Aggressive Driving and Road Rage Behaviors on Freeways in San Diego, California: Spatial and Temporal Analyses of Observed and Reported Variations

The California Highway Patrol in San Diego County receives cellular telephone calls reporting unsafe driving. The content of the calls varies, with drivers complaining about speeding cars driving over 161 km/h (100 mph) and other drivers weaving and cutting off or tailgating. In some cases, the driving conditions were even more volatile with drivers describing harassment, assaults with a weapon, or running other vehicles off the road. There were about 1,987 reported incidents from the freeways of San Diego for the months of April, June, and September 1998. The information received by the dispatchers was tabulated and put into five different categories. Analyses indicated that 24.6 percent of the calls were for “Aggressive Driving 1” (speeding plus some other behavior, such as unsafe lane changes or passing); “Aggressive Driving 2” (weaving and cutting) was reported most frequently (27.1 percent of all calls); about 12.5 percent of the calls were for “Aggressive Driving 3” (tailgating); “Speeding Alone” calls comprised 19.8 percent of the total; and the rest were for “Road Rage” (16.1 percent). Of the 1,987 calls, 33 percent were generated on Interstate 5, the busiest and longest in the county, followed by Interstate 15, which accounted for 22 percent of the calls. The high number of calls can be attributed to the high average daily traffic volumes at each interchange and the longer interstate lengths. Similarly, Interstate 8 seemed to have a lower number of calls than expected, because the urban portion of the freeway is not as long and the remaining distance had fewer vehicles at each interchange. This was further corroborated and both volume and length were robustly correlated with the number of phone reports per freeway. Additionally, chi-square tests indicated that the time of the day and day of the week influenced the type and number of calls received.