## 3 Classification
### Types of VRUs
#### 3.1.1 Pedestrians
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Publication** & **VRU Type** & **Mode** & **Notification Recipient** & **Type** & **VRU Device** & **Technology** & **Role** \\ \hline [PERSON] et al. [3] & pedestrian & direct & both & safety & smartphone & 802.11p & active \\ V2 ProVu [4] & pedestrian & direct & pedestrian & safety & smartphone & Wi-Fi & passive \\ [PERSON] et al. [5] & pedestrian & hybrid & both & safety & smartphone & Cellular & active \\  & cyclist & & & & Wi-Fi & \\ WiFiHonk [15] & pedestrian & direct & both & safety & smartphone & Wi-Fi & passive \\ Wisfae [29] & pedestrian & direct & vehicle & safety & smartphone & Wi-Fi & active \\ Audi [17] & pedestrian, & direct & both & safety & smartphone & Wi-Fi & active \\  & cyclist & & & & & & \\ [PERSON] and Kim [18] & pedestrian & direct & – & safety & smartphone & 802.11p & active \\ [PERSON] and Flach [19] & pedestrian & hybrid & – & safety & smartphone & Cellular & active \\ [PERSON] et al. [30] & pedestrian & indirect & both & safety & smartphone & Cellular & active \\ pSafety [31] & pedestrian & indirect & both & safety & smartphone & Cellular & active \\ [PERSON] et al. [32] & pedestrian & indirect & vehicle & safety & smartphone & 802.11p, & passive \\ [PERSON] et al. [33] & pedestrian & direct & vehicle & safety & smartphone & Wi-Fi & passive \\ [PERSON] et al. [20] & pedestrian & indirect & – & safety & smartphone & Cellular & active \\ V2 Psense [34] & pedestrian & indirect & pedestrian & safety & smartphone & Cellular & passive \\ LP9S [21] & pedestrian & direct & vehicle & safety & tag & 802.15.4 & passive \\ General Motors [22] & pedestrian & direct & vehicle & safety & smartphone & Wi-Fi & active \\ [PERSON] et al. [9] & pedestrian & direct & - & safety & smartphone & Wi-Fi & active \\ [PERSON] et al. [23] & pedestrian & direct & both & safety & smartphone & Wi-Fi & active \\ [PERSON] et al. [24] & pedestrian & direct & both & safety & smartphone & Wi-Fi & active \\ [PERSON] et al. [35] & pedestrian & direct & both & safety & smartphone & Wi-Fi & active \\ POPS [25] & pedestrian & hybrid & pedestrian & safety & smartphone & Cellular & active \\ [PERSON] et al. [26] & pedestrian & direct & both & safety & smartphone & 802.11p & active \\ Ko-TAG [27] & pedestrian, & direct & vehicle & safety & tag & localization & passive \\ cyclist & & & & & & & \\ [PERSON] et al. [28] & pedestrian & direct & vehicle & safety & smartphone & 700 MHz ITS & active \\ C-AEB [36] & cyclist & direct & vehicle & safety & smartphone & 802.11p & active \\ [PERSON] et al. [37] & cyclist & indirect & vehicle & safety & smartphone & Wi-Fi & active \\ [PERSON] et al. [38] & indirect & cyclist & safety & helmet, & Cellular & active \\  & & & & & smartphone & 802.11p & \\ Motowarn [39] & cyclist & direct & vehicle & safety & iBeacon & Bluetooth & active \\ Motowarn [39] & MTW & direct & vehicle & safety & OBU & 802.11p & active \\ [PERSON] [8] & MTW & direct & both & safety & smartphone & Wi-Fi & active \\ [PERSON] et al. [40] & cyclist & direct & cyclist & convenience & smartphone & – & passive \\ [PERSON] et al. [7] & pedestrian & indirect & both & convenience & smartphone & – & active \\ [PERSON] et al. [41] & pedestrian & indirect & both & convenience & smartphone & 802.11p & active \\ TIMON [42] & cyclist & hybrid & both & convenience & smartphone & Cellular, & active \\ MTW & & & & & & & 802.11p & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of efforts. that communicates with the vehicle's on-board localization unit. This communication helps vehicles to localize the pedestrians and bicyclists.