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From page 57... ... 57 The Haddon Matrix was used initially to ensure that a comprehensive set of factors would be considered in studying the dramatic drop in traffic fatalities in the United States after 2007. The results showed that not all elements of the matrix -- vehicle, driver, and environment -- contributed equally. Read the entire page →
From page 58... ... 58 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 8.1 Variable Influence Estimated from the Count Models This discussion of results is based on the MNCS model (i.e., model not controlling for state) and the MCS model (model controlling for state) Read the entire page →
From page 59... ... Discussion of Results 59 Variable Expected association with traffic fatalities Expected mechanism Total VMT Positive Increase in VMT increases exposure to traffic crashes and therefore fatalities. Proportion rural VMT Positive Increased proportion of rural VMT increases proportion of travel on riskier roads, leading to more fatalities. Read the entire page →
From page 60... ... 60 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 fatalities predicted by the economic variables, while line segment B depicts the predicted reduction from all variables in the model. Line segment C represents the observed drop in fatalities from 2007. Read the entire page →
From page 61... ... Discussion of Results 61 a) MNCS model b) Read the entire page →
From page 62... ... 62 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 a) MNCS model b) Read the entire page →
From page 63... ... Discussion of Results 63 a) MNCS model b) Read the entire page →
From page 64... ... 64 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 correlation between roadway spending and state characteristics. It is possible, for instance, that capital spending was related to economic conditions within a state. Read the entire page →
From page 65... ... Discussion of Results 65 laws become stricter. Each category -- DUI, safety-belt, and motorcycle helmet laws -- was considered separately in the models, and a combined effect was evaluated to assess the effectiveness of regulatory policies. Read the entire page →
From page 66... ... 66 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 all the states. The proportion of the predicted reduction in fatalities that can be attributed to vehicle fleet safety, on average over the period 2008 to 2012, was 13% for the MCS model and 12% for the MNCS model. Read the entire page →
From page 67... ... Discussion of Results 67 in the MCS model and marginally significant in the MNCS model. Accordingly, it cannot be said with certainty that the effect was not 0. Read the entire page →
From page 68... ... 68 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 accounted for about 8% of the decline in fatalities attributed to economic factors; the decline was 15% from economic variables in the MCS model. Per capita GDP was likely connected to traffic fatalities by influencing the types and amounts of travel (VMT) Read the entire page →
From page 69... ... Discussion of Results 69 8.1.7 Effects of Individual Factors within the Regulatory Factors Table 8-5 lists the parameters that were included in the regulatory factors grouping, the change in each parameter between 2007 and 2011, and the associated effects on traffic fatalities in the MNCS and MCS models. 8.1.8 DUI Rating Both models indicated that an increase in DUI ratings was associated with a decline in fatalities. Read the entire page →
From page 70... ... 70 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 model and a small decrease in the MCS model. The parameter was not statistically significant in either model. Read the entire page →
From page 71... ... Discussion of Results 71 8.2.1 Economic Factors Economic factors explained most of the decline in traffic fatalities over the period. Economic effects were captured mainly by four measures: unemployment for teens and young adults (ages 16 to 24) Read the entire page →
From page 72... ... 72 Identification of Factors Contributing to the Decline of Traffic Fatalities in the United States from 2008 to 2012 factors that operated to set the baseline level of safety over the period. The study, however, was focused on the substantial drop in traffic fatalities after 2007. Read the entire page →
From page 73... ... Discussion of Results 73 highway spending would have an immediate and dramatic effect on traffic fatalities. Improvements in infrastructure roll out incrementally and over a long period of time. Read the entire page →

From page 57...

... 57 The Haddon Matrix was used initially to ensure that a comprehensive set of factors would be considered in studying the dramatic drop in traffic fatalities in the United States after 2007. The results showed that not all elements of the matrix -- vehicle, driver, and environment -- contributed equally.