Topic 1

Title: Development of an Accident Visual Analysis & Data Integration Tool
State Job Number: 14706
Final Report, February 2001 (1,257 KB)
Executive Summary, (76 KB)

Implementation Plan, (97 KB)

This project develops a visualization and integration tool for crash data analysis. Based on a client server data communication system between the central database and distributed users, safety engineers at local districts can download crash data for a specific roadway section in a given time window. They can view crash characteristics through data mapping and attribute listing, and analyze the data using nested query or sorting operations and statistical graphs. A visualization module in the system can be used to construct the collision diagram according to the types, movements, and points of impact of the vehicles involved in the crash. Preliminary tests using crash data obtained from the Ohio Department of Public Safety have shown the effectiveness and efficiency of this tool in crash data analysis.

 

Topic 2

Title: Identification of Pavement Marking Colors
State Job Number: 14733
Final Report, April 2002 (574 KB)
Executive Summary, (9 KB)

Implementation Plan, ( KB) Not available yet

Current pavement marking color specifications are given in terms of a single color with no indication of acceptable tolerances. Recently proposed standards include tolerances, but neither current nor proposed standards are based on psychophysical data. Although there is a substantial body of research regarding the visibility of pavement markings, very little has been done to test their discriminability. This research compared data obtained through a color scaling procedure, proposed standards, and existing markings. Older and younger subjects and normal and color deficient subjects participated in the color scaling study. Older and younger subjects judged colors similarly, but there were notable differences between the color judgments of normal and color deficient subjects. The findings from this study indicate that it is reasonable to specify a range of chromaticities acceptable for pavement marking colors that will be useful during both daytime and nighttime and on a variety of backgrounds or pavement types. Modifications were made to the current proposed specifications in light of these color scaling data.

 

Topic 3

Title: Rational Schedule of Base Accident Rates for Rural Highways in Ohio - Phase II
State Job Number: 14752
Final Report, June 2003 (859 KB)
Executive Summary, (136 KB)

RITA Manual, (565KB)

Implementation Plan, ( KB) Not available yet

A "base accident rate", also known as "expected value", allows safety engineers or planners to objectively determine whether an accident pattern at a study location is significantly higher than the same accident pattern at other locations with similar geometric, traffic, and environmental factors. This study was conducted to develop base accident rates for rural highways at non-intersections in Ohio using all the available data from Ohio Department of Transportation’s database. Using a random sampling technique, 30% of the data for each of the 12 districts was extracted and a comprehensive database was created for each district. Then, the highway sections were generally divided into uniform segments of length 0.25 mile. For each highway segment, population density data within one-mile radius was generated. Additional data, namely, number of residential and business driveways, number of passing zones, horizontal and vertical curves, and guardrail length were manually recorded using photo-log discs. 

 

Topic 4

Title: Field Evaluation of Unlighted Overhead Guide Signs Using Older Drivers
State Job Number: 14812
Final Report, August 2003 (6,483 KB)
Executive Summary, (21 KB)

Implementation Plan, (109 KB)

In the preceding Unlighted Overhead Guide Sign Feasibility Study, it was determined that the lighting of overhead guide signs on freeways could be eliminated if white micro-prismatic Type VII or Type IX legends were used on green beaded Type III backgrounds.  Because the expert panel in that study was limited to ODOT engineers who were relatively young (average age 38), it was considered necessary to conduct a second study to ensure that these unlighted overhead guide signs would meet the needs of older drivers, who have typically degraded visual capabilities.  Additionally, there was interest in evaluating Type VIII and microprismatic Type III sheeting materials, which were not included in the first study.  

Topic 5

Title: Development of Crash Reduction Factors
State Job Number: 14801
Final Report, September 2005 (472 KB)
Executive Summary, (40 KB)

Implementation Plan, (80 KB)

Crash reduction factors (CRFs) represent the proportion of crashes that are expected to be eliminated from a site as a result of receiving a specific spot improvement(s). CRFs are used to identify and prioritize the most effective safety improvement measures and prioritize and allocate available resources optimally for a highway safety project. Crash reduction factors, which are based on previous research and field studies of before- and after crash statistics, need to be revised and updated periodically to reflect the most current knowledge regarding the effectiveness of various highway improvement measures. The validity of the CRFs is a key factor in maintaining project prioritization and resource allocation tasks in an optimal and orderly manner. Crash reduction factors have not been updated in Ohio since the early 1980s. It is important to verify and update these CRFs periodically to ensure their accuracy.

Topic 6

Title: Evaluation and Design of ODOT’s Type 5 Guardrail with Tubular Backup
State Job Number: 134161
Final Report, February 2006 (13,702 KB)
Executive Summary, (97 KB), best printed double sided on 11x17

Implementation Plan, (77 KB)

The purpose of this project was to assess the performance of both the ODOT GR-2.2 guardrail and the ODOT GR-3.4 transition system under NCHRP Report 350 test level 3 (TL-3) conditions, propose any modifications that would improve their crashworthiness and, ultimately ensure that the final designs qualify for use on the National Highway System (NHS) as TL-3 systems. Finite element analyses of the guardrail and transition system were performed using the LS-DYNA finite element software to simulate NCHRP Report 350 Test 3-10 and Test 3-11 impact scenarios. The analysis results indicated that the original ODOT GR-2.2 guardrail would successfully meet all NCHRP Report 350 test level 3 safety criteria. The analyses also indicated that the performance of the system could be significantly improved with simple modifications to the guardrail. The integrated system of the Nested Type 5 Guardrail with Tubular Backup and the ODOT GR-3.4 transition was considered the most practical and feasible design improvement and was therefore recommended as a final design.

Topic 7

Title: Crash Reduction Factors for Education and Enforcement Strategies in Ohio
State Job Number: 134220
Final Report, May 2007 (1,812 KB)
Executive Summary, (39 KB)

Implementation Plan, ( KB) Not available yet

ODOT has a goal of reducing total crashes by 10% by 2015.  Driver education, licensing, testing, and enforcement strategies are all tools that can be used to help reduce the incidence of accidents, particularly among teenage drivers, who are involved in accidents well out of proportion to their numbers in the overall driver population.  In order to determine which strategies are likely to provide the best results, ODOT needs to have some quantitative estimate of the effectiveness of each strategy in terms of the amount of reduction it provides, in other words a crash reduction factor (CRF). A comprehensive literature and web search was conducted to determine driver education, licensing and enforcement practices, and CRF values used by other states and countries. An electronic survey of all states was conducted to get information about driver education, licensing programs, testing and enforcement measures, the state of the art in traffic safety practices, and CRFs. The relatively few CRFs obtained for driver education, licensing programs, and traffic enforcement measures were compared to those obtained for traffic engineering measures. Based on the analysis of all the information obtained only a limited number of quantitative CRFs exist for any of the driver education, licensing and enforcement measures in any of the states in the US. Published studies where the effects on reducing crashes for new measures with sound statistical evaluations using proper control groups appear to be almost non-existent in the US. CRFs for driver education, licensing programs, and enforcement measures based on the estimates by traffic safety experts were found for Switzerland in the VESIPO report and the cost/benefit ratios for some selected Swiss measures were found. It has to be noted that even the Swiss CRFs are based on partial estimates and have not been truly validated with before and after studies using actual data except for one blood alcohol content measure (“Reduction of BAC limit from 0.08% to 0.05%” with extensive advertising and  strict enforcement).  Since some of the CRFs found were from countries outside the US, such as Switzerland and Canada, and since the road transportation system of the US is fairly similar to Western Europe the strategies used for crash reduction will usually be applicable to Ohio.  The range for the CRFs reported in the literature for driver education, driver licensing, testing and enforcement are summarized in the conclusion section of the report. The ranges for CRFs for driver education, licensing programs, and enforcement measures are less than 1% to 32%, 0%-17% and 2%-51% respectively.  A prioritized implementation plan based on the highest CRFs reported has been proposed for driver education, licensing and enforcement.

 

Topic 8

Title: Crash Base Rates for Intersections in Ohio
State Job Number: 134166
Final Report, February 2007 (1,513 KB)

 

Ohio’s crashes at intersections are about 40% of the total yet 1/3 of these result in injuries compared to 1/4 for the rest of the system. On the Rural State System there are over 100 fatal crashes, 7,000 injury crashes and 14,000 property damage crashes in a given year for intersections alone. The department is committed to reducing these numbers. Ohio Department of Transportation (ODOT) annually identifies high crash intersections (based on the number, severity and cost of crashes) for safety studies and subsequent improvements. All crashes for intersections on a facility are grouped by the type of facility such as 2-lane, 4-lane divided or undivided, but there is no consideration given to the type of intersection, e.g. number of approaches, number of lanes in each approach, type of traffic control or existence of left and/or right turn lanes. The crash experiences at 3-legged and 4-legged intersections, for example, are expected to be quite different and should be known when identifying the high crash intersection locations. A better method to identify high crash intersections will direct safety resources for the improvements where they are most needed. The objective of this study is to develop a process or processes to ensure intersection crashes are analyzed based on intersection geometrics, traffic control and environmental factors. The validity of the process will be established and intersection crash base rates will be developed by studying appropriate variables for intersection crashes.

 

Topic 9

Title: Crash Base Rates for Freeways/Reduction Strategies for Rear End Crashes Volume 1: Crash Base Rates for Freeways in Ohio
State Job Number: 134230
Final Report, June 2007 (1,88 KB)
Executive Summary, (80 KB)

The identification of freeway segments that are considered hazardous and the determination of effective remedies to alleviate the situation pose a challenge to traffic engineers and planners.

A problem location is one that presents a risk to the users in terms of high probability of crash occurrence or severity. A safety analysis of a specific location can include a "base crash rates" analysis for identifying crash patterns at the study location. After the crash rate for each crash type is calculated for a study freeway segment, each crash rate can be compared to the "base crash rate" for locations with similar geometric, traffic, and environmental factors. If the calculated crash rate for any crash type at a particular location is found to be higher than the "base crash rate," then that location is chosen for further study to determine if a safety problem actually exists at that location and, if so, what counter measure(s) can be used.