As a driving school instructor, while discussing driver distractions, I’ve often been asked “What’s the difference between talking on a cell phone and talking with a passenger?” My answer has always been that the person on the cell phone can’t say “Watch out for that car up ahead!” Also, unlike the person on the other end of the cell phone, the passenger can stop talking when he or she recognizes that the driver is facing a difficult driving situation. Now the scientific evidence is in proving that my answer was correct.

Researchers at the University of Illinois observed drivers while negotiating through different driving situations such as merging and encountering unpredictable drivers on a simulated course.

They observed the drivers under four different scenarios:

• Driver alone,
• Driver speaking to a passenger,
• Driver speaking to someone on a hands-free mobile device,
• Driver speaking to someone who could see the driver and observe the driving scene via hands-free videophone.

The research showed that (no surprise) driving alone was safest because it allowed the driver to operate without any distractions. However, when driving with passengers who could observe the driving environment, especially one who had driving experience of their own, they found the passengers could be quite helpful. Just as in my answer to my students, they found that the passenger could help in navigating, moderate their conversation when driving was difficult, and warn of hazards ahead.

Again, no surprises here, they found that drivers talking on a cell phone were more likely to be involved in a crash.

The big surprise to the researchers was the results of drivers talking to someone outside the car on a video relay where the other person could see both the driver and the driving scene. In those situations, the outside person acted similarly to passengers inside the car as far as picking up on the driving hazards ahead and moderating their conversation.

Read more:Travelling with a passenger makes you a SAFER driver – but only if they are aware of road conditions