ecgd 4121 – transportation engineering i lecture 7 faculty of applied engineering and urban...
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ECGD 4121 – Transportation Engineering IECGD 4121 – Transportation Engineering I
Lecture 7Lecture 7
Faculty of Applied Engineering and Urban PlanningFaculty of Applied Engineering and Urban Planning
Civil Engineering DepartmentCivil Engineering Department
11stst Semester 2009/2010 Semester 2009/2010
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ContentContent
• Speed StudiesSpeed Studies
• Volume StudiesVolume Studies
• Travel Time & Delay StudiesTravel Time & Delay Studies
• Parking Studies Parking Studies
Speed StudiesSpeed Studies
Basic Methods:Basic Methods:
• Pneumatic road tube Pneumatic road tube
• Inductive loop detectorsInductive loop detectors
• Video detectorsVideo detectors
• OthersOthers
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Speed StudiesSpeed Studies
Speed characteristics expressed using:Speed characteristics expressed using:
• Average speed (arithmetic mean)Average speed (arithmetic mean)
• Median speedMedian speed
• Modal speedModal speed
• iithth percentile spot speed (85 percentile spot speed (85thth, 95, 95thth))
• Standard deviationStandard deviation
• Basic statistic analysesBasic statistic analyses
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Volume characteristics expressed using:Volume characteristics expressed using:
• Average Annual Daily Traffic (AADT)Average Annual Daily Traffic (AADT)
• Average Daily Traffic (ADT)Average Daily Traffic (ADT)
• Peak Hour Volume (PHV)Peak Hour Volume (PHV)
• Vehicle Miles of Travel (VMT)Vehicle Miles of Travel (VMT)
• Vehicle Classification (VC)Vehicle Classification (VC)
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Data AnalysesData Analyses
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Data AnalysesData Analyses
Average Annual Daily Traffic (AADT)Average Annual Daily Traffic (AADT)
• Vehicles per day (VPD) in both directionsVehicles per day (VPD) in both directions
• Expressed as average of 24 hours counts Expressed as average of 24 hours counts
for 365 days (1 year)for 365 days (1 year)
• Used for determining and assigning traffic Used for determining and assigning traffic
trends, feasibility studies, etctrends, feasibility studies, etc
Average Daily Traffic (ADT)Average Daily Traffic (ADT)
• Vehicles per day (VPD) in both directionsVehicles per day (VPD) in both directions
• Expressed as average of 24 hours counts for a Expressed as average of 24 hours counts for a
number of days less than 1 yearnumber of days less than 1 year
• Used for planning, measurement of current Used for planning, measurement of current
demand, evaluate traffic flowdemand, evaluate traffic flow
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Data AnalysesData Analyses
hour)peak within minutes 15 during (4)(Volume
VolumeHour Peak FactorHour Peak
PHF
PHVDHVVolumeHourly Design
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Data AnalysesData Analyses
)(4)(PV
PHVPHF
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Example: The afternoon peak hour traffic flow Example: The afternoon peak hour traffic flow
data for westbound traffic on a major road are:data for westbound traffic on a major road are:
4:45pm-5:00pm4:45pm-5:00pm 400 vehicles400 vehicles
5:00pm-5:15pm5:00pm-5:15pm 700 vehicles700 vehicles
5:15pm-5:30pm5:15pm-5:30pm 600 vehicles600 vehicles
5:30pm-5:45pm5:30pm-5:45pm 400 vehicles400 vehicles
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Data AnalysesData Analyses
Data Analyses:Data Analyses:
• PHV = 400 + 700 + 600 + 400 = 2100 vehiclesPHV = 400 + 700 + 600 + 400 = 2100 vehicles
• PVPV1515 = 700 vehicles = 700 vehicles
• PHF = 2100/(4)(700) = 0.75PHF = 2100/(4)(700) = 0.75
• DHV = 2100/0.75 = 2800 vehiclesDHV = 2100/0.75 = 2800 vehicles
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Data AnalysesData Analyses
Methods of Counting:Methods of Counting:
• Manual methodsManual methods
• Automatic methodsAutomatic methods
Surface detectors such as pneumatic road Surface detectors such as pneumatic road
tubes tubes
Subsurface detectors such as magnetic or Subsurface detectors such as magnetic or
electric contact deviceselectric contact devices
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Traffic Volume CountingTraffic Volume Counting
Types of Counts:Types of Counts:
• Cordon countsCordon counts
• Screen line countsScreen line counts
• Intersection countsIntersection counts
• Pedestrian volume countsPedestrian volume counts
• Periodic volume countsPeriodic volume counts
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Traffic Volume CountingTraffic Volume Counting
Adjustment of periodic counts:Adjustment of periodic counts:
• Using data from continuous counting stations Using data from continuous counting stations
we can obtain the Hourly Expansion Factorswe can obtain the Hourly Expansion Factors
• HEF = total volume for 24-hr period/volume HEF = total volume for 24-hr period/volume
for a particular hourfor a particular hour
• HEF is used to expand counts of durations HEF is used to expand counts of durations
shorter than 24 hr to 24-hr volumes (must use shorter than 24 hr to 24-hr volumes (must use
HEF obtained from similar class of roads)HEF obtained from similar class of roads)21
Traffic Volume CountingTraffic Volume Counting
Adjustment of periodic counts:Adjustment of periodic counts:
• Daily Expansion Factors (DEF) = Average Daily Expansion Factors (DEF) = Average
total volume for week/average volume for total volume for week/average volume for
particular dayparticular day
• DEF is used to determine weekly volumes DEF is used to determine weekly volumes
from counts of 24-hr duration (must use DEF from counts of 24-hr duration (must use DEF
obtained from similar class of roads)obtained from similar class of roads)
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Traffic Volume CountingTraffic Volume Counting
Adjustment of periodic counts:Adjustment of periodic counts:
• Monthly Expansion Factors (MEF) =AADT/ADT Monthly Expansion Factors (MEF) =AADT/ADT
for particular monthsfor particular months
• MEF is used to determine AADT from ADT for MEF is used to determine AADT from ADT for
a given month (must use DEF obtained from a given month (must use DEF obtained from
similar class of roads)similar class of roads)
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Traffic Volume CountingTraffic Volume Counting
Travel Time & Delay StudiesTravel Time & Delay Studies
Studying the route from “A” to “B” to:Studying the route from “A” to “B” to:
• Determine travel timeDetermine travel time
• Determine route efficiencyDetermine route efficiency
• Identify delay locationsIdentify delay locations
• Evaluate “before & after” performanceEvaluate “before & after” performance
• Feasibility studiesFeasibility studies
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Travel-time estimation: The moving car methodTravel-time estimation: The moving car method25
Travel Time & Delay StudiesTravel Time & Delay Studies
• Requires one testing vehicle, one driver, and Requires one testing vehicle, one driver, and three observers on board.three observers on board.
• Observer #1: counts mean time the testing car Observer #1: counts mean time the testing car takes to travel eastward and westward.takes to travel eastward and westward.
• Observer #2: counts the number of vehicles Observer #2: counts the number of vehicles traveling in opposite directiontraveling in opposite direction
• Observer #3: counts the number of vehicles Observer #3: counts the number of vehicles that overtook and are overtaken by the testing that overtook and are overtaken by the testing vehiclevehicle
• Driver: if possible try to balance the number of Driver: if possible try to balance the number of vehicles (overtaking vs. overtook)vehicles (overtaking vs. overtook)
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Travel Time & Delay StudiesTravel Time & Delay Studies
• The characteristics of the parking facility and The characteristics of the parking facility and
parking behaviorparking behavior
• Parking facility: full time and part timeParking facility: full time and part time
• Parking behavior: short time and long time – Parking behavior: short time and long time –
rate of use of a parking spacerate of use of a parking space
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Parking StudiesParking Studies
Definition of Parking Terms:Definition of Parking Terms:• Space-hour: the use of a single parking space Space-hour: the use of a single parking space
during a period of time.during a period of time.• e.g., one space-hour can be either one vehicle e.g., one space-hour can be either one vehicle
parked one hour at one parking lot, or two vehicles parked one hour at one parking lot, or two vehicles parked 30 minutes each at one parking lot. parked 30 minutes each at one parking lot.
• e.g., the maximum capacity of a full time (8:00 AM e.g., the maximum capacity of a full time (8:00 AM – 6:00 PM) garage with 200 parking lots is: (200 – 6:00 PM) garage with 200 parking lots is: (200 vehicles)(10 hours) = 2000 veh.hr.vehicles)(10 hours) = 2000 veh.hr.
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Parking StudiesParking Studies
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