S24 Speed Studies LTC2013 - [PDF Document] (2024)

  • 7/29/2019 S24 Speed Studies LTC2013

    1/44

    2012 ARCADIS27 February 20131

    I-10 Speed Study

    Texas State Line to Mississippi State LineMultiple Parishes

    Akhil Chauhan, PE, PTOE, PTP

    2.19.2013

    Louisiana Transportation Conference

    Imagine the result

  • 7/29/2019 S24 Speed Studies LTC2013

    2/44

    2012 ARCADIS27 February 20132

    Safety

    Moment

  • 7/29/2019 S24 Speed Studies LTC2013

    3/44

    2012 ARCADIS27 February 20133

    DOTD Jody Colvin

    Ty Hampton

    Darryl Mack

    ARCADIS

    Thomas Montz

    Justin Maderia

    Reza Taromi

    Joshua Chatelain

    Acknowledgements

  • 7/29/2019 S24 Speed Studies LTC2013

    4/44

    2012 ARCADIS27 February 20134

    Speed & Safety

    Speed Limit Policy

    Project Needs & Goals

    I-10 Speed Study: Approach & Analysis

    Data Collection

    Roadway Attributes Inventory

    Crash Analysis

    Speed Analysis

    GIS Database

    Speed Profile

    Conclusions

    Outline

  • 7/29/2019 S24 Speed Studies LTC2013

    5/44

    2012 ARCADIS27 February 20135

    1. Three HSM 2010 Roadway Safety Factors

    Vehicle Regulated by NHTSA

    Roadway Regulated by AASHTO

    Human Un-Regulated

    2. Vehicle Factors

    Vehicle Safety Features Not Covered in this Study

    3. Roadway Factors

    Roadway Geometry, Site Characteristics

    4. Human Factors

    Driver Attention & Information Processing (PRT)

    Operating Speeds

    Operating Speed Regulated by Posted Speed Limit

    Speed & Safety

  • 7/29/2019 S24 Speed Studies LTC2013

    6/44

    2012 ARCADIS27 February 20136

    1. Enhances Safety

    Limiting Function

    Coordinating Function

    2. Limiting Function

    Upper Speed Boundary

    Fines/Incarceration if Exceeded

    Limits Probability & Severity of Crashes

    3. Coordinating Function

    Uniform Operating Speeds Reduced Potential for

    Conflict

    Speed Limit Purpose

  • 7/29/2019 S24 Speed Studies LTC2013

    7/44

    2012 ARCADIS27 February 20137

    Speed Limit History

    1. Pre 1974 States Set Speed Limit

    2. 1974 1987National Maximum Speed Limit (NMSL) = 55 mph

    3. 1987 States Set Speed Limit

    Interstates Increased to 65 mph

    4. 1995 NMSL Repealed; States Set Maximum Speed Limit

    References: 1.http://en.wikipedia.org/wiki/National_Maximum_Speed_Law

  • 7/29/2019 S24 Speed Studies LTC2013

    8/44

    2012 ARCADIS27 February 20138

    Regional Experience

    1. Louisiana:

    Maximum Posted Speed Limit = 70 mph

    Posted Speed Limit > 70 mph if Engineering Study Warrants

    Ex: I-49 Posted at 75 mph for ~ 200 miles

    Opelousas to Shreveport

    2. Texas:

    Some Counties

    Post 80 mph

    1 Facility

    Post 85 mph

    References: 1.http://theadvocate.com/csp/mediapool/sites/Advocate/assets/templates/FullStoryPrint.csp?cid=340351&preview=y

    2.http://www.dallasnews.com/news/transportation/20110406-some-texas-speed-limits-could-be-bumped-to-85-the-fastest-in-the-nation.ece

  • 7/29/2019 S24 Speed Studies LTC2013

    9/44

    2012 ARCADIS27 February 20139

    Nationwide Speed Limits

    References: 1.http://en.wikipedia.org/wiki/Speed_limits_in_the_United_States

  • 7/29/2019 S24 Speed Studies LTC2013

    10/44

    2012 ARCADIS27 February 201310

    Need: Develop Database:

    Interstate Highways

    Major & Minor Arterials

    Database Includes:

    Existing Speed Profiles

    Roadway Attributes

    Crash Statistics

    Speed Analysis Results

    Goal: Provide Information to Improve Safety & Mobility(3Es)

    Enforcement

    Education

    Engineering

    Project Needs & Goals

    References: 1. http://blog.ub.ac.id/midcool/category/sti/

    I-10

    I-12 I-20 I-49

    I-55

    Centralized Speed

    Database

  • 7/29/2019 S24 Speed Studies LTC2013

    11/44

    Imagine the result

  • 7/29/2019 S24 Speed Studies LTC2013

    12/44

    2012 ARCADIS27 February 201312

    Crash & ADT from 2008 - 2010 Highway Needs Database

    GIS Shape Files

    Traffic Volumes, Operating Speeds &Vehicle Headway

    15 Base Sites

    At Least 1 Site per Parish

    25 Additional Sites In Urban Areas

    Data Collection

  • 7/29/2019 S24 Speed Studies LTC2013

    13/44

    2012 ARCADIS27 February 201313

    Crash Density, ADT, Geometric Attributes

  • 7/29/2019 S24 Speed Studies LTC2013

    14/44

    2012 ARCADIS27 February 201314

    Crashes vs Milepoint

  • 7/29/2019 S24 Speed Studies LTC2013

    15/44

    2012 ARCADIS27 February 201315

    Highway Needs Database & GIS Shape Files

    Developed GIS Tool to Create Database

    Field Verified

    Databases using

    Specially Developed

    Data Entry Form

    (ArcPad)

    Roadway Attributes Inventory

  • 7/29/2019 S24 Speed Studies LTC2013

    16/44

    2012 ARCADIS27 February 201316

    Field-Verified Data Collection Sites

  • 7/29/2019 S24 Speed Studies LTC2013

    17/44

    2012 ARCADIS27 February 201317

    I-10 Speed Data Collection Sites

    #1

    #2

    #3

    #4 #8

    #5

    #6

    #7#9

    #10

    #11

    #12 #14 #16 - #21

    #13 #15

    #22

    #24

    #23

    #25

    #26

    #27

    #40

    #39

    #37

    #35

    #36

    #38

    Gulf of Mexico

    Texas/Louisiana State Line Lafayette

    New Orleans

    Baton Rouge

    References: 1. Google Earth

    N

    Louisiana\Mississippi State Line

    ## Denotes one of 15 Base Sites

    #28

    #29

    #30

    #32 to #34

    #31

  • 7/29/2019 S24 Speed Studies LTC2013

    18/44

    2012 ARCADIS27 February 201318

    By Direction By Parish

    By Segment Characteristics 54% Rural vs.

    46% Urban

    By Crash Type By Crash Frequency - Plotted by Mile Point

    Rate Comparison - Crash, Fatality & Injury Rates

    vs. Statewide Average Rates

    Crash Analysis

    I 10 EB C h T b P i h

  • 7/29/2019 S24 Speed Studies LTC2013

    19/44

    2012 ARCADIS27 February 201319

    2. Crash Analysis (Continued)

    Crashes by Type - Eastbound

    4. Project AnalysisI-10 EB Crash Types, by Parish

    I 10 WB C h T b P i h

  • 7/29/2019 S24 Speed Studies LTC2013

    20/44

    2012 ARCADIS27 February 201320

    2. Crash Analysis (Continued)

    Crashes by Type - Westbound

    4. Project AnalysisI-10 WB Crash Types, by Parish

  • 7/29/2019 S24 Speed Studies LTC2013

    21/44

    2012 ARCADIS27 February 201321

    Crash Analysis by Parish

  • 7/29/2019 S24 Speed Studies LTC2013

    22/44

  • 7/29/2019 S24 Speed Studies LTC2013

    23/44

    2012 ARCADIS27 February 201323

    Crash Rates by Parish Urban, EB

  • 7/29/2019 S24 Speed Studies LTC2013

    24/44

    2012 ARCADIS27 February 201324

    Crash Rates by Parish Rural, WB

  • 7/29/2019 S24 Speed Studies LTC2013

    25/44

    2012 ARCADIS27 February 201325

    Crash Rates by Parish Urban, WB

    I 10 EB C h R t S

  • 7/29/2019 S24 Speed Studies LTC2013

    26/44

    2012 ARCADIS27 February 201326

    2. Crash Analysis (Continued)

    Crash Frequency & Rate Comparison - Eastbound

    4. Project AnalysisI-10 EB Crash Rates Summary

    I 10 WB C h R t S

  • 7/29/2019 S24 Speed Studies LTC2013

    27/44

    2012 ARCADIS27 February 201327

    2. Crash Analysis (Continued)

    Crash Frequency & Rate Comparison - Westbound

    4. Project AnalysisI-10 WB Crash Rates Summary

  • 7/29/2019 S24 Speed Studies LTC2013

    28/44

    2012 ARCADIS27 February 201328

    Completed 40 Sites 80 Locations Wednesday 10 am to 2 pm

    By Parish

    Cumulative Speed Frequency Curve 50th/85th/95th PercentileSpeeds

    10 mph Pace

    Speed Variance % Free-Flowing Vehicles

    Speed Analysis

  • 7/29/2019 S24 Speed Studies LTC2013

    29/44

    2012 ARCADIS27 February 201329

    Cumulative & Vehicles per Speed Interval

    Speed Frequency Curves

  • 7/29/2019 S24 Speed Studies LTC2013

    30/44

    2012 ARCADIS27 February 201330

    Speed Frequency Tables

  • 7/29/2019 S24 Speed Studies LTC2013

    31/44

    2012 ARCADIS27 February 201331

    Operating Speed Maps

  • 7/29/2019 S24 Speed Studies LTC2013

    32/44

    2012 ARCADIS27 February 201332

    Speed Frequency and Summary, by Site

  • 7/29/2019 S24 Speed Studies LTC2013

    33/44

    2012 ARCADIS27 February 201333

    GIS Database

    GIS D t b

  • 7/29/2019 S24 Speed Studies LTC2013

    34/44

    2012 ARCADIS27 February 201334

    GIS Database

  • 7/29/2019 S24 Speed Studies LTC2013

    35/44

    2012 ARCADIS27 February 201335

    1. Three Corridors Identified:

    Uniform Crash Frequency & Severity

    Uniform Roadway Attributes

    > 60% Vehicles Traveling within 10 mph Pace

    2. EB & WB 18 Miles Calcasieu Parish

    3. EB 67 Miles Jefferson Davis, Acadia, Lafayette, St.Martin

    WB 98 Miles Jefferson Davis, Acadia, Lafayette, St. Martin,

    Iberville

    4. EB & WB 44 Miles Ascension, St. James, St. John

    Speed Profile

    I 10 EB Corridor Analysis

  • 7/29/2019 S24 Speed Studies LTC2013

    36/44

    2012 ARCADIS27 February 201336

    6. Corridor Analysis (Continued) - Eastbound

    4. Project AnalysisI-10 EB Corridor Analysis

    I 10 WB Corridor Analysis

  • 7/29/2019 S24 Speed Studies LTC2013

    37/44

    2012 ARCADIS27 February 201337

    6. Corridor Analysis (Continued) - Westbound

    4. Project AnalysisI-10 WB Corridor Analysis

    I 10 EB Corridor Analysis

  • 7/29/2019 S24 Speed Studies LTC2013

    38/44

    2012 ARCADIS27 February 201338

    6. Corridor Analysis (Continued) - Westbound

    I-10 EB Corridor Analysis

    I 10 WB Corridor Analysis

  • 7/29/2019 S24 Speed Studies LTC2013

    39/44

    2012 ARCADIS27 February 201339

    6. Corridor Analysis (Continued) - Westbound

    I-10 WB Corridor Analysis

  • 7/29/2019 S24 Speed Studies LTC2013

    40/44

    2012 ARCADIS27 February 201340

    Crash Type

    Rear-End, Side Swipe & Single Vehicle Crashes

    80% to 90% of Crashes in each Parish

    Crash Frequency

    East Baton Rouge Parish

    24% Crashes in 5% Study Length

    Fatalities

    Calcasieu Parish & Orleans Parish

    28% of Fatalities in 17% Study Length

    Injuries Orleans Parish

    20% of Injuries in 11% Study Length

    Crash Analysis Conclusions

  • 7/29/2019 S24 Speed Studies LTC2013

    41/44

    2012 ARCADIS27 February 201341

    In General

    50th % Speeds 5 mph > Posted Speed Limit

    85th % Speeds 10 mph > Posted Speed Limit

    95th % Speeds 15 mph > Posted Speed Limit

    Lower Limit 10 mph Pace = Posted Speed Limit

    Speed Analysis Conclusions

    Over of I-10 traffic (51% to 75%) approximatelymatches orexceeds the posted speed limit.

  • 7/29/2019 S24 Speed Studies LTC2013

    42/44

    2012 ARCADIS27 February 201342

    Determine how to improve safety and efficiency.

    Enforcement

    Promote Benefits of Limiting Function Promote Benefits ofCoordinating Function

    Education

    Promote Importance of Posted Speed

    Limit

    Engineering

    Update Posted Speed Limit

    Corridor Analysis ConclusionsProper combination of 3 Es may beanalyzed for

    any corridor identified along I-10.

  • 7/29/2019 S24 Speed Studies LTC2013

    43/44

    2012 ARCADIS27 February 201343

    Appropriate Posted Speed Limit Balances Safety &Mobility

    85th Percentile Speeds

    6 mph - 10 mph > Posted Speed Limit Across I-10

    Database Summarizes Information to determine best way to

    improve safety

    Enforcement Education

    Engineering

    I-10 Speed Study Conclusions

    This speed study provides database ofinformation to determinehow safety &

    efficiency of I-10 corridor can be optimized.

  • 7/29/2019 S24 Speed Studies LTC2013

    44/44

    Imagine the result

    Questions or Comments?

    Akhil Chauhan, PE, PTOE, PTP

    [emailprotected]

    T. (225)-292-1004

S24 Speed Studies LTC2013 - [PDF Document] (2024)

FAQs

What is the 85th percentile theory? ›

This is based on the theory that most drivers are reasonable and do not want to get in an accident, but do want to get to their destination as quickly as possible. Therefore, a speed at which 85 percent of people drive is figured to be the highest safe speed for that road.

How are speed limits calculated? ›

The most widely accepted method of determining the posted speed limit is to set the speed limit at what is called the “85th percentile speed”, which is the speed at or below which 85 percent of the traffic is moving.

What is the highest speed limit in the United States? ›

The highest posted speed limit in the country is 85 mph (137 km/h) and can be found only on Texas State Highway 130, a toll road that bypasses the Austin metropolitan area for long-distance traffic.

How can I study with high speed? ›

How to learn faster: 5 ways to tune your brain for new things
  1. Learning quickly gives you a great competitive edge for personal and professional development. ...
  2. Teach others (or just pretend)
  3. Make breaks. ...
  4. Take notes by hand.
  5. Don't be afraid to take a nap!
  6. Use different study methods.

What is speed studies? ›

Spot speed studies are used to determine the speed distribution of a traffic. stream at a specific location. The data gathered in spot speed studies are used to determine vehicle speed. percentiles, which are useful in making many speed-related decisions.

What is the 85th percentile speed study? ›

The 85th percentile speed is defined as, “the speed at or below which 85 percent of all vehicles are observed to travel under free-flowing conditions past a monitored point.” Another way to consider this is the speed at which only 15% of traffic violate on average.

What is the basic speed law? ›

California has a “Basic Speed Law” that states “No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of, the highway, and in no event at a speed which endangers the safety of persons or ...

Top Articles
Latest Posts
Article information

Author: Dr. Pierre Goyette

Last Updated:

Views: 5245

Rating: 5 / 5 (50 voted)

Reviews: 89% of readers found this page helpful

Author information

Name: Dr. Pierre Goyette

Birthday: 1998-01-29

Address: Apt. 611 3357 Yong Plain, West Audra, IL 70053

Phone: +5819954278378

Job: Construction Director

Hobby: Embroidery, Creative writing, Shopping, Driving, Stand-up comedy, Coffee roasting, Scrapbooking

Introduction: My name is Dr. Pierre Goyette, I am a enchanting, powerful, jolly, rich, graceful, colorful, zany person who loves writing and wants to share my knowledge and understanding with you.