Lesson 4: Crash Prediction Module (CPM)

Transcription

1 Go back to: Table of Contents Go to the next lesson Overview : Crash Prediction Module (CPM) The Crash Prediction Module estimates the frequency and severity of crashes that would be expected on a highway considering its geometric design and traffic characteristics. For more details, see the Crash Prediction Module Engineer s Manual. In the work problem, you will use the Crash Prediction Module to estimate the frequency and severity of crashes on IHSDM Pike for a 10-year period. Work Problem Exercise: - 4.1: Evaluate Existing IHSDM Pike without using Crash History Data 1

2 Exercise 4.1: Evaluate Existing IHSDM Pike without using Crash History Data I. Create a Crash Prediction Evaluation 1. If necessary, start IHSDM by double clicking the shortcut icon on your desktop screen, or on ihsdm.exe in the IHSDM software home directory. 2. To view the highways under the IHSDM Pike Project, click on the + sign to the left of the IHSDM Pike node to expand the tree. You should see highway nodes for ihsdm pike and route1 and an intersection node for route1/ihsdm pike. 3. To create an Evaluation for IHSDM Pike: a. Select the highway node corresponding to ihsdm pike by clicking it once. b. Click the New Evaluation button on the Button Panel to bring up the Select an evaluation type window in the desktop area. 2 c. Fill in or select: - Title: Crash Prediction 1 - Comment: Crash Prediction Evaluation - Description: Crash Prediction Evaluation of existing IHSDM Pike, without crash history data. - Evaluation type: Crash Prediction d. Click on Next.

3 II. Set the Evaluation Attributes 1. Set crash prediction attributes : a. Evaluation bounds: the defaults are the start and end stations of IHSDM Pike. Keep these default values. b. Policy: AASHTO 2004 Policy (English) c. Configuration: default d. Evaluation Period: i. First year of Analysis: 2007 ii. Last Year of Analysis: 2016 e. Crash History: leave the Use Crash History Data box unchecked f. Click Next 3

4 2. On the Specify crash prediction report screen, accept the default selections, and click Next. 4

5 3. IHSDM checked the highway data provided vs. the data that could be used for the crash prediction evaluation. The Data issues screen lists data elements that may need further review. The Passing Lane, Shoulder Section, Two Way Left Turn Lane (TWLTL), Turn Lane and Climbing Lane elements should appear in the list. TIP: To make changes to a data element listed in the table, click on the data element name to bring up a data editor for that element. Since IHSDM Pike does not have any of the elements listed (i.e., no passing lane, no shoulders, no TWLTL, no climbing lane), confirm that no changes are needed to the data at this time by selecting Next. 4. On the Evaluation settings summary screen, check the summary to ensure that the previous steps were completed properly. Make sure the box is checked for Show Report on Run Completion. Click Run to run the Evaluation. 5

6 III. Run CPM Evaluation 1. The status screen shows the progress of the evaluation. Once it is completed, the Show Report and Show Graph buttons become active. The Evaluation Report should open in an html browser automatically. Minimize the report for later access. IV. View/Interpret CPM Output 1. Generate CPM graphic output outside of the Evaluation Report: a. Click the Show Graph button on the status screen to open the crash prediction results graph in the Graph Editor. Click on the maximize icon in the upper right corner of the window for a better view. 6

7 There are two types of output generated by the CPM: 1. Graphs 2. Evaluation Report (including graphs with default format) Q 4.1.1: By visual inspection, which horizontal design element (red graph) has the highest crash rate (crashes/mi/year)? Horizontal design element with the highest crash rate (crashes/mi/year) b. Close the graph by clicking on the X in the upper right corner. 2. View/Interpret the CPM Evaluation Report: a. Maximize the Evaluation Report, or, if closed, click the Show Report button on the status window to open the Evaluation Report. b. Scroll through the Evaluation Report (or click on link in the Table of Contents) to find Expected Crash Rates and Frequencies Graphs are also available in the Evaluation Report using a default format 7

8 The table of contents is hyperlinked to selected sections of the Evaluation Report. Q 4.1.2: For the entire IHSDM Pike, from 2007 to 2016: i. What is the expected Total Number of Crashes for the highway? ii. What percentage of the Total Crashes is expected to be Fatal and Injury Crashes? iii. How many Fatal and Injury Crashes are expected? Expected Total number of Crashes for the highway for 2007 to 2016 Percentage of the Total Crashes expected to be Fatal and Injury Crashes Expected Fatal and Injury Crashes c. Scroll through the Evaluation Report (or click on link in the Table of Contents) to find the Expected Crash Frequencies and Rates (Segment) table Q 4.1.3: For the (curve) segment beginning at station and ending at station : 8

9 i. What is the Expected Number of Crashes for the Evaluation Period (2007 to 2016)? ii. What is the Expected Crash Rate (in crashes/mi/yr)? iii. What is the Expected Crash Rate (in crashes/million-veh-mi)? Expected number of crashes for the curve beginning at station , for 2007 to 2016 Expected crash rate for the curve (crashes/mi/yr) Expected crash rate for the curve (crashes/million-veh-mi) Q 4.1.4: For the intersection of IHSDM Pike and Route 1 (station ) i. What is the expected crashes/million entering vehicles? ii. What is the expected number of crashes/year for the intersection? Expected crashes/million-entering vehicles, for 2007 to 2016 Expected crashes/year for the intersection d. Scroll through the Evaluation Report (or click on link in the Table of Contents) to find the Expected Crash Frequencies and Rates by Horizontal Design Element table Q 4.1.5: For Curves 8 and 9 (i.e., the compound curve from station to i. What is the Expected Number of Crashes for the Evaluation Period (2007 to 2016)? ii. What are the Expected Crash Rates per mi/yr? Expected number of crashes for compound curve (sta to ) for 2007 to 2016 Expected crash rates for the curves (crashes/mi/yr) e. Close the Evaluation Report f. Close the Status screen by clicking the Close button. 9

10 Work Problem Answer Key Exercise 4.1 To access a pre-produced copy of the Evaluation Report for Exercise 4.1: 1. Go to the Tutorial/Evaluation_ Reports folder under your IHSDM directory. 2. Choose Exercise_4.1_CPM_ Report.htm Q 4.1.1: By visual inspection, which horizontal design element (red graph) has the highest crash rate (crashes/km/year)? Horizontal design element with the highest crash rate (crashes/mi/year) Horizontal curve from approximately to Q 4.1.2: For the entire IHSDM Pike, from 2007 to 2016: i. What is the expected Total Number of Crashes for the highway? ii. What percentage of the Total Crashes is expected to be Fatal and Injury Crashes? iii. How many Fatal and Injury Crashes are expected? Expected Total number of Crashes for the highway for 2007 to 2016 Percentage of the Total Crashes expected to be Fatal and Injury Crashes Expected Fatal and Injury Crashes % 33.3 Q 4.1.3: For the (curve) segment beginning at station and ending at station : iv. What is the Expected Number of Crashes for the Evaluation Period (2007 to 2016)? v. What is the Expected Crash Rate (in crashes/mi/yr)? vi. What is the Expected Crash Rate (in crashes/million-veh-mi)? Expected number of crashes for the curve beginning at station , for 2007 to 2016 Expected crash rate for the curve (crashes/mi/yr) Expected crash rate for the curve (crashes/million-veh-mi)

11 Q 4.1.4: For the intersection of IHSDM Pike and Route 1 (station ) iii. What is the expected crashes/million entering vehicles? iv. What is the expected number of crashes/year for the intersection? Expected crashes/millionentering vehicles, for 2007 to 2016 Expected crashes/year for the intersection Q 4.1.5: For Curves 8 and 9 (i.e., the compound curve from station to iii. What is the Expected Number of Crashes for the Evaluation Period (2007 to 2016)? iv. What are the Expected Crash Rates per mi/yr? Expected number of crashes for compound curve (sta to ) for 2007 to 2016 Expected crash rates for the curves (crashes/mi/yr) = ; Go back to: Table of Contents Go to the next lesson 11