###### Abstract
This testing method allows for the assessment of LED lamp performance in higher ambient temperatures and helps identify areas for improvement in heat dissipation, enabling designers to make informed decisions about balancing performance and cost when selecting cooling solutions for LED headlamps [14]. The longevity and efficiency of vehicle components, particularly LEDs, are significantly impacted by thermal conditions, as noted by [PERSON] [15; 16]. Standards such as AEC-Q101 and LV-124 dictate the thermal requirements and lifetime testing procedures for headlamps, which, in turn, influence the design of heat-dissipation solutions [9; 17; 18; 19]. The AEC-Q101 standard, specifically tailored for automotive electronic components, outlines various stress tests to ensure the reliability of semiconductor devices under harsh automotive conditions. These tests include temperature cycling, high-temperature storage, and power cycling, all of which are designed to simulate the thermal stresses that components will experience over their lifetime. The AEC-Q101 standard ensures that LEDs used in headlamps can withstand these conditions without significant degradation in performance or longevity [18]. The LV-124 standard includes tests like the high-temperature endurance test and the temperature cycling endurance test), which verify the maximum temperatures that components can endure throughout a vehicle's life, as simulated by various driving cycles. These standards ensure that headlamp components, including LEDs, can withstand the thermal stresses encountered during normal vehicle operation [20; 21]. However, the thermal conditions experienced by headlamp components can differ significantly between battery electric vehicles (BEVs) and internal combustion engine (ICE) vehicles, presenting potential opportunities for optimized component design and testing procedures [17]. The research article by [PERSON], [PERSON], and [PERSON] from Audi AG investigates the thermal load differences in the headlamp environment between battery electric vehicles (BEVs) and internal combustion engine vehicles (ICEVs). The study reveals that BEVs exhibit a lower thermal load on headlamps, especially at lower speeds typical of urban traffic. This is attributed to the absence of heat-generating engines in BEVs, which reduces the temperature stress on the headlamp systems. The findings suggest that BEVs may have an advantage over ICEVs in terms of thermal management for headlamps, and the data collected provide a basis for updating the thermal requirements for headlamp design in electric vehicles [22]. The aim of this paper is to gain a comprehensive understanding of the thermal management requirements in battery electric vehicles (BEVs) and compare them with those in internal combustion engine (ICE) vehicles to provide new opportunities for requirements and the design impact. The impact of these differences on headlamps was investigated. This analysis aims to improve the efficiency and performance of battery electric vehicles (BEVs) while promoting a sustainable and environmentally friendly future for the automotive industry. This paper investigates the effects of ambient vehicle temperature and engine type on the temporal proportion within specific temperature classes and the overall temporal distribution (time share) across the entire temperature histogram of an LED headlight. This study is driven by the following research questions:  
1. Is there an influence on the temporal proportion (TP) within different temperature classes (TCs) between the different engine types of battery electric vehicles (BEVs) and internal combustion engine (ICE) vehicles? 2. Is there an influence on the overall temporal proportion (TP) of different temperature classes (TCs) when considering the different engine types of BEVs and ICE vehicles separately? 3. Is there an influence on the temporal proportion (TP) within different temperature classes (TCs) across varying ambient vehicle temperatures (ATs)? These issues are explored in more detail in the following Section 3.