Why accidents occur at intersections

Researchers at Daimler investigate severe road traffic accidents in order to determine ways of recognizing such critical situations earlier or even avoiding them altogether.

 

“The annual figures from the German Federal Statistical Office show that a remarkable number of accidents occur at intersections and junctions. Altogether, around 80 percent of such accidents take place in cities, towns, and villages,” explains Frank. Despite the relatively low speed of traffic in urban areas, the risk of injury is high when, for example, a driver turning left overlooks an oncoming vehicle or runs into the side of a vehicle crossing the road. “We still know very little about what drivers actually do wrong in this kind of situation,” says Frank. “Where are they actually looking when they first recognize danger? How much time do they need to evaluate the situation and then react to it? And can special driver-assist systems maybe help prevent a crash?”

Detailed data

This is where accident research comes into play. “We conduct highly detailed investigations of serious accidents in Baden-Württemberg involving a current Mercedes-Benz vehicle,” explains researcher Uwe Nagel. “And in order to get a representative picture of road accidents in Germany as a whole, we’ve also helped initiate the GIDAS project.” GIDAS, the German In-Depth Accident Study, is the most comprehensive analysis of road traffic accident data in Germany, involving the investigation of some 2,000 accidents a year in the metropolitan areas of Hanover and Dresden. Teams from the Hanover Medical School and the Road Accident Research Department at the Technical University of Dresden document evidence at the scene of the accident, reconstruct the incident, and enter up to 5,000 items of information per case in a special database.

Daimler researchers reconstruct the precise ­details of a typical road traffic accident.

The simulation is based on documented evidence from accidents and witness statements.

“We selected four typical situations from the many different accidents so that we could then replicate them exactly in the driving simulator,” Frank explains. “The hazardous maneuver itself is embedded in a whole variety of harmless situations. That way, we can send test persons more or less unprepared into highly realistic accident situations and precisely observe their reactions under laboratory conditions.”

Sensors record reaction times, braking pressure, whether drivers swerve in an attempt to avoid a crash, and, if so, how hard they turn the steering wheel. “Afterward, we question the test persons about the incident. Because we know all the environment variables and always run each specific incident in an identical way, the results are highly commensurable.” And, of course, the simulator test has another inestimable advantage: situations like the one on the idyllic suburban street, which in reality would lead to a severe accident, can be replicated without any danger to either people or vehicles.