CE 7600: Highway Safety and Risk Management Dr. Tapan Datta.

CE 7600: Highway Safety and Risk Management

Dr. Tapan Datta

Paired T Test

Analysis Question: Is the before mean of a group of locations significantly different from the after mean

for the same locations?.Null Hypothesis: There is no difference between the before mean and

variance of a group of locations and the after mean and variances for the same locations.

XB – XA

SD/NWhere XB = Before sample mean XA = After Sample Mean

S2D = S2

B + S2A – 2 (XB1 – XB) (XA1 – XA)

1 N-1

N

J=1N = Number of Locations

If tcalculated > tcritical, difference in means is statistically significant where degrees of freedom = N-1

t =

Example of Paired T test

1 2 3 4 5 6Expected Crash Rate Without Treatment 2.75 3.34 2.9 0.43 1.28 1.37After Crash Rate 0.81 0.58 1.54 0.71 1.45 1.325

Locations(j) No. of Accidents (Length of period t)

Group

Mean of expected crash rate without treatment = 2.01

Mean of after period crash rate = 1.07

Variance of the expected crash rate without treatment = 1.31

Variance of the after crash rate = 0.17

t calculated

= 1.819; t critical = 1.476 @ = 0.10

Since, tcalculated > tcritical, difference between the before crash rate mean and the after crash rate mean is statistically significant at 90 % Level of confidence

E - Perform Economic Analysis

Methods to Use • Benefit/Cost Ratio Method - The ratio of the

benefits accrued from accident and/or severity reduction to costs needed to implement the countermeasures.

• Cost Effectiveness Method - The cost to the agency of preventing a single accident or accident type.

F - Prepare Evaluation Documentation

The evaluator must draw conclusions regarding the overall effectiveness and worth of the project and review the appropriateness of all activities of the evaluation study which lead to the final conclusions.

G - Develop and Update Effectiveness of Database

• An effectiveness database is an accumulation of sound project evaluation results which are directly usable as input to project selection and project development within the Planning Component.

• The data base should contain information on the accident reducing capabilities of a project in terms of average accident rate reduction.

• This information is a requirement for use in economic analysis of proposed projects.

RISK MANAGEMENT

What is Risk Management?

Risk Management for a road agency is the identification, measurement and treatment of potential traffic crashes and associated tort liability and monetary losses.

A well planned risk management system will enable a road agency to handle its exposure to traffic crash losses and associated tort liability in the most economical and effective way.

What is Risk?

Risk is defined as the variation in the possible outcomes in a given situation

– Pure Risk• When there is a chance of loss, but no

chance of gain.

– Speculative Risk• When there is a chance of gain as well

as loss.

Steps Involved in the Process

1. Risk Identification – identifying particular types of potential loss exposure

2. Estimation of potential losses associated with these exposures:

a) Probability that each particular type of loss will occur

b) Estimation of the total losses likely to occur during the planning period

c) Financial impact of these losses

Steps Involved in the Process

3. Selection of appropriate tools to be used in alleviating the risk

4. Implementation of risk management process

5. Monitoring and Evaluation

The Legal System

Plaintiff: one who makes the original complain against the other party

Defendant: the other party who is defending the complain

Attorney at Law: A person qualified in character and training to serve as an official of the court in representing people and agencies, and advising them in regard to law.

American Legal System1. Federal Statutory Law

– enacted by the U.S. Congress– enforced by the President through executive

branch of government– interpreted by

• U.S. District Courts• U.S. Circuit Courts of Appeals• U.S. Supreme Court

– seldom involved in tort liability• Federal Government cannot be sued except with

their permission

American Legal System (Cont.)

2. State Statutory Law– enacted by state legislative bodies– enforced by the Governor and executive

agencies– interpreted by state trial courts, appellate

courts, and State Supreme Court

American Legal System (Cont.)

3. Municipal Court or “City Court”– judicial arm of municipal government– legislative equivalent is the City Council– executive equivalent is the Mayor

U.S. Court System

1. U.S. District Court– trial court– one or several districts in each state

2. Circuit Courts of Appeals– 11 circuits each with a court of appeals– intermediate between the trial court and

the Supreme Court

U.S. Court System (Cont.)

3. U.S. Supreme Court– highest court in the nation– appellate court– ultimate decision forum for all legal questions,

state and federal

• 4. Specialty Courts– maritime courts– patent courts– U.S. courts of Claims

Michigan’s State Court System

1. Municipal Court– independent courts operated by city

governments– courts of original jurisdiction – monetary limitations– scope: enforce municipal code

– traffic fines– disturbing the peace charges, etc

Michigan’s State Court System (Cont.)

2. Probate with Probate Judge– judge hears cases in chambers – formal filing of wills

3. District Courts– lowest level of original jurisdiction– claims up to $10,000– cases heard by judge or jury

Michigan’s State Court System (Cont.)

4. Circuit Courts– highest ranking trial court– lawsuits over $10,000– cases heard by a jury

– unless the state is the defendant

5. Court of Civil Appeals– intermediate appellate court– claims less than $10,000– does not exist in Michigan

Types of Law

Statutory Law- enacted by a legislative body

Case Law - body of the law created by judgesRegulatory Law - enacted by a regulatory agency with more detailed

provisions of a legislative enactmentSubstantive Law - applies to any substance of any given issue

Types of Law (Cont.)Procedural Law

- procedures to be followed in pursuing a legal remedy

Criminal Law - enforcement of standards of conduct by the

State - State is always a party to the criminal case Civil Law - non-criminal law dealing with regulation

Concept of Tort and Negligence

Tort - a civil wrong or injury. The person/agency performing the tort is liable for damages.

Negligence – failure to use reasonable care in dealing with others.

Concept of Tort and Negligence

In order to win a judgment on the grounds of negligence, the plaintiff must prove:

• Defendant (road agency) had a duty to use reasonable care toward plaintiff (road user).

• Defendant breached that duty (negligence)• Defendant’s negligence was a proximate cause of

plaintiff’s injury.• Plaintiff incurred resulting damages.

Notice of Defect• Actual Notice

– Simplest form, e.g., a complaint call.

• Constructive Notice– If defects exist for an “unreasonable” length of

time, it should have been discovered by the road agency.

• Statutory Notice– A “readily apparent” defect for 30 days, the road

agency is conclusively presumed to know it with sufficient time to correct it.

• Notice by Own Actions– IF entity’s own actions cause the defect, no

notice is required.

Jury vs. Judge Trial

• A dispute not settled or abandoned prior to trial may be submitted to a judge or a jury

• Juries consist of persons selected from the community to pass upon guilt in criminal matters, and to decide disputed factual questions in civil matters.

• In state courts, attorneys are allowed to question the jurors to determine their impartiality.

Jury vs. Judge Trial

• One aspect of jury system both praised and criticized is that: Jurors need not to give any reasons for their

opinions. Jurors are free to disregard the law if they

so desire. While the judge instructs the jury as to the

law, they are, for all practical purposes, free to do as they choose.

PROCEDURES USED IN LAW SUIT

• Initiating a Complaint

– Filing a Complaint • A complaint is a document asserting a legal

stance claiming that someone and/or something was wrong.

– Service of Complaint and Summons• A “Summons” is a command to a party to

either appear for a trial or to file a document of denial, which is called an “Answer”

• Initiating a Complaint (continued)

– Filing of Answer• After an “Answer” has been filed, the case is

said to be at “Issue”

– Other Pleadings• Plaintiff may wish to file a “Response”, which

is a document responding to the “Answer”. Defendant may file a “Counterclaim”.


• Discovery of FactsA process sanctioned by the court in which attorneys representing each party gather information about the case. It is designed to reveal strengths and weaknesses of the case and thereby permit an appraisal of settlement potential.

– Interrogatories • Written questions about the case submitted by

one party to the other

– Requests for admissions• Written statements of facts addressed to one

party by other with a demand for admission of such statements of fact


• Discovery of Facts (Continued)– Depositions

• Established procedures for oral questions to be asked by an attorney to other parties, witnesses or experts, with the answers given under oath. A word-for-word transcript is made by a court reporter.

– Production of Documents• Requesting and obtaining documents from

the other party


• Mediation-ArbitrationA third party dispute resolution system that resembles litigation, but has important differences.

– Third party seeks to mediate disputes between the adversarial parties by aiding in the negotiation process with a view toward settlement

– If the parties do not agree to a settlement of the dispute, the third party then uses normal arbitration power to decide the case

– Mediator-Arbitrator is selected in advance by the parties

– Designed to avoid costs, inefficiencies and unpredictability of the judicial system


• The Trial1. Jury selection (If a jury trial)

• Challenges for cause• Preemptory challenges

2. Opening statements of counsel (Not evidence)

3. Plaintiff’s case• Witnesses: Direct examination• Witnesses: Cross examination• Documentary evidence


• The Trial (continued)

4. Defendant’s case (same sequence as Plaintiff’s)

5. Closing statements of counsel (Not evidence)

6. Jury instructions by court

7. Jury deliberations and verdict

8. Judgment of court


• Post-Trial Activities

It is important to collect data on the number of claims and losses, the categories in which the losses occur.

– Classify functional areas and geographic locations that are most likely to generate new lawsuits and large judgments

– Target resources to improve those facilities for which the agency is most vulnerable


• Selecting Cases to AppealThe basis for appealing a court decision is an alleged error in trial procedure or application of the law.

– Jurors finding of the facts of the case cannot be appealed

– For small awards, it is impractical to be concerned about an appeal

– A well-conceived loss mitigation program will carefully select those cases for appeal that would otherwise set adverse precedents


Risk Management System

An ideal goal for all agencies would be the elimination of all traffic crashes, which is not realistically achievable.

A Risk Management System permits a road agency to target specific improvements which will minimize traffic crashes, lawsuits, and the fiscal losses.

Objectives of Risk Management System

1. To minimize the number of lawsuits filed against a road agency

2. To minimize the number of those suits that are ultimately lost or settled adversely

3. To minimize the total dollar damages from tort liability

Programs and Processes in Risk Management System

Programs• Crash reduction• Loss reduction• Defect surveillance• Public relations

Processes• Risk identification• Resource allocation• Risk management evaluation


Risk Identification Process

Crash Reduction Program Loss Reduction Program

Defect Surveillance Program

Public RelationsProgram

Resource Allocation Process

Countermeasure Implementation

Risk Management Evaluation Process

Transfer Lessons from Evaluationto Various Programs

Program Components of Risk Management System

1. Crash Reduction Program- Identify hazardous locations- Identify alternative countermeasures- Select the most suitable countermeasures- Implement and review the selected

countermeasures- Evaluate effectiveness


2. Loss Reduction Program• Crash site investigation• Review the history of complaints• Perform a liability assessment• Administer discovery process(es)• Coordinate expert witnesses and deposition needs• Coordinate all aspects with attorney(s)• Determine trial support needs• Review and critique all aspects of trial procedures• Provide risk management recommendations


3. Defect Surveillance Program

• Up-to-date inventories• Citizens’ complaint system• Employee review system• Complaint deposition system


4. Public Relations Program

• Coordination with local radio stations to encourage reporting of defect and crash surveillance information

• Public information news releases to create a positive image of the road agency

Inputs to the Risk Management System


Crash Reduction Program Loss Reduction Program

Defect Surveillance

Program

Public Relations

Program

CrashHistory

RoadwayData

TrafficData

PastLawsuitsHistory

History ofJudgments &Settlements

Citizens’Complaint

Data

EmployeeReview

Data

ComplaintDisposition

Data

MediaAvailability

MediaSupport

Key Process Within the Risk Management System

1. Risk Identification ProcessConsists of one or more of the following

activities• Determine crash rates• Determine severity rates• Determine fatality rates• Determine various exposure measures• Determine frequency and rate of lawsuits


1. Risk Identification Process(Continued)• Categorize roadway situations by type

• high, medium, and low probability of generating lawsuits against the agency

• Determine probability of crashes for each type of roadway situation

• Determine the risk factor (i.e., a factor based on crash history and defects)

• Rank ordering of situations by risk factor

Roadway Categories:- Urban-Rural- Number of lanes - Intersection, tangent and curve sections- Traffic volumes- Percent grades- Types of shoulder and shoulder widths- Type of traffic control- Type of defects, etc.



2. Resource Allocation Process- Identify the types of deficiencies by roadway

situations- Estimate safety improvement costs- Estimate judgment/settlement costs- Determine benefits derived from risk

reduction/elimination- Determine benefit/cost ratios- Determine resource allocation strategy


3. Risk Management Evaluation Process- Conduct a highway safety evaluation

program following FHWA documents- Determine the reduction or increase in the

lawsuit rate- Determine the reduction or increase in the

judgment settlement rate- Perform significance testing- Determine the benefit (loss) from the risk

management program

Goals of a Risk Management System

Minimization of:• Highway traffic crashes• Highway traffic crash severity• Highway traffic crash potential• Lawsuits stemming from highway traffic

crashes• Losses from lawsuits

Key Individuals in a Typical Road Agency

• Policy Makers

• Highway Designers

• Highway Operational Personnel

• Highway Maintenance Personnel

• Enforcement Personnel

• Defense Attorneys

• Risk Management Analysts

Data Needs

Historic and current data • Traffic crashes• Roadways• Roadsides• Traffic control devices• Maintenance • Lawsuits

Crash Data

A comprehensive historical crash database (for a minimum of 3 years), as well as current crash data, inclusive of the entire roadway network, which entails:

• A roadway location index• A system for entering and locating all

reported traffic crashes• A procedure for retrieving crash data on

demand

Roadway Data

Roadway database should contain the following information for each segment of roadway:

• Classification by urban, suburban, rural• Number of lanes by direction• Lane widths• Shoulder type and width• Alignment• Grades• Roadway condition• Traffic volume• Others

Roadway Data

Road agencies should establish a computerized database.

– Photologs

– Videologs

– Asset management systems

Pavement Condition Inventory• Location reference and length of section• Classification• Geometry

– Number of lanes, lane width, shoulder type and width,

• Pavement Type• Condition Assessment of Pavement Distress

– Location, Type and Severity• Cracking: alligator, longitudinal or transverse• Patches• Rutting and depressions• Weathering and raveling• Potholes • Others

Traffic Sign Inventory• Location Information• Sign Information

– Sign message and code – Sign Condition– Retro-reflectivity

• Support information– Type and condition

• Standard or Nonstandard• Date of Last Maintenance • Life Expectancy

Traffic Signal Inventory

• Location Information• Signal Information

– Number and size of signal heads

• Controller Information– Type, make, model

• Pedestrian Signal Information• Signal Timing Information

– Number of Plans– Days/Hours of Operation – Cycle length, phasing and timing details

• Maintenance Information

Pavement Marking Inventory– Longitudinal Pavement Markings– Transverse Pavement Markings– Word/Symbol Pavement Markings

• Location Information

• Type/Color

• Condition

• Retro-reflectivity

Sidewalk/Handicap Ramp Inventory

• Location Information

• Width/Length/Material

• Condition of Sidewalk

• Presence of Handicap Ramp

GIS Base-map for the City of Detroit

Longitudinal Pavement Marking Inventory

Word Pavement Marking Inventory

Pavement Marking Inventory on Warren Avenue

Pavement Marking Data Inventory in GIS

Loss Data

The following data should be compiled for the lawsuit complaints, depositions, judgments, post-trial analyses, etc:

• Type of roadway situation involved in the lawsuit, e.g., intersection, curve, tangent, urban-rural, number of lanes, etc.

• Type of crash, including severity• Vehicle speeds involved in the crash• Nature of alleged defect• Expert witnesses used by defense and plaintiff• Details of post-trial analysis• Any other information which can assist in the loss

reduction program

Defect DataIrrespective of the size of a roadway system under the jurisdiction of an agency, the agency should perform a comprehensive inventory of roadway defects. Following typical roadway defects should be identified and inventoried:

Shoulder• Significant drop-off• Soft shoulder• No shoulder• Drainage ditch too close to the edge of pavement

Defect Data

Designs• Improper super elevation• Sight distance restrictions

Surface• Slippery• Large pot holes• Washboarding and rutting (gravel roads)

Defect Data

Work Zone• Nonstandard traffic control devices• Inadequate advance warning• Nonreflecting signing• Improper delineation• lack of barriers separating traffic and workers

Defect DataSigns• Nonstandard• Obstructed view of sign• Nonreflectorized• Absence when needed

Roadside Obstacles• Utility poles, sign posts• Bridge abutments and piers• Trees• Boulders

Defect DataBridges• Too narrow• Inadequate bridge rails

Railroad Crossings• Absence of standard signs and markings• Absence of flashers and/or gates when warranted

Drainage• Inadequate drainage of the pavement surface• Ponding• Clogged inlet gates

Defect Data

Signals• Unwarranted signals• Absence when needed• Improper timing design• Improper phasing

Markings• Absence of edgelines when warranted• Obliterated or badly worn lines

Defect Data

Guardrail• Nonstandard• Improper end treatment

Maintenance• Lack of appropriate ice and snow removal

and/or treatment• Inadequate grading of gravel roads• Permitting any of above-mentioned defects to

develop and/or remain for an unreasonable time


A process by which a road agency systematically identifies its liability exposure using past data and state-of-the-art analysis techniques.

Knowledge of where future traffic crashes are most likely to occur, and situations where the risk of being sued is greatest is essential information for a road agency.

This knowledge can then be usedTo alter the roadway features (make it safer)To alter strategies, maintenance policies and procedures

In order to identify potential risks one must have access to and analyze:

• Crash category• Lawsuit history within the agency, and/or• Lawsuit history in the region


In order to identify potential risks one must have access to and analyze:

• Crash category• Lawsuit history within the agency, and/or• Lawsuit history in the region


The risk identification process is rigorous for larger road agencies, like State DOT, large county and large cities.

For small road road agencies, risk identification may have to be based on:

• Risk trends in the region• Roadway situations which have been identified by

others as high risk locations for local roadway environments, and/or

• Observed defects on the roadway and its environment

Crash History

A complete review of past crash data is necessary to provide answers to questions like:

• Where are the roadway crashes occurring?• What types of roadway situations are experiencing

roadway crashes?• Where are the injury and fatal crashes happening?• What are the crash, injury and fatality rates at

various roadway situation types?

Crash HistoryFor larger road agencies with computerized crash database, these questions can be answered by performing the following analysis:

1. Divide the roadway system into urban, suburban and rural categories

2. Subdivide crash database into the above categories3. Identify in each of the three categories the following

situation types:• Intersections of various numbers of approach

lanes and configurations• Tangent sections• Curves – isolated, winding• Grades – isolated, rolling

Crash History

(Continued)

4. Accumulate crash data by each type of the situation types for urban, suburban and rural categories

5. Perform a count of each type of situation within each category

6. Determine 3-year crash history for each situation type within the category

ExampleA county road agency has the following road mileage categories:A. 500 road miles in urban areasB. 800 road miles in suburban areasC. 700 road miles in rural areas

The three year crash history distributed among three categories is:

A. 6,000 total crashes (60 fatal, 2,000 injury & 3,940 PDO)B. 4,000 total crashes (40 fatal, 1,500 injury & 2,460 PDO)C. 2,000 total crashes (100 fatal, 1,000 injury & 900 PDO)

Example (contd.)The county has the following roadway situations within each category of the road systems:A. Urban

• 2,400 intersections• 800 5 lane-5 lane• 800 4 lane-4 lane• 300 5 lane-2 lane• 300 4 lane-2 lane• 200 2 lane-2 lane

• 400 miles of tangent sections• 150 miles of 5 lane• 150 miles of 4 lane• 100 miles of 2 lane

• 100 isolated curves• 50 winding sections• 30 roadway segments with grades• 25 roadway segments with rolling terrain

Example (contd.)

Similar characteristics for the suburban and rural road systems would also be available.

For each category and situation type:– Determine the crash, injury and fatality rates

to assess the crash experience and associated risk

– Should also consider exposure factors Traffic Volumes

1. Develop of probability density functions P(x) for the occurrence of crashes

– Develop using a vast amount of actual data– Assume a probability density function

• Poisson distribution• Assume mean value of occurrence using the mean of the

historical data

2. Develop loss probability functions– Monetary loss data associated with the crash would also

be obtained• Using a vast amount of actual data or the Poisson Distribution

3. Determination of the most probable causes of crashes from past history

4. Determination of the costs of countermeasures

Risk Analysis

5. Determination of loss risk functions:

Simple form:Expected loss at ‘X’ failures = P(x) * loss amount

where: x = No. crashes

Complex form:Expected loss at ‘X’ failures = P(x) * loss amount + f(defects)

where: f(x) = function of defects in the system related to accidents based on historical data

f(defects) = w1d1 + w2d2 + ……………wndn

where: wi = weighting factors in the same unit as loss values, often in monetary units

Risk Analysis

6. Economic analysis

7. Development of alternative decision strategies

8. Management decision making

9. Implementation of countermeasures

Risk Analysis

Determination of Probability of Traffic Crashes

M TOTAL = Mean total crashes in a particular situation type

for a specific roadway category per unit time per location.

M INJURY = Mean injury crashes in a particular situation type

for a specific roadway category per unit time per location.

M FATAL = Mean fatal crashes in a particular situation type for

a specific roadway category per unit time per location.

Expected values of future crashes at any particular situation/category site can be determined as follows:

Example (contd.)

Suppose, there are 30 injury crashes at the 100 isolated curves in the study area.

The expected value of future crashes at these types of curves can be computed as:• 30 injury crashes per 100 curves per 3 years, or• 10 injury crashes per 100 curves per year

Probability of Occurrences:

where P (x) = Probability that there will be “x” number of occurrences over a specific time frame

M = Mean or expected value of total, fatal or injury crash over the same time frame

X = Number of occurrences

= M, where = standard deviation

P (x) =x!

MX . e-M

Example (contd.)M = 30 crashes per 3 years/100 curves = 0.10 injury crashes/curve/year Standard deviation = 0.316 crashes /curve/yr

(0.1)0 . e-0.1

Similarly, P (1) = 0.0905, P (2) = 0.0045, P (3) = 0.001Probability of 0 to 3 injury crashes, P (0 to 3)

= P (0) + P (1) + P (2) + P (3) = 0.9999Therefore, P (> 3 injury crashes) = 1 – 0.9999

= 0.0001

P (0) =0!

= 0.905

P(X=x)

1 2

Poisson Distribution with a mean crash occurrence =0.10

x

0.2

0.4

0.6

0.8

1.0

0 3

0.0905

0.905

0.0045 0.001

Example (contd.)

Loss Probability Functions Example

• Suppose an agency has the following loss data and probabilities

• Annual Loss ($/year) Probability $0 0.606

$ 5,000,000 0.273 $10,000,000 0.100 $20,000,000 0.015 $50,000,000 0.003 $100,000,000 0.002

$200,000,000 0.001

• Probability that agency will not suffer any losses is 0.61

• Probability that agency will suffer some loss = 0.39 (= 1- 0.61)

• Probability that agency will suffer losses > $20M:

= 0.015 + 0.003 + 0.002 + 0.001 = 0.021

• Expected loss can be computed as:$0(0.606) + $5M(0.273) + $10M (0.1) + $20M (0.015) + $50M (0.003) + $100M (0.002) + $200M (0.001) = $3.215 x106 per year

• Next step is to determine the cost of eliminating exposure to potential loss through various countermeasure strategies

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