Yes, combining asphalt art with proven traffic calming techniques is a win – win!
Asphalt Art + Traffic Calming
In the fall of 2020, the City of Kansas City, Mo. was one of sixteen cities selected for a $25,000 grant from Bloomberg Philanthropies to install asphalt art.
Working closely with Midtown KC Now and KCMO Public Works Department, we selected the intersection of Westport Road and Wyandotte Street with the hopes of not only beautifying the intersection through vibrant asphalt murals but also making the intersection safer for all users.
We set out to quantify the hypothesized safety improvements in two key ways. By recording the ‘before and after’ speed of cars traveling through the intersection and measuring the distance of the crosswalks pedestrians must traverse to cross the street.
If you experienced this intersection before the installation and have since experienced the intersection afterwards then you know you can intrinsically feel the safety improvement of the intersection. Automobiles appear to move slower, the intersection sounds quieter, and motorists even stop to allow you to cross the street! While it probably doesn’t require a data scientist to recognize this intersection is safer, Former New York Mayor Michael Bloomberg once famously said “In God we trust; all others bring data”.
So that’s what we’ve done. We’ve obtained and compiled data to ensure we could prove our eyes correctly to confirm traffic is moving slower resulting in a safer environment for all users.
Travel Speeds Before Implementation
The recorded average speed moving through the intersection during an afternoon in the fall determined the average and high speeds were as follows:
Eastbound – 28 MPH Average, 49 High speed recorded
Westbound – 25 MPH Average, 37 High speed recorded
Southbound – 25 MPH Average, 31 High speed recorded
Northbound 21 MPH Average, 26 High speed recorded
While the average speeds were not as high as we had anticipated the ‘High’ speed of each direction was way too fast for an intersection to be safe. The highest speed recorded, 49 miles per hour, was twice as high as the posted speed limit!
Study after study has shown slower automobile speeds are safer for all road users; including pedestrians. bicyclists, and motorists. The odds of a fatality resulting from a car crash are directly correlated with the speed of the automobile. According to research, a crash involving an automobile traveling over 40 miles per hour increases the odds of a pedestrian fatality to 90%+.
Thus we knew, if we were able to slow the travel speeds, we would be improving the safety of the intersection and perhaps even saving lives, if a crash was to occur.
Travel Speeds After Implementation
In order to slow the traffic we added stop signs to Westport Road, where the most flagrant speeding was occurring. In addition to the stop signs the curb extensions, which created the canvasses for the artists to create the asphalt art murals, narrowed the travel lanes which encourages motorists to travel slower when passing through or turning at the intersection.
We knew through previous projects, this was an effective strategy and fortunately the data proved us correct! The travel speeds recorded at the intersection after implementation looked like such:
Eastbound – 13 MPH Average, 23 MPH high speed
Westbound – 14 MPH Average, 22 MPH high speed
Southbound – 14 MPH Average, 19 MPH high speed
Northbound – 13 MPH Average, 18 MPH high speed
The design and implementation cut the average travel speeds roughly in half! Even more impressively is what the implementation did to the high speeds. Where we previously recorded a high speed of 49 miles per hour, we now recorded a high speed of 23 miles per hour. This improvement changes the odds of a pedestrian dying of a car crash from about 90% to 10%!
Crossing Distances
Another key metric to quantifying safety improvements at the intersection is the length of the crosswalks. The crossing distances were originally fairly lengthy ranging from 43′ – 70′. After the implementation we cut down the crossing distances to 25′ – 30′! Similar to the reductions in travel speeds, this implementation reduced the crossing distances roughly in half.
Based on the data and observations of the user behavior at this intersection, we feel confident concluding that using asphalt art to calm traffic and improve safety is an effective strategy. Intersections all over Kansas City and through out the United States are plagued with high speed traffic. Fortunately, there are proven strategies to combat this issue and even better, these improvements can be done quickly and inexpensively!
