One of the most dangerous places on the road for everyone is the intersection. Intersections, at their core, are the largest points of conflict between cars, pedestrians, or any road user. This means safe streetscape design is vital in order to maintain safety. 

If you want to ensure safety in these intersections, it is important that you identify which ones are actually the most dangerous. Crash data from the past couple decades is available from Kentucky State Police, so we can use that to delineate the most crash-inducing, injury-inducing, and deadly intersections in the city. The intersections were split up this way in order to avoid some difficult question weighing death versus injury in deciding what was most dangerous overall.

The total number of collisions within 60 feet of an intersection point were collected. This number was then normalized by the average traffic count (AADT) of the two roads meeting at the intersection.  There are around 1500 intersections in the city, so all the maps and data will just be the top 10 for the sake of visualization. While each section has a top 10, there are only 21 intersections total due to repeats.

Most Collisions

Within the top 10 most collision-prone intersections, you can see a clear geographic trend emerge. All but two of these intersections are in western Louisville. 22nd Street is the most common street in the top 10, appearing in 3 of these intersections. All but one of the roads are within the urban core of Louisville, although the urban core does have a much higher density of intersections.

Many intersections feature some aspect of dangerous road design. The most dangerous is a highway exit into an urban area, so there is a rapid reduction in speed. Many of the intersections with the most collisions prior to being normalized with AADT were also highway exits. Roads such as Broadway that are repeat offenders fall into the category of “stroads”, trying to be both a street and a road, resulting in dangerous design. Other repeat offenders such as 22nd St may not be “stroads”, but have other issues such as being one-way.

W Chestnut & 22nd, a meeting of two one-way roads (source: Google Streetview)

Most Injuries

The injury rate and collision rate maps are very similar. All but two of the intersections are located in western Louisville. St. Catherine and 1st is still the highest ranking, although only slightly more than Oak and 22nd. Broadway vanishes from the top 10, largely being replaced by Oak St, which now ties for 22nd in being the most common. These intersections have a lot of overlap, therefore largely having the same design impairments that make collisions more likely: one-way streets, large roads, lack of street trees, wide turning angles, etc.

Fatality Rate

While there are some repeats, the fatality rate is relatively unique compared to the last two sections. The top 10 are more distributed throughout the city, and there are more suburban roads. These suburban roads tend to have higher AADTs which has kept them out of the past sections. Another change is that this time there are no repeat offenders, although some intersections are located somewhat close to each other.

The change in geography could be indicative of changes in road design. Suburban roads tend to have significantly higher speeds than urban roads, so collisions that do occur have a higher chance of being deadly. Higher speed also often indicates the presence of design flaws. The suburban roads have some similar issues to urban roads; they are very rarely one-way, but can be very wide with wide turning angles. 

Lower Hunters Trace and Greenbelt Highway (source: Google Streetview)

It is paramount that we know what intersections in this city are the most dangerous, but it is also worth nothing that many of these roads and streets are expected to go through redesigns in the coming years. Chestnut and Market are getting major changes through the Reimagine 9th Street project. Broadway will go through a significant transformation as well through Broadway all the Way. Every single one of these corridors are fixable, and within a relatively short time frame. Renowned urban planner Jeff Speck talked about some of this in his recent visit; simple restriping and reorienting can radically change the streetscape of an area. You can change one-way to two-way, implement road diets, decrease turning angles at intersections, add bike lanes, and more.