Should be working.

BigBaseV2/src/backend/backend.cpp

@@ -94,6 +94,7 @@ namespace big
 			looped::vehicle_instant_brake();
 			looped::vehicle_is_targetable();
 			looped::vehicle_rainbow_paint();
+			looped::vehicle_seatbelt();
 			looped::vehicle_speedo_meter();
 		}QUEUE_JOB_END_CLAUSE
 

BigBaseV2/src/backend/looped/looped.hpp

@@ -45,6 +45,7 @@ namespace big
 		static void vehicle_is_targetable();
 		static void vehicle_ls_customs();
 		static void vehicle_rainbow_paint();
+		static void vehicle_seatbelt();
 		static void vehicle_speedo_meter();
 
 		static void weapons_ammo_special_type();

BigBaseV2/src/backend/looped/vehicle/seatbelt.cpp

@@ -0,0 +1,21 @@
+#include "backend/looped/looped.hpp"
+#include "natives.hpp"
+
+namespace big
+{
+	static bool b_last_seatbelt = false;
+
+	void looped::vehicle_seatbelt()
+	{
+		bool b_seatbelt = g->vehicle.seatbelt;
+
+		if (b_seatbelt || (!b_seatbelt && b_seatbelt != b_last_seatbelt))
+		{
+			PED::SET_PED_CONFIG_FLAG(self::ped, 32, g->vehicle.seatbelt);
+
+			PED::SET_PED_CAN_BE_KNOCKED_OFF_VEHICLE(self::ped, g->vehicle.seatbelt);
+
+			b_last_seatbelt = g->vehicle.seatbelt;
+		}
+	}
+}

BigBaseV2/src/core/globals.hpp

@@ -218,6 +218,7 @@ namespace big
 			bool ls_customs = false; // don't save this to disk
 			bool pv_teleport_into = false;
 			int rainbow_paint = 0;
+			bool seatbelt = false;
 			speedo_meter speedo_meter{};
 			fly fly{};
 		};
@@ -474,6 +475,7 @@ namespace big
 			this->vehicle.is_targetable = j["vehicle"]["is_targetable"];
 			this->vehicle.pv_teleport_into = j["vehicle"]["pv_teleport_into"];
 			this->vehicle.rainbow_paint = j["vehicle"]["rainbow_paint"];
+			this->vehicle.seatbelt = j["vehicle"]["seatbelt"];
 
 			this->vehicle.speedo_meter.type = (SpeedoMeter)j["vehicle"]["speedo_meter"]["type"];
 			this->vehicle.speedo_meter.left_side = j["vehicle"]["speedo_meter"]["left_side"];
@@ -704,6 +706,7 @@ namespace big
 						{ "is_targetable", this->vehicle.is_targetable },
 						{ "pv_teleport_into", this->vehicle.pv_teleport_into },
 						{ "rainbow_paint", this->vehicle.rainbow_paint },
+						{ "seatbelt", this->vehicle.seatbelt },
 						{
 							"speedo_meter", {
 								{ "type", (int)this->vehicle.speedo_meter.type },

BigBaseV2/src/views/vehicle/view_vehicle.cpp

@@ -20,6 +20,8 @@ namespace big
 		ImGui::SameLine();
 		ImGui::BeginGroup();
 
+		ImGui::Checkbox("Seatbelt", &g->vehicle.seatbelt);
+
 		components::button("Repair", [] {
 
 			vehicle::repair(self::veh);