translation.en: Or we can monitor the velocity with which people are moving with their phones on a highway, and the phone company can see, as the velocity is slowing down, that there's a traffic jam.
translation.zh: 或者我们能监测 人们在高速公路上带着电话移动的速度， 电话公司能看到， 如果速度慢下来， 那么就发生了交通堵塞。