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Incorporating Reliability Performance Measures into the Transportation Planning and Programming Processes: Technical Reference (2014) / Chapter Skim
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Pages 162-171

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From page 162...
... 161 F U.S. DOT GUIDANCE ON PERFORMANCE MEASURES F.1 CALCULATION PROCEDURES FOR KEY INTEGRATED CORRIDOR PERFORMANCE MEASURES FROM SIMULATION OUTPUTS A core element of the integrated corridor management (ICM)
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From page 163...
... 162 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE Travel Time Our basic unit of observation in calculating ICM-related performance measures is a trip ๐‘– made between an origin ๐‘œ, finishing at a destination ๐‘‘, starting at a particular time ฯ„ using mode ๐‘š. We record travel time from a single run of the simulation under operational conditions ๐‘˜ for this unit of observation as = ฯ„t ti k o d m k , , , .1 Operational conditions here refer to a specific set of simulation settings reflecting a specific travel demand pattern and collection of incidents derived from a cluster analysis of observed traffic count data and incident data.
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From page 164...
... 163 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE The average number of trips by mode from o to d starting in interval t over all conditions k โˆˆ K: โˆ‘=ฯ„ ฯ„ โˆˆ n n po d m o d m k k K k, , , , , , (F.2a) Combining across modes, the average travel time of trips from o to d starting in interval t under operational condition k: โˆ‘ =ฯ„ ฯ„ ฯ„ ฯ„ T T n n o d k o d m k o d m k m o d k, , , , , , , , , , (F.3)
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From page 165...
... 164 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE For this reason, the minimum threshold may also be calculated as the travel time derived in the pre-ICM case under a substantially reduced demand pattern with no incidents or weather impacts. The reduced demand pattern should generate a large enough number of trips to generate travel time statistics by mode for every set of trips from o to d starting in interval t (i.e., ฯ„> โˆ€ฯ„n o d m0 , , ,o d m, , , 0 )
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From page 166...
... 165 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE To identify the 95th percentile travel time, we first generate an ordered list of travel times by o,d,t: ๏‹ ๏‹= ๏ฃฎ๏ฃฐ ๏ฃน๏ฃป โ‰ค =ฯ„ ฯ„ ฯ„ ฯ„ ฯ„ ฯ„+T T T T T j JT , , , , where for all 1o d o d o d o dJ o dj o dj, , , ,1 , ,2 , , , , , ,1 (F.11) The 95th percentile travel time from this list is identified using the probabilities associated with each operational condition.
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From page 167...
... 166 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE the calculation of variance also includes the consideration of the probabilities of each operational condition.2 โˆ‘ ( )
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From page 168...
... 167 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE Equation F.16 finds the average PMT for all trips from o to d starting in interval t over all operational conditions k โˆˆ K: โˆ‘=ฯ„ ฯ„ โˆˆ X X po d o d k k K k, , , , (F.16) Equation F.17 defines the aggregate PMT across all o,d,t: โˆ‘= ฯ„ ฯ„ ฯ„ โˆ€ X X no d o d o d, , , , , , (F.17)
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From page 169...
... 168 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE Equation F.23 defines the aggregate PMD across all o,d,t: โˆ‘= ฯ„ ฯ„ ฯ„ โˆ€ Z Z no d o d o d, , , , , , (F.23) For example, in the Dallas ICM Corridor, the simulation period is from 5:30 a.m.
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From page 170...
... 169 INCORPORATING RELIABILITY PERFORMANCE MEASURES INTO THE TRANSPORTATION PLANNING AND PROGRAMMING PROCESSES: TECHNICAL REFERENCE Estimated total trip travel time for a trip that cannot be completed before the simulation ends is the accumulated travel time, plus the time to travel the remaining distance at average trip speed:    { }( ) = + โˆ’ฯ„t t X x vmax ,0ik ik o d ik ik.
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