I ran across the following NBC story, which has a couple of problems that I’ll discuss below:
Worst Franklin County Intersections Revealed
By Matt Alvarez
Published: June 5, 2009
COLUMBUS, Ohio—NBC 4 has obtained a report from the Mid-Ohio Regional Planning Commission which breaks down the most deadly and dangerous intersections in Central Ohio.
According to MORPC, the most dangerous intersection in Central Ohio sits on the northeast side of Columbus.
Transportation experts say Cleveland Avenue and Morse Road is the worst intersection in Columbus, with 357 accidents between 2005 and 2007.
A total of two people died as a result of car accidents in the intersection along with a number of injury accidents.
Okay, so Cleveland & Morse has the highest crash frequency of any intersection in Franklin County. Does that make it “the worst” intersection? In short, no. More important than crash frequencies are crash rates. The number of crashes at an intersection can be expected to be somewhat correlated to the traffic volumes on the two streets. That’s why a rate, which measures the crashes per vehicle entering the intersection is more useful. The average severity of crashes is also important. Fatalities and serious injuries cost more than property-damage-only crashes.
Secondly, NBC (and everyone else) need to stop using the term “accidents.” An accident implies that there is nobody to blame, but most of the time there is. The preferred terms would be crashes, collisions, or incidents. I went to the MORPC web site to get the full list of data and their description of the data is expectedly much more professional:
* Between the years of 2005 and 2007, a total of 124,533 crashes involving nearly 335,000 people occurred in MORPC’s transportation planning area. This is a 3 percent reduction to the number of crashes reported between 2003 and 2005. During this time frame, 304 people lost their lives and over 47,000 were injured.
* On average, a person is killed every 3.6 days and 43 people are injured every day in a traffic crash in our region.
* A total of 940 bicycle units and 1,356 pedestrians were involved in crashes during the 3-year frame.
* In 2007 alone, over 12% of all crashes in Ohio occurred in our area.
* This number of crashes equates to approximately 41,500 crashes per year or 114 crashes per day.
The full list of intersections is available here as a PDF document. As it turns out, Cleveland and Morse doesn’t have the highest crash rate. Noe-Bixby & Refugee/Chatterton does. Neither of those two intersections is ranked number one by MORPC though, which used a combination of frequency, rate, and severity to create its list. That dishonor is held by Hamilton & Livingston.
It quickly becomes obvious by looking at the list that the major high-speed suburban-style arterials are the ones on this top 40 list. Hamilton, Morse, 161, Dublin-Granville, Hilliard-Rome, Cleveland, etc… This made me think it might be fun to map the high crash locations. Click on the image for a link to an interactive version.
Interestingly, there really weren’t any locations in an urban context. Even at Cleveland & 5th, just 2.2 miles northeast of downtown, the four corners contain three suburban-style fast-food restaurants and a large vacant lot. Livingston & James might be the most urban location on the list, where at least two buildings are located on a corner.
I’m not sure exactly what to make of this observation. Why would urban streets be safer? After all, they have all those pesky pedestrians and bicylists in the way, limited sight lines due to buildings on the corners, and fixed hazardous roadside objects like trees and light poles. I suspect it has a lot to do with speed. All that stuff (peds, trees, buildings, etc…) in an urban location really makes drivers slow down. When drivers slow down, they have more reaction time, better peripheral vision, and less severe crashes. The other reason, and probably the bigger one, is that most urban streets have lower traffic volumes than those big high-speed suburban aterials. This is because they have fewer lanes and there is a denser grid of streets that distribute traffic to multiple routes. Just something to think about for you other planners and engineers out there.