Intelligent lane control signs (ILCS) are displays above lanes that warn drivers of incidents ahead. They’re becoming increasingly popular in high-crash areas of busy metropolitan areas as a way to reduce congestion and improve safety. Their effectiveness, however, depends on driver compliance.
In a recent project, U of M researchers set out to determine whether drivers are, in fact, heeding the messages displayed via these high-tech warning systems. To do so, they studied the effectiveness of ILCS messages during incidents in the high-crash area of westbound I-94 along the south edge of downtown Minneapolis.
“This two-mile stretch of road experiences more crashes than any other freeway location in Minnesota, with crash events observed almost every other day on average,” says John Hourdos, director of the Minnesota Traffic Observatory and the study’s principal investigator.
For the MnDOT-funded project, researchers analyzed 28 specific incidents using loop detector and lane-change data. “Instead of taking the more traditional approach of testing and measuring the effect an ILCS system has on overall congestion, we aimed to evaluate and quantify the effect the system has on drivers—specifically, on inducing desirable lane selection behavior,” says Hourdos.
Findings indicate that the use of ILCS for incident management has a significant effect on driver behavior, specifically in prompting proper lane selection during capacity-reducing incidents.
“We saw that the ILCS were capable of emptying the incident lane well upstream of the obstruction caused by the incident, even when the next lane was considerably congested,” says Hourdos. “After a certain point, the preferred operational strategy may be to display an innocuous message such as ‘Use Caution’ rather than instructing drivers to change lanes in order to preserve the storage capacity of all lanes upstream of an incident.”
Read the full article in the May 2016 issue of Catalyst.