diff --git a/rust_qsim/src/simulation/network/flow_cap.rs b/rust_qsim/src/simulation/network/flow_cap.rs
index 99e36131..ab5d4b60 100644
--- a/rust_qsim/src/simulation/network/flow_cap.rs
+++ b/rust_qsim/src/simulation/network/flow_cap.rs
@@ -18,6 +18,12 @@ impl Flowcap {
     /**
     Updates the accumulated capacity if the time has advanced.
      */
+    // TODO: Must know how many vehicles are in the buffer (see updateFastFlowAccumulation)
+
+    /// TODO:
+    /// The capacity of the buffer is the flowcapacityPerTimeStpe
+    /// Check if the accumalated flow capacity of the buffer is not exceeded.
+    /// Update flow capacity
     pub fn update_capacity(&mut self, now: u32) {
         if self.last_update_time < now {
             let time_steps: f32 = (now - self.last_update_time) as f32;
diff --git a/rust_qsim/src/simulation/network/link.rs b/rust_qsim/src/simulation/network/link.rs
index 2cdb28c5..e698695e 100644
--- a/rust_qsim/src/simulation/network/link.rs
+++ b/rust_qsim/src/simulation/network/link.rs
@@ -114,6 +114,28 @@ impl SimLink {
         }
     }
 
+    /// This method pushes a vehicle directly into the buffer
+    pub fn push_veh_to_buffer(&mut self, vehicle: InternalVehicle, _now: u32) {
+        match self {
+            SimLink::Local(ll) => ll.push_veh_to_buffer(vehicle),
+            SimLink::In(il) => il.local_link.push_veh_to_buffer(vehicle),
+            SimLink::Out(_) => {
+                panic!("Can't push vehicle to buffer on out link")
+            }
+        }
+    }
+
+    /// This method pushes a vehicle to the waiting list, which has priority over vehicles in q
+    pub fn push_veh_to_waiting_list(&mut self, vehicle: InternalVehicle) {
+        match self {
+            SimLink::Local(ll) => ll.push_veh_to_waiting_list(vehicle),
+            SimLink::In(il) => il.local_link.push_veh_to_waiting_list(vehicle),
+            SimLink::Out(_) => {
+                panic!("Can't push vehicle to waiting list on out link")
+            }
+        }
+    }
+
     pub fn pop_veh(&mut self) -> InternalVehicle {
         match self {
             SimLink::Local(ll) => ll.pop_front(),
@@ -149,6 +171,8 @@ impl SimLink {
 pub struct LocalLink {
     pub id: Id<Link>,
     q: VecDeque<VehicleQEntry>,
+    buffer: VecDeque<InternalVehicle>,
+    waiting_list: VecDeque<InternalVehicle>,
     length: f64,
     free_speed: f32,
     storage_cap: StorageCap,
@@ -183,6 +207,8 @@ impl LocalLink {
         LocalLink {
             id,
             q: VecDeque::new(),
+            buffer: VecDeque::new(),
+            waiting_list: VecDeque::new(),
             length: 1.0,
             free_speed: 1.0,
             storage_cap: StorageCap::new(0., 1., 1., 1.0, 7.5),
@@ -215,6 +241,8 @@ impl LocalLink {
         LocalLink {
             id,
             q: VecDeque::new(),
+            buffer: VecDeque::new(),
+            waiting_list: VecDeque::new(),
             length,
             free_speed,
             storage_cap,
@@ -238,12 +266,56 @@ impl LocalLink {
         });
     }
 
+    pub fn push_veh_to_buffer(&mut self, vehicle: InternalVehicle) {
+        // self.storage_cap.consume(vehicle.pce);
+        self.buffer.push_back(vehicle);
+    }
+
+    /// Push a vehicle into the waiting list.
+    pub fn push_veh_to_waiting_list(&mut self, vehicle: InternalVehicle) {
+        // self.storage_cap.consume(vehicle.pce);
+        self.waiting_list.push_back(vehicle);
+    }
+
+    /// This method fills the buffer from two sources with priority:
+    /// 1) Check if there are vehicles in the waiting list and move them to the buffer.
+    /// 2) Check if there are vehicles in the queue that have reached their earliest exit time and
+    /// move them to the buffer.
+    pub fn do_sim_step(&mut self, now: u32) {
+        self.update_flow_cap(now);
+        self.apply_storage_cap_updates();
+        self.add_waiting_to_buffer();
+        self.add_queue_to_buffer(now);
+    }
+
+    fn add_queue_to_buffer(&mut self, now: u32) {
+        while let Some(front) = self.q.front() {
+            if front.earliest_exit_time <= now {
+                //TODO check with self.flow_cap.has_capacity();
+                let veh = self.q.pop_front().unwrap().vehicle;
+                self.storage_cap.release(veh.pce);
+                self.buffer.push_back(veh);
+            } else {
+                break;
+            }
+        }
+    }
+
+    fn add_waiting_to_buffer(&mut self) {
+        while let Some(veh) = self.waiting_list.pop_front() {
+            self.buffer.push_back(veh);
+        }
+    }
+
+    /// This method returns the next/first vehicle from the buffer and removes it from the buffer.
     pub fn pop_front(&mut self) -> InternalVehicle {
-        let veh = self.q.pop_front().unwrap_or_else(|| panic!("There was no vehicle in the queue. Use 'offers_veh' to test if a vehicle is present first."));
-        self.flow_cap.consume_capacity(veh.vehicle.pce);
-        self.storage_cap.release(veh.vehicle.pce);
-        self.stuck_timer.reset();
-        veh.vehicle
+        if let Some(veh) = self.buffer.pop_front() {
+            // self.storage_cap.release(veh.pce);
+            self.flow_cap.consume_capacity(veh.pce);
+            self.stuck_timer.reset();
+            return veh;
+        }
+        panic!("There was no vehicle in the buffer.");
     }
 
     pub fn update_flow_cap(&mut self, now: u32) {
@@ -251,17 +323,13 @@ impl LocalLink {
         self.flow_cap.update_capacity(now);
     }
 
+    /// This method returns the next vehicle that is allowed to leave the connection and checks
+    /// whether flow capacity is available.
     pub fn q_front(&self, now: u32) -> Option<&InternalVehicle> {
-        // check if we have flow cap left for current time step, otherwise abort
-        if !self.flow_cap.has_capacity() {
-            return None;
-        }
-
-        // peek if fist vehicle in queue can leave
-        if let Some(entry) = self.q.front() {
-            if entry.earliest_exit_time <= now {
+        if let Some(entry) = self.buffer.front() {
+            if self.flow_cap.has_capacity() {
                 self.stuck_timer.start(now);
-                return Some(&entry.vehicle);
+                return Some(entry);
             }
         }
 
diff --git a/rust_qsim/src/simulation/network/sim_network.rs b/rust_qsim/src/simulation/network/sim_network.rs
index 7e2eff25..f45ddf12 100644
--- a/rust_qsim/src/simulation/network/sim_network.rs
+++ b/rust_qsim/src/simulation/network/sim_network.rs
@@ -234,13 +234,21 @@ impl SimNetworkPartition {
             );
         });
 
+        // If events_publisher is None, this is the start of the route and the vehicle goes
+        // into the waiting list. `fill_buffer` prioritizes draining waiting_list into buffer.
+        let is_route_begin = events_publisher.is_none();
+
         if let Some(publisher) = events_publisher {
             publisher
                 .borrow_mut()
                 .publish_event(now, &Event::new_link_enter(link.id(), &vehicle.id));
         }
 
-        link.push_veh(vehicle, now);
+        if is_route_begin {
+            link.push_veh_to_waiting_list(vehicle);
+        } else {
+            link.push_veh(vehicle, now);
+        }
         self.veh_counter += 1;
 
         Self::activate_link(&mut self.active_links, link.id().clone());
@@ -292,8 +300,8 @@ impl SimNetworkPartition {
         active_nodes: &mut IntSet<Id<Node>>,
         now: u32,
     ) -> bool {
-        link.update_flow_cap(now);
-        link.apply_storage_cap_updates();
+        // Move all vehicles that completed their link travel into the buffer.
+        link.do_sim_step(now);
         // the node will only look at the vehicle at the at the top of the queue in the next timestep
         // therefore, peek whether vehicles are available for the next timestep.
         if link.q_front(now + 1).is_some() {