"Highway" is a poorly defined term. In most state vehicle codes it is explicitly defined as any public right-of-way intended for vehicles to travel on. So the quiet residential street with a 25 mph speed limit is legally a 'highway' in California and many other states. OTOH, most people use the term more restrictively, for example limiting it to major arterial roads, frequently only to those that have some state or federal 'highway' number assigned to them. Still others use the term only for limited-access roads such as the interstate highway system. Without further clarification, it's easy for one person's comments about 'highways' to be misinterpreted by others who are using a different definition.