Clear Zone

Subasish Das
UL Lafayette

CASTS Lab
Feb 4, 2015

About Myself


http://subasish.github.io
  • PhD candidate in Systems Engineering [expected Summer 2015]
  • Research areas include:
    • traffic safety analysis
    • machine learning and knowledge discovery
    • data visualization

Outline

  1. Introduction
  2. Clear Zone
  3. Drainage Devices
  4. Breakaway Devices
  5. Barrier Testing
  6. Introduction to Barriers
  1. End Treatments
  2. Bridge Rails and Transitions
  3. Length of Need
  4. Crash Cushions
  5. Median Barriers
  6. Work Zone Applications

Clear Zones

What is Clear Zone?

Clear Zones

A traversable area that starts at the edge of the traffic lane, includes the shoulder, and extends laterally a sufficient distance to allow a driver to stop or return to the road before encountering a hazard or overturning.

Available Clear Zone

The area bordering the roadside, starting at the edge of the traveled way, available for safe use by errant vehicles.

Design Clear Zone

Area Needed

Available Clear Zone

Area Available

The Big Question about Design Clear Zone: What’s a Sufficient Distance?

Design Clear Zone Influence Factors

  • Design Speed
  • Traffic Volume
  • Parallel Slopes
  • Horizontal Curvature

Design Clear Zone Influence Factors

  • Design Speed
  • Traffic Volume
  • Parallel Slopes
  • Horizontal Curvature

Fill Slopes

Recoverable

Non-Recoverable

Critical

Relationship of Roadside Crashes and ADT

Calculating Design Clear Zone

Example 1: Recoverable Slope

Example 1: Recoverable Slope

Example 2: Combination Slopes

Non-Recoverable Slopes

Example 4: Non-Recoverable Slope

Example 4: Non-Recoverable Slope

Example 4: Non-Recoverable Slope

Example 5: Combination Slopes w/ Ditch

Calculation

  • Calculate the percentage of the recommended clear-zone range available from the edge of through traveled way to the PVI of the foreslope 14.5 ft / 20 ft x 100 = 73% and 14.5 ft / 24 ft x 100 = 60 %.
  • Subtract these percentages from 100% and multiply results by the recommended range of clear zones for the backslope (100% – 73%) x 16 ft = 4.3 ft and (100% – 60%) x 18 ft = 7.2 ft. The range of required clear zone on the backslope is 4.3 to 7.2 ft.
  • Add the available clear zone on the foreslope to the range of values determined previously 14.5 ft + 4.3 ft = 18.8 ft and 14.5 ft + 7.2 ft = 21.7 ft. The adjusted clear-zone range is 18.8 to 21.7 ft.

Design Clear Zone Influence Factors

  • Design Speed
  • Traffic Volume
  • Parallel Slopes
  • Horizontal Curvature

Curves Present Particular Safety Problems

Horizontal Curve

Horizontal Curves with Adjustments

Table: Horizontal Curve Adjustments

Non-Traversable Ditches

  • Locate beyond the clear zone
  • Flatten Ditch Foreslope
  • Clear Backslope of Potential Hazards

Example 3: Combination Slopes w/ Ditch

Calculate preferred Channel Cross Section

Curbs: No Reduction of Clear Zone!

Table F-11 Bumper Trajectory 6 Inch Type A Curb

Review

  • Not an absolute value
  • Some vehicles will go beyond CZ
  • Design vs. available
  • Must be smooth and hazard free
  • Maintain a consistent width
  • Make roadside safe as practical

Review Ques 1

A 1V:2H slope is best described as:

a. Clinical

b. Critical

c. Criminal

d. Awesome

Review Ques 2

Which of the following is not a factor in the determination of design clear zone?

a. Side slopes

b. Vertical curve

c. Horizontal curve

d. Speed

Review Ques 3

Determination of design clear zone is a very accurate process.

a. True

b. False

Learning outcomes

  • Define and calculate clear zone widths
  • Apply the clear zone concept effectively
  • Make horizontal curve adjustments
  • Recognize slope categories
  • Define traversable ditches

Clear Zone is done.

Hay wait. Here's a 30 min video!!!

IMAGE ALT TEXT HERE

No Way. Toooo long. Watch it later

Now what??

Data Visualization Softwares

  • Statistical software 'R' [nearly 6,500 packages]
  • Python [Ipython Notebook, numpy, scipy]
  • D3.js
  • three.js

R

require(maps)
data(canada.cities)
head(canada.cities, 2)

           name country.etc    pop   lat    long capital
1 Abbotsford BC          BC 157795 49.06 -122.30       0
2      Acton ON          ON   8308 43.63  -80.03       0

IPython Notebook

The IPython Notebook is a web-based interactive computational environment where you can combine code execution, text, mathematics, plots and rich media into a single document.

Example

D3.js

  • D3.js is a JavaScript library for manipulating documents based on data. D3 helps you bring data to life using HTML, SVG and CSS.
  • D3’s emphasis on web standards gives you the full capabilities of modern browsers without tying yourself to a proprietary framework.

Example

three.js

Three.js is a lightweight cross-browser JavaScript library/API used to create and display animated 3D computer graphics on a Web browser.

Example

That's all