Introducción al Manual de Seguridad en Carreteras, HSM...

Introducción al Manual de Seguridad en Carreteras, HSM 2010

Benjamín Colucci Ríos, PhD, PE, JD, [email protected]ático

Auspiciado Por:Centro de Transferencia de Tecnología en Transportación

17 y 20 de octubre de 2014

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mailto:[email protected]

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Buenos Días

Temas a cubrir: HSM Día 2

TALLER/WORKSHOP AM: RURAL

•Estimar los choques esperadosen carreteras rurales doscarriles en dos direcciones(Cap. 10 HSM)

•Uso de aplicación desarrolladaen Excel para estimar choquesaplicando metodología HSM

TALLER/WORKSHOP PM: URBANO

•Estimar los choques esperadospara arterias urbanas y sub-urbanas (Cap. 12 HSM)

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Temas a cubrir: HSM Día 2 (cont.)

•Site Selection Criteria for Determining Local Calibration Factors (Cr)

•Crash Modification Factor (CMF) Clearinghouse –FHWA http://www.cmfclearinghouse.org

•The future of HSM• New Changes in HSM 2010 (NCHRP 17-45)

•How the HSM fits within the Puerto Rico Strategic Highway Safety Plan (SHSP-PR): 2014-2018

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Workshop # 1 AMRural two way-two lane road

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Situation

Highway PR-114, a rural two-lane, two-way road segment located in the Municipality of Cabo Rojothat was treated with center-line rumble strips in 2012.

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Situation (cont.)•This segment is currently being investigated for alleged significant crash frequency during the past year 2013. Specifically, it consists of the following 3 segments: ◦ a 1.5 mile tangent segment followed by

◦ a 6.5° horizontal curve with an intersection angle of 60 °and

◦ a 1.0 mile tangent segment after the point of tangency.

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Situation (cont.)•Concrete utility poles (not shown in thephotograph) with a longitudinal spacing of 150 ft.were located at 3 ft. from the pavement edge whenthe crashes occurred in 2013.

•The concrete poles were removed by theDepartment of Transportation and Public Worksdue to the high incidents of “single vehicle run-offthe road” crashes that impacted the utility poles.

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Situation (cont.)•The proportion of total night time crashes forunlighted roadway segments that involve a fatalityor injury is 38% and the remaining 62% involveproperty damage only.

•The proportion of total crashes that occur at nightfor unlighted roadway segments is 37%.

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Rural Two-lane, Two-way Road Segment

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Pertinent Data:•Design speed: 50 mph

•AADT: 1,800 veh/day

•Lane width: 11 ft.

•Shoulder width: 2 ft.

•Shoulder type: gravel

•Vertical Alignment: 3.0 %

•AASHTO Green Book superelevation rate: 0.065 ft/ft

•Maximum (actual) superelevation rate: 0.08 ft/ft

•Coefficient of side friction: 0.14 ft/ft

•CMF for Centerline Rumble Strips in PR: 0.91

•Driveways ◦ North Bound: 2

◦ South Bound: 1

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Assumptions•Calibration Factor equal to 1.0.

•There is no spiral transition present in this horizontal alignment.

•There are no guardrails installed in the roadside.

•No left-turn lanes are provided.

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Required•Radius of curvature

•Minimum radius of curvature for the design speed

•Does the horizontal curve satisfy minimum AASHTO requirements?

•Length of horizontal curve

•Predicted total crash frequency for roadway segment base conditions

•Superelevation Variance

•Driveway Density

•Roadside Hazard Rating

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Required (cont.)•Crash Modification Factors (CMF’s) applicable only to the horizontal curves segment

1. CMF for the effect of lane width on total crashes2. CMF for the effect of lane width on related crashes3. CMF for the effect of shoulder width and type on total crashes4. CMF for related crashes based on shoulder width5. CMF for related crashes based on shoulder type6. CMF for the effect of horizontal alignment on total crashes7. CMF for the effect of superelevation variance on total crashes8. CMF for the effect of driveway density on total crashes9. CMF for effect of roadside design10. CMF for the effect of lighting of total crashes

•Combined Crash Modification Factor (CMF)

•Predicted Average Crash Frequency

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Workshop # 1 AMRural two way-two lane road

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Solution

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Solution

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Workshop #2 PM Urban

URBAN AND SUBURBAN ARTERIAL ROADS

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Urban Arterial RoadsUrban = an area typified by high densities of development or concentrations of population (population > 5,000 people)

Arterial = road that provides high level of service at a great speed for uninterrupted distance, with some degree of access control.

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Urban Arterial Predicted CrashesAs per Highway Safety Manual Chapter 12

Example utilizing:HSM worksheets

HSM Excel Spreadsheet

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HSM Worksheets…

Found in Appendix A of the Highway Safety Manual 2010

Multiple sheets arranged in a logical order

Organizes the information needed to calculate the crash frequency

Provides the equation and table references for guidance

Online Excel spreadsheet version available on the HSM website

How to obtain the Excel Tool:

22www.highwaysafetymanual.org

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Tools

Choose the Excel Spreadsheet that pertains to your road characteristics:

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Now, let’s try some sample problems…

Beta Versions…

A Two-Lane Undivided Arterial Roadway Segment•2.5 mile length of Calle Méndez Vigo, Dorado, PR

•15,000 veh/day

•2.0 mi of parallel on-street commercial parking on each side of street

•50 driveways (30 minor commercial, 1 major commercial, 5 majorresidential, 10 minor residential, 4 minor industrial/institutional)

•Utility poles located 5 feet from the side of the road (12 poles per mile)

•Lighting present

•30-mph posted speed

•Collision type distributions are the default values in HSM 2010

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Example of Two-Lane Undivided Urban Arterial: Calle Méndez Vigo (Dorado, PR)

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Required:•Crash Modification Factors (CMF’s) applicable

1. CMF for the effect of on-street parking

2. CMF for the effect of roadside fixed objects

3. CMF for the effect of the median width

4. CMF for the effect of lighting

5. CMF for the effect of automated speed enforcement



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Situation:•A 2.5 mile long road segment located on an arterial in the urban City of Dorado

•What is the predicted crash frequency of the road segment?

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First, find out what is site type from Table 12-1:

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Worksheet 1A: Let’s Get Started

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AADTMAX = 53,800 (veh/day)

30

1.00

Offset to roadside fixed objects (ft) [If greater than 30 or Not Present, input 30]

Calibration Factor, Cr

Minor commercial driveways (number) --

Other driveways (number)

Speed Category

Roadside fixed object density (fixed objects / mi)

--

0

Minor residential driveways (number) --

--

--

Worksheet 1A -- General Information and Input Data for Urban and Suburban Roadway Segments

General Information Location Information

Agency or Company Roadway Section

Analyst Roadway

JurisdictionDate Performed

Input Data Base Conditions Site Conditions

Analysis Year

Length of segment, L (mi) --

None

Roadway type (2U, 3T, 4U, 4D, ST) --

--

Proportion of curb length with on-street parking --

Type of on-street parking (none/parallel/angle)

AADT (veh/day)

Major residential driveways (number)

Auto speed enforcement (present / not present) Not Present

Median width (ft) - for divided only 15

Lighting (present / not present) Not Present

--

Major commercial driveways (number) --

Major industrial / institutional driveways (number)

Minor industrial / institutional driveways (number)

--

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Worksheet 1A: General Input for Urban & Suburban Roadway Segments


530

1.00 1.00

Offset to roadside fixed objects (ft) [If greater than 30 or Not Present, input 30]

Calibration Factor, Cr

Minor commercial driveways (number) -- 30

Other driveways (number)

Speed Category

Roadside fixed object density (fixed objects / mi)

0

4

--

12

10

0

Minor residential driveways (number) --

Posted Speed 30 mph or Lower

--

--

0

Worksheet 1A -- General Information and Input Data for Urban and Suburban Roadway Segments


Agency or Company T2 Center Roadway Section MP 0.0 to MP 1.5

Analyst YR Roadway 2-Lane Undivided Arterial Segment

Jurisdiction Puerto RicoDate Performed 10/17/14


Analysis Year 2014

Length of segment, L (mi) -- 2.5

None

Roadway type (2U, 3T, 4U, 4D, ST) -- 2U

-- 15,000

Proportion of curb length with on-street parking -- 0.8

Type of on-street parking (none/parallel/angle) Parallel (Comm/Ind)

AADT (veh/day)

Major residential driveways (number)

Auto speed enforcement (present / not present) Not Present Not Present

Median width (ft) - for divided only 15 Not Present

Lighting (present / not present) Not Present Present

5

--

Major commercial driveways (number) -- 1

Major industrial / institutional driveways (number)

Minor industrial / institutional driveways (number)

--

Next Calculate the CMF’s

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Where is the CMF information?

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On Street Parking CMF (Equation 12-32)𝐶𝑀𝐹1𝑟 = 1 + 𝑝𝑝𝑘 × (𝑓𝑝𝑘 −1.0))

Where:CMF1r = crash modification factor for the effect of on-street parking on total crashesfpk = factor from Table 12-19ppk = proportion of curb length with on-street parking = (0.5 Lpk / L)Lpk = sum of curb length with on-street parking for both sides of the road combined (miles)L = length of roadway segment (miles)

On Street Parking CMF (Equation 12-32)

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𝑝𝑝𝑘 =0.5 2 𝑚𝑖𝑙𝑒𝑠 + 2 𝑚𝑖𝑙𝑒𝑠

2.5 𝑚𝑖𝑙𝑒𝑠

𝑝𝑝𝑘 = 0.8

𝐶𝑀𝐹1𝑟 = 1 + 0.8 ∗ (2.074 − 1.0)

𝐶𝑀𝐹1𝑟=1.86

𝐶𝑀𝐹1𝑟 = 1 + 𝑝𝑝𝑘 × (𝑓𝑝𝑘 − 1.0)

Where:CMF1r = crash modification factor for the effect of on-street parking on total crashesfpk = factor from Table 12-19ppk = proportion of curb length with on-street parking = (0.5 Lpk / L)Lpk = sum of curb length with on-street parking for both sides of the road combined (miles)L = length of roadway segment (miles)

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Roadside Fixed Objects CMF (Eqn 12-33)

Where:

CMF2r = crash modification factor for the effect of roadside fixed objects on total crashes

foffset = fixed-object offset factor from Table 12-20

Dfo = fixed-object density (fixed objects/ mile) for both sides of the road combined

pfo = fixed-object collisions as a proportion of total crashes from Table 12-21

𝐶𝑀𝐹2𝑟 = 𝑓𝑜𝑓𝑓𝑠𝑒𝑡 × 𝐷𝑓𝑜 × 𝑝𝑓𝑜 + (1.0 − 𝑝𝑓𝑜)

Roadside Fixed Objects CMF (Equation 12-33)

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𝑓𝑜𝑓𝑓𝑠𝑒𝑡 = 0.133

𝑃𝑓𝑜 = 0.059

𝐶𝑀𝐹2𝑟 = 0.133 ∗ 12 ∗ 0.059 + (1.0 − 0.059)

𝐶𝑀𝐹2𝑟 = 1.03

𝐶𝑀𝐹2𝑟 = 𝑓𝑜𝑓𝑓𝑠𝑒𝑡 × 𝐷𝑓𝑜 × 𝑝𝑓𝑜 + (1.0 − 𝑝𝑓𝑜)

Where:

CMF2r = crash modification factor for the effect of roadside fixed objects on total crashes

Foffset = fixed-object offset factor from Table 12-20

Dfo = fixed-object density (fixed objects/ mile) for both sides of the road combined

Pfo = fixed-object collisions as a proportion of total crashes from Table 12-21

Median Width CMF (Table 12-22)

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CMF=1 is used for:• Medians without traffic

barriers• For undivided facilities

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Lighting CMF (Equation 12-34)

CMF4r = crash modification factor for the effect of roadway segment lighting on total crashespinr = proportion of total nighttime crashes for unlighted roadway segments that involve a fatality or injuryppnr = proportion of total nighttime crashes for unlighted roadway segments that involve property damage onlyPnr = proportion of total crashes for unlighted roadway segments that occur at night

𝐶𝑀𝐹4𝑟 = 1.0 − (𝑝𝑛𝑟 × (1.0 − 0.72 × 𝑝𝑖𝑛𝑟 − 0.83 × 𝑝𝑝𝑛𝑟))

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Lighting CMF (Equation 12-34)

pinr=0.424 ppnr=0.576 pnr=0.316

𝐶𝑀𝐹4𝑟 = 1.0 − (0.316 × 1.0 − 0.72 × 0.424 − 0.83 × 0.576 )

𝐶𝑀𝐹4𝑟 = 0.93

𝐶𝑀𝐹4𝑟 = 1.0 − (𝑝𝑛𝑟 × (1.0 − 0.72 × 𝑝𝑖𝑛𝑟 − 0.83 × 𝑝𝑝𝑛𝑟))

CMF4r = crash modification factor for the effect of roadway segment lighting on total crashespinr = proportion of total nighttime crashes for unlighted roadway segments that involve a fatality or injuryppnr = proportion of total nighttime crashes for unlighted roadway segments that involve property damage onlyPnr = proportion of total crashes for unlighted roadway segments that occur at night

Automated Speed Enforcement CMFNo automated speed enforcement (base condition):◦ CMF=1

If there is automated speed enforcement:◦ Fatal and Injury Crashes – CMF=0.83

◦ Non-injury (PDO) – CMF=0.95

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Combined CMFs𝐶𝑀𝐹(𝑐𝑜𝑚𝑏𝑖𝑛𝑒𝑑) = 𝐶𝑀𝐹1𝑟 ×

𝐶𝑀𝐹2𝑟 × 𝐶𝑀𝐹3𝑟 × 𝐶𝑀𝐹4𝑟 ×𝐶𝑀𝐹5

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𝐶𝑀𝐹 𝑐𝑜𝑚𝑏𝑖𝑛𝑒𝑑 = 1.86 × 1.03 × 1.00 × 0.93 × 1.00

𝐶𝑀𝐹 𝑐𝑜𝑚𝑏𝑖𝑛𝑒𝑑 = 1.79

Worksheet 1B: CMF’s

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CMF combCMF 2r CMF 3r CMF 4r CMF 5r

(1)*(2)*(3)*(4)*(5)

CMF 1r

CMF for On-Street

Parking

CMF for Roadside

Fixed Objects

from Section 12.7.1

CMF for Automated Speed

Enforcement

from Equation 12-32 from Equation 12-33 from Table 12-22 from Equation 12-34

(6)

Combined CMF

(5)

Worksheet 1B -- Crash Modification Factors for Urban and Suburban Roadway Segments

(1) (2) (3)

CMF for Median Width

(4)

CMF for Lighting

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Next calculate SPFs By Collision Type

Multiple-vehicle collision – two or more moving motor vehicles involved in the crash in the following manners:• rear-end

• head-on

• angle

• sideswipe

• other

Single-vehicle collision – one moving motor vehicle involved in a crash in the following manners: collision with parked vehicle, collision with animal, collision with fixed object, collision with other object, non-collision, other

Worksheet 1C: Multiple-Vehicle Nondriveway

47

(6) (7) (8) (9)

a b

Predicted

Nbrmv

SPF Coefficients

Initial Nbrmv

Proportion of Total

Crashes

Calibration

Factor, Cr

from Table 12-3

Overdispersion

Parameter, k

Combined

CMFs

(6) from

Worksheet 1B

(2)

Crash Severity

Level

Adjusted

Nbrmv

Total

Fatal and Injury

(FI)

(1)

Worksheet 1C -- Multiple-Vehicle Nondriveway Collisions by Severity Level for Urban and Suburban Roadway Segments

(3) (4) (5)

from Table 12-3 from Equation 12-10 (4)TOTAL*(5)

(4)FI/((4)FI+(4)PDO)

(6)*(7)*(8)

Property

Damage Only

(PDO)

(5)TOTAL-(5)FI

Table 12-3

48

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Equation 12-10𝑁𝑏𝑟𝑚𝑣 = exp(𝑎 + 𝑏 × ln 𝐴𝐴𝐷𝑇 + ln(𝐿))

Where:

AADT=average annual daily traffic volume (veh/day) on roadway segment

L= length of roadway segment (mi)

a, b = regression coefficients

Nbrmv (total)= exp (-15.22+1.68 x ln(15,000)+ln(2.5) )=6.365

Nbrmv (FI)=exp (-16.22+1.66 x ln(15,000)+ln(2.5) )= 1.932

Nbrmv (PDO)=exp(-15.62+1.69 x ln(15,000)+ln(2.5) )= 4.697

But wait! 1.932+4.697≠ 6.365 Not finished yet…

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Equations 12-11 and 12-12

In order to adjust the values…

𝑁𝑏𝑟𝑚𝑣 = 6.365(1.932

1.932+4.697)= 1.855

𝑁𝑏𝑟𝑚𝑣= 6.365 – 1.855 = 4.510

*Multiply these values by the combined CMFs (1.79) and the calibration factor (1.0)

𝑁𝑏𝑟𝑚𝑣(𝐹𝐼) = 𝑁𝑏𝑟𝑚𝑣(𝑡𝑜𝑡𝑎𝑙)𝑁′𝑏𝑟𝑚𝑣(𝐹𝐼)

𝑁′𝑏𝑟𝑚𝑣 𝐹𝐼 +𝑁′𝑏𝑟𝑚𝑣(𝑃𝐷𝑂)Equation 12-11

𝑁𝑏𝑟𝑠𝑣(𝑃𝐷𝑂) = 𝑁𝑏𝑟𝑠𝑣(𝑡𝑜𝑡𝑎𝑙) − 𝑁𝑏𝑟𝑠𝑣 𝐹𝐼 Equation 12-12

Worksheet 1C: Multiple Vehicle Nondriveway Crashes by Severity

(6) (7) (8) (9)

a b

-15.22 1.68 6.365 1.79 1.00 11.410

Predicted

Nbrmv

SPF Coefficients

Initial Nbrmv

Proportion of Total

Crashes

Calibration

Factor, Cr

from Table 12-3

Overdispersion

Parameter, k

Combined

CMFs

(6) from

Worksheet 1B

(2)

6.365

1.855

Crash Severity Level

-15.62 1.69 0.87

Adjusted

Nbrmv

Total

Fatal and Injury (FI) -16.22 1.66

(1)

Worksheet 1C -- Multiple-Vehicle Nondriveway Collisions by Severity Level for Urban and Suburban Roadway Segments

(3) (4) (5)

from Table 12-3 from Equation 12-10 (4)TOTAL*(5)

0.65

0.84

1.00

3.325

8.085

(4)FI/((4)FI+(4)PDO)

1.000

0.2911.00

(6)*(7)*(8)

1.932 1.79

Property Damage Only (PDO)0.709

(5)TOTAL-(5)FI4.697 4.510 1.79

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Nbrmv (total) = 11.410 crashes/ yrNbrmv (FI) = 3.325 crashes/ yrNbrmv (PDO) = 8.085 crashes/ yr

Worksheet 1D: Multiple Nondriveway Crashes by Type

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Predicted N brmv ( PD O)

(crashes/year)

from Table 12-4(9)PDO from Worksheet

1C(9)FI from Worksheet 1C

Predicted N brmv ( F I)

(crashes/year)

Proportion of

Collision Type ( F I)

from Table 12-4

Total

(2)*(3)FI (4)*(5)PDO (3)+(5)

(2) (4) (6)

Predicted N brmv (TOTAL)

(crashes/year)

Worksheet 1D -- Multiple-Vehicle Nondriveway Collisions by Collision Type for Urban and Suburban Roadway Segments

(3)(1)

Collision Type Proportion of

Collision Type (PDO)

Sideswipe, same direction

Rear-end collision

Head-on collision

Angle collision

Sideswipe, opposite direction

Other multiple-vehicle collision

(5)

(9)TOTAL from Worksheet 1C

Table 12-4

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Worksheet 1D: Multiple Nondriveway Crashes by Type

Predicted N brmv ( PD O)

(crashes/year)

from Table 12-4(9)PD O from Worksheet

1C

(9)F I from Worksheet

1C

Predicted N brmv ( F I)

(crashes/year)

Proportion of Collision

Type( F I)

from Table 12-4

1.000 1.000Total 3.325 8.085 11.410

(2)*(3)FI (4)*(5)PDO (3)+(5)

(2) (4) (6)

Predicted N brmv (TOTAL) (crashes/year)

Worksheet 1D -- Multiple-Vehicle Nondriveway Collisions by Collision Type for Urban and Suburban Roadway Segments

(3)(1)

Collision Type Proportion of Collision

Type (PDO)

Sideswipe, same direction

Rear-end collision

Head-on collision

Angle collision

Sideswipe, opposite direction

Other multiple-vehicle collision

0.730

0.068

0.085

0.015

0.073

0.029

(5)

(9)TOTA L from Worksheet 1C

8.7176.290

0.226

0.283

0.050

0.243

0.096

2.427

0.445

0.428

0.778

0.004

0.079

0.031

0.055

0.258

0.921

0.300

0.687

0.5250.053

0.032

0.639

0.251

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Worksheet 1E: Single Vehicle Crashes by Severity

55

(6) (7) (8) (9)

a b

Combined

CMFs

Calibration

Factor, Cr

Predicted

Nbrsv

(5)TOTAL-(5)FIProperty Damage Only (PDO)

Fatal and Injury (FI)(4)FI/((4)FI+(4)PDO)

Total


SPF Coefficients Overdispersion

Parameter, k Initial Nbrsv

Worksheet 1E -- Single-Vehicle Collisions by Severity Level for Urban and Suburban Roadway Segments

(1) (2) (3) (4) (5)

Proportion of Total

Crashes

Adjusted

Nbrsv

from Table 12-5from Table 12-5 from Equation 12-13 (4)TOTAL*(5)

(6) from

Worksheet 1B(6)*(7)*(8)

Table 12-5

56

13

Equation 12-13𝑁𝑁 𝑏𝑟s𝑣=exp(𝑎+𝑏×ln(𝐴𝐴𝐷𝑇)+ln〖(𝐿)〗

Where:




Nbrsv (total)= exp (-5.47+0.56 x ln(15,000)+ln(2.5)) =2.296

Nbrsv (FI)=exp (-3.96+0.23 x ln(15,000)+ln(2.5)) = 0.435

Nbrsv (PDO)=exp(-6.51+0.64 x ln(15,000)+ln(2.5)) = 1.751

Next…

57


58


𝑁𝑏𝑟𝑠𝑣 = 2.2960.435

0.435+1.751= 0.457

𝑁𝑏𝑟s𝑣= 2.296 – 0.457 = 1.839

Multiply these values by the combined CMFs (1.79) and the calibration factor (1.0)

𝑁𝑏𝑟𝑠𝑣(𝐹𝐼) = 𝑁𝑏𝑟𝑠𝑣(𝑡𝑜𝑡𝑎𝑙)𝑁′𝑏𝑟𝑠𝑣(𝐹𝐼)

𝑁′𝑏𝑟𝑠𝑣 𝐹𝐼 +𝑁′𝑏𝑟𝑠𝑣(𝑃𝐷𝑂)Equation 12-14

𝑁𝑏𝑟𝑠𝑣(𝑃𝐷𝑂) = 𝑁𝑏𝑟𝑠𝑣(𝑡𝑜𝑡𝑎𝑙) − 𝑁𝑏𝑟𝑠𝑣 𝐹𝐼 Equation 12-15

Worksheet 1E: Single Vehicle Crashes by Severity

(6) (7) (8) (9)

a b

-5.47 0.56 2.296 1.79 1.00 4.115

Combined

CMFs

Calibration

Factor, Cr

Predicted

Nbrsv

(5)TOTAL-(5)FI 1.839 1.79 1.00 3.2960.801

0.457 1.79 0.8190.199

Property Damage Only (PDO) -6.51 0.64 0.87 1.751

Fatal and Injury (FI) -3.96 0.23 0.50 0.435(4)FI/((4)FI+(4)PDO)

Total 0.81 2.296 1.000


SPF Coefficients Overdispersion

Parameter, k Initial Nbrsv

1.00

Worksheet 1E -- Single-Vehicle Collisions by Severity Level for Urban and Suburban Roadway Segments

(1) (2) (3) (4) (5)

Proportion of Total

Crashes

Adjusted

Nbrsv

from Table 12-5from Table 12-5 from Equation 12-13 (4)TOTAL*(5)

(6) from

Worksheet 1B(6)*(7)*(8)

59

Nbrsv (total) = 4.115 crashes/ yrNbrsv (FI) = 0.819 crashes/ yrNbrsv (PDO) = 3.296 crashes/ yr

Worksheet 1F: Single Vehicle Crashes by Type

60

Other single-vehicle collision

Collision with fixed object

Collision with other object

(4)*(5)PDO (3)+(5)

Collision with animal

(2)*(3)FI

Total

Proportion of

Collision Type (PDO)

Predicted N brsv ( PD O)

(crashes/year)Predicted N brsv (TOTAL)

(crashes/year)Collision Type

Proportion of

Collision Type ( F I)

Predicted N brsv ( F I)

(crashes/year)

from Table 12-6

(2) (3) (4) (5) (6)

(9)FI from Worksheet 1E from Table 12-6(9)PDO from Worksheet

1E(9)TOTAL from Worksheet 1E

Worksheet 1F -- Single-Vehicle Collisions by Collision Type for Urban and Suburban Roadway Segments

(1)

Table 12-6

61

Worksheet 1F: Single Vehicle Crashes by Type

0.010 0.008

Other single-vehicle collision 0.241 0.197 0.162 0.534 0.731

0.013 0.043 0.051

Collision with fixed object 0.723 0.592 0.759 2.502 3.094

Collision with other object

(4)*(5)PDO (3)+(5)

Collision with animal 0.026 0.021 0.066 0.218 0.239

(2)*(3)FI

Total 1.000 0.819 4.115


Type (PDO)

Predicted N brsv ( PD O)

(crashes/year) Predicted N brsv (TOTAL) (crashes/year)

Collision Type


Type( F I)

Predicted N brsv ( F I)

(crashes/year)

from Table 12-6

(2) (3) (4) (5)

1.000 3.296

(6)

(9)F I from Worksheet

1Efrom Table 12-6

(9)PD O from Worksheet

1E(9)TOTA L from Worksheet 1E

Worksheet 1F -- Single-Vehicle Collisions by Collision Type for Urban and Suburban Roadway Segments

(1)

62

Column (3) Nbrsv (FI) = 0.819 crashes/ yrColumn (5) Nbrsv (PDO) = 3.296 crashes/ yrColumn (6) Nbrsv (total) = 4.115 crashes/ yr

Worksheet 1G: Multiple Vehicle Driveway Related by Driveway Type

63

Minor residential

Other

Total

Major residential

Minor commercial

Major industrial/institutional

Minor industrial/institutional

from Table 12-7from Table 12-7

Number of

driveways, nj Equation 12-16Driveway Type

Major commercial

Worksheet 1G -- Multiple-Vehicle Driveway-Related Collisions by Driveway Type for Urban and Suburban Roadway Segments

(1) (2) (3)

from Table 12-7

Crashes per driveway

per year, Nj

(4) (5) (6)

Coefficient for traffic

adjustment, tInitial Nbrdwy

Overdispersio

n parameter, k

nj * Nj * (AADT/15,000)t

--

Table 12-7

64


Minor residential

Other

Total

1

30

0

4

Major residential 5

10

Minor commercial




Number of driveways,

nj Equation 12-16

0.000

0.092

Driveway Type

Major commercial


(1) (2) (3)

from Table 12-7


per year, Nj

(4) (5) (6)



Overdispersion

parameter, k

nj * Nj * (AADT/15,000)t

0

--

0.158

0.050

0.172

0.023

0.083

0.016

0.025

--

1.000

--

0.000

2.325 0.81

--

0.158

0.415

0.160

1.000

1.000

1.000

1.000

1.000

1.000

1.500

65

N taken from the given information


Minor residential

Other

Total

1

30

0

4

Major residential 5

10

Minor commercial




Number of driveways,

nj Equation 12-16

0.000

0.092

Driveway Type

Major commercial


(1) (2) (3)

from Table 12-7


per year, Nj

(4) (5) (6)



Overdispersion

parameter, k

nj * Nj * (AADT/15,000)t

0

--

0.158

0.050

0.172

0.023

0.083

0.016

0.025

--

1.000

--

0.000

2.325 0.81

--

0.158

0.415

0.160

1.000

1.000

1.000

1.000

1.000

1.000

1.500

66

Variables Nj and t taken from Table 12-7

Equation 12-16𝑁𝑁 𝑏𝑟dwy=exp (a+b x ln(AADT) + ln(L))

Where:




Nbrdwy (total)= exp (-5.47+0.56 x ln(15,000)+ln(2.5) =2.296

Nbrdwy (FI)=exp (-3.96+0.23 x ln(15,000)+ln(2.5) = 0.435

Nbrdwy (PDO)=exp(-6.51+0.64 x ln(15,000)+ln(2.5) = 1.751

Next…

67

68



𝑁𝑏𝑟𝑠𝑣 = 2.2960.435

0.435+1.751= 0.457

𝑁𝑏𝑟s𝑣= 2.296 – 0.457 = 1.839

Multiply these values by the combined CMFs (1.79) and the calibration factor (1.0)

𝑁𝑑𝑟𝑤𝑦(𝐹𝐼) = 𝑁𝑏𝑟𝑑𝑤𝑦(𝑡𝑜𝑡𝑎𝑙) × 𝑓𝑑𝑤𝑦 (12-17)

𝑁𝑏𝑟𝑑𝑤𝑦(𝑃𝐷𝑂) = 𝑁𝑏𝑟𝑑𝑤𝑦(𝑡𝑜𝑡𝑎𝑙) − 𝑁𝑏𝑟𝑑𝑤𝑦(𝐹𝐼) (12-18)

Where:Fdwy = proportion of driveway-related collisions that involve fatalities or injuries

Worksheet 1H: Multiple Vehicle Driveway Related Crashes by Severity

69

(4) (5) (6) (7)

(4)*(5)*(6)

Proportion of total

crashes (fdwy)

Adjusted

Nbrdwy

Combined CMFsPredicted

Nbrdwy

Worksheet 1H -- Multiple-Vehicle Driveway-Related Collisions by Severity Level for Urban and Suburban Roadway Segments

(1) (2) (3)

Total


Initial Nbrdwy

from Table 12-7

Fatal and injury (FI)

Property damage only (PDO)

--

--

(5)TOTAL from

Worksheet 1G(2)TOTAL * (3)

(6) from

Worksheet 1B

Calibration factor, Cr

70

Table 12-7 (for severity proportions)

Worksheet 1H: Multiple Vehicle Driveway Related Crashes by Severity

(4)

2.325

0.751

1.574

(5) (6) (7)

(4)*(5)*(6)

Proportion of total

crashes (fdwy)

Adjusted

Nbrdwy

Combined CMFs Predicted Nbrdwy

Worksheet 1H -- Multiple-Vehicle Driveway-Related Collisions by Severity Level for Urban and Suburban Roadway Segments

(1) (2) (3)

Total


Initial Nbrdwy

1.000 4.168

from Table 12-7



2.325

--

--

(5)TOTAL from Worksheet

1G

0.677

1.79

1.79

1.79

1.00

1.00

1.00

1.346

2.821

(2)TOTAL * (3)(6) from Worksheet

1B

Calibration factor, Cr

0.323

71

Worksheet 1I: Vehicle-Pedestrian Crashes

72

(6) (7)

fpedr

-- 0.00

Worksheet 1I -- Vehicle-Pedestrian Collisions for Urban and Suburban Roadway Segments

(1) (8)(2) (3) (4) (5)

Predicted Nbrdwy Predicted Nbr Predicted Npedr

from Table

12-8

Calibration

factor, Cr (5)*(6)*(7)(2)+(3)+(4)(7) from

Worksheet 1H


Total

Fatal and injury (FI) --

Predicted Nbrsv

(9) from

Worksheet 1E

Predicted Nbrmv

-- -- --

(9) from

Worksheet 1C

0.000

Table 12-8

73

Worksheet 1I: Vehicle-Pedestrian Crashes(6) (7)

fpedr

0.036 1.00

-- 1.00


(1) (8)(2) (3) (4) (5)


from Table

12-8

Calibration

factor, Cr (5)*(6)*(7)(2)+(3)+(4)(7) from Worksheet 1HCrash Severity Level

Total


11.410

--

Predicted Nbrsv

(9) from Worksheet 1E

Predicted Nbrmv

--

4.168

--

19.693

--

(9) from Worksheet 1C

0.709

0.709

4.115

74

(6) (7)

fpedr

0.036 1.00

-- 1.00


(1) (8)(2) (3) (4) (5)


from Table

12-8

Calibration


Total


11.410

--

Predicted Nbrsv


Predicted Nbrmv

--

4.168

--

19.693

--


0.709

0.709

4.115

(6) (7)

fpedr

0.036 1.00

-- 1.00


(1) (8)(2) (3) (4) (5)


from Table

12-8

Calibration


Total


11.410

--

Predicted Nbrsv


Predicted Nbrmv

--

4.168

--

19.693

--


0.709

0.709

4.115

Worksheet 1J: Vehicle-Bicycle Crashes

75

(6) (7)

fbiker

-- 0.00

Worksheet 1J -- Vehicle-Bicycle Collisions for Urban and Suburban Roadway Segments

(1) (2) (3) (4) (5) (8)


Predicted Nbrmv Predicted Nbrsv Predicted Nbrdwy Predicted Nbr Calibration

factor, Cr

Predicted Nbiker

(9) from

Worksheet 1C

(9) from

Worksheet 1E

(7) from

Worksheet 1H(2)+(3)+(4)

from Table

12-9(5)*(6)*(7)

Total

Fatal and injury (FI) -- -- -- -- 0.000

Table 12-9

76

Worksheet 1J: Vehicle-Bicycle Crashes(6) (7)

fbiker

0.018 1.00

-- 1.00

Worksheet 1J -- Vehicle-Bicycle Collisions for Urban and Suburban Roadway Segments

(1) (2) (3) (4) (5) (8)


Predicted Nbrmv Predicted Nbrsv Predicted Nbrdwy Predicted Nbr Calibration

factor, Cr

Predicted Nbiker

(9) from Worksheet 1C (9) from Worksheet 1E (7) from Worksheet 1H (2)+(3)+(4)from Table

12-9(5)*(6)*(7)

Total 11.410 4.115 4.168 19.693 0.354

Fatal and injury (FI) -- -- -- -- 0.354

77

Worksheet 1K: Crash Severity Distribution

78

(3) (4)(1)

(8) from Worksheet 1I and 1J

(5) from Worksheet 1D and 1F; and

(7) from Worksheet 1H

(6) from Worksheet 1D and 1F;

(7) from Worksheet 1H; and

Fatal and injury (FI) Property damage only (PDO) Total

MULTIPLE-VEHICLE

Rear-end collisions (from Worksheet 1D)

Head-on collisions (from Worksheet 1D)



Collision with other object (from Worksheet 1F)

Other single-vehicle collision (from Worksheet 1F)

Collision with bicycle (from Worksheet 1J)

Collision with pedestrian (from Worksheet 1I)

SINGLE-VEHICLE

Subtotal

Total

Angle collisions (from Worksheet 1D)

Sideswipe, same direction (from Worksheet 1D)

Sideswipe, opposite direction (from Worksheet 1D)

Driveway-related collisions (from Worksheet 1H)

Other multiple-vehicle collision (from Worksheet 1D)

Subtotal

Collision with animal (from Worksheet 1F)

Collision with fixed object (from Worksheet 1F)

Worksheet 1K -- Crash Severity Distribution for Urban and Suburban Roadway Segments

(2)


Collision type

Worksheet 1K: Crash Severity Distribution

(3) (4)(1)


(5) from Worksheet 1D and 1F; and

(7) from Worksheet 1H



Fatal and injury (FI) Property damage only (PDO) Total

MULTIPLE-VEHICLE

Rear-end collisions (from Worksheet 1D)

Head-on collisions (from Worksheet 1D)

8.717

0.258



6.290

0.0320.226

Collision with other object (from Worksheet 1F)

Other single-vehicle collision (from Worksheet 1F)

10.906

Collision with bicycle (from Worksheet 1J)

Collision with pedestrian (from Worksheet 1I) 0.709

SINGLE-VEHICLE

0.283

0.050

0.243

1.346

0.354

4.671

0.921

0.197

0.096

Subtotal

Total

2.427

0.300

0.687

4.168

0.525

0.639

0.251

0.445

2.821

0.428

0.000

Angle collisions (from Worksheet 1D)

Sideswipe, same direction (from Worksheet 1D)

Sideswipe, opposite direction (from Worksheet 1D)

Driveway-related collisions (from Worksheet 1H)

Other multiple-vehicle collision (from Worksheet 1D)

Subtotal

1.882

Collision with animal (from Worksheet 1F)

Collision with fixed object (from Worksheet 1F)

15.577

Worksheet 1K -- Crash Severity Distribution for Urban and Suburban Roadway Segments

(2)

6.554

0.218

2.502

0.043

0.534

0.000

3.296 5.179

20.756

0.709

0.354

0.239

3.094

0.051

0.731


14.203

Collision type

0.021

0.592

0.008

79

FI Crashes = 6.554 PDO Crashes = 14.203 Total Crashes = 20.756

Worksheet 1L: Summary of Results

80

(4)

Predicted average crash

frequency, N predicted rs

(crashes/year)

Roadway segment length, L

(mi)

(Total) from Worksheet 1K

Total


(1)


(2)


Crash rate (crashes/mi/year)

(2) / (3)

(3)

Worksheet 1L -- Summary Results for Urban and Suburban Roadway Segments

Worksheet 1L: Summary of Results

(4)

Predicted average crash

frequency, N predicted rs

(crashes/year)Roadway segment length, L (mi)


Total


2.50

2.50

(1)


(2)


20.8

6.6

14.2

Crash rate (crashes/mi/year)

(2) / (3)

2.50

8.3

2.6

5.7

(3)

Worksheet 1L -- Summary Results for Urban and Suburban Roadway Segments

81

Urban 4 Leg Signalized Intersection(This example using the Excel Tool)

82

Pertinent Data:•1 left-turn lane on each of the two major road approaches

•No right-turn lanes

•Protected left-turn signal phasing on major road (both approaches)

•AADT (major rd) = 20,000 veh/ day

•AADT (minor rd) = 8,000 veh/ day

•Lighting is present

83

Pertinent Data (cont.):•1 bus stop 400 ft from the intersection

•A high school is located 800 ft from the intersection

•Coqui Bar, Coco Bar, Fiesta Bar, and Margarita Bar located within 1,000 ft of the intersection

•No approaches with prohibited right-turn-on-red

•4-lane undivided major road

•2-lane undivided minor road

•Pedestrian volume = 1,200 ped/day

84

Assumptions:•The calibration factor = 1.00

•The maximum number of lanes crossed by a pedestrian is assumed to be 4

•Collision type distributions are the default values from HSM 2010

85

86

Required:•Crash Modification Factors (CMF’s) applicable only to the four-leg signalized intersections

1. CMF for the effect of left-turn lanes

2. CMF for the effect of left-turn signal phasing

3. CMF for the effect of right-turn lanes

4. CMF for the effect of right-turn-on-red

5. CMF for the effect of lighting

6. CMF for the effect of red-light cameras

7. CMF for the effect of bus stops

8. CMF for the effect of schools

9. CMF for the effect of alcohol sales establishments



First, find out what is the site type from Table 12-1:

87

Safety Performance Functions for Urban and Suburban Arterials (Table 12-2)

88

89



Type of left-turn signal phasing for Leg #4 (if applicable) --

Number of alcohol sales establishments within 300 m (1,000 ft) of the intersection 0

Not PresentSchools within 300 m (1,000 ft) of the intersection (present/not present)

Number of approaches with left-turn lanes (0,1,2,3,4) [for 3SG, use maximum value of 3]

0

--

Number of approaches with right-turn lanes (0,1,2,3,4) [for 3SG, use maximum value of 3]

Intersection red light cameras (present/not present)

--

Type of left-turn signal phasing for Leg #1

Maximum number of lanes crossed by a pedestrian (nlanesx)

Sum of all pedestrian crossing volumes (PedVol) -- Signalized intersections only

Type of left-turn signal phasing for Leg #2

Intersection lighting (present/not present) Not Present

Calibration factor, Ci

AADT minor (veh/day)

Number of bus stops within 300 m (1,000 ft) of the intersection 0

Type of left-turn signal phasing for Leg #3 --

0

--

Number of approaches with left-turn signal phasing [for 3SG, use maximum value of 3]

Permissive

Not Present

Number of approaches with right-turn-on-red prohibited [for 3SG, use maximum value of 3] 0

Data for signalized intersections only: --

Worksheet 2A -- General Information and Input Data for Urban and Suburban Arterial Intersections


Analyst Roadway

Intersection type (3ST, 3SG, 4ST, 4SG) --

Analysis Year


Number of major-road approaches with left-turn lanes (0,1,2) 0

Number of major-road approaches with right-turn lanes (0,1,2) 0

Agency or Company Intersection

Date Performed Jurisdiction

--AADT major (veh/day)

1.00

Data for unsignalized intersections only: --

--

Worksheet 2A – Urban and Suburban Arterial Intersections

Worksheet 2B – Double Check the Values!

90

CMF Intersection Left-Turn Lane (Table 12-24):

CMF Intersection Left-Turn Lane = 0.81

91

CMF Left-Turn Phasing Signal (Table 12-25):

2 approaches, therefore must multiply 0.94 x 0.94 = 0.88

CMF Left-Turn Phasing Signal = 0.88

92

CMF of Right-Turn Lanes (Table 12-26):Are there right-turn lanes?

CMF Right-Turn Lanes = 1.0 (Base Condition)

93

CMF for Right Turn on RedRight turn on red is not prohibited (base condition)

Therefore CMF 4i = 1.00

If the movement was prohibited, use Equation 12.35

94

CMF of lighting (Table 12-27):

Equation 12-36: CMF (lighting)=1-0.38 x P (night)

P (night): 1 - 0.38 x 0.235 = 0.91

CMF 5i = 0.91

95

CMF for Red Light CamerasNo cameras (base condition)

CMF6i Red Light Cameras = 1.00

If there were cameras, use Equation 12-37

96

Worksheet 2C – Double Check the Values!

97

Table 12-10

98

Worksheet 2D – Double Check the Values!

99

Table 12-11

100

Worksheet 2E – Double Check the Values!

101

102

Table 12-12

Worksheet 2F – Double Check the Values!

103

Table 12-13

104

Worksheet 2G – Does not apply to intersections

105

Worksheet 2H – Double Check the Values!

106

Table 12-28 (CMF Bus Stops) :

CMF Bus Stops = 2.78

107

Table 12-29 (CMF Presence of Schools) :CMF School = 1.35

108

Table 12-30 (CMF Alcohol Sales):CMF Alcohol Sales = 1.12

109

Worksheet 2I – Double Check the Values!

110

Table 12-14:

111

Worksheet 2J – Double Check the Values!

112

113

Table 12-17

Worksheets 2K & 2L – Crash Summaries

114

115

Crash severity level

Worksheet 2L -- Summary Results for Urban and Suburban Arterial Intersections

(1) (2)

Property damage only (PDO) 2.5

Total


4.1

1.6

Predicted average crash frequency, Npredicted int

(crashes/year)


Empirical Bayes Method116

Empirical Bayes Method:

117

Evaluate the predicted number ofcrashes using the Empirical BayesMethod

Empirical Bayes Method:

118

Used to combined observed crashfrequency data for a given site withpredicted crash frequency data frommany similar sites to estimate itsexpected crash frequency.

The advantages of using EB Method for crash data analysis

119

“The Empirical Bayes method addresses two problems of safety estimation;

1. it increases the precision of estimates beyond what is possible when one is limited to the use of a two-three year history accidents, and

2. it corrects for the regression-to-mean bias.

The increase in precision is important when the usual estimate is too imprecise to be useful. The elimination of the regression to mean bias is important whenever the accident history of the entity is in some way connected with the reason why its safety is estimated.”

Hauer, et al. Estiating Safety by the Empirical Bayes Method: A Tutorial, website: http://www.ctre.iastate.edu/educweb/ce552/docs/Bayes_tutor_hauer.pdf

The project – Using EmpiricalBayes Method•What is the expected crash frequency of the project for a particular yearusing the site-specific EB Method?• The following is the breakdown of the observed crashes per section type:

2U Segment

•Multiple-vehicle non-driveway = 4

•Single-vehicle = 6

•Multiple-vehicle driveway related = 1

4SG Segment

•Multiple-vehicle = 8

•Single-vehicle = 2

120

Worksheet 3A: Predicted Crashes by Severity & Type Using EB Method (Segment)

121

Worksheet 3A: Predicted Crashes by Severity & Type Using EB Method (Intersection)

122

Column#7: Weighted Adjustment, w

𝑤 =1

1+𝑘× 𝑎𝑙𝑙 𝑠𝑡𝑢𝑑𝑦 𝑦𝑒𝑎𝑟𝑠 𝑁𝑝𝑟𝑒𝑑𝑖𝑐𝑡𝑒𝑑

123

Multiple-vehicle non-driveway (segment):

𝑤 =1

1+0.84×11.41= 0.094

Column#8: Expected Average Crash Frequency, Nexpected

124

𝑁𝑒𝑥𝑝𝑒𝑐𝑡𝑒𝑑 = 𝑤 × 𝑁𝑝𝑟𝑒𝑑𝑖𝑐𝑡𝑒𝑑 + (1 − 𝑤) × 𝑁𝑜𝑏𝑠𝑒𝑟𝑣𝑒𝑑

Multiple-vehicle Non-driveway Collisions (Segment):

𝑁𝑒𝑥𝑝𝑒𝑐𝑡𝑒𝑑 = 0.094 × 11.41 + 1 − 0.094 × 7 = 7.417 𝑐𝑟𝑎𝑠ℎ𝑒𝑠/𝑦𝑟

Worksheet 3B: Predicted Pedestrian & Bicycle Crashes

125

Worksheet 1I, Column 8

Worksheet 2J, Column 7Worksheet 2I, Column 7

Worksheet 1J, Column 8

Worksheet 3C: Site Specific EB Method Results

126

Calibration Factor (Cr) Formula

Where:

Cr = constant used to multiply the base SPF to correct the number of expected crashes at the applied location

Nobserved = number of observed crashes for the selected set of sites

Npredicted = number of predicted crashes

Note:

Appendix A in Part C of the HSM contains a detailed procedure to obtain the c-factor.

𝐶𝑟 = 𝑁𝑜𝑏𝑠𝑒𝑟𝑣𝑒𝑑 𝑁𝑝𝑟𝑒𝑑𝑖𝑐𝑡𝑒𝑑

127

Site Selection Criteria to Determine the Calibration Factor (Cr)

1. Between 30-50 sites minimum should be selected through random sampling

2. Sites should be long enough to be representative of a roadway section, but no shorter than 0.10 mile in length

3. Sites must exhibit at least 100 crashes per year

4. A minimum of three years of historical crash data must be used

128

Crash Modification Factors Clearinghouse Website http://www.cmfclearinghouse.org

129

New Changes for the HSM 2010

NCHRP 17-45, May 2012

The Enhanced Safety Prediction Methodology And Analysis Tool For

Freeways And Interchanges

130

PRSHSP

131

• Available: http://www.carreterasegurapr.com/Content/docs/Puerto_Rico_SHSP_2014-2018_English.pdf

• Strategic Plan for years 2014 - 2018

Topics Covered:

132

• Highway Safety in the Commonwealth of Puerto Rico

• The planning and development process

• The emphasis areas• Future steps in the

implementation• Evaluation of the Strategic

Highway Safety Plan

133

Flowchart of the 2014 Puerto Rico SHSP Developmentand Implementation Process

Predictive Model for Freeway Segments (NCHRP 17-45)

1. Rural freeway◦ with four through lanes,

◦ with six through lanes,

◦ with eight through lanes,

2. Urban freeway ◦ with four through lanes,

◦ with six through lanes,

◦ with eight through lanes, and

◦ with ten through lanes.

134

Predictive Model for Ramp and Collector Distributor (C-D) Road Segments

RURAL

1. Entrance ramp with one lane,

2. Exit ramp with one lane,

3. C-D road with one lane

URBAN

1. C-D road with one lane,

2. C-D road with two lanes,

3. Entrance ramp with one lane,

4. Entrance ramp with two lanes,

5. Exit ramp with one lane, and

6. Exit ramp with two lanes.

135

136

Gracias por su atención

Introducción al Manual de Seguridad en Carreteras, HSM...

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