Last week, we looked at the number of motor vehicle injuries occurring in the San Jose area and concluded that traffic safety around GJEL’s San Jose office is getting worse. According to California’s latest traffic records, the number of collisions leading to injury increased each year from 2013 to 2015 and was trending up again through the first half of 2016. Full-year results for 2016 should be available in August.
Not all injury collisions are alike. That’s why we’re delving into public information about the primary causes of injury collisions in this week’s post. It’s not enough to tell drivers to be safe and obey traffic laws, expecting that these basic warnings will change behavior on the roadways. People need to know what are the factors that contribute to collisions in their community. Public officials especially ought to know if we’re seeing improvements in these contributing factors or not. The short answer is that the San Jose area is heading in the wrong direction almost across the board.
It’s worth noting that there may be some subjectivity in the way that law enforcement determines the primary collision factor when an injury occurs. If a driver is speeding and following too closely behind other vehicles, can everyone agree which of these behaviors was the primary collision factor? Not always. But with over 18,000 collision records spanning a 2.5-year period, we should be able to draw some meaningful conclusions about what’s making the San Jose-area roads more dangerous with each passing year.
Top causes of injury collisions
Most motor vehicle collisions involving injuries come down to these three factors: unsafe speed, improper turning, and failure to observe the right-of-way of automobiles. There are a lot of other reasons why people get injured on the road. California reports on 21 specific factors in its annual reports of fatal and injury motor vehicle traffic collisions, including everything from driving under the influence of alcohol or drugs to hazardous parking. (Hazardous parking was the primary cause of 4 injury collisions over the past 2.5 years.) Here are the top 5 causes of motor vehicle injury collisions in Santa Clara County.
Primary injury collision factors, by percentage and number of collisions (in parentheses)
| 2014 | 2015 | First half 2016 | |
| Unsafe speed | 35.5%(2,387) | 36.4%(2,706) | 37.3%(1,459) |
| Improper turning | 12.9%(867) | 12.9%(957) | 14.1%(553) |
| Automobile right-of-way | 10.5%(706) | 10.4%(770) | 10.8%(423) |
| Traffic signals & signs | 7.6%(512) | 7.8%(579) | 7.3%(287) |
| Driving / bicycling under the influence | 6.2%(414) | 5.5%(409) | 5.7%(223) |
California Statewide Integrated Traffic Records System, https://iswitrs.chp.ca.gov/
As the above table shows, the three biggest problem areas are getting worse over time. Even less significant collision factors not shown in the table are getting worse, such as following too closely behind other vehicles. Two collisions factors have become less of a problem in recent years, driving on the wrong side of the road and unsafe starting or backing. But these improvements account for only 20 fewer injury collisions while the most vexing collision factors add up to hundreds of injury collisions per year.
The top contributing causes of motor vehicle fatalities are different than the causes of motor vehicle injuries, but these factors are also getting worse. We’re listing only the top 4 factors, because there’s a 3-way tie for 5th place.
Primary fatality collision factors, by percentage and number of collisions (in parentheses)*
| 2014 | 2015 | First half 2016 | |
| Pedestrian violations | 14.4%(15) | 15.0%(19) | 23.7%(9) |
| Driving / bicycling under the influence | 13.5%(14) | 12.6%(16) | 21.1%(8) |
| Improper turning | 14.4%(15) | 15.0%(19) | 18.4%(7) |
| Unsafe speed | 14.4%(15) | 16.5%(21) | 10.5%(4) |
California Statewide Integrated Traffic Records System, https://iswitrs.chp.ca.gov/
*Three factors—traffic signals & signs, unsafe starting and backing, and driving on the wrong side of the road—each accounted for 5.3% of fatalities in 2016.
One can hope that improvements among the primary collisions factors leading to traffic fatalities are sustainable. In the first half of 2016, California traffic records show no fatalities due to unsafe lane changes or failure to observe the pedestrian right-of-way while these factors together contributed to 11 fatalities in 2015. A reduction in fatalities due to unsafe speed, from 21 in 2015 to 4 during the first half of 2016, is also encouraging. Given that unsafe speed remains the leading cause of injury collisions, however, this might just be a statistical anomaly due to a small sample size.
Andy Gillin received his Bachelor’s Degree from the University of California at Berkeley and his law degree from the University of Chicago. He is the managing partner of GJEL Accident Attorneys and has written and lectured in the field of plaintiffs’ personal injury law for numerous organizations. Andy is a highly recognized wrongful death lawyer in California.