Highway 47

Drivers are more likely to crash on Fridays and more accidents take place on Highway 47 around 3 p.m. than any other time of day.

Those are just a few of the eye-opening stats discovered by the group conducting a study of the 13-mile corridor between Washington and St. Clair.

In February, the Lochmueller Group was hired to perform the study and the municipalities on the committee agreed to pay them $185,000. 

Lochmueller project engineer Cheryl Sharp said the corridor has been divided into three sections: north rural (from Steutermann Road to Independence Drive), urban (Union area, including Highway 50) and south rural (from Highway 50 to the North Outer Road outside St. Clair).

“We have done a lot of data collection,” Sharp said. “A lot of data collection and gathered a lot of historical information.”

Traffic Rates

Sharp explained the analysis collected traffic data at eight different points along the corridor: south of Steutermann Road, north of Forest Hills Drive, north of Independence, between Old County Farm Road and Main Street, between Highways 47 and 50, south of Highway 50, halfway between College and Schuchart roads, and north of the North Outer Road in St. Clair.

Of the eight points, the overall average daily traffic flow was just over 20,000 cars per day traversing the corridor. 

The highest traffic area was the section where Highway 47 and Highway 50 are together, with 37,433 cars. 

The collection points in the areas nearest Washington averaged about 19,000 cars and the areas to the south closer to St. Clair averaged about 14,000 cars per day.


The average speed of cars traveling on the corridor was calculated by Lochmueller using historical data from 2011 to 2015.

Sharp explained the northern sections of the corridor experience the lowest speeds because there are more vehicles, and even though only 3 percent of the traffic is large trucks, they play the largest role in congestion.

“In many areas, drivers aren’t even meeting the posted speed limits,” Sharp said. “Also in those areas, school buses and mail carriers have limited room to work on the shoulders.”

Although the posted speed limit is 55, the average speed on the northern section of the corridor is 51 miles per hour. 

According to the study, southbound speeds on Highway 47 between Washington and Union range between 43 and 58 miles per hour. 

Northbound speeds in the same section range between 41 and 58 miles per hour.

Sharp said speeds in the southern section tend to increase due to longer straightaways and fewer cross streets and intersections.

The average speed in the southern section is 53 with southbound speeds ranging between 67 and 44. Northbound speeds range between 57 and 51.


Although the frequency of crashes is lower in the southern section, because of the higher speeds, the severity of crashes was higher as well.

The study shows a total of 188 crashes between 2011 and 2015 in the southern section of Highway 47 with an annual average of 38. Eight percent of those were head-on and 59 percent were rear-end crashes.

In the urban area near Union, there were 628 crashes in the same five-year time frame, but the study reports the severity of the crashes was much less.

Each year, there was an average of 125 crashes, 68 percent were rear-end, and only 6 percent were head-on.

Sharp also pointed out 19 percent of the crashes were at an angle, which could be attributed to lower gaps between cars by frustrated drivers and unsignalized driveways.

Rear-end crashes dominate the northern section of the corridor, making up 84 percent of the total 284 recorded.

The study attributes the average of 56 crashes per year to few signals with long queues causing unexpected stops. The lack of turn lanes and high speed could also be factors in the rear-end collisions. 

Throughout the entire corridor there were a total of 1,100 crashes, with the majority taking place between 3 and 4 p.m. 

The No. 1 day for crashes was Friday with 246 reported.