The Story Skid Marks Tell

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Lesson Plan
Lesson Powerpoint
Lesson Spreadsheet (Applet)
Lesson Rubric
Scene Questions
Worksheets
Pre-Test
Post-Test
Pre-Test and Post-Test Results
Student Sample One
Student Sample Two
Student Sample Three

Author: William Long and Beth Reynolds
School District: Northwest Tech BOCES
Subject: Mathematics
Grade Range: 11-12
1. TITLE/CONTEXT OF LEARNING EXPERIENCE:

  • A.CN.6 Recognize and apply mathematics to situations in the outside world.
  • A.R.6 Use mathematics to show and understand physical phenomena.
  • A.PS.8 Determine information required to solve a problem, choose methods for obtaining the information, and define parameters for acceptable solutions.

The purpose of this learning experience is to introduce students in the Criminal Justice Program at BOCES to the basic concepts involved in identifying vehicle speed through skid mark analysis. Since the students in this program are high school juniors and seniors in pursuit of post-secondary education in criminal justice and law, they need to be familiar with a variety of investigative processes including accident reconstruction involving the use of skid marks.

The main focus of the learning experience is application of the formula for calculating speed of a vehicle prior to braking based on skid distance, drag factor, and braking efficiency.

Since the lessons involve application of formulas, use of calculators, measurement, and problem solving, students need to have at least rudimentary skills in these areas to be successful with this learning experience.

2. ESSENTIAL QUESTION

How do accident investigators determine the speed of a vehicle by taking into consideration measurements and observations made at the scene of an accident?

3. ASSESSMENT PLAN

Students complete a 10 question true/false pretest to assess their level of prior knowledge. A post-test is used to gauge improvement.

Each of the three lessons presented requires students to complete worksheets which are evaluated for completeness and accuracy of application of concepts presented using the attached rubric. Student progress is monitored throughout the learning experience by observation and students are made aware of their performance levels through discussions of problems on the worksheets.

5. PROCEDURE

Lesson One:

To pique their interest, students are asked to view and discuss a news clip about an accident in which an 18 year-old boy is killed crossing an isolated country highway and skid marks are the only evidence available. The question of how police determine the speed of the vehicle involved in such an accident provides motivation for learning more about the relationship between skid marks and speed.

The attached PowerPoint presentation entitled The Story Skid Marks Tell is used to introduce types of tire marks, drag factor, braking efficiency, the skid distance/speed formula, and examples of its application. When drag factor is discussed, one student volunteer is asked to demonstrate the concept by dragging a classmate across a carpeted surface, then a tiled surface. Throughout the presentation, students record important information about each aspect of the application on the attached note sheet. Students practice use of the formula with problems on one of the skid distance worksheets.

Lesson Two:

To review concepts presented in the previous lesson, students work in teams to create a scenario to be evaluated using the skid distance formula, trade results with another team, and solve each other’s problems. Discussion of student solutions provides the opportunity for the teacher to revisit essential points from the first lesson.

The teacher then demonstrates the use of the Skid Distance Applet. This is an interactive worksheet created in Microsoft Excel. It allows students to adjust the level of each variable in the formula and to view its effect on the determination of speed. Students practice using the applet with examples from two worksheets.

Lesson Three:

The stage is set for this culminating lesson by asking students to discuss how an accident reconstruction expert would obtain evidence necessary to conduct an analysis if called in to confer on an accident that occurred several weeks before. The teacher may need to guide students to insure that all necessary factors are considered. One of the skid distance worksheets may be used at this point to review once again the use of the formula.

The teacher then demonstrates the use of the scale in an accident diagram to determine skid distance at an accident scene and explains methods of determining drag factor and braking efficiency. Students working in teams move among four stations set up with accident diagrams, index cards with drag factor and braking efficiency information, rulers, and calculators. At each station they are required to analyze given information and answer questions on the accident scene worksheets. When all students have completed the activity, the teacher reviews student responses and discusses solutions.

Summary: The news clip from the first lesson is replayed and students are asked to discuss how police determine the speed of a vehicle in such accident situations.

6. RESOURCES

7. INSTRUCTIONAL/ENVIRONMENTAL MODIFICATIONS

Activities engaged in throughout the lessons may be modified as necessary to meet the needs of the students. When working in teams, students with weaker skills should be matched with those with stronger backgrounds and abilities.

[We were fortunate enough to be able to team teach this lesson with Mr. Long, a Criminal Justice instructor, available to provide expertise in the methods of investigation, and Mrs. Reynolds, a math consultant, on hand to clarify mathematical concepts. This allowed us ample opportunity to work one-on-one with individual students as well as groups of students.]

8. TIME REQUIRED

  • Planning = 1 hour
  • Implementation = 1 - 1.5 hours per lesson
  • Assessment = 1 hour

9. REFLECTION

Students found this learning experience to be very engaging, not only because the topic pertains to a career field they are interested in, but because it teaches an important life skill lesson. It brings home the point that stopping a vehicle traveling at even a nominal speed takes more distance than a driver often anticipates. Since a variety of instructional activities are included, the lessons tend to reach students no matter their learning style. The PowerPoint presentation and interactive worksheet lend a technical aspect to the learning experience, making it more interesting and memorable. For those hands-on learners, using actual accident diagrams to determine measurements for the calculation of vehicle speed helped them see how the concepts presented in the previous lessons could actually be applied in real life situations.

This topic will be revisited later in the school year when the weather improves to the point where our friends at the Ogdensburg Police Department can lay down some actual skid marks in our parking lot. We will then work with the students to measure the marks, calculate the speed of the vehicle prior to the skid, and compare our results to the officer’s account.