Self-driving cars are so popular that the University of Michigan has even established a town called Mcity to allow car manufacturers to safely test their autonomous cars.

While Mcity can be used to simulate（模拟）many real-life road conditions，it can't help test gestures drivers use to communicate their intention（意图）to other drivers，pedestrians or cyclists. To find a solution，US car manufacturer Ford，with researchers from Virginia Tech，at the beginning considered using text as a way to communicate the car's intention，but decided it would probably not work universally. The option of using symbols was also rejected，because research shows that a majority of people do not have a good understanding of what they mean.

Finally, the researchers settled on light signals. A white light warned that there were no humans in the car. A slow blinking one indicated that the car was coming to a stop, while a rapidly flashing light cautioned passersby that the car was about to speed up.

Then came the big challenge—testing the signals on real roads. "We needed to try out this new lighting to communicate the intention of the vehicle, but if you've got a driver behind the seat, you still have natural communication between humans," said Andy Shaudt, who led the research team. "So we needed to make it look like a driverless car."

The team designed a car seat costume（戏装）that the driver would wear to cover his or her face and upper body. Of course，the drivers could see very clearly. The researchers then equipped the car with cameras to capture human reactions to a light bar，which flashed one of the three signals when appropriate. Six drivers，all keeping their hands low on the wheel so as not to be noticed，took turns to test driving the car through the busy streets.

The overall reaction to the flashing lights was very encouraging. Who knew costumes could be useful for more than Halloween？

   If you are already making the time to exercise, it is good indeed! With such busy lives, it can be hard to try and find the time to work out. 【小题1】 Working out in the morning provides additional benefits beyond being physically fit.

Your productivity is improved. Exercising makes you more awake and ready to handle whatever is ahead of you for the day. 【小题2】

Your metabolism(新陈代谢) gets a head start. 【小题3】 If you work out in the mornings, then you will be getting the calorie(卡路里) burning benefits for the whole day, not in your sleep.

【小题4】 Studies found that people who woke up early for exercise slept better than those who exercised in the evening. Exercise energizes you, so it is more difficult to relax and have a peaceful sleep when you are very excited.

【小题5】 If you work out bright and early in the morning, you will be more likely to stick to healthy food choices throughout the day. Who would want to ruin their good workout by eating junk food? You will want to continue to focus on positive choices.

There are a lot of benefits to working out, especially in the mornings. Set your alarm clock an hour early and push yourself to work out! You will feel energized all day long.