What's "speed down the shoulders" mean? Is this an idiom?
Native speaker’s answer
Rebecca
A "shoulder" is the emergency lane on the right side of a highway, used to make emergency stops. When people "speed down the shoulders," it means that they are driving down the emergency lane in order to avoid traffic on the regular lanes, which is a very dangerous thing to do. Ex: Never speed down highway shoulders. You could slow down traffic or even cause an accident. Ex: I had to make an emergency stop on the shoulder because my lights weren't working.