The type of texting makes a difference, with reading messages affecting braking time more than writing them.

To find why and how much drivers are impaired during texting, the Utah researchers selected 20 men and 20 women between the ages of 19 and 23 both in single task straight driving and a dual task driving and texting in a high fidelity simulator. The participants were experienced texters with an average of nearly 5 years driving experience, they received and sent messages while the researchers monitored their brake onset time, following distance, lane maintenance, and collisions. The crash risk due to texting is substantial. One explanation is drivers who text tend to decrease their minimum following distance and also experience delayed reaction time. It took drivers in the study an average of 30 percent longer to react when they were texting and 9 percent longer when they talked on a cell phone, compared with driving only.