# The Impact of Spoofing Attacks in Connected Autonomous Vehicles under Traffic Congestion Conditions
## 3 System Model  
### Topology  
The purpose of this article is to simulate a real traffic model, highlighting the conditions of a relatively small city, such as Erlangen, in Germany. For this reason, we assume that each new vehicle is added at a relatively fast rate, within the simulation environment, which is \(R=1/3\) vehicle/s. Vehicles start their route from the city's university and head towards the same final destination, as shown in Figure 1. They form a platoon of vehicles, for which we assume that the motion model is the known Gipps model, which is an absolute collision-free car-following model [11]. In the context of the Gipps model [15; 16], the safe speed refers to the maximum speed a driver can travel at any given time while ensuring they can safely stop before reaching the vehicle ahead. This speed considers the driver's reaction time, the deceleration capabilities of both the leading and following vehicles, and the current speed and position of the vehicles. The safe speed in the Gipps model is influenced by parameters such as maximum acceleration, reaction time, desired speed, and minimum gap distance. All the values for these parameters were chosen (see Table 1) based on the fact that the traffic is in an urban environment, where there are frequent stops and the presence of intersections and pedestrians. Specifically, the minimum gap distance is set around 2.0 to 5.0 m for urban environments. Therefore, we select a mean value of about 2.5 m. On the other hand, the safety distance in the Gipps model is the minimum distance that must be maintained between a vehicle and the one ahead to prevent a collision, considering their current speeds and deceleration capabilities. This distance ensures that if the leading vehicle decelerates suddenly, the following vehicle can stop in time to avoid a crash. According to the above, a vehicle needs to move with a safe speed at about 40-50 km/h, so as to constantly maintain a minimum safety distance at about 30-50 m (assuming that the parameter of minimum gap distance is 2.5 m), even if its leading vehicle stops abruptly due to unspecified factors on the road.  
All the members of the platoon contain backward- and forward-facing radars in order to detect obstacles in front of them. All platoon-connected vehicles periodically send unicast \(WSM\) messages to the following vehicles that contain motion-related information, such as position, speed, acceleration, etc. Also, there is a RSU in the area that relays the WSMs being exchanged. However, if the first platoon vehicles detect any traffic disturbance (i.e., an accident between vehicles or accidents among vehicles and pedestrians), they may change their route, real-time, in order to reach their destination faster. Therefore, to guarantee the safety on the road containing autonomous self-driving cars, sensor-related solutions that calculate vehicles positions and those based on wireless V2V should correlate. To this end, in these technologies, it is very important that the exchanged data need to be protected and their integrity guaranteed.  
Figure 1: Vehicle route, highlighting its start and end points.