## 1 Introduction
These vehicles will estimate the confidence interval at 98 to 99 per cent, which ultimately means engineers would have to decide how high the confidence interval must be. Thus, engineers would need to consider what object is ahead, i.e., plastic bag or a person making this an essential line of enquiry in this field of research. While most of the research in self-driving car technologies is in its infancy, developing new technologies to handle collision is welcomed, which could, in turn, be adopted by regular non-self-driving vehicles. Safety intervention policies in reducing variations in speed play an essential role in reducing collision rates. Interventions include speed humps, roundabouts, road markings, signposts and traffic lights. However, the measures that have been found to increase speed limit adherence are those that physically prevent a vehicle from driving faster than necessary, such as speed humps [15]. Safety measures deployed in vehicles have also lead to a decrease in collisions. The European Union has made it mandatory through legislative requirements for vehicles to be fitted with advanced emergency braking systems and other measures, which lead to a decrease of 5000 fatal collisions on European roads per year [16]. Alternatively, signposts that show the expected speed limit do not automatically imply that drivers will match the indicated speed limit. The authors in [17] refer to static speed limit signposts as passive speed control. They argue that passive control alone is generally only sufficient at sites where the hazards are obvious, and drivers understand and accept the speed limitation [15]. Ultimately, the authors in [18] found that active signalling, using dynamic signs informing a driver that they are exceeding the speed limit, has more effect than passive control since drivers may also interpret the signal as an indication for impending danger. In addition, the authors in [19] found that, when comparing a signpost with a marked police car in increasing speed adherence, the police car had a significant effect on driving speed the drivers were in active fear of being reprimanded. According to [20], features such as edge markings that visually narrow the road, the vicinity of buildings, reduced carriageway widths, barriers in the carriageway and pedestrian activity all tend to reduce speed. The concepts discussed above provide insight into the literature on empirical evidence of collisions in Great Britain, the impact of speeding, safety intervention policies and road design. However, the decision to speed or comply with speed limits comes down to the individual driver. Speeding is a major contributory factor to roadside accidents [21]. To date, the majority of research in this area has investigated an extensive range of important factors from the viewpoint of those who exceed speed limits. This focus is understandable, given that faster vehicle speeds increase both risks of crash involvement and severity of crash outcomes [22]. The earlier statistics show that work needs to be done to curb the number of accidents on urban roads. This study will utilise a novel 3D Urban Traffic Agent-Based Model [23] to conduct several experiments by testing multiple traffic density and speed limit adherence parameters to illustrate how these measures impact vehicle collisions among a heterogeneous agent population of vehicles in a simplification of an urban environment. This study adopts the widely accepted definition of collisions, defined by [24] as: \"an observational situation in which two or more road users approach each other in space and time to such an extent that a collision is imminent if their movements remain unchanged\". The study ultimately aims to assess the impact traffic density and speed limit adherence have on collision rates by utilising a novel agent-based model to provide recommendations on reducing these rates and inform policy. Section 2 introduces the agent-based modelling methodology by describing what it is and how it has been adopted in similar research.