The reaction times of people texting as they drove fell by 35 percent, while those who had consumed the legal limit of alcohol, or taken cannabis, fell by 21 percent and 12 percent respectively, according to the study.

The study, which was commissioned by motoring group RAC Foundation, also found that the ability to stay in lanes or maintain a safe distance from the vehicle in front was worse than drivers under the influence of cannabis.

"This research demonstrates how dangerous it is to drive and text," TRL Senior Human Factors Researcher Nick Reed said in a statement.

He said drivers who texted were distracted by taking their hand off the wheel to use their phone, by trying to read small text on the phone display and by thinking about how to write their message.

"This combination of factors resulted in the impairments to reaction time and vehicle control that place the driver at a greater risk than having consumed alcohol to the legal limit for driving," Reed told reporters.

One conclusion researchers made about why texting is so dangerous is the length of time it takes to compose a message while driving.

The TRL said that composing a text message behind the wheel took 63 seconds, in which time a car travels half a mile within town centre speed limits and over a mile within motorway speed limits.

Nearly half of all 18-24 year-olds admitted to texting as they drove, a separate survey by the RAC Foundation discovered.

The TRL study selected 17 people from the 18-24 year-old age group to take part in a simulated road test, in which they were asked to read, write, and ignore texts on a variety of roads.

"The participants in this study were almost unanimous in their view that drink-driving was the most dangerous action on the road," RAC Director Stephen Glaister said.

He said the research clearly showed that a motorist who is texting is significantly more impaired than a motorist at the legal limit for alcohol.

"No responsible motorist would drink and drive," Glaister said in the statement. "We need to ensure that text devotees understand that texting is one of the most hazardous things that can be done while in charge of a motor car."

英国交通研究实验室（TRL）日前开展的一项研究发现，开车时发短信比酒后或服药后开车更危险。

研究显示，开车时发短信的人反应能力会下降35%，而少量饮酒后驾车或者服用过大麻的人则分别下降21%和12%。

此外，该项受“英国皇家飞行俱乐部（RAC）基金会驾驶组”委托开展的研究发现，开车时发短信的人控制车道和保持安全车距的能力比服用了大麻的司机差。

“交通研究实验室人为因素组”资深研究员尼克?里德在一份声明中说：“这项研究表明，开车时发短信有多么危险。”

他说，如果你在开车时发短信，就必须从方向盘上腾出一只手来去拿手机查看信息，还要想着如何回复，这都会分散你的注意力.

里德在接受采访时说：“这几个因素会影响司机的反应速度和对车的控制能力，由此产生的风险比少量饮酒后开车还要大。”

为什么开车时发短信如此危险呢？研究人员得出的结论是，问题就出在编写短信的那段时间。

交通实验室称，开车时编写一条短信需要63秒的时间，而车在63秒内可在市区行驶半英里，在高速公路上则可行驶一英里以上。

“英国皇家飞行俱乐部基金会”开展的另一项调查显示，在18岁至24岁的受访者中，近一半的人承认自己在开车时发过短信。

交通研究试验室从这一年龄段的受访者中挑选了17人参加一个模拟驾驶测试，要求他们在不同的路况下查看、编写或不看短信。

英国皇家飞行俱乐部主管斯蒂芬?格莱斯特说：“受访者几乎一致认为酒后驾车最危险。

而研究结果清楚地表明，开车时发短信的人比酒后驾车的人反应要迟钝得多。”

格莱斯特在声明中说：“酒后驾车是不负责任的表现。所以我们要让爱发短信的人意识到，发短信是他们开车时最危险的行为之一。”