## 4 Data Collection and Preparation
### Generating Non-Crash Cases for the Crash Likelihood Modeling
\begin{table}
\begin{tabular}{|c c c c c|} \hline \hline
**Variable** & **Type** & **Class** & **Source** & **Description** \\ \hline LANES & Categorical & Proactive & NJCMS & Number of lanes (the values are; 2, 3, 4, or 5) \\ Hour & Categorical & Proactive & NJCR & Time of the crash or non-crash (hour of the day) \\ Month & Categorical & Proactive & NJCR & Time of the crash or non-crash (month of the crash) \\ MEDIAN\_NY & Binary & Proactive & NJCR & Median type (protected or non-protected) \\ Weekend & Binary & Proactive & NJCR & Day of the week (weekend of weekday) \\ Sun glare & Binary & Proactive & NJCMS & The effect of sun glare (0 = no effect, or 1 = Sun glare existed) \\ CAPLINK & Continuous & Proactive & NJCMS & Link capacity (vehicles/hour) \\ VC\_RATIO & Continuous & Proactive & NJCMS & Volume-to-capacity ratio at the highway section during a given hour of the day and month [unless] \\ Vol16\_Tr & Continuous & Proactive & NJCMS & Hourly truck volume ratio \\ Hourly & & & & Hourly precipitation at the highway section during the hour of the crash or non-crash event obtained from the weather records for the closest weather station [inches/hour] \\ Hourly Visibility & Continuous & Proactive & NWS & Hourly visibility at the highway section during the hour of the crash or non-crash event obtained from the weather records for the closest weather station [miles]. \\ \hline \hline speed\_avg\_1015 & Continuous & Proactive & RTITS & Average speed at the highway section [miles/hour]. It is calculated for each crash and non-crash event as an average of 1 min prevailing speeds for the pertinent highway section over a 10 min period (5-15 min) prior to the crash or non-crash event. \\ \hline speed\_sd\_1015 & Continuous & Proactive & RTITS & Standard deviation of speed at the cash location [miles/hour]. It is calculated as a standard deviation of 1 min prevailing speeds for the pertinent highway section over a 10 min period (5-15 min) prior to the crash or non-crash event. \\ \hline speedup\_sd\_1015 & Continuous & Proactive & RTITS & Standard deviation of speed at the upstream highway section [miles/hour]. It is calculated as a standard deviation of 1 min prevailing speeds for the pertinent highway section over a 10 min period (5-15 min) prior to the crash or non-crash event. \\ \hline speeddown\_sd\_1015 & Continuous & Proactive & RTITS & Standard deviation of speed at the downstream highway section [miles/hour]. It is calculated as a standard deviation of 1 min prevailing speeds for the pertinent highway section over a 10 min period (5-15 min) prior to the crash or non-crash event. \\ \hline speedup\_dif\_1015 & Continuous & Proactive & RTITS & Deviation of speed from the speed limit [miles/hour] at the upstream roadway segment. Calculated as the difference between the average speed (speed\_avg) and the speed limit (obtained for the upstream roadway segment from the NJCMS dataset). \\ \hline speeddown\_dif\_1015 & Continuous & Proactive & RTITS & Deviation of speed from the speed limit [miles/hour] at the downstream roadway segment. Calculated as the difference between the average speed (speed\_avg) and the speed limit (obtained for the downstream roadway segment from the NJCMS dataset). \\ \hline Shape\_Leng & Continuous & Proactive & RTITS & Length of the highway segment [miles] \\ Age & Categorical & Reactive & NJCR & Driver’s age in years (the classes are defined as age \(\leq\) 25, 25 \(\leq\) age \(\leq\) 60, and age \(>\) 60) \\ Veh\_age & Categorical & Reactive & NJCR & Vehicle age in years (the classes are defined as: 0 \(<\) age \(\leq\) 5, 5 \(<\) age \(\leq\) 10, and age \(>\) 10) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Definition of the explanatory variables used in the study. when generating non-crash cases for the analysis. After completing this step, the study dataset for the crash likelihood model had additional 40,620 records representing non-crash cases (in addition to the 10,155 crash records).