Midwest Research Institute Overview - PowerPoint PPT Presentation

Loading...

PPT – Midwest Research Institute Overview PowerPoint presentation | free to download - id: 1301cb-NWRhM



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Midwest Research Institute Overview

Description:

an opposing vehicle that appears during d1 is a long way from the passing vehicle ... speed of opposing is 5 to 15 mph less than speed of passing vehicle, with higher ... – PowerPoint PPT presentation

Number of Views:48
Avg rating:3.0/5.0
Slides: 110
Provided by: KBa1
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Midwest Research Institute Overview


1
Midwest Research Institute
Solutions through science and technology
NCHRP Project 15-26 Passing Sight Distance
Criteria April 5, 2005
2
Project Objectives
  • Evaluate the design and operational criteria for
    determining minimum PSD
  • Modify the existing criteria or develop new
    criteria

3
Project Scope
  • PSD Criteria for Geometric Design
  • AASHTO Green Book
  • PSD Criteria for Marking of Passing and
    No-Passing Zones
  • MUTCD

4
Project Tasks
  • Task 1 Review current PSD criteria and models
  • COMPLETE
  • Task 2 Review literature and research in
    progress
  • COMPLETE
  • Task 3 Identify factors that potentially
    contribute to PSD requirements
  • COMPLETE

5
Project Tasks
  • Task 4 Critique PSD criteria and develop work
    plan
  • COMPLETE
  • Task 5 Prepare interim report
  • COMPLETE AFTER PANEL DISCUSSIONS

6
Project Tasks
  • Task 6 Execute approved work plan
  • WILL BEGIN WHEN AUTHORIZED
  • Task 7 Prepare new or modified PSD criteria
  • WILL FOLLOW TASK 6

7
Project Tasks
  • Task 8 Prepare final report
  • WILL FOLLOW TASKS 6 7
  • Task 9 Prepare and deliver final presentations
  • WLL FOLLOW TASK 8

8
Project Schedule
  • Planned Start Date for Phase II
  • 2/1/05
  • Actual Start Date for Phase II
  • 4/6/05 ?
  • Approximately two months behind schedule

9
Project Schedule
  • Submit Draft Final Report
  • 2/28/06
  • Submit Revised Final Report
  • 5/31/06

10
Outline of Presentation
  • Review of Current PSD Criteria
  • Section 2 of interim report
  • Assessment of Current PSD Criteria and
    Alternative Models
  • Sections 3 and 4 of the interim report

11
Outline of Presentation
  • Potential Work Plans for Execution in Phase II
  • Section 5 of interim report
  • Priorities and Budget Allocations for Phase II
  • Section 6 of the interim report

12
PSD Design Criteria
  • AASHTO Green Book
  • PSD d1 d2 d3 d4
  • d1 P-R time plus initial acceleration
  • d2 distance traveled in left lane
  • d3 clearance distance
  • d4 distance traveled by opposing vehicle
    2/3 d2

13
PSD Design Criteria
  • ASSUMPTIONS
  • Passed vehicle travels at uniform speed
  • Passing vehicle reduces speed and trails the
    passed vehicle as it enters the passing section
    (delayed pass)

14
PSD Design Criteria
  • Passing driver requires a short period to
    perceive the passing section and begin to
    accelerate
  • d1 maneuver time 3.6 to 4.5 sec (older field
    data)
  • d1 acceleration rate 1.38 to 1.51 mph/sec
  • (2 to 2.2 ft/sec2)

15
PSD Design Criteria
  • Passing is accomplished under
  • delayed start
  • hurried return in the face of opposing traffic

16
PSD Design Criteria
  • Left-lane distance (d2)
  • average speed of passing vehicle during left-lane
    occupancy exceeds speed of passed vehicle by 10
    mph
  • at low speeds, passing vehicle above design
    speed, passed vehicle below design speed
  • at speeds of 55 mph or more, both vehicles below
    design speed
  • left-lane occupancy time 9.3 to 7.3 sec,
    depending on speed (older field data)

17
PSD Design Criteria
  • Clearance distance (d3)
  • 100 to 300 ft, depending upon speed
  • Opposing vehicle distance (d4)
  • d4 d2 would allow for completion of passing
    maneuver without need to abort
  • d4 2/3 d2 will require abort in some cases

18
PSD Design Criteria
  • CRITIQUE
  • AASHTO model is extremely conservative
  • If model were d1 d2 d3 d2, passing driver
    would know that no abort is required even before
    beginning to pass
  • If model d1 d2 d3 2/3 d2, an abort is
    potentially required only very early in the
    maneuver

19
PSD Design Criteria
  • Inclusion of P-R and initial acceleration
    distance (d1) is very conservative
  • passing maneuver could be aborted easily and
    safely if opposing vehicle appears during d1
  • an opposing vehicle that appears during d1 is a
    long way from the passing vehicle

20
PSD Design Criteria
  • Ending section of adequate PSD when PSD falls
    below d1 d2 d3 2/3 d2 is extremely
    conservative
  • at the end of the section of adequate PSD, a
    passing driver has almost enough sight distance
    to start a pass and complete it without the need
    to abort
  • passes can be started safety beyond this point,
    if the passing driver can abort the maneuver, if
    an opposing vehicle appears

21
PSD Design Criteria
  • Assumption of passed vehicle speed substantially
    less than design speed, particularly for design
    speeds of 55 mph or more, is not conservative
  • Assumption of constant speed differential
    between passing and passed vehicles, independent
    of design speed is questionable

22
PSD Marking Criteria
  • MUTCD
  • presents warrants for no-passing zones
  • passing zones merely happen where no-passing
    zones are not warranted
  • where the distance between successive no-passing
    zones is less than 400 ft, no-passing markings
    should connect the zones

23
PSD Marking Criteria
  • There is no quantitative model for the MUTCD
    criteria
  • MUTCD criteria were first developed in a 1940
    AASHO policy

24
PSD Marking Criteria
  • MUTCD/1940 AASHO ASSUMPTIONS
  • no P-R time needed for pass initiation because
    passing driver can abort the maneuver if an
    opposing vehicle appears
  • speed of passing vehicle is equal to 85th
    percentile speed or posted or statutory speed
    limit

25
PSD Marking Criteria
  • speed differential between passing and passed
    vehicle ranges from 10 to 25 mph, with higher
    speed differentials at higher speeds
  • speed of opposing is 5 to 15 mph less than speed
    of passing vehicle, with higher speed
    differentials at higher speeds
  • compromise between PSD values for delayed and
    flying passes

26
PSD Marking Criteria
  • CRITIQUE
  • Speed of passing vehicle equal to 85th percentile
    speed or speed limit is conservative
  • many passing vehicles may travel faster

27
PSD Marking Criteria
  • Speed differential between passing and passed
    vehicles that increases with increasing speed is
    not conservative
  • it seems more likely that speed differential
    would decrease as the speed of the passed vehicle
    increases

28
PSD Marking Criteria
  • Speed of opposing vehicle less than 85th
    percentile speed or speed limit seems unrealistic
  • Consideration of flying passes is not
    conservative
  • Minimum 400-ft passing zones are not compatible
    with delayed passes on high-speed highways

29
Comparison of PSD Criteria
30
Comparison of PSD Criteria
31
Comparison of PSD Criteria
  • AASHTO Criteria
  • Driver eye height 3.50 ft
  • Target height 3.50 ft (reduced from 4.25 ft in
    2001)
  • MUTCD Criteria
  • Driver eye height 3.50 ft
  • Target height 3.50 ft

32
International PSD Criteria
  • PSD Design Criteria _at_ 100 km/h
  • Australia (more than US at beginning of PSD, less
    than US at end of PSD)
  • Austria (about the same as the US)
  • Britain (less than US at beginning of PSD, much
    less at end of PSD)
  • Canada (about the same as the US)
  • Germany (slightly less than the US)
  • Greece (slightly less than the US)
  • South Africa (about the same as the US)

33
International PSD Criteria
  • PSD Marking Criteria _at_ 100 km/h
  • Australia (slightly less than the US)
  • Britain (less than the US)
  • Canada (more than the US)
  • South Africa (about the same as the US)

34
Safety Performance for Passing Maneuvers
  • HSIS study (1994) found that
  • passing-related accidents constitute 2 of total
    non-intersection accidents on rural two-lane
    highways
  • passing-related accidents are more severe than
    non-passing related accidents

35
Safety Performance for Passing Maneuvers
  • Fatal and serious injury accidents
  • 13.9 of passing-related accidents
  • 9.4 of total accidents
  • Passing-related accidents are estimated to
    constitute 3 of total fatal and serious injury
    accidents on rural two-lane highways

36
Safety Performance for Passing Maneuvers
  • FARS 2003 data
  • 13,000 fatal accidents/year at non-intersection
    locations on rural two-lane highways
  • if 3 are passing-related accidents, there are
    390 fatal passing-related accident per year
  • Not all passing-related accidents involve limited
    PSD

37
Safety Performance for Passing Maneuvers
  • COLLISION TYPES FOR PASSING-RELATED ACCIDENTS
  • Single-vehicle ROR 30
  • Sideswipe, same direction 25
  • Sideswipe, opp direction 7
  • Rear-end 17
  • Head-on 7
  • Other/unknown 15

38
Safety Performance for Passing Maneuvers
  • Safety record of passing-related accidents is
    generally good
  • It is unlikely that safety performance of rural
    two-lane highways can be modified significantly
    by changing PSD criteria
  • Potential cost-effectiveness of changes to PSD
    criteria need be investigated

39
PSD Criteria in Relation to the Good Safety
Record of Passing Maneuvers
  • PSD design criteria are conservative
  • PSD values used in marking criteria are more
    appropriate than they seem
  • Short 400-ft passing zones may not be often used
    for high-speed passes
  • Most drivers may be conservative in making
    passing judgments
  • A buffer area is present downstream of every
    passing zone

40
Conceptual Presentation of the Changes in Sight
Distance Needed to Complete or Abort a Passing
Maneuver as the Passing Maneuver Progresses
AASHTO
d1 d2 d3 2/3 d2
MUTCD
41
Critical Position in the Passing Maneuver
  • Models based on the critical position assume that
    drivers may abort the passing maneuver until the
    critical position is reached

42
Critical Position in the Passing Maneuver
  • Critical position concept
  • any passing driver who has not yet reached the
    critical position must have sufficient PSD to
    abort the maneuver
  • any passing driver who has passed the critical
    position must have sufficient PSD to complete the
    maneuver
  • any passing driver at the critical position must
    have sufficient PSD to complete or abort the
    maneuver

43
Critical Position in the Passing Maneuver
  • Two models based on the critical position provide
    PSD values similar to the MUTCD
  • Glennon (1988)
  • Hassan et al. (1996)

44
Critical Position in the Passing Maneuver
  • First recognized by VanValkenburg and Michael
    (1971)
  • they called it the point of no return
  • they visually identified the critical position as
    occurring when the vehicles are approximately
    abreast (rear bumper of passed vehicle opposite
    middle of passing vehicle)
  • field measurements of distance traveled by the
    passing vehicle from the abreast position to the
    completion of the pass

45
Critical Position in the Passing Maneuver
  • Weaver and Glennon (1972)
  • defined the critical position as the point at
    which the time required to complete the maneuver
    is equal to the time required to abort the
    maneuver
  • proposed a PSD model that did not incorporate
    this definition
  • stated that critical position occurs when
    vehicles are approximately abreast

46
Critical Position in the Passing Maneuver
  • Harwood and Glennon (1976)
  • defined the critical position as the point at
    which the sight distance required to complete the
    maneuver is equal to the sight distance required
    to abort the maneuver
  • proposed a PSD model that did not incorporate
    this definition

47
Critical Position in the Passing Maneuver
  • Lieberman (1982)
  • used critical position concept in modeling PSD
  • defined needed PSD as d7 PSDc
  • d7 is distance to from the start of the pass to
    the critical position
  • formulated a model to determine the relative
    position of the passing and passed vehicles at
    the critical position (?c)
  • model for ?c appears incomplete

48
Critical Position in the Passing Maneuver
  • Saito (1984)
  • postulated that there are two possible locations
    of the critical position in a passing maneuver
  • head-to-tail position (head of passing vehicle
    opposite tail of passed vehicle)
  • abreast position (passing vehicle alongside
    passed vehicle)
  • model inputs are not fully stated

49
Critical Position in the Passing Maneuver
  • Glennon (1988)
  • formulated PSD model based on equivalent sight
    distance to complete and abort a passing maneuver
    from the critical position
  • included an explicit model to calculate the
    relative positions of the passing and passed
    vehicles at the critical position (?c)

50
Critical Position in the Passing Maneuver
  • Glennon (1988)
  • included terms for the lengths of the passing and
    passed vehicles
  • incorporated speed differential between passing
    and passed vehicles that decreases as speed
    increases
  • deceleration rate in abort maneuver 8
    ft/sec2 (as opposed to 11 ft/sec2 in SSD)

51
Critical Position in the Passing Maneuver
52
Critical Position in the Passing Maneuver
  • Harwood and Glennon (1989)
  • used Glennon model with some changes in input
    data from Glennon (1988)
  • passenger car length, 19 ft rather than 16 ft
  • truck length 75 ft
  • smaller speed differential for truck as the
    passing vehicle
  • lower deceleration rate in aborting a pass, 5
    ft/sec2 for a truck, as opposed to 8 ft/sec2 for
    a passenger car

53
Critical Position in the Passing Maneuver
54
Critical Position in the Passing Maneuver
  • Rilett at al. (1989)
  • recommended a minimum speed for passing abort
    maneuver Vd 2m
  • inclusion of a minimum speed substantially
    lengthens PSD values
  • Good et al. (1991) stated that it is unreasonable
    to expect that, in the face of an opposing
    vehicle, the passing driver would decelerated to
    Vd 2m and then continue at constant speed

55
Critical Position in the Passing Maneuver
  • Rilett at al. (1989)
  • recommended headway after pass abort greater than
    the 1 sec used by Glennon
  • 1 sec headway appears appropriate for passenger
    cars
  • headway greater than 1 sec appears needed for
    trucks

56
Critical Position in the Passing Maneuver
  • Hassan et al. (1996)
  • recommended two modifications to the Glennon
    model
  • recommended incorporation of P-R time for pass
    abort decision (but this may already be part of
    the Glennon model)
  • recommended providing PSD for pass completion
    where critical position occurs with passing
    vehicle ahead of passed vehicle (positive value
    of ?c)

57
Critical Position in the Passing Maneuver
58
Critical Position in the Passing Maneuver
59
Critical Position in the Passing Maneuver
60
Critical Position in the Passing Maneuver
61
Buffer Area Downstream of Passing Zones
62
Buffer Area Downstream of Passing Zones
  • Buffer area results from short zone marking
    concept
  • passes must legally be completed prior to end of
    zone
  • drivers can complete passes safely even if in
    critical position at end of zone
  • used in 46 of the 50 states

63
PSD Marking Criteria
  • HSIS study suggests no major safety problems
    associated with PSD marking criteria
  • Glennon and Hassan et al. models suggest that
    MUTCD criteria may be about right, but for the
    wrong reason
  • Differences between Glennon and Hassan et al.
    models need to be resolved

64
PSD Marking Criteria
  • Cost of changing PSD criteria would be
    substantial remeasuring PSD for all two-lane
    roads with centerlines
  • Cost-effectiveness of potential changes in
    marking criteria needs to be resolved

65
Potential Approach to PSD Marking Criteria
  • IF SUPPORTED BY PHASE II RESULTS
  • Retain MUTCD criteria
  • Offer a better engineering rationale for the
    MUTCD criteria based on the Glennon model, the
    Hassan et al. model, or some variation of these
    models

66
Potential Approach to PSD Marking Criteria
  • Consider need to change 400-ft minimum passing
    zone length

67
Short Passing Zones
  • Cant accommodate delayed passes on high-speed
    highways
  • May accommodate some flying passes
  • May accommodate passing very slow-moving vehicles
    tractor on the road
  • May not contribute much to LOS
  • Do drivers use short zones legally? safely?

68
Short Passing Zones
  • Jones (1970)
  • Texas roadways with 70-mph speed limits
  • field studies at three passing zones with lengths
    of 400, 640, and 880 ft
  • comparative data for passing zones with lengths
    of 1,640 and 2,600 ft

69
Short Passing Zones
  • Jones (1970)
  • defined passing opportunity as
  • trailing vehicle within 4 car lengths (80 ft)
  • appeared to be awaiting a change to pass
  • average of 125 passing opportunities observed per
    zone

70
Short Passing Zones
71
PSD Design Criteria
  • What is the rationale for use of longer PSD
    values in design than in marking?
  • Does the good safety record of passing maneuvers
    indicate that current marking criteria are
    sufficient for safety?
  • Does the use of longer PSD values in design than
    in marking enhance safety?
  • Should the design process explicitly consider the
    passing and no-passing zones that will be marked
    on the completed highway?

72
Potential Alternative Approaches to PSD Marking
Criteria
  • 1 Retain current AASHTO Green Book criteria
  • 2 Use the same PSD criteria for design as for
    marking
  • 3 Use PSD criteria for design with a defined
    relationship to PSD criteria for marking
  • PSD X PSDc

73
Potential Alternative Approaches to PSD Marking
Criteria
  • 4 - Use the same PSD criteria for design as for
    marking, but count only passing sections with
    specified minimum length
  • 5 Use longer value of PSD to define beginning
    of passing section and shorter PSD to define end
    of passing section

74
Other Issues
  • Trucks
  • Older drivers

75
PSD for Trucks
76
PSD for Trucks
77
PSD for Trucks
  • Glennon model may need longer headway after abort
    for truck as passing vehicle
  • Truck can pass PC on any vertical curve where PC
    can pass a truck reevaluate in light of changed
    object heights

78
PSD for Trucks
  • PC passing truck or truck passing PC may not be a
    logical design or marking scenario
  • would eliminate some current passing zones and
    shorten others
  • would prohibit some passes of PCs that are safe
    and are currently legal
  • would reduce LOS
  • might encourage illegal passes
  • no indication of safety benefits

79
Older Drivers
  • Reduced P-R time
  • Reduced visual acuity
  • Reduced ability to judge distances and speeds
  • Less likely to travel at high speeds
  • Less likely to pass
  • Less aggressive
  • More likely to drive passed vehicle than passing
    vehicle

80
PSD for Older Drivers
  • FHWA Highway Design Handbook for Older Drivers
    recommended using Green Book PSDs instead of
    MUTCD PSDs
  • NCHRP Project 20-7(118) recommended caution in
    implementing this Handbook recommendation

81
PSD for Older Drivers
  • Use of longer PSD in marking would eliminate some
    current passing zones and shorten others
  • Older drivers would still probably be more
    reluctant than younger drivers to pass
  • Handbook recommendation did not consider the
    safety cushion provided by the buffer area

82
Key Considerations in Changing PSD Criteria
  • Safety considerations (effect on accident
    frequency and severity)
  • Traffic operational considerations (effect on
    level of service)
  • Economic considerations (benefits to compensate
    for increased costs) on both existing and new
    highways
  • Rationality and consistency of PSD criteria
    (understanding and acceptance by engineers)

83
Potential Phase II Work Plans
  • A Benefit-cost analysis
  • B Identify and analyze of passing- related
    accidents
  • C Review accident data for field sites
  • D Safety of passing maneuvers completed beyond
    the end of a passing zone

84
Potential Phase II Work Plans
  • E Safety and operations of short passing zones
  • F Field data to quantify parameters of revised
    PSD models
  • G Application of PSD criteria to actual
    terrain
  • H Traffic operational effects of alternative
    PSD criteria

85
Potential Phase II Work Plans
  • I Comparison of PSD and SSD criteria
  • J Guidance on determination of percentage of
    roadway length with PSD

86
A Benefit-Cost Analysis for Changing PSD
Marking Criteria
  • Objective
  • determine whether safety benefits could possibly
    justify cost of remeasuring PSD
  • need to quantify
  • cost per mile of remeasuring PSD
  • number of miles of two-lane roads with marked
    centerlines
  • number of accidents equivalent to cost of
    remeasuring
  • number of accidents available for reduction

87
BIdentification and Analysis of Passing-Related
Accidents
  • Objective Conduct further evaluation of
    passing-related accidents
  • Identify passing-related accidents in manner
    similar to HSIS study
  • Obtain more complete severity data
  • Estimate available PSD at accident sites
  • Determine portion of passing zone (or no-passing
    zone) where accidents occur

88
BIdentification and Analysis of Passing-Related
Accidents
  • Investigate involvement of trucks
  • Investigate involvement of older drivers in
    passing, passed, and opposing vehicles
  • Determine weather and pavement conditions under
    which passing-related accidents occur

89
CReview of Accident Data for Field Sites
  • Objective
  • Assure that field sites used in Work Plans D and
    F do not have adverse accident experience
  • Determine accident experience for field sites in
    Work Plan E

90
DSafety of Maneuvers Completed Beyond the End of
a Passing Zone
  • Objective Determine the extent and consequences
    of pass completions beyond the end of a passing
    zone
  • Sites to be used
  • passing zone length 1,000 to 2,500 ft
  • frequent passing activity
  • no-passing zone for at least 2,000 ft downstream
    of passing zone

91
DSafety of Maneuvers Completed Beyond the End of
a Passing Zone
  • Data to be collected
  • percent of maneuvers completed in marked passing
    and no-passing zones
  • relative positions of passing and passed vehicles
    at the end of the passing zone
  • location of passing vehicles return to normal
    lane
  • sight distance at return to normal lane
  • traffic conflicts or severity of return maneuver
  • Video recording and manual observation

92
ESafety and Operations of Short Passing Zones
  • Objectives Determine whether short passing
    zones
  • create safety problems
  • contribute substantially to LOS
  • Sites to be used
  • passing zone length 400 to 800 ft
  • Data to be collected
  • similar to Work Plan D

93
FQuantify Parameters of Revised PSD Models
  • Objective Quantify parameters of alternative
    models
  • speed differential between passing and passed
    vehicles
  • distance traveled by the passing vehicle from the
    beginning of passing zone to the critical
    position
  • deceleration rate use in aborting a passing
    maneuver

94
FQuantify Parameters of Revised PSD Models
  • Data collection approach
  • Video recording
  • Manual observation
  • Traffic classifiers or laser guns for speed
    measurement

95
GApplication of Revised PSD Criteria to Actual
Terrain
  • Objective Investigate effects of changing PSD
    design and marking criteria
  • Obtain plan and profile data for actual terrain
  • as-built plans
  • Washington HSIS data

96
GApplication of Revised PSD Criteria to Actual
Terrain
  • How will revised PSD criteria change
  • percentage of roadway length that meets design
    PSD criteria
  • percentage of roadway length in marked passing
    zones
  • lengths of passing zones
  • PSD available within passing zones
  • Relative contributions of PSD criteria and
    terrain

97
GApplication of Revised PSD Criteria to Actual
Terrain
  • Interviews with experienced designers
  • choice of target percentage of roadway length
    that meets design PSD criteria
  • application of design criteria

98
HTraffic Operational Effects of Alternative PSD
Criteria
  • Objective How will revised PSD design and
    marking criteria affect the level of service on
    two-lane highways?
  • Tool TWOPAS traffic operational computer
    simulation model

99
I Comparison of PSD and SSD Criteria
  • Compare PSD values used in design and marking to
    SSD values used in design
  • Compare resulting vertical curve lengths in light
    of
  • sight distance criteria
  • assumed driver eye height
  • assumed object height

100
J Guidance on Percentage of Roadway Length with
Design PSD
  • Provide guidance or recommendations on average
    frequency of passing opportunities that should be
    provided on two-lane highways
  • dependent on traffic volumes
  • dependent on vehicle mix
  • needs to implement desired LOS for functional
    class and terrain

101
J Guidance on Percentage of Roadway Length with
Design PSD
  • Added passing lanes along the road may reduce the
    need for PSD to maintain LOS between passing lanes

102
Project Budget
  • Phase I 64,066
  • Phase II 235,934
  • TOTAL 300,000

103
Phase I Budget
  • Budgeted expenditures 64,066
  • Actual expenditures (est.) 61,000
  • Unexpended funds (est.) 3,066

104
Allocation of Phase II Budget
105
Cost Estimates for Task 7 Work Plans
  • A Benefit-cost analysis of PSD 10,000
  • marking revisions
  • B Identification and analysis of 100,000
  • passing-related accidents
  • C Review of accident data for 5,000
  • field study sites
  • D Safety of passing maneuvers 30,000
  • completed beyond the end
  • of the passing zone

106
Cost Estimates for Task 7 Work Plans
  • E Safety and operations of 30,000
  • short passing zones
  • F Field data collection to quantify 50,000
  • PSD models
  • G Application of revised PSD 10,000
  • to actual terrain
  • H Traffic operational effects 15,000
  • of alternative PSD criteria

107
Cost Estimates for Task 7 Work Plans
  • I Comparison of PSD and SSD 5,000
    criteria
  • J Guidance on determining the 10,000
  • percentage of roadway length
  • with adequate PSD
  • TOTAL 265,000

108
Cost Estimates for Task 7 Work Plans
  • Estimated cost for all 10 work plans
    265,000
  • Available funds for Task 7
  • 181,000
  • Difference
  • 84,000

109
Potential Modifications
  • Eliminate Work Plan B entirely
  • saves 100,000
  • frees up 16,000 for field work
  • Scale back Work Plan B to 16,000
  • existing data bases only
  • no videolog review
  • no hard-copy accident report review
About PowerShow.com