Heat transfer efficiency/capability. better. less. Ethylene glycol has superior heat transfer efficiency due to lower viscosity - but more fluid must be circulated to transfer the same amount of energy since Propylene glycol has higher specific heat. Viscosity.
Rotaries, still in use in some parts of the country, are typically larger circles through which vehicles move at higher speeds, while neighborhood traffic circles are typically smaller than roundabouts, and used primarily to calm traffic. In a roundabout, there is no need to change lanes to exit, and traffic moves in a counterclockwise direction. A roundabout also has geometry that forces slower speeds and features islands at the approaches and yield signs. Here are instructions from the Federal Highway Administration on how to use a roundabout:
To turn left at a roundabout, use the left lane. 1  Position your vehicle in the left lane unless arrows on the road or signs indicate otherwise. 2  Use your left indicator when you enter the roundabout. 3  Give way to all vehicles already on the roundabout.  Remain in the left lane as you complete your turn.