Highway maintenance crews conduct various work operations, such as roadway repairs, bridges maintenance, landscaping, snow removal, etc. The proximity to speeding traffic, the extreme work environment, and the movement of large equipment and materials expose highway maintenance workers to various types of hazards and risks. Yet, the safety of highway maintenance crews received minimal attention in the literature. In response, a safety toolbox was designed previously to help highway maintenance supervisors to prepare for pre-task safety talks tailored to specific highway maintenance operations. Although the toolbox intervention is a common practice in the construction industry, the designed toolbox was the first try of such intervention in the highway maintenance sector. This paper presents a summative evaluation conducted to assess the effectiveness of safety toolbox talks on safety awareness among highway maintenance crews. The evaluation was performed by conducting baseline and post-use safety knowledge assessments to evaluate participants’ knowledge gain, and reaction assessment to evaluate participants reaction and attitude towards the intervention. The results showed that presenting relevant customized safety knowledge in the form of pre-task safety talks significantly improved safety awareness among highway maintenance crews. The study suggests that toolbox interventions can be effectively utilized to improve safety awareness among highway maintenance workers.