Write Up:

While the ultimate goal for this measure is to eliminate work zone crashes, the objective is to reduce the number of protective vehicle/truck-mounted attenuator (TMA) crashes below the previous four-year average.

In the third quarter of 2024, MoDOT reported six TMA crashes. The number of crashes through the third quarter of 2024 saw a 34% reduction as compared to the year-to-date average of the previous four years. These crashes can cause less than $100 in damage to the TMA, but most require a new protective vehicle unit costing approximately $50,000, not including damage to the truck, staff time, lost wages or potential medical expenses. The most significant impact from TMA crashes is the potential lifelong severe injuries that can affect an injured employee’s value of life for which no cost can be quantified.  

This quarter, two employees were involved in a TMA crash and sought medical attention for their injuries. All TMA crashes this quarter occurred during daytime operations, predominately in urban areas. Those operations in which crashes occurred included one pothole patching, one striping, two sweeping, one spraying and one occurred while performing drainage work.

Purpose of the Measure:

MoDOT owns more than 500 truck- or trailer-mounted attenuators used to help save lives by absorbing the impact of a crash in a work zone. By measuring the number of TMA/protective vehicle hits, MoDOT can identify and share information about higher-risk activities that could result in a crash and develop strategies to eliminate work zone crashes. 

Measurement and Data Collection:

When a TMA incident occurs, a claim report is completed. The claim report and any associated police reports are reviewed by Risk Management Technicians for interpretation. A statewide work zone incident team reviews TMA incidents and seeks strategies for operations improvement to reduce or eliminate the incidents. Only incidents where the TMA was in an active work zone protecting workers are included in this data. This measure is reported based on quarters of a calendar year.