The object of research is the performance of a standard single-sided bridge guardrail when impacted by heavier New Energy Vehicles, including electric and hybrid passenger cars. The study assesses whether current road barriers, initially designed for a limited range of vehicle weight and speed, are adequate in handling the increasing dynamic loads from electric and hybrid vehicles. Method. The research was conducted using numerical simulations based on a standardized testing method. Detailed vehicle models representing three weight categories were used: a B-class (1525 kg), a C-class (1750 kg), and a sport utility vehicle (2000 kg). The simulations modeled a collision with the barrier at a speed of 100 km/h. The analysis focused on barrier deflection, vehicle body deformation, and the Acceleration Severity Index. Results. The study revealed that as vehicle mass increases, the guardrail deflection grows only slightly because of its high stiffness. However, there is a significant increase in the deformation of the vehicle’s structural load-bearing parts. For the sport utility vehicle with a curb weight of 2000 kg, the damage was severe. The calculated injury severity index for heavier vehicles surpasses the allowable limits for passenger cars, indicating that current road barriers do not offer sufficient safety for the occupants of heavier electric and hybrid vehicles.