the stop bar) Read the entire page →
From page 99... ... EXAMPLE USE How much and at which locations did offset adjustments improve progression along a corridor? EXHIBIT 3-36 shows cyclic flow profiles for an eight-intersection corridor with each intersection having its own flow profile. Read the entire page →
From page 100... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.22 OFFSET ADJUSTMENT DIAGRAM STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify corridors with potential for progression improvement from offset adjustments. • Estimate impact of proposed offset adjustments. Read the entire page →
From page 101... ... DESCRIPTION This metric reports potential progression quality for individual coordinated approaches along a corridor. If calculated for approaches along several corridors, it can be used to quickly determine locations where an agency will have the greatest return on investment when adjusting offsets. Read the entire page →
From page 102... ... CALIBRATION REFERENCES An adjustment is made to the vehicle detection times to estimate the time each vehicle arrives at the stop bar. This can be done by adding the travel time to the detection time. Read the entire page →
From page 103... ... EXAMPLE USE What is the potential for progression improvement along a coordinated corridor? EXHIBIT 3-38 is an example Offset Adjustment Diagram for a corridor with five intersections: 10 approaches labeled eastbound (eb) Read the entire page →
From page 104... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.23 TRAVEL TIME AND AVERAGE SPEED STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify corridors with high/low travel times and speeds. Read the entire page →
From page 105... ... Some detection may be required depending on the type of technology being used to track vehicles. DESCRIPTION Travel time and speed are metrics that can be shared with decision-makers and the public to effectively communicate signal timing impacts on vehicles, pedestrians, bicycles, and other modes of travel. Read the entire page →
From page 106... ... REFERENCES • Day et al. Read the entire page →
From page 107... ... EXAMPLE USE 2 Where are the most critical intersections based on travel times and reliability? EXHIBIT 3-40 is an example of aggregated travel time data. Read the entire page →
From page 108... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.24 TIME-SPACE DIAGRAM STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify corridors with small green bands (i.e., poor opportunities for progression) Read the entire page →
From page 109... ... DESCRIPTION The Time-Space Diagram is a classic representation of signal coordination and a basic design tool for creating timing plans. The y-axis represents space (linear distance along a corridor) Read the entire page →
From page 110... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.25 PREEMPTION DETAILS STAKEHOLDERS ORGANIZATIONAL PLANNING DESIGN AND CONSTRUCTION OPERATIONS MAINTENANCE DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections with high numbers of preemption events. • Identify intersections with preemption events causing high delay for other transportation system users. Read the entire page →
From page 111... ... DESCRIPTION Preemption is the interruption of normal operations to serve a preferred vehicle (e.g., train, emergency vehicle) Read the entire page →
From page 112... ... EXAMPLE USE Are vehicles being consistently cleared from the railroad tracks during the track clearance green interval? EXHIBIT 3-42 shows railroad preemption details overlaid with occupancy data for detection zones located between a signalized intersection and railroad tracks. Read the entire page →
From page 113... ... OBJECTIVES EQUIPMENT HEALTH VEHICLE DELAY VEHICLE PROGRESSION PEDESTRIANS BICYCLES RAIL EMERGENCY VEHICLES TRANSIT TRUCKS SAFETY 3.26 PRIORITY DETAILS DATA SOURCES VENDOR-SPECIFIC CENTRAL SYSTEM LOWRESOLUTION AVI/AVL/SEGMENT SPEED CONTROLLER HIGHRESOLUTION APPLICATIONS • Identify intersections with high numbers of priority events. • Identify intersections with priority events causing high delay for other transportation system users. Read the entire page →
From page 114... ... DESCRIPTION DETECTION NEEDS CALIBRATION REFERENCES Priority is the preferential treatment of one vehicle class (e.g., transit, trucks) over another (e.g., cars) Read the entire page →
From page 115... ... EXAMPLE USE 2 How often are priority requests being made on a bus rapid transit corridor? EXHIBIT 3-44 summarizes priority request details for a bus rapid transit (BRT) Read the entire page →
From page 116... ... 3.27 REFERENCES 1. Brennan, T.M., C.M. Read the entire page →
From page 119... ... 45. Smaglik, E.J., D Read the entire page →

From page 30...

... CHAPTER FOCUS Chapter 3 contains detailed information for 26 signal performance measures. After practitioners have applied the selection process introduced in Chapter 2, they should use the information in this chapter to learn more about the signal performance measures that have been chosen (i.e., required inputs, resulting outputs, example applications, and additional references)