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From page 501... ... 499 INTRODUCTION This appendix shows how a travel time reliability monitoring system (TTRMS) can be used to address questions about network reliability. Read the entire page →
From page 502... ... 500 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY OVERVIEW OF USE CASES The use cases fit the template shown in Table D.1. The template calls for a definition of the type of person asking the question (user) Read the entire page →
From page 503... ... 501 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Agency administrators and planners typically want summary information about system performance. They want to know how various factors (e.g., growing demand or inclement weather) Read the entire page →
From page 504... ... 502 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.3. USE CASES FOR A TRAVEL TIME RELIABILITY MONITORING SYSTEM Category Subgroup Use Case System administrators and planners Administrators AE1: See what factors affect reliability AE2: Assess the contributions of the factors AE3: View the travel time reliability of a subarea AE4: Assist planning and programming decisions AE5: Document agency accomplishments AE6: Assess progress toward long-term reliability goals AE7: Assess the reliability impact of a specific investment Planners AP1: Find the facilities with highest variability AP2: Assess the reliability trends over time for a route AP3: Assess changes in the hours of unreliability for a route AP4: Assess the sources of unreliability for a route AP5: Determine when a route is unreliable AP6: Assist rural freight operations decisions Roadway network managers and users Managers MM1: View historical reliability impacts of adverse conditions MM2: Be alerted when the system is struggling with reliability MM3: Compare a recent adverse condition with prior ones MM4: Gauge the impacts of new arterial management strategies MM5: Gauge the impacts of new freeway management strategies MM6: Determine pricing levels using reliability data Drivers -- constrained trips MC1: Understand departure times and routes for a trip MC2: Determine a departure time and route just before a trip MC3: Understand the extra time needed for a trip MC4: Decide how to compensate for an adverse condition MC5: Decide en route whether to change routes Drivers -- unconstrained trips MU1: Determine the best time of day to make trip MU2: Determine how much extra time is needed Transit system Transit planners TP1: Determine routes with the least travel time variability TP2: Compare exclusive bus lanes with mixed-traffic operations Transit schedulers TS1: Acquire reliability data for building schedules TS2: Choose departure times to minimize arrival uncertainty Transit operators TO1: Identify routes with the poorest reliability TO2: Review reliability for a route TO3: Examine the potential impacts of bus priority on a route TO4: Assess a mitigating action for an adverse condition Transit passengers TC1: Determine the on-time performance of a trip TC2: Determine an arrival time just before a trip TC3: Determine a friend's arrival time TC4: Understand a trip with a transfer Freight system Freight service providers FP1: Identify the most reliable delivery time FP2: Estimate a delivery window FP3: Identify how to maximize the probability of an on-time delivery FP4: Assess the on-time probability for a scheduled shipment FP5: Assess the impacts of adverse highway conditions FP6: Determine the start time for a delivery route FP7: Find the departure time and routing for a set of deliveries FP8: Solve the multiple vehicle routing problem under uncertainty FP9: Alter delivery schedules in real time Freight customers FC1: Minimize shipping costs due to unreliability FC2: Determine storage space for just-in-time deliveries FC3: Find the lowest-cost reliable origin FC4: Find the warehouse site with the best distribution reliability Read the entire page →
From page 505... ... 503 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY AGENCY ADMINISTRATORS AND PLANNERS This section describes the use cases that agency administrators and planners might employ to learn about system reliability, determine what factors cause the system to be unreliable, and track reliability performance over time. Agency Administrators Agency administrators are responsible for making decisions about how to expand the network and how to operate it. Read the entire page →
From page 506... ... 504 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 10 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx shows the three routes: I-5 (Route 1) , I-805/SR-15/I-5 (Route 2) Read the entire page →
From page 507... ... 505 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY done automatically. (The Guide and case studies illustrate how this can be done and the challenges involved.) Read the entire page →
From page 508... ... 506 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.2. Five-minute average weekday travel rates for three routes in San Diego. Read the entire page →
From page 509... ... 507 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.3. Five-minute average weekday travel rates plotted against VMT per hour for three routes in San Diego. Read the entire page →
From page 510... ... 508 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Obviously, changing these criteria affects the selection process. Basically, it changes the separation between observations that are considered "normal, high congestion" and those that are attributed to high demand on top of high congestion. Read the entire page →
From page 511... ... 509 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY travel rate observed for the entire year. Because the number of observations varied from one 5-minute period to another, the SVs were divided by the number of observations n (effectively creating an average per observation so that the results would be comparable among the 5-minute time periods) Read the entire page →
From page 512... ... 510 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.5. CDFs by regime for the three routes in San Diego. Read the entire page →
From page 513... ... 511 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Assess the Contributions of the Factors (AE2) The objective in this use case is to determine how various factors affect system reliability. Read the entire page →
From page 514... ... 512 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY that even though Figure D.5 suggests the SR-15 route may have the lowest average travel rates most of the day, the most reliable route is I-5. Figure D.4 suggests that SR-163 is the least reliable route. Read the entire page →
From page 515... ... 513 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY help manage the severity of these events when they occur during congested operation. In this case, for the demand conditions there is a significant shift in the travel rates from 50 to 80 s/mi even at the zero percentile. Read the entire page →
From page 516... ... 514 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.6. SEMIVARIANCES FOR EACH REGIME FOR THREE ROUTES IN SAN DIEGO Route Condition Normal Demand Weather Special Events Incidents ∑(SV* Read the entire page →
From page 517... ... 515 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY different from the CDFs for normal operation under less-congested conditions. Incidents, weather, special events, and higher-than-normal demand all have a significant effect on reliability during highly congested conditions. Read the entire page →
From page 518... ... 516 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 is to select the subarea of interest. In this case it is the same portion of the San Diego metropolitan area. Read the entire page →
From page 519... ... 517 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Returning to Table D.6 and reexamining the average SVs provides a more detailed sense of the similarities and differences among the regimes. For example, the SR-15 route has many of the highest average SV values (e.g., 3,751 for weather under high congestion; 3,032 for incidents under high congestion) Read the entire page →
From page 520... ... 518 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY A description of the use case can build off AE1. Imagine a hypothetical situation in which the conditions portrayed for SR-163 are the status of that route at the end of 2009; the SR-15 conditions are for that same route (SR-163) Read the entire page →
From page 521... ... 519 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Even though the agency may be doing a better job of managing the consequences of the events, the distribution of the severity of the events may make it difficult to see the impacts in a simple measure like the SV. Note in Table D.11 that the SV values for the special event and incident events show increases in the SV values from Year X to Year Y and then decreases from Year Y to Year Z Read the entire page →
From page 522... ... 520 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 37 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx incident events show increases in the SV values from Year X to Year Y and then decreases from Year Y to Year Z Whether progress has been made is unclear. Read the entire page →
From page 524... ... 522 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Table D.11 and Figure D.7 can be used again for this purpose. Assuming the same hypothetical situation previously described, these two exhibits show how the performance of this hypothetical facility has changed in response to agency treatments. Read the entire page →
From page 525... ... 523 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.13. CONTRIBUTORS TO UNRELIABILITY Congestion Level Nonrecurring Event All Vehicle Hours of Delay (%) Read the entire page →
From page 526... ... 524 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY This use case is identical to AE4 or AE5 except that the focus is on a region or system instead of a route. The steps in the analysis are effectively the same, and the results would be interpreted in the same manner. Read the entire page →
From page 527... ... 525 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY the impact can be assessed. The procedure involved is similar to that presented in AE4. Read the entire page →
From page 528... ... 526 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Assess the Reliability Trends over Time for a Route (AP2) An agency planner wants to see how travel time variability is changing over time for a route. Read the entire page →
From page 529... ... 527 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY The data used in AE4 can be repurposed here to answer the question posed. As indicated there, Table D.11 shows the average SV values by regime for each of three years for a hypothetical facility. Read the entire page →
From page 530... ... 528 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Notice that almost all of the hours of unreliable operation are during the high-congestion, normal regime. Moreover, those hours are largely unchanged across the years. Read the entire page →
From page 531... ... 529 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 3 involves labeling each of the data points based on the regime to which it belongs: combinations of nominal loading condition (demand-to-capacity ratio) and nonrecurring event (including none) Read the entire page →
From page 532... ... 530 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 59 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx Figure D.10. Plots of average travel time against time of day and VMT per hour, I-8 westbound, San Diego. Read the entire page →
From page 533... ... 531 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 60 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx Figure D.11. Average semivariance (SV) Read the entire page →
From page 534... ... 532 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Several trends are clear from Tables D.21 and D.22: • Although many 5-minute time periods are spent in the normal condition, the SV is never particularly large, reaching only 45 in the high-congestion, normal regime; • The regime with the highest SV is high congestion, weather, followed by high congestion, incidents; moderate congestion, special events; moderate congestion, incidents; and low congestion, weather. The SVs for all other regimes are relatively small; • There are 99 (of a total of 1,872) Read the entire page →
From page 535... ... 533 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY This use case can be addressed using any one of the routes examined before. The metric can again be the SV, and the time frames can be those for which data were available: all of 2011 in the case of I-5, SR-15, and SR-163; and November 3, 2008, until February 27, 2009, in the case of I-8. Read the entire page →
From page 536... ... 534 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Notice that the trends are quite different for I-8 versus the other three facilities. I-8 has all of its hours of unreliable operation during nonrecurring events (weather, special events, and incidents) Read the entire page →
From page 537... ... 535 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Assist Rural Freight Operations Decisions (AP6) In this use case, an agency planner wants to help out with rural freight operations. Read the entire page →
From page 538... ... 536 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.13. Placerville to South Lake Tahoe. Read the entire page →
From page 539... ... 537 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY To address the use case, Step 1 is to select the route and area of interest. In this instance, it is US-50 from Placerville to South Lake Tahoe. Read the entire page →
From page 540... ... 538 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Table D.27 presents a summary of the travel times for each condition. One can see that the three most adverse conditions in the absence of incidents are heavy snow, snow and fog, and freezing fog. Read the entire page →
From page 541... ... 539 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.16. CDFs for trip times during adverse conditions. Read the entire page →
From page 542... ... 540 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY timely updating variable message signs with expected delay information. Knowing the impacts also helps the operator provide better pretrip information, such as anticipated speeds and delay times, and encourage people to plan ahead or take alternate routes or modes. Read the entire page →
From page 543... ... 541 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.17. Interstate 5 in Sacramento. Read the entire page →
From page 544... ... 542 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY in the southbound direction under four regimes: high congestion, normal; high congestion, weather; uncongested, normal; and uncongested, weather. Not enough data points exist for weather combined with incidents to produce meaningful CDFs. Read the entire page →
From page 545... ... 543 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.20. Daily trends in individual vehicle travel times, I-5 southbound. Read the entire page →
From page 546... ... 544 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 84 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx individual trip times can be seen. Midmorning it began to rain (at about Observation 46,000) Read the entire page →
From page 547... ... 545 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.22. Spreads in individual vehicle travel times. Read the entire page →
From page 548... ... 546 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.22 provides an example of how the 5th and 75th percentile values vary. There is some evidence that the spread between the 5th and 75th percentile travel times decreases as the 5th percentile increases. Read the entire page →
From page 549... ... 547 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.23. CDFs for individual vehicle travel times in several regimes. Read the entire page →
From page 550... ... 548 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY This use case is similar to incident detection or identification of times when the system's behavior has become unstable. As in Use Case MM1 and elsewhere, under heavy congestion or under adverse nonrecurring conditions (i.e., when the system is under stress) Read the entire page →
From page 551... ... 549 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.24. Trends in travel time percentiles and their standard deviations. Read the entire page →
From page 552... ... 550 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Compare a Recent Adverse Condition with Prior Ones (MM3) In this use case, the roadway manager wants to see if the agency did a better job of handling a recent adverse condition than it has in the past with similar adverse conditions. Read the entire page →
From page 553... ... 551 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY • January 29 at 9:30 p.m. to January 30 at 9:00 p.m.; • February 15 at 6:00 p.m. Read the entire page →
From page 554... ... 552 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Gauge the Impacts of New Arterial Management Strategies (MM4) The user wants to gauge the effectiveness of new arterial management strategies in terms of travel times and travel time variability. Read the entire page →
From page 555... ... 553 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY No data were collected during the case studies that could be used to address this use case. However, the analysis procedure is effectively identical to that used in Use Cases AE4 and AE5. Read the entire page →
From page 556... ... 554 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Understand Departure Times and Routes for a Trip (MC1) A driver wants to understand in advance the travel times and routing options for a trip that will be made frequently. Read the entire page →
From page 557... ... 555 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY synthesize individual vehicle travel times from 5-minute mean travel times obtained from loop detector data by using automatic vehicle identification data. In this case, Bluetooth data collected in Sacramento were used. Read the entire page →
From page 558... ... 556 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.26. Travel time CDFs for three routes in San Diego. Read the entire page →
From page 559... ... 557 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.35. 90TH PERCENTILE TRAVEL TIMES FOR EACH ROUTE UNDER VARIOUS CONDITIONS Route 90th Percentile Travel Time (min) Read the entire page →
From page 560... ... 558 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.27. Travel time CDFs for aggressive drivers. Read the entire page →
From page 561... ... 559 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.36. 90TH PERCENTILE TRAVEL TIMES FOR AGGRESSIVE DRIVERS FOR EACH ROUTE UNDER VARIOUS CONDITIONS Route 90th Percentile Travel Time (min) Read the entire page →
From page 562... ... 560 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY reformulated as follows: Which among the eight expected arrival times of interest will minimize the driver's travel time, and on which route? Two analyses are presented for answering this question. Read the entire page →
From page 563... ... 561 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.28. Half-hour TT-CDFs for three routes in San Diego under the normal condition. Read the entire page →
From page 564... ... 562 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY The analysis above considers all drivers. A second analysis was conducted to see what the distribution of travel times would be for aggressive (10th percentile) Read the entire page →
From page 565... ... 563 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.29. Half-hour TT-CDFs for aggressive drivers for three routes in San Diego under the normal condition. Read the entire page →
From page 566... ... 564 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Understand the Extra Time Needed for a Trip (MC3) This is a variant on the prior two use cases. Read the entire page →
From page 567... ... 565 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the origin and destination. In this use case, the ones shown in Figure D.1 are selected. Read the entire page →
From page 568... ... 566 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Decide How to Compensate for an Adverse Condition (MC4) A driver wants to know how much extra time to allow so that he or she arrives at an event on time given that the event will create congestion, or wants to be aware of the changes to the travel time because of an incident, bad weather, special event, or lane closure for a trip she or he plans to take. Read the entire page →
From page 569... ... 567 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the origin and destination. In this use case, the ones shown in Figure D.1 are selected. Read the entire page →
From page 570... ... 568 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 126 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx Figure D.32. CDF of distribution of extra time needed for three routes. Read the entire page →
From page 571... ... 569 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 128 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx Figure D.33. CDF of distribution of extra time needed for aggressive drivers for three routes. Read the entire page →
From page 572... ... 570 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.42. 90TH PERCENTILE VALUES OF EXTRA TIME NEEDED FOR THREE ROUTES Route 90th Percentile Extra Travel Time Needed (min) Read the entire page →
From page 573... ... 571 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY For the purposes of illustrating this use case, picture the following scenario. In Step 1 assume the driver is traveling on the freeway and at around 5:00 p.m., the driver reaches the junction where the three routes (SR-163, I-5, and SR-15) Read the entire page →
From page 574... ... 572 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 133 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx Figure D.34. CDF representing distribution of travel times when operating conditions change from normal to normal with incident for various driver classes for three routes. Read the entire page →
From page 575... ... 573 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.45. 90TH PERCENTILE TRAVEL TIME VALUES FOR NORMAL WITH INCIDENT OPERATING CONDITIONS FOR VARIOUS DRIVER CLASSES FOR THREE ROUTES Driver Type 90th Percentile Travel Time Normal with Incident (min) Read the entire page →
From page 576... ... 574 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 135 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx Figure D.35. CDF representing distribution of travel times when operating conditions change from weather to weather with incident for various driver classes for three routes. Read the entire page →
From page 577... ... 575 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.46. 90TH PERCENTILE TRAVEL TIMES WHEN OPERATING CONDITIONS CHANGE FROM WEATHER TO WEATHER WITH INCIDENT FOR VARIOUS DRIVER CLASSES FOR THREE ROUTES Driver Type 90th Percentile Travel Time Combined Weather and Incident (min) Read the entire page →
From page 578... ... 576 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the origin and destination. In this use case, the ones shown in Figure D.1 are selected. Read the entire page →
From page 579... ... 577 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.36. Half-hour TT-CDFs for three routes in San Diego under the normal condition, for aggressive drivers. Read the entire page →
From page 580... ... 578 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.37 presents TT-CDF plots for each route under inclement weather conditions. It can be inferred that travel times on SR-163 are highly unreliable under bad weather, and that it is best to avoid this route under these conditions. Read the entire page →
From page 581... ... 579 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.37. Half-hour TT-CDFs for three routes in San Diego under the weather condition, for aggressive drivers. Read the entire page →
From page 582... ... 580 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Determine How Much Extra Time Is Needed (MU2) A user wants to know how much extra time to allow so that he or she can arrive on time for a special event (e.g., a baseball game) Read the entire page →
From page 583... ... 581 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the origin and destination. In this use case, the ones shown in Figure D.1 are again selected. Read the entire page →
From page 584... ... 582 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY The AVL-equipped buses generate the following information for every stop: • Route ID; • Trip ID (based on factors such as the time of departure) ; • The latitude and longitude of the bus when it stops; • Stop ID of the location where the bus stops (based on the latitude and longitude of the location where it stops) Read the entire page →
From page 585... ... 583 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the routes and conditions of interest. In this case, the routes are the nine with AVL-equipped buses, and the time frame is August 2011, the month for which data were collected. Read the entire page →
From page 586... ... 584 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY TABLE D.52. STANDARD DEVIATIONS FOR DIFFERENCES FROM SCHEDULED STOP TIMES BY ROUTE Route Standard Deviation (min) Read the entire page →
From page 588... ... 586 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY As Figure D.39 shows, Route 88 performs much better than Route 7. At the 90th percentile, the buses on Route 7 are as much as 8 minutes late leaving their stops, but the buses on Route 88 are only 3 minutes late. Read the entire page →
From page 589... ... 587 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY This use case addresses an issue that lies at the heart of building good route schedules. As with the highway- (auto-) Read the entire page →
From page 590... ... 588 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY That there are challenges with schedule reliability is evident from Figure D.41. Shown are all the differences from scheduled stop times for all equipped buses and all routes for the data received. Read the entire page →
From page 591... ... 589 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 159 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx Figure D.41. Schedule deviations for Route 7 in San Diego. Read the entire page →
From page 592... ... 590 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY For qualitative affirmation that the route has schedule challenges, the on-time performance of several buses can be examined. Plotted in Figure D.43 are the schedule deviations by stop for five buses. Read the entire page →
From page 593... ... 591 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY A good sense of how much time to add to the route can be obtained by examining Figure D.44. Shown is the CDF for the lateness of buses at Stop 60, almost at the end of the route. Read the entire page →
From page 594... ... 592 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Choose Departure Times to Minimize Arrival Uncertainty (TS2) A scheduler wants to choose departure times for a route that will minimize the likelihood that the stops are not on time. Read the entire page →
From page 595... ... 593 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 176 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx The TT-PDF between 99343 and 10314 is shown in Figure D.45. The CDF is based on 115 observations of trip times between these two stops during August. Read the entire page →
From page 596... ... 594 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY A reliability monitoring system needs to give transit system service providers two types of reliability information. First, reliability metrics for general traffic along bus routes that operate in mixed traffic (more than 99% of all route miles in the United States) Read the entire page →
From page 597... ... 595 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY the greatest deviations from the scheduled stop times from the 80th percentile onward, and Route 15 has the greatest deviations from the 20th to the 80th percentiles. These differences help illustrate the fact that there is not a single right answer to the question of which route is the poorest. Read the entire page →
From page 598... ... 596 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 178 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx occurred 11 times, and for which the average travel time was 43.05 minutes with a standard deviation of 4.93 minutes. About 48% of the time (3 + 25 + 27 observations) Read the entire page →
From page 599... ... 597 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY conflicting traffic. Data on the amount of signal delay experienced by buses would help support the case for transit signal priority and justify its potential impacts on other traffic. Read the entire page →
From page 600... ... 598 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY This use case focuses on seeing if a mitigating action improves the reliability of a bus route under adverse conditions. Unfortunately, during August 2011, the time period during which the data were collected, no significant adverse conditions arose, nor were actions taken to mitigate those adverse conditions. Read the entire page →
From page 601... ... 599 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY This use case is the fundamental building block of the analysis procedures related to transit riders. It focuses on determining the on-time performance for a specific trip, from an origin stop to a destination stop, on the same bus route. Read the entire page →
From page 602... ... 600 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Of the 115 observations, the buses are late departing from the origin stop and late arriving at the destination 27 times. The average travel time in this condition is 55.15 minutes, and the standard deviation is 6.57 minutes. Read the entire page →
From page 603... ... 601 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY needed. Toward evening, the time needed drops back to 60 minutes and then to less than 50 minutes, and by about 11:00 p.m., only 40 minutes needs to be allowed. Read the entire page →
From page 604... ... 602 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Understand a Trip with a Transfer (TC4) A rider wants to find out, in advance, what time to leave and what route(s) Read the entire page →
From page 605... ... 603 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY The team hoped that all the buses on Routes 11 and 7 would be equipped with monitoring devices, but such was not the case. Only about half of them were. Read the entire page →
From page 606... ... 604 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Figure D.48. Distributions of relative departure times and travel times between stops. Read the entire page →
From page 607... ... 605 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY they are skewed toward longer values. For Route 7, the distribution is almost uniform between 120 and 300 seconds (2 to 5 minutes) Read the entire page →
From page 608... ... 606 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY developed by the data analysis. A large-scale simulation would have been needed to sample all of the records in the two data sets; but by sampling the data sets directly, the team could ensure that the combinations of values used in the simulation were combinations observed in the field, not ones created through a synthesizing process. Read the entire page →
From page 609... ... 607 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY FREIGHT USE CASES This section presents use cases for freight service providers and customers. The vehicles involved are assumed to be trucks and vans, but the methodologies pertain to other freight modes, such as rail, water, and air freight. Read the entire page →
From page 610... ... 608 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Travel time reliability matters to all these carriers, especially the ones that have promised delivery times, like FedEx. Shippers and receivers often specify pickup and delivery windows because they are ship or receive multiple items per day. Read the entire page →
From page 611... ... 609 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY weekdays in 2009, 100 truck trips were simulated, one for each percentile based on the average travel time observed. Step 3 is to define what is meant by the on-time delivery window. Read the entire page →
From page 612... ... 610 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY during the p.m. peak. Read the entire page →
From page 613... ... 611 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY By reviewing the plot in Figure D.54, it is possible to see that the smallest on-time window occurs at 10:15 a.m. and lasts for approximately 2.5 minutes. Read the entire page →
From page 614... ... 612 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the origin and destination. In this use case, the O–D pair shown in Figure D.1 was used again. Read the entire page →
From page 615... ... 613 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Assess the On-Time Probability for a Scheduled Shipment (FP4) A user wants to obtain the probability of an on-time arrival based on a scheduled departure time, a desired delivery time, and route. Read the entire page →
From page 616... ... 614 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the origin, destination, and route of interest. In this use case, the O–D pair shown in Figure D.1 was used again. Read the entire page →
From page 617... ... 615 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Determine the Start Time for a Delivery Route (FP6) This use case focuses on a truck making multiple deliveries. Read the entire page →
From page 618... ... 616 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Find the Departure Time and Routing for a Set of Deliveries (FP7) A trucking company wants to plan the schedule for a delivery route (tour) Read the entire page →
From page 619... ... 617 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Solve the Multiple Vehicle Routing Problem Under Uncertainty (FP8) A user wants to create a set of routes (tours) Read the entire page →
From page 620... ... 618 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Freight Customers The following use cases demonstrate monitoring system functionalities that are helpful for freight customers. Minimize Shipping Costs Due to Unreliability (FC1) Read the entire page →
From page 621... ... 619 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Step 1 involves selecting the origin and destination. In this use case, an origin and destination between which there are four routes for delivery options are assumed. Read the entire page →
From page 622... ... 620 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY 217 2014.04.23 15 L02 Guide Appendix D_Final for composition.docx [Insert Figure D.58] [caption] Read the entire page →
From page 623... ... 621 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY From Figure D.61, it can be seen that when probability is below 40%, the best option is Option 4. When probability is greater than 40% and smaller than 70%, the best option is Option 2, but Option 3 is best when probability is 75% to 95%. Read the entire page →
From page 624... ... 622 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Determine Storage Space for Just-in-Time Deliveries (FC2) A user wishes to set up a just-in-time delivery system and wants to know how much storage space is needed at the receiving location. Read the entire page →
From page 625... ... 623 GUIDE TO ESTABLISHING MONITORING PROGRAMS FOR TRAVEL TIME RELIABILITY Find the Warehouse Site with the Best Distribution Reliability (FC4) A user wants to site a distribution center so that it maximizes delivery reliability to the destinations it serves. Read the entire page →

From page 501...

... 499 INTRODUCTION This appendix shows how a travel time reliability monitoring system (TTRMS) can be used to address questions about network reliability.