We’ve all seen the car ads promoting new built-in computer systems capable of giving drivers directions by integrating data about the weather, traffic congestion, and roadblocks, mapping out the most efficient route possible. A new study however by U of T Professor Baher Abdulhai and Horace Look of the Department of Civil Engineering suggests that Dynamic Route Guidance Systems (DRGs) may actually increase the risk of accidents.

According to Prof. Abdulhai, DRGs work by having “traffic operation centers that gather information from field devices recording traffic volumes and speeds every 20 to 30 seconds. A DRG would connect to the nearest center and download current travel time estimations.

Currently in Toronto, some systems are available for about $2,000 to $4,000, but they are based on digital maps and global positioning systems that give you directions only based on distance [without incorporating information about traffic volumes].”

While Abdulhai doesn’t “think there are any people in Toronto using these systems yet…there are many people using them in the U.S., Europe, and of course Japan.”

Prof. Abdulhai studied this issue using a computer model of an inner city layout. When 60 per cent of the cars in the model were DRG equipped during rush hour, the model predicted about five more accidents per year.

The explanation behind this seems to be that if there is an obstruction to avoid, when more people are using DRGs, more people end up taking the same route to avoid that obstruction. Common sense dictates that if more people are suddenly taking the same path, more accidents are likely to happen. The number of turns that a driver takes can also increase the risk of an accident. When using DRGs, drivers will often have to go through more intersections and perform more turns.

Dr. Abdulhai studied another type of in-car computer system, Safety-Enhanced Route Guidance Systems (SRGs), which are supposed to minimize the number of turns the driver takes. The study found that SRGs found do decrease the risk of accidents, but DRGs cut traveling time in half.

This is a preliminary study however, using only a small inner-city grid, and the results are not meant to be conclusive. “This study is only the first stab at the subject, and the network used is intentionally small for us to understand what is going on. In larger networks, many other factors can come into play and can mask what we want to test. In the near future, we intend to expand the network.” Perhaps further studies will find ways to help us balance both speed and safety.