MoDOT has completed its study for your request at the Veterans Memorial Parkway & W. O’Fallon Dr intersection for an all-way stop controlled condition. MoDOT collected traffic volume counts on June 13th, 2023 to establish a base volume for the intersection. We also obtained a crash history for that intersection for the previous 5 years through the Missouri State Highway Patrol database.
As you mentioned in your original email, there is also construction occurring at the intersection to build an apartment complex at the corner. Researching the development through the City of O’Fallon it is permitted to be a Senior Living Apartment complex. Using nationally recognized trip generation numbers provided by the Institute of Transportation Engineers we added those expected volumes to the current volumes that we collected in June. A senior living facility does not generate the peak traffic that a normal ‘working class’ apartment complex would generate, primarily due to the situation that there would be more retirees at that facility who wouldn’t need to drive to work in the morning and can spread out their driving trips throughout the day should they choose to.
In our analysis of the crash history indicated that there was not a pattern of accidents where an all-way stop controlled intersection would relieve or reduce the number of accidents at the intersection. Nearly half of the recorded accidents were classified as “rear end” type crashes, which a stop sign would not be able to correct. The other accidents were a mixture of drivers either leading up to or taking the turn into the subdivision too aggressively, or speeding/inattention while driving.
After analyzing the traffic volumes, a three way stop sign is not warranted for this location. The lack of volume approaching the intersection from all approaches was below the threshold even with the added volumes projected from the senior living apartment facility. We also analyzed the request for a separated left turn lane and the volumes also do not warrant a left turn bay due to a lack of overall volume on the roadway.
Veterans Memorial Parkway is considered an outer road for the I-70 interstate system. When an incident occurs on the interstate, Veterans Memorial Parkway can act as a diversion route for the travelling public. With traffic diverting on the outer road system it reduces the queuing that occurs on the interstate which lessens the possibility that a serious high-speed accident can occur towards the end of the backup after the initial accident. Studies have shown that those secondary accidents that occur after the initial accident are usually more severe as sudden speed changes from 60+ mph to zero have a probability of a driver not seeing the condition in time. Having the ability to move even an extra 100 vehicles around an incident can make a difference, even if it causes some temporary congestion issues for the normal daily users of the outer road.
