One of the key reasons gridlock happens is our inability to maintain a constant speed.

交通堵塞的主要原因之一是我们无法保持恒定的速度。

What we want to achive is a round link turn, which keeps my speed constant and in control.

我们想要的是一个连接处平滑的转弯，这样可以 保持滑行速度恒定，并使速度在自己的掌控中。

To be an inertial observer, one has to maintain a constant speed and direction relative to the rest of the universe.

作为惯性观测者，必须相对于宇宙的其余部分保持恒定的速度和方向。

Well, as a planet orbits the Sun it may not keep a constant speed but it does maintain its angular momentum.

当行星绕太阳运行时，它可能不会保持恒定的速度，但它的角动量会保持不变。

Outside forces can change an object's direction or speed,   but constant forces create a constant speed.

外力可以改变物体的方向或速度，但恒定的力会产生恒定的速度。

In a 2008 experiment, drivers were instructed to drive along a circular road, following the car in front of them while trying to maintain a constant speed.

在2008年的一项实验中，司机们被要求沿着环形道路行驶。他们要在在保持恒定速度的同时跟随着前面的车辆。