Which factor contributes most to brake wear in heavy vehicles?

Answer: B — Hard braking in stop-and-go traffic

The choice that contributes most to brake wear in heavy vehicles is hard braking in stop-and-go traffic. This type of driving increases the frequency and intensity with which the brakes are applied, leading to higher friction and heat generation. In heavy vehicles, which already exert significant force due to their weight, the impact of hard braking is magnified, resulting in accelerated wear on brake components. While other factors like the frequent use of the emergency brake or using non-standard replacement parts can impact overall vehicle performance and systems, they do not directly correlate with the constant and forceful application of brakes seen in stop-and-go situations. Additionally, regular weight checks during loading help ensure vehicles are not overloaded, which is important but does not inherently lead to brake wear like repeated hard braking does. Therefore, the context of driving conditions has a primary influence on brake wear.