deletions | additions       diff --git a/subsection_Analysis_Zone_At_each__.tex b/subsection_Analysis_Zone_At_each__.tex  index e6b429d..6d43712 100644  --- a/subsection_Analysis_Zone_At_each__.tex  +++ b/subsection_Analysis_Zone_At_each__.tex 
...
\subsection{Analysis \subsection{Merging  Zone} At each Swedish roundabout, two cameras were positioned in such a way to cover the entire roundabout completely, and to cover at least one merging zone in each camera completely. The use of analysis the merging  zones as units the unit  of study instead study---instead  of roundabouts as a whole is whole---is  that, while many factors such as land use are shared, many more are not. This includes flows and flow ratios especially, but may also include geometric factors such as lane configuration, signalisation, presence of a crosswalk, approach angle, etc. which can vary from one merging zone to the next even within the same roundabout \cite{St_Aubin_2013b}. Studying merging zones individually also better encapsulated encapsulates  the microscopic nature of the data being collected and analysed: roundabouts are often large enough for road user interactions on different sides of the roundabout to occur independently. independently \citep[this is especially true if center islands obstruct view][]{Jensen_2014}.  Table~\ref{tab:analysis_zones} lists a summary of the sites, the analysis merging  zones at each roundabout studied  and the geometric and land use characteristics of each. each, as well as a summary of historical accident data at each roundabout.    \begin{table}  \caption{Analysis Zones Inventory} 
...
  \subsection{Beahavoural Measures}  \begin{itemize}  \item Approach The parameters of interest for this particular study are  speed (exiting)  \item Approach (and  speed (continuing)  \item Conflicting speed (exiting)  \item Conflicting speed (continuing)  \item Gap profiles), time-to-collision (TTC) \citep{Hayward_1971}, and yielding post-encroachment  time \item Conflicts (constant velocity time-to-collision)  \end{itemize} (yPET), an ordinary PET measure \citep{allen1978analysis} measured specifically at the yield line. Speed and yPET are measured directly from the road user trajectories as they occur.  TTC requires the modeling of potential collisions. Typically, potential collisions are defined as collision courses of constant velocity, i.e. ``with movement remaining unchanged'' \citep{Amundsen_1977}. Given the non-linear environment of roundabouts, a more sophisticated motion prediction collision course model is needed. For this work, the discretised motion pattern developped specifically as a result of motion prediction issues in roundabouts \citep{St_Aubin_2014} is used.